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Sample records for candidate exoplanet companion

  1. Most sub-arcsecond companions of Kepler exoplanet candidate host stars are gravitationally bound

    SciTech Connect

    Horch, Elliott P.; Howell, Steve B.; Everett, Mark E.; Ciardi, David R. E-mail: steve.b.howell@nasa.gov E-mail: ciardi@ipac.caltech.edu

    2014-11-01

    Using the known detection limits for high-resolution imaging observations and the statistical properties of true binary and line-of-sight companions, we estimate the binary fraction of Kepler exoplanet host stars. Our speckle imaging programs at the WIYN 3.5 m and Gemini North 8.1 m telescopes have observed over 600 Kepler objects of interest and detected 49 stellar companions within ∼1 arcsec. Assuming binary stars follow a log-normal period distribution for an effective temperature range of 3000-10,000 K, then the model predicts that the vast majority of detected sub-arcsecond companions are long period (P > 50 yr), gravitationally bound companions. In comparing the model predictions to the number of real detections in both observational programs, we conclude that the overall binary fraction of host stars is similar to the 40%-50% rate observed for field stars.

  2. THE MASS OF THE CANDIDATE EXOPLANET COMPANION TO HD 136118 FROM HUBBLE SPACE TELESCOPE ASTROMETRY AND HIGH-PRECISION RADIAL VELOCITIES

    SciTech Connect

    Martioli, Eder; McArthur, Barbara E.; Benedict, G. Fritz; Armstrong, Amber; Bean, Jacob L.; Harrison, Thomas E.

    2010-01-01

    We use Hubble Space Telescope fine guidance sensor astrometry and high-cadence radial velocities for HD 136118 from the Hobby-Eberly Telescope with archival data from Lick to determine the complete set of orbital parameters for HD 136118 b. We find an orbital inclination for the candidate exoplanet of i{sub b} = 163.{sup 0}1 +- 3.{sup 0}0. This establishes the actual mass of the object, M{sub b} = 42{sup +11}{sub -18} M{sub J} , in contrast to the minimum mass determined from the radial velocity data only, M{sub b} sin i approx 12 M{sub J} . Therefore, the low-mass companion to HD 136118 is now identified as a likely brown dwarf residing in the 'brown dwarf desert'.

  3. Undercover Stars Among Exoplanet Candidates

    NASA Astrophysics Data System (ADS)

    2005-03-01

    events by monitoring the brightness of a very large number of stars over extended time intervals. During the past years, it has also included a search for periodic, very shallow "dips" in the brightness of stars, caused by the regular transit of small orbiting objects (small stars, brown dwarfs [2] or Jupiter-size planets). The OGLE team has since announced 177 "planetary transit candidates" from their survey of several hundred thousand stars in three southern sky fields, one in the direction of the Galactic Centre, another within the Carina constellation and the third within the Centaurus/Musca constellations. The nature of the transiting object can however only be established by subsequent radial-velocity observations of the parent star. The size of the velocity variations (the amplitude) is directly related to the mass of the companion object and therefore allows discrimination between stars and planets as the cause of the observed brightness "dip". A Bonanza of Low-Mass Stars An international team of astronomers [3] has made use of the 8.2-m VLT Kueyen telescope for this work. Profiting from the multiplex capacity of the FLAMES/UVES facility that permits to obtain high-resolution spectra of up to 8 objects simultaneously, they have looked at 60 OGLE transit candidate stars, measuring their radial velocities with an accuracy of about 50 m/s [4]. This ambitious programme has so far resulted in the discovery of five new transiting exoplanets (see, e.g., ESO PR 11/04 for the announcement of two of those). Most of the other transit candidates identified by OGLE have turned out to be eclipsing binaries, that is, in most cases common, small and low-mass stars passing in front of a solar-like star. This additional wealth of data on small and light stars is a real bonanza for the astronomers. Constraining the Relation Between Mass and Radius Low-mass stars are exceptionally interesting objects, also because the physical conditions in their interiors have much in common with

  4. Spectroscopy of Kepler Candidate Exoplanet Host Stars

    NASA Astrophysics Data System (ADS)

    Everett, Mark E.; Howell, Steve B.; Silva, David R.; Szkody, Paula

    2014-02-01

    Currently the NASA Kepler Mission has identified 3449 exoplanet candidates, one third with estimated radii R_p<2.5R_oplus and orbiting faint (m_Kep>14.5) host stars. The NASA sponsored Kepler Follow-up Program is focusing on small exoplanet candidates (R_p<2.5R_oplus) and those in habitable zone orbits. Planet radii estimates depend on estimates of host star radii. Based on spectra previously obtained at the KPNO Mayall 4-m for 220 stars with candidate exoplanets, Everett et al. (2013) have shown that many host stars are larger than originally assumed (up to factor of 2). Therefore, the exoplanet candidates they host must be larger than originally assumed, which conversely reduces the number of known Earth- sized exoplanet candidates. Determination of the frequency of such Earth-sized planets is a cornerstone Kepler mission objective and of keen general interest. These Mayall spectra were also used to confirm the Buchhave et al. (2012) result that exoplanet candidates larger than 4R_oplus in short-period orbits are preferentially associated with host stars with solar or higher metallicity, using a fainter and larger sample of stars than Buchhave et al. In short, followup Mayall optical spectroscopy is critical to confirming the detection of Earth-sized exoplanets, a Kepler cornerstone goal, as well as characterizing the relationship between host star properties and planetary system properties. Here, we propose to continue our reconnaissance survey with a focus on the smallest (most rare) exoplanet candidates orbiting the faintest Kepler host stars.

  5. Speckle Imaging of Kepler Exo-planet Transit Candidate Stars

    NASA Astrophysics Data System (ADS)

    Howell, Steve B.; Horch, Elliott; Sherry, William

    2009-08-01

    The NASA Kepler mission was successfully launched on 6 March 2009 and will begin science operations near 1 May. At the present time, commissioning tests are being performed and all spacecraft and science instruments are nominal. Kepler's main science focus is to discover Earth-like exo-planets via photometric transit detection. ``Hot Jupiters" will be found by the hundreds (using current ground-based statistics) but Earth-sized planets (up to 2.5 Earth radii) will be more difficult, yet are the holy grail of the mission. To take the list of candidate transiting planets found by Kepler and move them to probable or certain exo-planet detections, a decision tree of false positive elimination will occur. While earth-sized exo-planets can not currently be confirmed from the ground, many of the false positive eliminations steps can be performed. This proposal aims to obtain high resolution speckle imaging to 1) finish the characterization of ~500 comparison sample stars in the Kepler field of view prior to any transit information as a sample to place planet host stars in context with and to 2) observe Kepler exo-planet transit candidates in order to eliminate the largest false positive contributor in any transit search - background eclipsing binary stars or faint companion stars.

  6. On the Stellar Companion to the Exoplanet Hosting Star 30 Arietis B

    NASA Astrophysics Data System (ADS)

    Kane, Stephen R.; Barclay, Thomas; Hartmann, Michael; Hatzes, Artie P.; Jensen, Eric L. N.; Ciardi, David R.; Huber, Daniel; Wright, Jason T.; Quintana, Elisa V.

    2015-12-01

    A crucial aspect of understanding planet formation is determining the binarity of the host stars. Results from radial velocity (RV) surveys and the follow-up of Kepler exoplanet candidates have demonstrated that stellar binarity certainly does not exclude the presence of planets in stable orbits and the configuration may in fact be relatively common. Here we present new results for the 30 Arietis system which confirms that the B component hosts both planetary and stellar companions. Keck AO imaging provides direct detection of the stellar companion and additional RV data are consistent with an orbiting star. We present a revised orbit of the known planet along with photometry during predicted transit times. Finally, we provide constraints on the properties of the stellar companion based on orbital stability considerations.

  7. KEPLER OBSERVATIONS OF THREE PRE-LAUNCH EXOPLANET CANDIDATES: DISCOVERY OF TWO ECLIPSING BINARIES AND A NEW EXOPLANET

    SciTech Connect

    Howell, Steve B.; Rowe, Jason F.; Bryson, Stephen T.; Sherry, William; Von Braun, Kaspar; Ciardi, David R.; Feldmeier, John J.; Horch, Elliott; Van Belle, Gerard T.

    2010-12-20

    Three transiting exoplanet candidate stars were discovered in a ground-based photometric survey prior to the launch of NASA's Kepler mission. Kepler observations of them were obtained during Quarter 1 of the Kepler mission. All three stars are faint by radial velocity follow-up standards, so we have examined these candidates with regard to eliminating false positives and providing high confidence exoplanet selection. We present a first attempt to exclude false positives for this set of faint stars without high-resolution radial velocity analysis. This method of exoplanet confirmation will form a large part of the Kepler mission follow-up for Jupiter-sized exoplanet candidates orbiting faint stars. Using the Kepler light curves and pixel data, as well as medium-resolution reconnaissance spectroscopy and speckle imaging, we find that two of our candidates are binary stars. One consists of a late-F star with an early M companion, while the other is a K0 star plus a late M-dwarf/brown dwarf in a 19 day elliptical orbit. The third candidate (BOKS-1) is an r = 15 G8V star hosting a newly discovered exoplanet with a radius of 1.12 R{sub Jupiter} in a 3.9 day orbit.

  8. MICROLENSING BINARIES WITH CANDIDATE BROWN DWARF COMPANIONS

    SciTech Connect

    Shin, I.-G.; Han, C.; Gould, A.; Skowron, J.; Udalski, A.; Szymanski, M. K.; Kubiak, M.; Soszynski, I.; Pietrzynski, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozlowski, S.; Wyrzykowski, L.; Sumi, T.; Dominik, M.; Beaulieu, J.-P.; Tsapras, Y.; Bozza, V.; Abe, F.; Collaboration: OGLE Collaboration; MOA Collaboration; muFUN Collaboration; and others

    2012-12-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing events discovered during the 2004-2011 observation seasons. Based on the low mass ratio criterion of q < 0.2, we found seven candidate events: OGLE-2004-BLG-035, OGLE-2004-BLG-039, OGLE-2007-BLG-006, OGLE-2007-BLG-399/MOA-2007-BLG-334, MOA-2011-BLG-104/OGLE-2011-BLG-0172, MOA-2011-BLG-149, and MOA-201-BLG-278/OGLE-2011-BLG-012N. Among them, we are able to confirm that the companions of the lenses of MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149 are brown dwarfs by determining the mass of the lens based on the simultaneous measurement of the Einstein radius and the lens parallax. The measured masses of the brown dwarf companions are 0.02 {+-} 0.01 M {sub Sun} and 0.019 {+-} 0.002 M {sub Sun} for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events with well-covered light curves increases with new-generation searches.

  9. Know the Star, Know the Planet. IV. A Stellar Companion to the Host Star of the Eccentric Exoplanet HD 8673b

    NASA Astrophysics Data System (ADS)

    Roberts, Lewis C., Jr.; Mason, Brian D.; Neyman, Christopher R.; Wu, Yanqin; Riddle, Reed L.; Shelton, J. Christopher; Angione, John; Baranec, Christoph; Bouchez, Antonin; Bui, Khanh; Burruss, Rick; Burse, Mahesh; Chordia, Pravin; Croner, Ernest; Das, Hillol; Dekany, Richard G.; Guiwits, Stephen; Hale, David; Henning, John; Kulkarni, Shrinivas; Law, Nicholas; McKenna, Dan; Milburn, Jennifer; Palmer, Dean; Punnadi, Sujit; Ramaprakash, A. N.; Roberts, Jennifer E.; Tendulkar, Shriharsh P.; Trinh, Thang; Troy, Mitchell; Truong, Tuan; Zolkower, Jeff

    2015-04-01

    HD 8673 hosts a massive exoplanet in a highly eccentric orbit (e = 0.723). Based on two epochs of speckle interferometry a previous publication identified a candidate stellar companion. We observed HD 8673 multiple times with the 10 m Keck II telescope, the 5 m Hale telescope, the 3.63 m Advanced Electro-Optical System telescope, and the 1.5 m Palomar telescope in a variety of filters with the aim of confirming and characterizing the stellar companion. We did not detect the candidate companion, which we now conclude was a false detection, but we did detect a fainter companion. We collected astrometry and photometry of the companion on six epochs in a variety of filters. The measured differential photometry enabled us to determine that the companion is an early M dwarf with a mass estimate of 0.33-0.45 M⊙ . The companion has a projected separation of 10 AU, which is one of the smallest projected separations of an exoplanet host binary system. Based on the limited astrometry collected, we are able to constrain the orbit of the stellar companion to a semimajor axis of 35-60 AU, an eccentricity ≤slant 0.5, and an inclination of 75°-85°. The stellar companion has likely strongly influenced the orbit of the exoplanet and quite possibly explains its high eccentricity.

  10. Ground Based Astrometric Search for Substellar Companions in Stellar Multiple Systems, The Case of the Exoplanet Host System HD 19994

    NASA Astrophysics Data System (ADS)

    Röll, T.; Seifahrt, A.; Neuhäuser, R.; Köhler, R.

    2010-12-01

    Due to the unknown inclination angle, radial velocity (RV) measurements only provide the minimum mass of companions. In combination with transit observations one can derive the true mass, but a transit is only observable for nearly edge-on systems. For all other systems, astrometry is the only method to get the true mass of an orbiting companion by measuring the reflex motion of the host star. In our ongoing astrometric search program we observe stellar multiple systems within a distance of 100 parsec in order to confirm RV exoplanet candidates and to search for unknown substellar companions. Here we present preliminary results of one of our targets, the binary HD 19994, which is known to harbour a RV planet candidate around the A component. From our astrometric observations over the last years, it seems that a high mass brown dwarf is orbiting the low-mass B component. Analysis of our data with speckle interferometry confirms the existence of an additional body.

  11. Robo-AO Kepler Planetary Candidate Survey. II. Adaptive Optics Imaging of 969 Kepler Exoplanet Candidate Host Stars

    NASA Astrophysics Data System (ADS)

    Baranec, Christoph; Ziegler, Carl; Law, Nicholas M.; Morton, Tim; Riddle, Reed; Atkinson, Dani; Schonhut, Jessica; Crepp, Justin

    2016-07-01

    We initiated the Robo-AO Kepler Planetary Candidate Survey in 2012 to observe each Kepler exoplanet candidate host star with high angular resolution, visible light, laser adaptive optics (AOs) imaging. Our goal is to find nearby stars lying in Kepler's photometric apertures that are responsible for the relatively high probability of false-positive exoplanet detections and that cause underestimates of the size of transit radii. Our comprehensive survey will also shed light on the effects of stellar multiplicity on exoplanet properties and will identify rare exoplanetary architectures. In this second part of our ongoing survey, we observed an additional 969 Kepler planet candidate hosts and we report blended stellar companions up to {{Δ }}m≈ 6 that contribute to Kepler's measured light curves. We found 203 companions within ˜4″ of 181 of the Kepler stars, of which 141 are new discoveries. We measure the nearby star probability for this sample of Kepler planet candidate host stars to be 10.6% ± 1.1% at angular separations up to 2.″5, significantly higher than the 7.4% ± 1.0% probability discovered in our initial sample of 715 stars; we find the probability increases to 17.6% ± 1.5% out to a separation of 4.″0. The median position of Kepler Objects of Interest (KOIs) observed in this survey are 1.°1 closer to the galactic plane, which may account for some of the nearby star probability enhancement. We additionally detail 50 Keck AO images of Robo-AO observed KOIs in order to confirm 37 companions detected at a <5σ significance level and to obtain additional infrared photometry on higher significance detected companions.

  12. High-contrast imaging search for stellar and substellar companions of exoplanet host stars

    NASA Astrophysics Data System (ADS)

    Mugrauer, M.; Ginski, C.

    2015-07-01

    We present the results of our high-contrast imaging survey of close stellar and substellar companions of exoplanet host stars, carried out with the adaptive optics imager NACO at the ESO Paranal observatory, in Chile. In total, 33 exoplanet host stars were observed with NACO in the Ks-band. New comoving companions could be identified close to the stars HD 9578, HD 96167, and HD 142245. The newly detected companions exhibit masses between 0.21 and 0.56 M⊙ and are located at projected separations from their primaries between about 190 and 510 au. In the case of HD 142245, we found evidence that the detected companion is actually a close binary itself with a projected separation of only about 4 au, i.e. HD 142245 might be a hierarchical triple stellar system, which hosts an exoplanet, a new member in the short list of such systems, presently known. In our imaging campaign, a limiting magnitude of Ks = 18.5 mag is reached in average in the background noise limited region around our targets at projected separations beyond about 100 au, which allows the detection of substellar companions with masses down to about 60 MJup. With our NACO observations we can rule out additional stellar companions at projected separations between about 30 and 370 au around the observed exoplanet host stars.

  13. CANDID: Companion Analysis and Non-Detection in Interferometric Data

    NASA Astrophysics Data System (ADS)

    Gallenne, A.; Mérand, A.; Kervella, P.; Monnier, J. D.; Schaefer, G. H.; Baron, F.; Breitfelder, J.; Le Bouquin, J. B.; Roettenbacher, R. M.; Gieren, W.; Pietrzynski, G.; McAlister, H.; ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Ridgway, S.; Kraus, S.

    2015-05-01

    CANDID finds faint companion around star in interferometric data in the OIFITS format. It allows systematically searching for faint companions in OIFITS data, and if not found, estimates the detection limit. The tool is based on model fitting and Chi2 minimization, with a grid for the starting points of the companion position. It ensures all positions are explored by estimating a-posteriori if the grid is dense enough, and provides an estimate of the optimum grid density.

  14. Combing the Brown Dwarf Desert with the APOGEE Catalog of Stellar and Substellar Companion Candidates

    NASA Astrophysics Data System (ADS)

    Troup, Nicholas William; De Lee, Nathan M.; Carlberg, Joleen K.; Nidever, David L.; Majewski, Steven R.; Stassun, Keivan; Covey, Kevin R.; Skrutskie, Michael F.; Allende-Prieto, Carlos; Hearty, Fred R.; APOGEE Substellar Companions Working Group

    2016-01-01

    While both exoplanets and stellar-mass companions have been found in extremely short-period orbits, there has been a paucity of brown dwarf (BD) companions orbiting Sun-like stars, a phenomenon known as the "Brown Dwarf Desert." However, more recent work has shown that this Desert might be limited in extent, only existing for small separation (a < 5-10 AU) companions, and may not be as "dry" as initially thought. It has been previously suggested that there may be an "F Dwarf Oasis," where the BD Desert observed for Solar-like stars ceases to exist for F dwarf stars. The Sloan Digital Sky Survey (SDSS-III) Apache Point Galactic Evolution Experiment (APOGEE) has compiled a catalog of ~400 of its most compelling stellar and substellar companion candidates orbiting host stars of various spectral types and evolutionary states. Among these candidates, approximately 100 had a derived companion mass in the BD regime (13-80 MJup), which is a significant increase compared to the number of known small separation (a < 1 AU) BD companions. Our sample appears to manifest the BD desert, but only for seperations < 0.2 AU rather than the previously held 5 AU. This is explained by one of the unique qualities of our sample when compared to previous companions surveys: Two-thirds of the BD candidates in our sample are orbiting evolved stars, most of which were F dwarfs during their main sequence lifetime, consistent with the notion of an F Dwarf Oasis. Using this sample, we further test this hypothesis by constraining the formation mechanisms of BD companions, and exploring their orbital evolution as their host evolves off the main sequence.

  15. A Systematic Search for Exoplanet Candidates in K2 Data

    NASA Astrophysics Data System (ADS)

    Kahre, Tarryn; Karnes, Katherine L.; Caldwell, Douglas A.; Smith, Jeffrey C.

    2016-01-01

    We present a catalog of 41 promising exoplanet candidates in 33 stellar systems from the K2 Campaign 3 data. The K2 Mission was developed upon the mechanical failure of the second of four reaction wheels, as the Kepler Spacecraft could not continue the original Kepler Mission. The Kepler Mission was a 4-year mission designed to determine the prevalence of exoplanets in our galaxy, and the configuration and diversity of those planetary systems discovered. The K2 Mission has a similar goal, though the spacecraft now points at fields along the ecliptic in ~75 day campaigns (Howell et al. 2014). Although the light curves in K2 data are noisier and have significant motion-induced systematics, it has been shown that there is success in finding exoplanets and exoplanet candidates (Foreman-Mackey et al. 2015; Montet et al. 2015). Utilizing the Transiting Planet Search and Data Validation from the Kepler Processing Pipeline, we systematically search K2 Campaign 3 for potential exoplanet candidates. Setting a 7.1s maximum folded statistic threshold minimum for a minimum of three transit events, we define our initial candidate list. Our list is further narrowed by the results from Data Validation, as it allows us to statistically identify false positives, such as eclipsing binaries or uncorrected roll-drift, in our sample. We further draw parallels between our results and other transit-searching pipeline results published for Campaign 3.

  16. Limits on Stellar Companions to Exoplanet Host Stars with Eccentric Planets

    NASA Astrophysics Data System (ADS)

    Kane, Stephen R.; Howell, Steve B.; Horch, Elliott P.; Feng, Ying; Hinkel, Natalie R.; Ciardi, David R.; Everett, Mark E.; Howard, Andrew W.; Wright, Jason T.

    2014-04-01

    Though there are now many hundreds of confirmed exoplanets known, the binarity of exoplanet host stars is not well understood. This is particularly true of host stars that harbor a giant planet in a highly eccentric orbit since these are more likely to have had a dramatic dynamical history that transferred angular momentum to the planet. Here we present observations of four exoplanet host stars that utilize the excellent resolving power of the Differential Speckle Survey Instrument on the Gemini North telescope. Two of the stars are giants and two are dwarfs. Each star is host to a giant planet with an orbital eccentricity >0.5 and whose radial velocity (RV) data contain a trend in the residuals to the Keplerian orbit fit. These observations rule out stellar companions 4-8 mag fainter than the host star at passbands of 692 nm and 880 nm. The resolution and field of view of the instrument result in exclusion radii of 0.''05-1.''4, which excludes stellar companions within several AU of the host star in most cases. We further provide new RVs for the HD 4203 system that confirm that the linear trend previously observed in the residuals is due to an additional planet. These results place dynamical constraints on the source of the planet's eccentricities, place constraints on additional planetary companions, and inform the known distribution of multiplicity amongst exoplanet host stars.

  17. Limits on stellar companions to exoplanet host stars with eccentric planets

    SciTech Connect

    Kane, Stephen R.; Hinkel, Natalie R.; Howell, Steve B.; Horch, Elliott P.; Feng, Ying; Wright, Jason T.; Ciardi, David R.; Everett, Mark E.; Howard, Andrew W.

    2014-04-20

    Though there are now many hundreds of confirmed exoplanets known, the binarity of exoplanet host stars is not well understood. This is particularly true of host stars that harbor a giant planet in a highly eccentric orbit since these are more likely to have had a dramatic dynamical history that transferred angular momentum to the planet. Here we present observations of four exoplanet host stars that utilize the excellent resolving power of the Differential Speckle Survey Instrument on the Gemini North telescope. Two of the stars are giants and two are dwarfs. Each star is host to a giant planet with an orbital eccentricity >0.5 and whose radial velocity (RV) data contain a trend in the residuals to the Keplerian orbit fit. These observations rule out stellar companions 4-8 mag fainter than the host star at passbands of 692 nm and 880 nm. The resolution and field of view of the instrument result in exclusion radii of 0.''05-1.''4, which excludes stellar companions within several AU of the host star in most cases. We further provide new RVs for the HD 4203 system that confirm that the linear trend previously observed in the residuals is due to an additional planet. These results place dynamical constraints on the source of the planet's eccentricities, place constraints on additional planetary companions, and inform the known distribution of multiplicity amongst exoplanet host stars.

  18. WHICH RADIAL VELOCITY EXOPLANETS HAVE UNDETECTED OUTER COMPANIONS?

    SciTech Connect

    Rodigas, Timothy J.; Hinz, Philip M.

    2009-09-01

    The observed radial velocity (RV) eccentricity distribution for extrasolar planets in single-planet systems shows that a significant fraction of planets are eccentric (e > 0.1). However, an RV planet's eccentricity, which comes from the Keplerian fitting, can be biased by low signal-to-noise ratio and poor sampling. Here, we investigate the effects on eccentricity produced by undetected outer companions. We have carried out Monte Carlo simulations of mock RV data to understand this effect and predict its impact on the observed distribution. We first quantify the statistical bias of known RV planets' eccentricities produced by undetected zero-eccentricity wide-separation companions and show that this effect alone cannot explain the observed distribution. We then modify the simulations to consist of two populations, one of zero-eccentricity planets in double-planet systems and the other of single planets drawn from an eccentric distribution. Our simulations show that a good fit to the observed distribution is obtained with 45% zero-eccentricity double planets and 55% single eccentric planets. Assuming that our two simulated populations of planets are a good approximation for the true RV population, matching the observed distribution allows us to determine the probability that a known RV planet's orbital eccentricity has been biased by an undetected wide-separation companion. Averaged over eccentricity we calculate this probability to be {approx}4%, suggesting that a small fraction of systems may have a yet to be discovered outer companion. Our simulations show that moderately eccentric planets, with 0.1 < e < 0.3 and 0.1 < e < 0.2, have a {approx}13% and {approx}19% probability, respectively, of having an undetected outer companion. We encourage both high-contrast direct imaging and RV follow-up surveys of known RV planets with moderate eccentricities to test our predictions and look for previously undetected outer companions.

  19. Exoplanets

    NASA Astrophysics Data System (ADS)

    Seager, S.

    2010-12-01

    -mass planets and those further from the star. All in all, technology enables slow but sure progress, and this fuels ongoing discovery. Theory, like observations, also takes time to unfold and mature. We can anticipate an "ultimate" planet formation model similar to the "millenimum simulation" for galaxy formation and evolution. In time, incorporating detailed physics as well as being able to reproduce the generic outcome of planet populations (mass, radius, and orbital characteristics, including period) will enable a deeper understanding of planet formation and migration. Similarly, the ideal exoplanet atmosphere code of the future could be a three-dimensional Monte Carlo code that includes radiative transfer with inhomogeneous cloud coverage and surface features, a code that also solves for the temperature structure and combines with a hydrodynamical simulation to calculate the three-dimensional temperature and wind structure. Classical orbital mechanics, already reinvigorated by interesting exoplanet systems (e.g., planets in resonant orbits, hot Jupiter exoplanets that orbit in the direction opposite to the stellar rotation), also has a role to play in explaining fundamental mechanisms of how planetary system configurations came to be. Orbital dynamics modeling is driving the search for moons and other unseen planet companions by their perturbations on transiting planet signatures. Exoplanets is a unique science because it involves so many disciplines within and beyond planetary science and astrophysics. The other disciplines include geophysics, high-pressure mineral physics, quantum mechanics, chemistry, and even microbiology. While exoplanet observations clearly belong under the branch of astronomy, for many years the whole discipline of exoplanets lacked a true home. Physics departments have said "Exoplanets: It's interesting, but is it physics?" Planetary and Earth science departments used to collecting real data in their hands from Earth and in situ measurements from

  20. Follow-up of Candidate Companions to Vega

    NASA Astrophysics Data System (ADS)

    Janson, Markus; Quanz, Sascha; Carson, Joseph; Thalmann, Christian; Lafreniere, David; Amara, Adam

    2014-12-01

    Vega hosts one of the most nearby massive debris disks, with a morphology that may be indicative of wide giant planetary companions. Its proximity and relatively young age also make it an attractive target for direct imaging searches for such companions. We therefore observed Vega with Spitzer during cycle 9, which provides the best sensitivity to planets in wide orbits that is available with any existing facility. Three candidates were discovered in the data which are substantially brighter at 4.5 micron than at 3.6 micron, while typical background sources have much smaller brightness differences between these bands. We now propose to follow the system up in a second epoch to test the three candidates for common proper motion with the primary star. If real, physical companions, the candidates have separations of 265-335 AU and masses of 2-3 Mjup according to evolutionary models (regardless of initial entropy conditions), and would therefore constitute the coldest and lowest-mass planets ever imaged outside of the Solar System.

  1. FIVE KEPLER TARGET STARS THAT SHOW MULTIPLE TRANSITING EXOPLANET CANDIDATES

    SciTech Connect

    Steffen, Jason H.; Batalha, Natalie M.; Borucki, William J.; Caldwell, Douglas A.; Haas, Michael J.; Jenkins, Jon M.; Koch, David; Lissauer, Jack J.; Buchhave, Lars A.; Fabrycky, Daniel C.; Fressin, Francois; Holman, Matthew J.; Latham, David W.; Cochran, William D.; Endl, Michael; Ford, Eric B.; Moorhead, Althea V.; Fortney, Jonathan J.; Howell, Steve B.; Isaacson, Howard

    2010-12-10

    We present and discuss five candidate exoplanetary systems identified with the Kepler spacecraft. These five systems show transits from multiple exoplanet candidates. Should these objects prove to be planetary in nature, then these five systems open new opportunities for the field of exoplanets and provide new insights into the formation and dynamical evolution of planetary systems. We discuss the methods used to identify multiple transiting objects from the Kepler photometry as well as the false-positive rejection methods that have been applied to these data. One system shows transits from three distinct objects while the remaining four systems show transits from two objects. Three systems have planet candidates that are near mean motion commensurabilities-two near 2:1 and one just outside 5:2. We discuss the implications that multi-transiting systems have on the distribution of orbital inclinations in planetary systems, and hence their dynamical histories, as well as their likely masses and chemical compositions. A Monte Carlo study indicates that, with additional data, most of these systems should exhibit detectable transit timing variations (TTVs) due to gravitational interactions, though none are apparent in these data. We also discuss new challenges that arise in TTV analyses due to the presence of more than two planets in a system.

  2. Five Kepler target stars that show multiple transiting exoplanet candidates

    SciTech Connect

    Steffen, Jason H.; Batalha, Natalie M.; Borucki, William J.; Buchhave, Lars A.; Caldwell, Douglas A.; Cochran, William D.; Endl, Michael; Fabrycky, Daniel C.; Fressin, Francois; Ford, Eric B.; Fortney, Jonathan J.; /UC, Santa Cruz, Phys. Dept. /NASA, Ames

    2010-06-01

    We present and discuss five candidate exoplanetary systems identified with the Kepler spacecraft. These five systems show transits from multiple exoplanet candidates. Should these objects prove to be planetary in nature, then these five systems open new opportunities for the field of exoplanets and provide new insights into the formation and dynamical evolution of planetary systems. We discuss the methods used to identify multiple transiting objects from the Kepler photometry as well as the false-positive rejection methods that have been applied to these data. One system shows transits from three distinct objects while the remaining four systems show transits from two objects. Three systems have planet candidates that are near mean motion commensurabilities - two near 2:1 and one just outside 5:2. We discuss the implications that multitransiting systems have on the distribution of orbital inclinations in planetary systems, and hence their dynamical histories; as well as their likely masses and chemical compositions. A Monte Carlo study indicates that, with additional data, most of these systems should exhibit detectable transit timing variations (TTV) due to gravitational interactions - though none are apparent in these data. We also discuss new challenges that arise in TTV analyses due to the presence of more than two planets in a system.

  3. Exoplanets

    NASA Astrophysics Data System (ADS)

    Seager, S.

    2010-12-01

    -mass planets and those further from the star. All in all, technology enables slow but sure progress, and this fuels ongoing discovery. Theory, like observations, also takes time to unfold and mature. We can anticipate an "ultimate" planet formation model similar to the "millenimum simulation" for galaxy formation and evolution. In time, incorporating detailed physics as well as being able to reproduce the generic outcome of planet populations (mass, radius, and orbital characteristics, including period) will enable a deeper understanding of planet formation and migration. Similarly, the ideal exoplanet atmosphere code of the future could be a three-dimensional Monte Carlo code that includes radiative transfer with inhomogeneous cloud coverage and surface features, a code that also solves for the temperature structure and combines with a hydrodynamical simulation to calculate the three-dimensional temperature and wind structure. Classical orbital mechanics, already reinvigorated by interesting exoplanet systems (e.g., planets in resonant orbits, hot Jupiter exoplanets that orbit in the direction opposite to the stellar rotation), also has a role to play in explaining fundamental mechanisms of how planetary system configurations came to be. Orbital dynamics modeling is driving the search for moons and other unseen planet companions by their perturbations on transiting planet signatures. Exoplanets is a unique science because it involves so many disciplines within and beyond planetary science and astrophysics. The other disciplines include geophysics, high-pressure mineral physics, quantum mechanics, chemistry, and even microbiology. While exoplanet observations clearly belong under the branch of astronomy, for many years the whole discipline of exoplanets lacked a true home. Physics departments have said "Exoplanets: It's interesting, but is it physics?" Planetary and Earth science departments used to collecting real data in their hands from Earth and in situ measurements from

  4. Planet Hunters. VIII. Characterization of 41 Long-period Exoplanet Candidates from Kepler Archival Data

    NASA Astrophysics Data System (ADS)

    Wang, Ji; Fischer, Debra A.; Barclay, Thomas; Picard, Alyssa; Ma, Bo; Bowler, Brendan P.; Schmitt, Joseph R.; Boyajian, Tabetha S.; Jek, Kian J.; LaCourse, Daryll; Baranec, Christoph; Riddle, Reed; Law, Nicholas M.; Lintott, Chris; Schawinski, Kevin; Simister, Dean Joseph; Grégoire, Boscher; Babin, Sean P.; Poile, Trevor; Jacobs, Thomas Lee; Jebson, Tony; Omohundro, Mark R.; Schwengeler, Hans Martin; Sejpka, Johann; Terentev, Ivan A.; Gagliano, Robert; Paakkonen, Jari-Pekka; Otnes Berge, Hans Kristian; Winarski, Troy; Green, Gerald R.; Schmitt, Allan R.; Kristiansen, Martti H.; Hoekstra, Abe

    2015-12-01

    The census of exoplanets is incomplete for orbital distances larger than 1 AU. Here, we present 41 long-period planet candidates in 38 systems identified by Planet Hunters based on Kepler archival data (Q0-Q17). Among them, 17 exhibit only one transit, 14 have two visible transits, and 10 have more than three visible transits. For planet candidates with only one visible transit, we estimate their orbital periods based on transit duration and host star properties. The majority of the planet candidates in this work (75%) have orbital periods that correspond to distances of 1-3 AU from their host stars. We conduct follow-up imaging and spectroscopic observations to validate and characterize planet host stars. In total, we obtain adaptive optics images for 33 stars to search for possible blending sources. Six stars have stellar companions within 4″. We obtain high-resolution spectra for 6 stars to determine their physical properties. Stellar properties for other stars are obtained from the NASA Exoplanet Archive and the Kepler Stellar Catalog by Huber et al. We validate 7 planet candidates that have planet confidence over 0.997 (3σ level). These validated planets include 3 single-transit planets (KIC-3558849b, KIC-5951458b, and KIC-8540376c), 3 planets with double transits (KIC-8540376b, KIC-9663113b, and KIC-10525077b), and 1 planet with four transits (KIC-5437945b). This work provides assessment regarding the existence of planets at wide separations and the associated false positive rate for transiting observation (17%-33%). More than half of the long-period planets with at least three transits in this paper exhibit transit timing variations up to 41 hr, which suggest additional components that dynamically interact with the transiting planet candidates. The nature of these components can be determined by follow-up radial velocity and transit observations.

  5. NICMOS Imaging Search for a Candidate Companion to Proxima Centauri

    NASA Astrophysics Data System (ADS)

    Silverstone, M. D.; Schneider, G.; Schultz, A. B.

    2001-05-01

    A candidate companion to Proxima Centauri (Prox Cen) was identified in Faint Object Spectrograph observations (Schultz, A.B. et al, 1998 AJ 115, 345). Subsequently, the field surrounding Prox Cen was observed at 3 epochs (UT 8 March, 1 July, and 13 October 1998) with NICMOS Camera 1 (0.043 arcsec/pix), in HST observing program GO/7847. At each epoch the field, which was oriented by the HST nominal roll, was observed in 4 dither positions in each of 3 filters (F160W, F165M, and F170M). The M5.5V star GL 905 was observed similarly at one epoch, to serve as a PSF reference for Prox Cen. This total survey covered approx. 300 square arcseconds near Prox Cen, of which about 80 square arcseconds was common to two epochs, and about 60 square arcseconds was imaged in all three epochs. We searched the PSF-subtracted images for common proper-motion and common parallax companions to this close (d ≈ 1.3 pc) primary. Background stars were identified by comparison to archival WFPC-2 images and differential astrometry between the epochs. We did not find multi-epoch evidence of candidate companions, though we have identified a number of single-epoch point-source like objects in the images. We derive upper limits for near-infrared flux densities from undetected companions as a function of projected distance. Support for this work was provided by NASA through grant number GO-07847.01-96A from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555.

  6. SPECTROSCOPY OF FAINT KEPLER MISSION EXOPLANET CANDIDATE HOST STARS

    SciTech Connect

    Everett, Mark E.; Silva, David R.; Howell, Steve B.; Szkody, Paula

    2013-07-10

    Stellar properties are measured for a large set of Kepler mission exoplanet candidate host stars. Most of these stars are fainter than 14th magnitude, in contrast to other spectroscopic follow-up studies. This sample includes many high-priority Earth-sized candidate planets. A set of model spectra are fitted to R {approx} 3000 optical spectra of 268 stars to improve estimates of T{sub eff}, log (g), and [Fe/H] for the dwarfs in the range 4750 {<=} T{sub eff} {<=} 7200 K. These stellar properties are used to find new stellar radii and, in turn, new radius estimates for the candidate planets. The result of improved stellar characteristics is a more accurate representation of this Kepler exoplanet sample and identification of promising candidates for more detailed study. This stellar sample, particularly among stars with T{sub eff} {approx}> 5200 K, includes a greater number of relatively evolved stars with larger radii than assumed by the mission on the basis of multi-color broadband photometry. About 26% of the modeled stars require radii to be revised upward by a factor of 1.35 or greater, and modeling of 87% of the stars suggest some increase in radius. The sample presented here also exhibits a change in the incidence of planets larger than 3-4 R{sub Circled-Plus} as a function of metallicity. Once [Fe/H] increases to {>=} - 0.05, large planets suddenly appear in the sample while smaller planets are found orbiting stars with a wider range of metallicity. The modeled stellar spectra, as well as an additional 84 stars of mostly lower effective temperatures, are made available to the community.

  7. AN EFFICIENT AUTOMATED VALIDATION PROCEDURE FOR EXOPLANET TRANSIT CANDIDATES

    SciTech Connect

    Morton, Timothy D.

    2012-12-10

    Surveys searching for transiting exoplanets have found many more candidates than they have been able to confirm as true planets. This situation is especially acute with the Kepler survey, which has found over 2300 candidates but has to date confirmed only a small fraction of them as planets. I present here a general procedure that can quickly be applied to any planet candidate to calculate its false positive probability. This procedure takes into account the period, depth, duration, and shape of the signal; the colors of the target star; arbitrary spectroscopic or imaging follow-up observations; and informed assumptions about the populations and distributions of field stars and multiple-star properties. Applying these methods to a sample of known Kepler planets, I demonstrate that many signals can be validated with very limited follow-up observations: in most cases with only a spectrum and an adaptive optics image. Additionally, I demonstrate that this procedure can reliably identify false positive signals. Because of the computational efficiency of this analysis, it is feasible to apply it to all Kepler planet candidates in the near future, and it will streamline the follow-up efforts for Kepler and other current and future transit surveys.

  8. Know the Star, Know the Planet. III. Discovery of Late-Type Companions to Two Exoplanet Host Stars

    NASA Astrophysics Data System (ADS)

    Roberts, Lewis C., Jr.; Tokovinin, Andrei; Mason, Brian D.; Riddle, Reed L.; Hartkopf, William I.; Law, Nicholas M.; Baranec, Christoph

    2015-04-01

    We discuss two multiple star systems that host known exoplanets: HD 2638 and 30 Ari B. Adaptive optics imagery revealed an additional stellar companion to both stars. We collected multi-epoch images of the systems with Robo-AO and the PALM-3000 adaptive optics systems at Palomar Observatory and provide relative photometry and astrometry. The astrometry indicates that the companions share common proper motion with their respective primaries. Both of the new companions have projected separations less than 30 AU from the exoplanet host star. Using the projected separations to compute orbital periods of the new stellar companions, HD 2638 has a period of 130 yr and 30 Ari B has a period of 80 yr. Previous studies have shown that the true period is most likely within a factor of three of these estimated values. The additional component to 30 Ari makes it the second confirmed quadruple system known to host an exoplanet. HD 2638 hosts a hot Jupiter and the discovery of a new companion strengthens the connection between hot Jupiters and binary stars. We place the systems on a color-magnitude diagram and derive masses for the companions which turn out to be roughly 0.5 solar mass stars.

  9. Follow-up spectroscopic observations of HD 107148 B: A new white dwarf companion of an exoplanet host star

    NASA Astrophysics Data System (ADS)

    Mugrauer, M.; Dinçel, B.

    2016-07-01

    We report on our follow-up spectroscopy of HD 1071478 B, a recently detected faint co-moving companion of the exoplanet host star HD 107148 A. The companion is separated from its primary star by about 35 arcsec (or 1790 AU of projected separation) and its optical and near infrared photometry is consistent with a white dwarf, located at the distance of HD 107148 A. In order to confirm the white dwarf nature of the co-moving companion, we obtained follow-up spectroscopic observations of HD 107148 B with CAFOS at the CAHA 2.2 m telescope. According to our CAFOS spectroscopy HD 107148 B is a DA white dwarf with an effective temperature in the range between 5900 and 6400 K. The properties of HD 107148 B can further be constrained with the derived effective temperature and the known visual and infrared photometry of the companion, using evolutionary models of DA white dwarfs. We obtain for HD 107148 B a mass of 0.56±0.05 M_ȯ, a luminosity of (2.0±0.2)×10-4 L_ȯ, log g [cm s-2])=7.95±0.09, and a cooling age of 2100±270 Myr. With its white dwarf companion the exoplanet host star HD 107148 A forms an evolved stellar system, which hosts at least one exoplanet. So far, only few of these evolved systems are known, which represent only about 5 % of all known exoplanet host multiple stellar systems. HD 107148 B is the second confirmed white dwarf companion of an exoplanet host star with a projected separation to its primary star of more than 1000 AU. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC).

  10. THE PHASES DIFFERENTIAL ASTROMETRY DATA ARCHIVE. V. CANDIDATE SUBSTELLAR COMPANIONS TO BINARY SYSTEMS

    SciTech Connect

    Muterspaugh, Matthew W.; Lane, Benjamin F.; Kulkarni, S. R.; Konacki, Maciej; Burke, Bernard F.; Colavita, M. M.; Shao, M.; Hartkopf, William I.; Boss, Alan P.; Williamson, M. E-mail: blane@draper.co

    2010-12-15

    The Palomar High-precision Astrometric Search for Exoplanet Systems monitored 51 subarcsecond binary systems to evaluate whether tertiary companions as small as Jovian planets orbited either the primary or secondary stars, perturbing their otherwise smooth Keplerian motions. Six binaries are presented that show evidence of substellar companions orbiting either the primary or secondary star. Of these six systems, the likelihoods of two of the detected perturbations to represent real objects are considered to be 'high confidence', while the remaining four systems are less certain and will require continued observations for confirmation.

  11. Resolved Companions of Cepheids: Testing the Candidates with X-Ray Observations

    NASA Astrophysics Data System (ADS)

    Evans, Nancy Remage; Pillitteri, Ignazio; Wolk, Scott; Karovska, Margarita; Tingle, Evan; Guinan, Edward; Engle, Scott; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.

    2016-04-01

    We have made XMM-Newton observations of 14 Galactic Cepheids that have candidate resolved (≥5″) companion stars based on our earlier HST Wide Field Camera 3 (WFC3) imaging survey. Main-sequence stars that are young enough to be physical companions of Cepheids are expected to be strong X-ray producers in contrast to field stars. XMM-Newton exposures were set to detect essentially all companions hotter than spectral type M0 (corresponding to 0.5 M⊙). The large majority of our candidate companions were not detected in X-rays, and hence are not confirmed as young companions. One resolved candidate (S Nor #4) was unambiguously detected, but the Cepheid is a member of a populous cluster. For this reason, it is likely that S Nor #4 is a cluster member rather than a gravitationally bound companion. Two further Cepheids (S Mus and R Cru) have X-ray emission that might be produced by either the Cepheid or the candidate resolved companion. A subsequent Chandra observation of S Mus shows that the X-rays are at the location of the Cepheid/spectroscopic binary. R Cru and also V659 Cen (also X-ray bright) have possible companions closer than 5″ (the limit for this study) which are the likely sources of X-rays. One final X-ray detection (V473 Lyr) has no known optical companion, so the prime suspect is the Cepheid itself. It is a unique Cepheid with a variable amplitude. The 14 stars that we observed with XMM constitute 36% of the 39 Cepheids found to have candidate companions in our HST/WFC3 optical survey. No young probable binary companions were found with separations of ≥5″ or 4000 au. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).

  12. Space weather: recovering the variation of the stellar EUV spectral Energy distribution from the companion exoplanet FUV transit observation

    NASA Astrophysics Data System (ADS)

    Ben-Jaffel, Lotfi; Guo, Jianheng

    2016-07-01

    The stellar extreme ultraviolet (EUV) irradiation determines the atmospheric properties of exoplanets. Recently, by varying the profiles of the EUV spectral energy distribution (SED), we tested the influences of stellar EUV SEDs on the physical and chemical properties of the escaping atmosphere (Guo & Ben-Jaffel, 2015). One of our major results was that the composition and species distributions in the atmosphere could be dramatically modified by the different profiles of the EUV SED. For exoplanets with a high hydrodynamic escape rate, the amount of atomic hydrogen produced by photoionization at different altitudes can vary by one to two orders of magnitude with the variation of stellar EUV SEDs. For exoplanet HD 189733b, it was possible to explain the time variability observed during transit in the Lyman-α line by the Hubble Space Telescope (HST) between 2010 and 2011 by a change in the EUV SED of the host K star. Our proposed technique provides a straightforward and easy-to-follow proxy to connect the EUV SED of the star with the planetary companion Lyman--α transit absorption, the monitoring of which may provide a direct measure of the stellar EUV flux. Here, we extend our study using new HST FUV observations.

  13. Transiting exoplanet candidates from K2 Campaigns 5 and 6

    NASA Astrophysics Data System (ADS)

    Pope, Benjamin J. S.; Parviainen, Hannu; Aigrain, Suzanne

    2016-06-01

    We introduce a new transit search and vetting pipeline for observations from the K2 mission, and present the candidate transiting planets identified by this pipeline out of the targets in Campaigns 5 and 6. Our pipeline uses the Gaussian Process-based K2SC code to correct for the K2 pointing systematics and simultaneously model stellar variability. The systematics-corrected, variability-detrended light curves are searched for transits with the Box Least Squares method, and a period-dependent detection threshold is used to generate a preliminary candidate list. Two or three individuals vet each candidate manually to produce the final candidate list, using a set of automatically-generated transit fits and assorted diagnostic tests to inform the vetting. We detect 147 single-planet system candidates and 5 multi-planet systems, independently recovering the previously-published hot Jupiters EPIC 212110888b, WASP-55b (EPIC 212300977b) and Qatar-2b (EPIC 212756297b). We also report the outcome of reconnaissance spectroscopy carried out for all candidates with Kepler magnitude Kp ≤ 13, identifying 12 targets as likely false positives. We compare our results to those of other K2 transit search pipelines, noting that ours performs particularly well for variable and/or active stars, but that the results are very similar overall. All the light curves and code used in the transit search and vetting process are publicly available, as are the follow-up spectra.

  14. Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems

    NASA Astrophysics Data System (ADS)

    Raghavan, D. R.; Henry, T. J.; Mason, B. D.; Subasavage, J. P.; Jao, W. C.; Beaulieu, T. D.; Hambly, N. C.

    2005-12-01

    We present results of a reconnaissance for stellar companions to all 131 radial-velocity-detected candidate extrasolar planetary systems known as of July 1, 2005. Common proper motion (CPM) companions were investigated using the multi-epoch STScI Digitized Sky Surveys (DSS), and confirmed by matching the trigonometric parallax distances of the primaries to companion distances estimated photometrically using SuperCOSMOS plate, CCD optical and 2MASS infrared photometry. We evaluate whether the ``companions" listed in the Washington Double Star Catalog (WDS) are gravitationally bound to the primary or coincidental alignments in the sky. We also attempt to confirm or refute companions listed in the Catalog of Nearby Stars (CNS), Hipparcos, and Duquennoy & Mayor, 1991. Our findings indicate that a lower limit of 29 (22%) of the 131 exoplanet systems have stellar companions, and an additional 7 (5%) have candidate companions. We report a previously unknown stellar companion to planet host HD 38529, and identify a companion candidate to HD 188015. We confirm 16 previously reported stellar companions to exoplanet hosts, and report 8 additional companions --- these are known stellar companions, but previously not recognized to be in exoplanet systems. In addition, we have confirmed the gravitational connection for a WDS entry for HD 222582. We have also found evidence for 20 entries in WDS that are not gravitationally bound companions --- they do not show any related proper motion in the DSS plates. At least three, and possibly five of the exoplanet systems are contained within triple star systems, and of these, HD 38529 may have a fourth stellar companion as well. Two of the exoplanet systems contain white dwarf companions. These results indicate that solar systems are found in a variety of stellar multiplicity environments -- singles, binaries, triples, and possibly quadruples; and that planets survive post-main-sequence evolution of companion stars.

  15. Algol: An Early Candidate for a Transiting Exoplanet

    NASA Astrophysics Data System (ADS)

    French, Linda M.; Stuart, I.

    2008-09-01

    Virtually every astronomy text credits John Goodricke (1764-1786) with the discovery of the period of variability of the star Algol (β Per) and with the explanation of its variation (eclipses by an unseen stellar companion). Today, Algol is considered a prototype of an eclipsing binary star. In actuality, John Goodricke worked in collaboration with his neighbor, mentor, and distant relative, Edward Pigott. As observed by Hoskin1, the observing journals2 of the two clearly show that the eclipse explanation originated with Edward. Both originally used the term "planet” to describe the eclipsing body. However, in Goodricke's 1783 paper describing Algol, he writes: "....I should imagine it could hardly be accounted for otherwise than either by the interposition of a large body revolving round Algol, or some kind of motion of its own, whereby part of its body, covered with spots or such like matter...."3 Goodricke was later to soften his stance still further after the two discovered several other variable stars; his last published work4 mentions only starspots as an explanation for the light variation of Algol. Although the physics of the time would not have allowed Goodricke and Pigott to distinguish between a star and a planet as the unseen companion, the eighteenth-century astronomers showed great prescience in realizing that the eclipses of Algol were just that. Their mental leap, at a time when astronomers were just beginning to think seriously of discovering planets around other stars, should not go unremembered by modern planetary scientists. Footnotes 1 Hoskin, M. (1982). In Stellar Astronomy, Science History Publications Ltd., Chalfont St. Giles, England. 2 Goodricke and Pigott journals. York City Archives, York, England. 3 Goodricke, J. G. (1783). Phil. Soc. Roy. Soc. London 73, 474-482. 4 Goodricke, J. G. (1786). Phil. Soc. Roy. Soc. London 76, 48-61.

  16. Carbon and Oxygen Abundances in the Hot Jupiter Exoplanet Host Star XO-2B and Its Binary Companion

    NASA Astrophysics Data System (ADS)

    Teske, Johanna K.; Schuler, Simon C.; Cunha, Katia; Smith, Verne V.; Griffith, Caitlin A.

    2013-05-01

    With the aim of connecting the compositions of stars and planets, we present the abundances of carbon and oxygen, as well as iron and nickel, for the transiting exoplanet host star XO-2N and its wide-separation binary companion XO-2S. Stellar parameters are derived from high-resolution, high signal-to-noise spectra, and the two stars are found to be similar in their T eff, log g, iron ([Fe/H]), and nickel ([Ni/H]) abundances. Their carbon ([C/H]) and oxygen ([O/H]) abundances also overlap within errors, although XO-2N may be slightly more C-rich and O-rich than XO-2S. The C/O ratios of both stars (~0.60 ± 0.20) may also be somewhat larger than solar (C/O ~ 0.50). The XO-2 system has a transiting hot Jupiter orbiting one binary component but not the other, allowing us to probe the potential effects planet formation might have on the host star composition. Additionally, with multiple observations of its atmosphere the transiting exoplanet XO-2b lends itself to compositional analysis, which can be compared to the natal chemical environment established by our binary star elemental abundances. This work sets the stage for determining how similar or different exoplanet and host star compositions are, and the implications for planet formation, by discussing the C/O ratio measurements in the unique environment of a visual binary system with one star hosting a transiting hot Jupiter. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  17. CARBON AND OXYGEN ABUNDANCES IN THE HOT JUPITER EXOPLANET HOST STAR XO-2B AND ITS BINARY COMPANION

    SciTech Connect

    Teske, Johanna K.; Schuler, Simon C.; Cunha, Katia; Smith, Verne V.; Griffith, Caitlin A.

    2013-05-01

    With the aim of connecting the compositions of stars and planets, we present the abundances of carbon and oxygen, as well as iron and nickel, for the transiting exoplanet host star XO-2N and its wide-separation binary companion XO-2S. Stellar parameters are derived from high-resolution, high signal-to-noise spectra, and the two stars are found to be similar in their T{sub eff}, log g, iron ([Fe/H]), and nickel ([Ni/H]) abundances. Their carbon ([C/H]) and oxygen ([O/H]) abundances also overlap within errors, although XO-2N may be slightly more C-rich and O-rich than XO-2S. The C/O ratios of both stars ({approx}0.60 {+-} 0.20) may also be somewhat larger than solar (C/O {approx} 0.50). The XO-2 system has a transiting hot Jupiter orbiting one binary component but not the other, allowing us to probe the potential effects planet formation might have on the host star composition. Additionally, with multiple observations of its atmosphere the transiting exoplanet XO-2b lends itself to compositional analysis, which can be compared to the natal chemical environment established by our binary star elemental abundances. This work sets the stage for determining how similar or different exoplanet and host star compositions are, and the implications for planet formation, by discussing the C/O ratio measurements in the unique environment of a visual binary system with one star hosting a transiting hot Jupiter.

  18. Transit, Secondary Eclipse, and Phase Curve Modeling to Characterize Kepler Exoplanet Candidates

    NASA Astrophysics Data System (ADS)

    Tarnas, Jesse; Redfield, Seth

    2016-01-01

    The high sensitivity and continuous coverage of Kepler allows for analysis of optical phase curves, which provide detailed exoplanet characterization by fitting photometric features caused by thermal emission, reflected light, Doppler boosting, and ellipsoidal variations. Combined with transit and secondary eclipse analysis to reduce model degeneracy, phase curves can resolve atmospheric characteristics, dayside-nightside temperatures, and even mass using single-band photometry. We will present an integrated phase curve, transit, and secondary eclipse analysis of Kepler exoplanet candidates, building on the phase curve model constructed by Serindag & Redfield (2015). Phase curves can also be present in non-transiting systems. We will explore the feasibility of detecting and characterizing these non-transiting exoplanets. We will also investigate the possibility of analyzing exoplanet phase curves in K2 data. We gratefully acknowledge support through a grant (14-K2GO1_2-0071) associated with the K2 Guest Observer — Cycle 1 program of Research Opportunities in Space and Earth Sciences (ROSES-2014; NNH14ZDA001N).

  19. Companions to APOGEE Stars. I. A Milky Way-spanning Catalog of Stellar and Substellar Companion Candidates and Their Diverse Hosts

    NASA Astrophysics Data System (ADS)

    Troup, Nicholas W.; Nidever, David L.; De Lee, Nathan; Carlberg, Joleen; Majewski, Steven R.; Fernandez, Martin; Covey, Kevin; Chojnowski, S. Drew; Pepper, Joshua; Nguyen, Duy T.; Stassun, Keivan; Nguyen, Duy Cuong; Wisniewski, John P.; Fleming, Scott W.; Bizyaev, Dmitry; Frinchaboy, Peter M.; García-Hernández, D. A.; Ge, Jian; Hearty, Fred; Meszaros, Szabolcs; Pan, Kaike; Allende Prieto, Carlos; Schneider, Donald P.; Shetrone, Matthew D.; Skrutskie, Michael F.; Wilson, John; Zamora, Olga

    2016-03-01

    In its three years of operation, the Sloan Digital Sky Survey Apache Point Observatory Galactic Evolution Experiment (APOGEE-1) observed >14,000 stars with enough epochs over a sufficient temporal baseline for the fitting of Keplerian orbits. We present the custom orbit-fitting pipeline used to create this catalog, which includes novel quality metrics that account for the phase and velocity coverage of a fitted Keplerian orbit. With a typical radial velocity precision of ˜100-200 m s-1, APOGEE can probe systems with small separation companions down to a few Jupiter masses. Here we present initial results from a catalog of 382 of the most compelling stellar and substellar companion candidates detected by APOGEE, which orbit a variety of host stars in diverse Galactic environments. Of these, 376 have no previously known small separation companion. The distribution of companion candidates in this catalog shows evidence for an extremely truncated brown dwarf (BD) desert with a paucity of BD companions only for systems with a\\quad \\lt 0.1-0.2 AU, with no indication of a desert at larger orbital separation. We propose a few potential explanations of this result, some which invoke this catalog’s many small separation companion candidates found orbiting evolved stars. Furthermore, 16 BD and planet candidates have been identified around metal-poor ([Fe/H] < -0.5) stars in this catalog, which may challenge the core accretion model for companions \\gt 10{M}{Jup}. Finally, we find all types of companions are ubiquitous throughout the Galactic disk with candidate planetary-mass and BD companions to distances of ˜6 and ˜16 kpc, respectively.

  20. NICMOS Imaging of 2MASSWJ 1207334-393254 - A Planetary-Mass Companion Candidate

    NASA Astrophysics Data System (ADS)

    Schneider, G.; Song, I.; Zuckerman, B.; Becklin, E.; Lowrance, P.; Macintosh, B.; Bessell, M.; Dumas, C.; Chauvin, G.

    2004-12-01

    2MASSWJ 1207334-393254, a likely member of the nearby TW Hya association (age app 10 Myr and app 70 pc from Earth), is an app 30 Mjupiter brown dwarf (M8V spectrum due to its youth) for which a putative candidate planetary-mass companion was identified by Chauvin et al (Astron. and Astroph. 425, L29) with VLT/NACO observations in April 2004. Earlier, 2MASSWJ 1207334-393254 had been scheduled for observation in HST cycle 13 in a NICMOS H-band coronagraphic companion detection survey (GO 10176), but was re-programmed as an early "follow-up" observation given the ground-based derived implications for shorter wavelength space-based detection and efficacious diagnostic photometric measurements. Here, we present NICMOS camera 1 imaging photometry observations of 2MASSWJ 1207334-393254 and its point-like companion candidate in three bands: F090M (0.80 - 1.00 microns; similar to I-band), F110M (1.00 - 1.20 microns) and F160W (1.40 - 1.60 microns; similar to H-band) obtained on 28 Aug 2004. For the 773.7 +/- 2.2 mas (app 55 AU projected separation) distant companion we find in-band magnitudes for the companion candidate of F090M = 22.34 +/- 0.35 (delta-F090M = +7.14), F110M = 20.61 +/- 0.15 and (delta-F110M = +7.02) F160W = 18.24 +/- 0.02 (delta-F160W = +5.62). The NICMOS [0.90] - [1.6] micron color index of +4.1 +/- 0.4 is consistent with expectations for the spectral energy distribution of a mid to late L-dwarf (e.g., I - H of app +4.4 for spectral type L4). At the likely age of this candidate, the NICMOS and longer wavelength VLT/NACO derived photometric measures may implicate an object of several Jupiter masses. If the candidate companion is (as is yet to be) demonstrated to exhibit common proper motion with 2MASSWJ 1207334-393254 then the first image of a gravitationally bound companion of planetary mass may have already been secured. This work is supported through grants to the GO 10176 and 10177 teams from STScI, which is operated by AURA, Inc., under NASA contract

  1. Robotic laser adaptive optics imaging of 715 Kepler exoplanet candidates using Robo-AO

    SciTech Connect

    Law, Nicholas M.; Ziegler, Carl; Morton, Tim; Riddle, Reed; Tendulkar, Shriharsh P.; Bui, Khanh; Dekany, Richard G.; Kulkarni, Shrinivas; Punnadi, Sujit; Baranec, Christoph; Ravichandran, Ganesh; Johnson, John Asher; Burse, Mahesh P.; Das, H. K.; Ramaprakash, A. N.

    2014-08-10

    The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. In this paper, we present the results from the 2012 observing season, searching for stars close to 715 Kepler planet candidate hosts. We find 53 companions, 43 of which are new discoveries. We detail the Robo-AO survey data reduction methods including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designed for large adaptive optics surveys. Our survey is sensitive to objects from ≈0.''15 to 2.''5 separation, with magnitude differences up to Δm ≈ 6. We measure an overall nearby-star probability for Kepler planet candidates of 7.4% ± 1.0%, and calculate the effects of each detected nearby star on the Kepler-measured planetary radius. We discuss several Kepler Objects of Interest (KOIs) of particular interest, including KOI-191 and KOI-1151, which are both multi-planet systems with detected stellar companions whose unusual planetary system architecture might be best explained if they are 'coincident multiple' systems, with several transiting planets shared between the two stars. Finally, we find 98% confidence evidence that short-period giant planets are two to three times more likely than longer-period planets to be found in wide stellar binaries.

  2. Spitzer Meets K2: Spitzer Studies of Candidate Exoplanets Identified by K2

    NASA Astrophysics Data System (ADS)

    Werner, Michael W.; Spitzer/K2 Study Team

    2016-01-01

    We are in the midst of a ~450 hr program of Spitzer photometry of candidate transiting planets orbiting M dwarf stars, identified in the K2 fields. Whereas the Kepler prime mission eschewed M stars, they have become a major focus of the community-driven target selection for K2. M stars are the most common stars in the galaxy, and planets orbiting M stars can be very attractive candidates for transit and eclipse atmospheric studies, including studies aimed at exploring potentially habitable exoplanets. We will review and show the results of the observations planned and executed to date, which total 21 transits of 16 planets orbiting 13 stars. Our results greatly improve on the characterization of the exoplanets and their orbits over what is possible from the K2 data alone. In addition, the improved ephemerides we generate will facilitate studies of interesting K2 targets from JWST. __________________________________________This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech.

  3. VizieR Online Data Catalog: Stellar companions of exoplanet host stars (Ginski+, 2012)

    NASA Astrophysics Data System (ADS)

    Ginski, C.; Mugrauer, M.; Seeliger, M.; Eisenbeiss, T.

    2013-01-01

    Our sample consists of stars with RV planet candidates discovered between 2008 and 2011. They are all observable from the Northern hemisphere with declinations down to -22° and a relatively even distribution in right ascension. All observations were carried out with the Calar Alto 2.2-m telescope in combination with the AstraLux instrument. (2 data files).

  4. Search for light curve modulations among Kepler candidates. Three very low-mass transiting companions

    NASA Astrophysics Data System (ADS)

    Lillo-Box, J.; Ribas, A.; Barrado, D.; Merín, B.; Bouy, H.

    2016-07-01

    Context. Light curve modulations in the sample of Kepler planet candidates allows the disentangling of the nature of the transiting object by photometrically measuring its mass. This is possible by detecting the effects of the gravitational pull of the companion (ellipsoidal modulations) and in some cases, the photometric imprints of the Doppler effect when observing in a broad band (Doppler beaming). Aims: We aim to photometrically unveil the nature of some transiting objects showing clear light curve modulations in the phase-folded Kepler light curve. Methods: We selected a subsample among the large crop of Kepler objects of interest (KOIs) based on their chances to show detectable light curve modulations, i.e., close (a< 12 R⋆) and large (in terms of radius, according to their transit signal) candidates. We modeled their phase-folded light curves with consistent equations for the three effects, namely, reflection, ellipsoidal and beaming (known as REB modulations). Results: We provide detailed general equations for the fit of the REB modulations for the case of eccentric orbits. These equations are accurate to the photometric precisions achievable by current and forthcoming instruments and space missions. By using this mathematical apparatus, we find three close-in very low-mass companions (two of them in the brown dwarf mass domain) orbiting main-sequence stars (KOI-554, KOI-1074, and KOI-3728), and reject the planetary nature of the transiting objects (thus classifying them as false positives). In contrast, the detection of the REB modulations and transit/eclipse signal allows the measurement of their mass and radius that can provide important constraints for modeling their interiors since just a few cases of low-mass eclipsing binaries are known. Additionally, these new systems can help to constrain the similarities in the formation process of the more massive and close-in planets (hot Jupiters), brown dwarfs, and very low-mass companions.

  5. Presenting new exoplanet candidates for the CoRoT chromatic light curves

    NASA Astrophysics Data System (ADS)

    Boufleur, Rodrigo; Emilio, Marcelo; Andrade, Laerte; Janot-Pacheco, Eduardo; De La Reza, Ramiro

    2015-08-01

    One of the most promising topics of modern Astronomy is the discovery and characterization of extrasolar planets due to its importance for the comprehension of planetary formation and evolution. Missions like MOST (Microvariability and Oscillations of Stars Telescope) (Walker et al., 2003) and especially the satellites dedicated to the search for exoplanets CoRoT (Convection, Rotation and planetary Transits) (Baglin et al., 1998) and Kepler (Borucki et al., 2003) produced a great amount of data and together account for hundreds of new discoveries. An important source of error in the search for planets with light curves obtained from space observatories are the displacements occuring in the data due to external causes. This artificial charge generation phenomenon associated with the data is mainly caused by the impact of high energy particles onto the CCD (Pinheiro da Silva et al. 2008), although other sources of error, not as well known also need to be taken into account. So, an effective analysis of the light curves depends a lot on the mechanisms employed to deal with these phenomena. To perform our research, we developed and applied a different method to fix the light curves, the CDAM (Corot Detrend Algorithm Modified), inspired by the work of Mislis et al. (2012). The paradigms were obtained using the BLS method (Kovács et al., 2002). After a semiautomatic pre-analysis associated with a visual inspection of the planetary transits signatures, we obtained dozens of exoplanet candidates in very good agreement with the literature and also new unpublished cases. We present the study results and characterization of the new cases for the chromatic channel public light curves of the CoRoT satellite.

  6. TWO NEARBY SUB-EARTH-SIZED EXOPLANET CANDIDATES IN THE GJ 436 SYSTEM

    SciTech Connect

    Stevenson, Kevin B.; Harrington, Joseph; Lust, Nate B.; Blecic, Jasmina; Hardy, Ryan A.; Cubillos, Patricio; Campo, Christopher J.; Lewis, Nikole K.; Montagnier, Guillaume; Moses, Julianne I.; Visscher, Channon

    2012-08-10

    We report the detection of UCF-1.01, a strong exoplanet candidate with a radius 0.66 {+-} 0.04 times that of Earth (R{sub Circled-Plus }). This sub-Earth-sized planet transits the nearby M-dwarf star GJ 436 with a period of 1.365862 {+-} 8 Multiplication-Sign 10{sup -6} days. We also report evidence of a 0.65 {+-} 0.06 R{sub Circled-Plus} exoplanet candidate (labeled UCF-1.02) orbiting the same star with an undetermined period. Using the Spitzer Space Telescope, we measure the dimming of light as the planets pass in front of their parent star to assess their sizes and orbital parameters. If confirmed today, UCF-1.01 and UCF-1.02 would be designated GJ 436c and GJ 436d, respectively, and would be part of the first multiple-transiting-planet system outside of the Kepler field. Assuming Earth-like densities of 5.515 g cm{sup -3}, we predict both candidates to have similar masses ({approx}0.28 Earth-masses, M{sub Circled-Plus }, 2.6 Mars-masses) and surface gravities of {approx}0.65 g (where g is the gravity on Earth). UCF-1.01's equilibrium temperature (T{sub eq}, where emitted and absorbed radiation balance for an equivalent blackbody) is 860 K, making the planet unlikely to harbor life as on Earth. Its weak gravitational field and close proximity to its host star imply that UCF-1.01 is unlikely to have retained its original atmosphere; however, a transient atmosphere is possible if recent impacts or tidal heating were to supply volatiles to the surface. We also present additional observations of GJ 436b during secondary eclipse. The 3.6 {mu}m light curve shows indications of stellar activity, making a reliable secondary eclipse measurement impossible. A second non-detection at 4.5 {mu}m supports our previous work in which we find a methane-deficient and carbon monoxide-rich dayside atmosphere.

  7. Using Kepler Candidates to Examine the Properties of Habitable Zone Exoplanets

    NASA Astrophysics Data System (ADS)

    Adams, Arthur D.; Kane, Stephen R.

    2016-07-01

    An analysis of the currently known exoplanets in the habitable zones (HZs) of their host stars is of interest both in the wake of the NASA Kepler mission and with prospects for expanding the known planet population through future ground- and space-based projects. In this paper, we compare the empirical distributions of the properties of stellar systems with transiting planets to those with transiting HZ planets. This comparison includes two categories: confirmed/validated transiting planet systems, and Kepler planet and candidate planet systems. These two categories allow us to present quantitative analyses on both a conservative data set of known planets and a more optimistic and numerous sample of Kepler candidates. Both are subject to similar instrumental and detection biases, and are vetted against false positive detections. We examine whether the HZ distributions vary from the overall distributions in the Kepler sample with respect to planetary radius as well as stellar mass, effective temperature, and metallicity. We find that while the evidence is strongest in suggesting a difference between the size distributions of planets in the HZ and the overall size distribution, none of the statistical results provide strong empirical evidence for HZ planets or HZ planet-hosting stars being significantly different from the full Kepler sample with respect to these properties.

  8. The SOPHIE search for northern extrasolar planets. VIII. Follow-up of ELODIE candidates: long-period brown-dwarf companions

    NASA Astrophysics Data System (ADS)

    Bouchy, F.; Ségransan, D.; Díaz, R. F.; Forveille, T.; Boisse, I.; Arnold, L.; Astudillo-Defru, N.; Beuzit, J.-L.; Bonfils, X.; Borgniet, S.; Bourrier, V.; Courcol, B.; Delfosse, X.; Demangeon, O.; Delorme, P.; Ehrenreich, D.; Hébrard, G.; Lagrange, A.-M.; Mayor, M.; Montagnier, G.; Moutou, C.; Naef, D.; Pepe, F.; Perrier, C.; Queloz, D.; Rey, J.; Sahlmann, J.; Santerne, A.; Santos, N. C.; Sivan, J.-P.; Udry, S.; Wilson, P. A.

    2016-01-01

    Long-period brown dwarf companions detected in radial velocity surveys are important targets for direct imaging and astrometry to calibrate the mass-luminosity relation of substellar objects. Through a 20-yr radial velocity monitoring of solar-type stars that began with ELODIE and was extended with SOPHIE spectrographs, giant exoplanets and brown dwarfs with orbital periods longer than ten years are discovered. We report the detection of five new potential brown dwarfs with minimum masses between 32 and 83 MJup orbiting solar-type stars with periods longer than ten years. An upper mass limit of these companions is provided using astrometric Hipparcos data, high-angular resolution imaging made with PUEO, and a deep analysis of the cross-correlation function of the main stellar spectra to search for blend effects or faint secondary components. These objects double the number of known brown dwarf companions with orbital periods longer than ten years and reinforce the conclusion that the occurrence of such objects increases with orbital separation. With a projected separation larger than 100 mas, all these brown dwarf candidates are appropriate targets for high-contrast and high angular resolution imaging. Based on observations made with ELODIE and SOPHIE spectrographs on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS/AMU), France.Tables 5-9 (RV data) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/585/A46

  9. THE WIDEST-SEPARATION SUBSTELLAR COMPANION CANDIDATE TO A BINARY T TAURI STAR

    SciTech Connect

    Kuzuhara, M.; Tamura, M.; Kudo, T.; Kandori, R.; Ishii, M.; Nishiyama, S.

    2011-04-15

    The results of near-infrared imaging and spectroscopy of a substellar companion (SR12 C), with a possible planetary mass, of a binary T Tauri star (SR12 AB) in the {rho} Ophiuchi star-forming region are presented. The object is separated by {approx}8.''7, corresponding to {approx}1100 AU at 125 pc, and has an H-band brightness of 15.2 mag and infrared spectra suggesting a spectral type of M9.0 {+-} 0.5. It is confirmed that SR12 C is physically related to the {rho} Ophiuchi star-forming region from its common proper motion with SR12 AB and its youth is confirmed by a gravity-sensitive spectral feature. Furthermore, based on the number of known members of the {rho} Ophiuchi star-forming region in the area in which SR12 AB exists, the probability of a chance alignment is {approx}1% and it is therefore likely that SR12 C is physically associated with SR12 AB. The mass of SR12 C is estimated by comparing its estimated luminosity and assumed age with the theoretical age-luminosity relation. SR12 C is identified as an extremely low-mass (0.013 {+-} 0.007 M{sub sun}) object, but its separation from its parent star is the widest among planetary-mass companion (PMC) candidates imaged to date. In addition, SR12 C is the first PMC candidate directly imaged around a binary star. This discovery suggests that PMCs form via multiple star formation processes including disk gravitational instability and cloud core fragmentation.

  10. A PSF-based approach to Kepler/K2 data. II. Exoplanet candidates in Praesepe (M 44)

    NASA Astrophysics Data System (ADS)

    Libralato, M.; Nardiello, D.; Bedin, L. R.; Borsato, L.; Granata, V.; Malavolta, L.; Piotto, G.; Ochner, P.; Cunial, A.; Nascimbeni, V.

    2016-08-01

    In this work we keep pushing K2 data to a high photometric precision, close to that of the Kepler main mission, using a PSF-based, neighbour-subtraction technique, which also overcome the dilution effects in crowded environments. We analyse the open cluster M 44 (NGC 2632), observed during the K2 Campaign 5, and extract light curves of stars imaged on module 14, where most of the cluster lies. We present two candidate exoplanets hosted by cluster members and five by field stars. As a by-product of our investigation, we find 1680 eclipsing binaries and variable stars, 1071 of which are new discoveries. Among them, we report the presence of a heartbeat binary star. Together with this work, we release to the community a catalogue with the variable stars and the candidate exoplanets found, as well as all our raw and detrended light curves.

  11. DIRECT IMAGING CONFIRMATION AND CHARACTERIZATION OF A DUST-ENSHROUDED CANDIDATE EXOPLANET ORBITING FOMALHAUT

    SciTech Connect

    Currie, Thayne; Debes, John; Rodigas, Timothy J.; Burrows, Adam; Itoh, Yoichi; Fukagawa, Misato; Kenyon, Scott J.; Kuchner, Marc; Matsumura, Soko

    2012-12-01

    We present Subaru/IRCS J-band data for Fomalhaut and a (re)reduction of archival 2004-2006 HST/ACS data first presented by Kalas et al. We confirm the existence of a candidate exoplanet, Fomalhaut b, in both the 2004 and 2006 F606W data sets at a high signal-to-noise ratio. Additionally, we confirm the detection at F814W and present a new detection in F435W. Fomalhaut b's space motion may be consistent with it being in an apsidally aligned, non-debris ring-crossing orbit, although new astrometry is required for firmer conclusions. We cannot confirm that Fomalhaut b exhibits 0.7-0.8 mag variability cited as evidence for planet accretion or a semi-transient dust cloud. The new, combined optical spectral energy distribution and IR upper limits confirm that emission identifying Fomalhaut b originates from starlight scattered by small dust, but this dust is most likely associated with a massive body. The Subaru and IRAC/4.5 {mu}m upper limits imply M < 2 M{sub J} , still consistent with the range of Fomalhaut b masses needed to sculpt the disk. Fomalhaut b is very plausibly 'a planet identified from direct imaging' even if current images of it do not, strictly speaking, show thermal emission from a directly imaged planet.

  12. Exoplanets Galore!

    NASA Astrophysics Data System (ADS)

    2000-05-01

    : 800 x 483 pix - 184k] Caption : A representation of the sizes and shapes of the orbits of the eight new planetary and brown-dwarf candidates. The colours indicate the deduced minimum masses: about one Saturn mass or less (red); between 1 and 3 Jupiter masses (green); above 10 Jupiter masses (blue). The dashed line indicates the size of the Earth's orbit (radius 150 million km). The sizes and shapes of the orbits of the eight new planets and brown-dwarf candidates are illustrated in Photo 12/00 . More details about the individual objects are given below. A sub-saturnian planet in orbit around HD 168746 HD 168746 is a quiescent solar-like star of type G5 in the constellation Scutum (The Shield). It is slightly less massive than the Sun (0.92 solar mass) and is located at a distance of about 140 light-years. The visual magnitude is 7.9, i.e. about six times too faint to be seen with the unaided eye. The Swiss team found a new planet that orbits this star every 6.4 days, a fairly short period. The orbit is circular and the deduced minimum mass of the planet is only 80% of the mass of planet Saturn. This is only the third exoplanet detected so far with a possible sub-saturnian mass. Two planets slightly more massive than Saturn around HD 83443 and HD 108147 The planetary candidates detected around HD 83443 (visual magnitude 8.2; in the constellation Vela - the Sail) and HD 108147 (7.0 mag; Crux - the Cross) also have very low minimum masses, 0.35 and 0.34 times the mass of planet Jupiter, or 1.17 and 1.15 times that of Saturn, respectively. The companion of HD 83443 is particularly remarkable, not only by virtue of its low mass - it is also the exoplanet so far detected with the shortest period (2.986 days) and the smallest distance to the central star, only 5.7 million km (0.038 AU), i.e., 26 times smaller than the Sun-Earth distance. HD 83443 is of type K0V, it is at a distance of 141 light-years and is somewhat less massive than our Sun (0.8 solar mass). Most

  13. The Robo-AO KOI Survey: Laser Adaptive Optics Imaging of Every Kepler Exoplanet Candidate

    NASA Astrophysics Data System (ADS)

    Ziegler, Carl; Law, Nicholas M.; Baranec, Christoph; Morton, Tim; Riddle, Reed L.

    2016-01-01

    The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star (KOI) with laser adaptive optics imaging to hunt for blended nearby stars which may be physically associated companions. With the unparalleled efficiency provided by the first fully robotic adaptive optics system, we perform the critical search for nearby stars (0.15" to 4.0" separation with contrasts up to 6 magnitudes) that pollute the observed planetary transit signal, contributing to inaccurate planetary characteristics or astrophysical false positives. We present approximately 3300 high resolution observations of Kepler planetary hosts from 2012-2015, with ~500 observed nearby stars. We measure an overall nearby star probability rate of 16.2±0.8%. With this large dataset, we are uniquely able to explore broad correlations between multiple star systems and the properties of the planets which they host. We then use these clues for insight into the formation and evolution of these exotic systems. Several KOIs of particular interest will be discussed, including possible quadruple star systems hosting planets and updated properties for possible rocky planets orbiting in the habitable zone.

  14. Exoplanets Galore!

    NASA Astrophysics Data System (ADS)

    2000-05-01

    : 800 x 483 pix - 184k] Caption : A representation of the sizes and shapes of the orbits of the eight new planetary and brown-dwarf candidates. The colours indicate the deduced minimum masses: about one Saturn mass or less (red); between 1 and 3 Jupiter masses (green); above 10 Jupiter masses (blue). The dashed line indicates the size of the Earth's orbit (radius 150 million km). The sizes and shapes of the orbits of the eight new planets and brown-dwarf candidates are illustrated in Photo 12/00 . More details about the individual objects are given below. A sub-saturnian planet in orbit around HD 168746 HD 168746 is a quiescent solar-like star of type G5 in the constellation Scutum (The Shield). It is slightly less massive than the Sun (0.92 solar mass) and is located at a distance of about 140 light-years. The visual magnitude is 7.9, i.e. about six times too faint to be seen with the unaided eye. The Swiss team found a new planet that orbits this star every 6.4 days, a fairly short period. The orbit is circular and the deduced minimum mass of the planet is only 80% of the mass of planet Saturn. This is only the third exoplanet detected so far with a possible sub-saturnian mass. Two planets slightly more massive than Saturn around HD 83443 and HD 108147 The planetary candidates detected around HD 83443 (visual magnitude 8.2; in the constellation Vela - the Sail) and HD 108147 (7.0 mag; Crux - the Cross) also have very low minimum masses, 0.35 and 0.34 times the mass of planet Jupiter, or 1.17 and 1.15 times that of Saturn, respectively. The companion of HD 83443 is particularly remarkable, not only by virtue of its low mass - it is also the exoplanet so far detected with the shortest period (2.986 days) and the smallest distance to the central star, only 5.7 million km (0.038 AU), i.e., 26 times smaller than the Sun-Earth distance. HD 83443 is of type K0V, it is at a distance of 141 light-years and is somewhat less massive than our Sun (0.8 solar mass). Most

  15. Robust high-contrast companion detection from interferometric observations. The CANDID algorithm and an application to six binary Cepheids

    NASA Astrophysics Data System (ADS)

    Gallenne, A.; Mérand, A.; Kervella, P.; Monnier, J. D.; Schaefer, G. H.; Baron, F.; Breitfelder, J.; Le Bouquin, J. B.; Roettenbacher, R. M.; Gieren, W.; Pietrzyński, G.; McAlister, H.; ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Ridgway, S.; Kraus, S.

    2015-07-01

    Context. Long-baseline interferometry is an important technique to spatially resolve binary or multiple systems in close orbits. By combining several telescopes together and spectrally dispersing the light, it is possible to detect faint components around bright stars in a few hours of observations. Aims: We provide a rigorous and detailed method to search for high-contrast companions around stars, determine the detection level, and estimate the dynamic range from interferometric observations. Methods: We developed the code CANDID (Companion Analysis and Non-Detection in Interferometric Data), a set of Python tools that allows us to search systematically for point-source, high-contrast companions and estimate the detection limit using all interferometric observables, i.e., the squared visibilities, closure phases and bispectrum amplitudes. The search procedure is made on a N × N grid of fit, whose minimum needed resolution is estimated a posteriori. It includes a tool to estimate the detection level of the companion in the number of sigmas. The code CANDID also incorporates a robust method to set a 3σ detection limit on the flux ratio, which is based on an analytical injection of a fake companion at each point in the grid. Our injection method also allows us to analytically remove a detected component to 1) search for a second companion; and 2) set an unbiased detection limit. Results: We used CANDID to search for the companions around the binary Cepheids V1334 Cyg, AX Cir, RT Aur, AW Per, SU Cas, and T Vul. First, we showed that our previous discoveries of the components orbiting V1334 Cyg and AX Cir were detected at >25σ and >13σ, respectively. The astrometric positions and flux ratios provided by CANDID for these two stars are in good agreement with our previously published values. The companion around AW Per is detected at more than 15σ with a flux ratio of f = 1.22 ± 0.30%, and it is located at ρ = 32.16 ± 0.29 mas and PA = 67.1 ± 0.3°. We made a

  16. A Candidate Substellar Companion to CoD -33(deg) 7795 (TWA 5)

    NASA Astrophysics Data System (ADS)

    Lowrance, P. J.; McCarthy, C. M.; Becklin, E. E.; Zuckerman, B.; Schneider, G.; Webb, R. A.; Hines, D. C.; Low, F. J.; Rieke, M. J.; Thompson, R. I.; Smith, B. A.; Meier, R.; Terrile, R. J.; Kirkpatrick, J. D.; Koerner, D. W.

    1998-12-01

    We present the discovery of a candidate substellar object as part of the NICMOS Instrument Design Team's survey of young stars in the solar vicinity using the sensitivity and spatial resolution afforded by the NICMOS coronagraph on the Hubble Space Telescope. The H=12.1 mag object was discovered approximately 2'' from the TW Hydrae Association member CoD -33(deg) 7795 (TWA 5), and the infrared photometry implies a spectral type M8-M8.5, with a temperature of ~ 2650K. We estimate that the probability of a chance alignment with a background object of this nature is < 2 x 10(-5) , and therefore postulate the object (TWA 5B) is physically associated at a projected separation of 100 AU. Given the youth of the primary ( ~ 10 Myr), current brown dwarf cooling models predict a mass of approximately 20 Jupiter masses for the companion. This work is supported in part by NASA grant NAG 5-3042 to the University of Arizona NICMOS Instrument Design Team. This poster is based on observations obtained with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555.

  17. Direct Detection of Exoplanet Host Star Companion Gamma Cep B Using CIAO at the 8-m Telescope Subaru

    NASA Astrophysics Data System (ADS)

    Schmidt, T.

    2007-06-01

    Gamma Cep is known as a single-lined spectroscopic triple system at a distance of 13.8 pc, composed of a K1 III-IV primary star with V= 3.2 mag, a stellar-mass companion in a 66-67 year orbit (Torres 2007) and a sub-stellar companion with mass times sin(i) = 1.7 Jupiter masses, that is most likely a planet (Hatzes et al. 2003). We used the Adaptive Optics camera CIAO at the Japanese 8m telescope Subaru on Mauna Kea, Hawaii, with the semi-transparent coronograph to block most of the light from the primary to be able to image Gamma Cep B directly. We could clearly detect Gamma Cep B and used a photometric standard to determine the magnitude of B after PSF subtraction of K = 7.3 +- 0.2 mag. With the data the orbit of the two stars could be refined and thus we were able to determine the dynamical masses of these two stars in the Gamma Cep system, namely 1.40 +- 0.12 solar masses for the primary and 0.409 +-0.018 solar masses for the secondary (consistent with a M4 dwarf) as well as a new minimum mass of the sub-stellar companion of mass times sin(i) = 1.60 +- 0.13 Jupiter masses.

  18. A lucky imaging multiplicity study of exoplanet host stars - II

    NASA Astrophysics Data System (ADS)

    Ginski, C.; Mugrauer, M.; Seeliger, M.; Buder, S.; Errmann, R.; Avenhaus, H.; Mouillet, D.; Maire, A.-L.; Raetz, S.

    2016-04-01

    The vast majority of extrasolar planets are detected by indirect detection methods such as transit monitoring and radial velocity measurements. While these methods are very successful in detecting short-periodic planets, they are mostly blind to wide sub-stellar or even stellar companions on long orbits. In our study, we present high-resolution imaging observations of 60 exoplanet hosts carried out with the lucky imaging instrument AstraLux at the Calar Alto 2.2 m telescope as well as with the new Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) high-resolution adaptive optics imager at the ESO/VLT in the case of a known companion of specific interest. Our goal is to study the influence of stellar multiplicity on the planet formation process. We detected and confirmed four previously unknown stellar companions to the exoplanet hosts HD 197037, HD 217786, Kepler-21 and Kepler-68. In addition, we detected 11 new low-mass stellar companion candidates which must still be confirmed as bound companions. We also provide new astrometric and photometric data points for the recently discovered very close binary systems WASP-76 and HD 2638. Furthermore, we show for the first time that the previously detected stellar companion to the HD 185269 system is a very low mass binary. Finally, we provide precise constraints on additional companions for all observed stars in our sample.

  19. Candidate Very-Low-Mass Companions to Nearby Stars Found in the WISE Survey

    NASA Astrophysics Data System (ADS)

    Mennen, Anne; Dutcher, D.; Lepine, S.; Faherty, J.

    2012-01-01

    We report the identification in the Wide-Field Survey Explorer (WISE) preliminary release of 36 probable very-low-mass companions to nearby stars from the SUPERBLINK proper motion catalogue. We examined all WISE sources within one arcminute of a subset of 156,000 SUPERBLINK stars with proper motions between 0.040 and 0.015 seconds of arc per year, photometric distances within 100 parsecs, and positions at least seven degrees from the galactic plane. Using proper motions calculated by comparing the WISE positions of the sources to those of their counterparts in the 2MASS Catalogue, we identified all WISE sources sharing a common proper motion with the SUPERBLINK star. We eliminated all sources detected in the Palomar Sky Survey blue plates, keeping only those red enough to be low-mass or brown dwarf companions. We used WISE and 2MASS colors to select only objects consistent with being M, L, or T dwarfs, leaving only 36 likely companions. Based on their color and assumed distances, we estimate the 36 low-mass companions to be either late M or early L dwarfs. Follow-up spectroscopic observations will be required for confirmation and formal spectral classification of the companions. We acknowledge the American Museum of Natural History and the National Science Foundation for their support.

  20. AN ALMA DISK MASS FOR THE CANDIDATE PROTOPLANETARY COMPANION TO FW TAU

    SciTech Connect

    Kraus, Adam L.; Andrews, Sean M.; Bowler, Brendan P.; Herczeg, Gregory; Ireland, Michael J.; Liu, Michael C.; Metchev, Stanimir; Cruz, Kelle L.

    2015-01-01

    We present ALMA observations of the FW Tau system, a close binary pair of M5 stars with a wide-orbit (300 AU projected separation) substellar companion. The companion is extremely faint and red in the optical and near-infrared, but boasts a weak far-infrared excess and optical/near-infrared emission lines indicative of a primordial accretion disk of gas and dust. The component-resolved 1.3 mm continuum emission is found to be associated only with the companion, with a flux (1.78 ± 0.03 mJy) that indicates a dust mass of 1-2 M {sub ⊕}. While this mass reservoir is insufficient to form a giant planet, it is more than sufficient to produce an analog of the Kepler-42 exoplanetary system or the Galilean satellites. The mass and geometry of the disk-bearing FW Tau companion remains unclear. Near-infrared spectroscopy shows deep water bands that indicate a spectral type later than M5, but substantial veiling prevents a more accurate determination of the effective temperature (and hence mass). Both a disk-bearing ''planetary-mass'' companion seen in direct light or a brown dwarf tertiary viewed in light scattered by an edge-on disk or envelope remain possibilities.

  1. Discovery of a Companion Candidate in the HD 169142 Transition Disk and the Possibility of Multiple Planet Formation

    NASA Astrophysics Data System (ADS)

    Reggiani, Maddalena; Quanz, Sascha P.; Meyer, Michael R.; Pueyo, Laurent; Absil, Olivier; Amara, Adam; Anglada, Guillem; Avenhaus, Henning; Girard, Julien H.; Carrasco Gonzalez, Carlos; Graham, James; Mawet, Dimitri; Meru, Farzana; Milli, Julien; Osorio, Mayra; Wolff, Schuyler; Torrelles, Jose-Maria

    2014-09-01

    We present L'- and J-band high-contrast observations of HD 169142, obtained with the Very Large Telescope/NACO AGPM vector vortex coronagraph and the Gemini Planet Imager, respectively. A source located at 0.''156 ± 0.''032 north of the host star (P.A. = 7.°4 ± 11.°3) appears in the final reduced L' image. At the distance of the star (~145 pc), this angular separation corresponds to a physical separation of 22.7 ± 4.7 AU, locating the source within the recently resolved inner cavity of the transition disk. The source has a brightness of L' = 12.2 ± 0.5 mag, whereas it is not detected in the J band (J >13.8 mag). If its L' brightness arose solely from the photosphere of a companion and given the J - L' color constraints, it would correspond to a 28-32 M Jupiter object at the age of the star, according to the COND models. Ongoing accretion activity of the star suggests, however, that gas is left in the inner disk cavity from which the companion could also be accreting. In this case, the object could be lower in mass and its luminosity enhanced by the accretion process and by a circumplanetary disk. A lower-mass object is more consistent with the observed cavity width. Finally, the observations enable us to place an upper limit on the L'-band flux of a second companion candidate orbiting in the disk annular gap at ~50 AU, as suggested by millimeter observations. If the second companion is also confirmed, HD 169142 might be forming a planetary system, with at least two companions opening gaps and possibly interacting with each other.

  2. DISCOVERY OF A COMPANION CANDIDATE IN THE HD 169142 TRANSITION DISK AND THE POSSIBILITY OF MULTIPLE PLANET FORMATION

    SciTech Connect

    Reggiani, Maddalena; Quanz, Sascha P.; Meyer, Michael R.; Amara, Adam; Avenhaus, Henning; Meru, Farzana; Pueyo, Laurent; Wolff, Schuyler; Absil, Olivier; Anglada, Guillem; Osorio, Mayra; Gonzalez, Carlos Carrasco; Graham, James; Torrelles, Jose-Maria

    2014-09-01

    We present L'- and J-band high-contrast observations of HD 169142, obtained with the Very Large Telescope/NACO AGPM vector vortex coronagraph and the Gemini Planet Imager, respectively. A source located at 0.''156 ± 0.''032 north of the host star (P.A. = 7.°4 ± 11.°3) appears in the final reduced L' image. At the distance of the star (∼145 pc), this angular separation corresponds to a physical separation of 22.7 ± 4.7 AU, locating the source within the recently resolved inner cavity of the transition disk. The source has a brightness of L' = 12.2 ± 0.5 mag, whereas it is not detected in the J band (J >13.8 mag). If its L' brightness arose solely from the photosphere of a companion and given the J – L' color constraints, it would correspond to a 28-32 M {sub Jupiter} object at the age of the star, according to the COND models. Ongoing accretion activity of the star suggests, however, that gas is left in the inner disk cavity from which the companion could also be accreting. In this case, the object could be lower in mass and its luminosity enhanced by the accretion process and by a circumplanetary disk. A lower-mass object is more consistent with the observed cavity width. Finally, the observations enable us to place an upper limit on the L'-band flux of a second companion candidate orbiting in the disk annular gap at ∼50 AU, as suggested by millimeter observations. If the second companion is also confirmed, HD 169142 might be forming a planetary system, with at least two companions opening gaps and possibly interacting with each other.

  3. SPLAT: Using Spectral Indices to Identify and Characterize Ultracool Stars, Brown Dwarfs and Exoplanets in Deep Surveys and as Companions to Nearby Stars

    NASA Astrophysics Data System (ADS)

    Aganze, Christian; Burgasser, Adam J.; Martin, Eduardo; Konopacky, Quinn; Masters, Daniel C.

    2016-06-01

    The majority of ultracool dwarf stars and brown dwarfs currently known were identified in wide-field red optical and infrared surveys, enabling measures of the local, typically isolated, population in a relatively shallow (<100 pc radius) volume. Constraining the properties of the wider Galactic population (scale height, radial distribution, Population II sources), and close brown dwarf and exoplanet companions to nearby stars, requires specialized instrumentation, such as high-contrast, coronagraphic spectrometers (e.g., Gemini/GPI, VLT/Sphere, Project 1640); and deep spectral surveys (e.g., HST/WFC3 parallel fields, Euclid). We present a set of quantitative methodologies to identify and robustly characterize sources for these specific populations, based on templates and tools developed as part of the SpeX Prism Library Analysis Toolkit. In particular, we define and characterize specifically-tuned sets spectral indices that optimize selection of cool dwarfs and distinguish rare populations (subdwarfs, young planetary-mass objects) based on low-resolution, limited-wavelength-coverage spectral data; and present a template-matching classification method for these instruments. We apply these techniques to HST/WFC3 parallel fields data in the WISPS and HST-3D programs, where our spectral index set allows high completeness and low contamination for searches of late M, L and T dwarfs to distances out to ~3 kpc.The material presented here is based on work supported by the National Aeronautics and Space Administration under Grant No. NNX15AI75G.

  4. Search for Exoplanets around Young Stellar Objects by Direct Imaging

    NASA Astrophysics Data System (ADS)

    Uyama, Taichi; Tamura, Motohide; Hashimoto, Jun; Kuzuhara, Masayuki

    2015-12-01

    SEEDS project, exploring exoplanets and protoplanetary disks with Subaru/HiCIAO, has observed about 500 stars by Direct Imaging from 2009 Dec to 2015 Apr. Among these targets we explore around Young Stellar Objects (YSOs; age ≦ 10Myr) which often have the protoplanetary disks where planets are being formed in order to detect young exoplanets and to understand the formation process. We analyzed 66 YSOs (about 100 data in total) with LOCI data reduction. We will report the results (companion candidates and detection limit) of our exploration.

  5. Exoplanet habitability.

    PubMed

    Seager, Sara

    2013-05-01

    The search for exoplanets includes the promise to eventually find and identify habitable worlds. The thousands of known exoplanets and planet candidates are extremely diverse in terms of their masses or sizes, orbits, and host star type. The diversity extends to new kinds of planets, which are very common yet have no solar system counterparts. Even with the requirement that a planet's surface temperature must be compatible with liquid water (because all life on Earth requires liquid water), a new emerging view is that planets very different from Earth may have the right conditions for life. The broadened possibilities will increase the future chances of discovering an inhabited world. PMID:23641111

  6. The EXOTIME Monitoring Program Discovers Substellar Companion Candidates around the Rapidly Pulsating Subdwarf B Stars V1636 Ori and DW Lyn

    NASA Astrophysics Data System (ADS)

    Schuh, S.; Silvotti, R.; Lutz, R.; Kim, S.-L.; Exotime Collaboration

    2014-04-01

    The EXOTIME monitoring program has discovered sub-stellar companion candidates around the rapidly pulsating subdwarf B stars V1636 Ori and DW Lyn using the timing method. Here we motivate our continuing search, and refer to descriptions of the photometric data collected, the data analysis and the characteristics of the O-C diagrams obtained. We also discuss our on-going efforts to consolidate the candidate discoveries with additional simulations and confirm them with independent methods.

  7. Validation and Characterization of K2 Exoplanet Candidates with NIR Transit Photometry from the 4m Mayall and 3.5m WIYN Telescopes

    NASA Astrophysics Data System (ADS)

    Colón, Knicole D.; Barclay, Thomas

    2016-06-01

    We present new ground-based near-infrared (NIR) transit photometry of exoplanet candidates recently discovered by the NASA K2 mission. These observations support the confirmation and characterization of these newly discovered transiting exoplanets, many which are in the super-Earth to mini-Neptune size regime and orbit cool, nearby stars. We specifically used NEWFIRM on the 4m Mayall telescope and WHIRC on the 3.5m WIYN telescope, both located at Kitt Peak National Observatory, to observe several K2 exoplanet candidates in transit. To our knowledge, these facilities have not been tested for such high-precision differential transit photometry before. Follow-up transit photometry with the high spatial resolution NIR cameras installed on the Mayall and WIYN telescopes allows us to confirm the transit host, which is critical given the large pixel scale of the Kepler spacecraft. NIR transit photometry in particular allows us to verify that the transit is achromatic, after comparing the NIR transit depth to the transit depth measured in the optical from K2. Finding a different depth in different bandpasses indicates that the candidate is instead an eclipsing binary false positive. Furthermore, NIR transit photometry provides robust constraints on the measured planet radius, since stellar limb darkening is minimized in the NIR. Finally, the high-precision and high-cadence photometry we achieve allows us to refine the transit ephemeris, which is crucial for future follow-up efforts with other facilities like NASA's James Webb Space Telescope. The capabilities of these ground-based facilities therefore approach those of space telescopes, since we are able use these ground-based observatories to refine transit parameters and constrain properties for the exoplanets that K2 is discovering, all the way down to super-Earth-size planets.

  8. SOPHIE velocimetry of Kepler transit candidates. XVII. The physical properties of giant exoplanets within 400 days of period

    NASA Astrophysics Data System (ADS)

    Santerne, A.; Moutou, C.; Tsantaki, M.; Bouchy, F.; Hébrard, G.; Adibekyan, V.; Almenara, J.-M.; Amard, L.; Barros, S. C. C.; Boisse, I.; Bonomo, A. S.; Bruno, G.; Courcol, B.; Deleuil, M.; Demangeon, O.; Díaz, R. F.; Guillot, T.; Havel, M.; Montagnier, G.; Rajpurohit, A. S.; Rey, J.; Santos, N. C.

    2016-03-01

    While giant extrasolar planets have been studied for more than two decades now, there are still some open questions as to their dominant formation and migration processes, as well as to their atmospheric evolution in different stellar environments. In this paper, we study a sample of giant transiting exoplanets detected by the Kepler telescope with orbital periods up to 400 days. We first defined a sample of 129 giant-planet candidates that we followed up with the SOPHIE spectrograph (OHP, France) in a 6-year radial velocity campaign. This allowed us to unveil the nature of these candidates and to measure a false-positive rate of 54.6 ± 6.5% for giant-planet candidates orbiting within 400 days of period. Based on a sample of confirmed or likely planets, we then derived the occurrence rates of giant planets in different ranges of orbital periods. The overall occurrence rate of giant planets within 400 days is 4.6 ± 0.6%. We recovered, for the first time in the Kepler data, the different populations of giant planets reported by radial velocity surveys. Comparing these rates with other yields, we find that the occurrence rate of giant planets is lower only for hot Jupiters but not for the longer-period planets. We also derive a first measurement of the occurrence rate of brown dwarfs in the brown-dwarf desert with a value of 0.29 ± 0.17%. Finally, we discuss the physical properties of the giant planets in our sample. We confirm that giant planets receiving moderate irradiation are not inflated, but we find that they are on average smaller than predicted by formation and evolution models. In this regime of low-irradiated giant planets, we find a possible correlation between their bulk density and the iron abundance of the host star, which needs more detections to be confirmed. Based on observations made with SOPHIE on the 1.93 m telescope at Observatoire de Haute-Provence (CNRS), France.RV data (Appendices C and D) are only available at the CDS via anonymous ftp to

  9. KNOW THE STAR, KNOW THE PLANET. I. ADAPTIVE OPTICS OF EXOPLANET HOST STARS

    SciTech Connect

    Roberts, Lewis C.; Turner, Nils H.; Ten Brummelaar, Theo A.; Mason, Brian D.; Hartkopf, William I. E-mail: nils@chara-array.org E-mail: bdm@usno.navy.mil

    2011-11-15

    The results of an adaptive optics survey of exoplanet host stars for stellar companions are presented. We used the Advanced Electro-Optical System telescope and its adaptive optics system to collect deep images of the stars in the I band. Sixty-two exoplanet host stars were observed and fifteen multiple star systems were resolved. Of these eight are known multiples, while seven are new candidate binaries. For all binaries, we measured the relative astrometry of the pair and the differential magnitude in the I band. We improved the orbits of HD 19994 and {tau} Boo. These observations will provide improved statistics on the duplicity of exoplanet host stars and provide an increased understanding of the dynamics of known binary star exoplanet hosts.

  10. A Discovery of a Candidate Companion to a Transiting System KOI-94: A Direct Imaging Study for a Possibility of a False Positive

    NASA Technical Reports Server (NTRS)

    Takahashi, Yasuhiro; Narita, Norio; Hirano, Teruyuki; Kuzuhara, Masayuki; Tamura, Motohide; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Hashimoto, Jun; Sato, Bun'ei; Abe, Lyu; Brandner, Wolfgang; Brandt, Timothy D.; Carson, Joseph C.; Currie, Thayne; Egner, Sebastian; Feldt, Markus; Goto, Miwa; Grady, Carol A.; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S.; Henning, Thomas; Hodapp, Klaus W.; McElwain, Michael W.

    2013-01-01

    We report a discovery of a companion candidate around one of Kepler Objects of Interest (KOIs), KOI-94, and results of our quantitative investigation of the possibility that planetary candidates around KOI-94 are false positives. KOI-94 has a planetary system in which four planetary detections have been reported by Kepler, suggesting that this system is intriguing to study the dynamical evolutions of planets. However, while two of those detections (KOI-94.01 and 03) have been made robust by previous observations, the others (KOI-94.02 and 04) are marginal detections, for which future confirmations with various techniques are required. We have conducted high-contrast direct imaging observations with Subaru/HiCIAO in H band and detected a faint object located at a separation of approximately 0.6 sec from KOI-94. The object has a contrast of approximately 1 × 10(exp -3) in H band, and corresponds to an M type star on the assumption that the object is at the same distance of KOI-94. Based on our analysis, KOI-94.02 is likely to be a real planet because of its transit depth, while KOI-94.04 can be a false positive due to the companion candidate. The success in detecting the companion candidate suggests that high-contrast direct imaging observations are important keys to examine false positives of KOIs. On the other hand, our transit light curve reanalyses lead to a better period estimate of KOI-94.04 than that on the KOI catalogue and show that the planetary candidate has the same limb darkening parameter value as the other planetary candidates in the KOI-94 system, suggesting that KOI-94.04 is also a real planet in the system.

  11. Detecting the Companions and Ellipsoidal Variations of RS CVn Primaries. II. o Draconis, a Candidate for Recent Low-mass Companion Ingestion

    NASA Astrophysics Data System (ADS)

    Roettenbacher, Rachael M.; Monnier, John D.; Fekel, Francis C.; Henry, Gregory W.; Korhonen, Heidi; Latham, David W.; Muterspaugh, Matthew W.; Williamson, Michael H.; Baron, Fabien; ten Brummelaar, Theo A.; Che, Xiao; Harmon, Robert O.; Schaefer, Gail H.; Scott, Nicholas J.; Sturmann, Judit; Sturmann, Laszlo; Turner, Nils H.

    2015-08-01

    To measure the stellar and orbital properties of the metal-poor RS CVn binary o Draconis (o Dra), we directly detect the companion using interferometric observations obtained with the Michigan InfraRed Combiner at Georgia State University's Center for High Angular Resolution Astronomy (CHARA) Array. The H-band flux ratio between the primary and secondary stars is the highest confirmed flux ratio (370 ± 40) observed with long-baseline optical interferometry. These detections are combined with radial velocity data of both the primary and secondary stars, including new data obtained with the Tillinghast Reflector Echelle Spectrograph on the Tillinghast Reflector at the Fred Lawrence Whipple Observatory and the 2 m Tennessee State University Automated Spectroscopic Telescope at Fairborn Observatory. We determine an orbit from which we find model-independent masses and ages of the components ({M}A=1.35+/- 0.05 {M}⊙ , {M}B=0.99+/- 0.02 {M}⊙ , system age = 3.0\\mp 0.5 Gyr). An average of a 23-year light curve of o Dra from the Tennessee State University Automated Photometric Telescope folded over the orbital period newly reveals eclipses and the quasi-sinusoidal signature of ellipsoidal variations. The modeled light curve for our system's stellar and orbital parameters confirm these ellipsoidal variations due to the primary star partially filling its Roche lobe potential, suggesting most of the photometric variations are not due to stellar activity (starspots). Measuring gravity darkening from the average light curve gives a best-fit of β =0.07+/- 0.03, a value consistent with conventional theory for convective envelope stars. The primary star also exhibits an anomalously short rotation period, which, when taken with other system parameters, suggests the star likely engulfed a low-mass companion that had recently spun-up the star.

  12. TWO PLANETARY COMPANIONS AROUND THE K7 DWARF GJ 221: A HOT SUPER-EARTH AND A CANDIDATE IN THE SUB-SATURN DESERT RANGE

    SciTech Connect

    Arriagada, Pamela; Minniti, Dante; Anglada-Escude, Guillem; Butler, R. Paul; Crane, Jeffrey D.; Shectman, Stephen A.; Thompson, Ian; Wende, Sebastian

    2013-07-01

    We report two low-mass companions orbiting the nearby K7 dwarf GJ 221 that have emerged from reanalyzing 4.4 yr of publicly available HARPS spectra complemented with 2 years of high-precision Doppler measurements with Magellan/PFS. The HARPS measurements alone contain the clear signal of a low-mass companion with a period of 125 days and a minimum mass of 53.2 M{sub Circled-Plus} (GJ 221b), falling in a mass range where very few planet candidates have been found (sub-Saturn desert). The addition of 17 PFS observations allows the confident detection of a second low-mass companion (6.5 M{sub Circled-Plus }) in a hot orbit (3.87 day period, GJ 221c). Spectroscopic and photometric calibrations suggest that GJ 221 is slightly depleted ([Fe/H] {approx} -0.1) compared to the Sun, so the presence of two low-mass companions in the system confirms the trend that slightly reduced stellar metallicity does not prevent the formation of planets in the super-Earth to sub-Saturn mass regime.

  13. Statistical properties of exoplanets

    NASA Astrophysics Data System (ADS)

    Udry, Stéphane

    Since the detection a decade ago of the planetary companion of 51 Peg, more than 165 extrasolar planets have been unveiled by radial-velocity measurements. They present a wide variety of characteristics such as large masses with small orbital separations, high eccentricities, period resonances in multi-planet systems, etc. Meaningful features of the statistical distributions of the orbital parameters or parent stellar properties have emerged. We discuss them in the context of the constraints they provide for planet-formation models and in comparison to Neptune-mass planets in short-period orbits recently detected by radial-velocity surveys, thanks to new instrumental developments and adequate observing strategy. We expect continued improvement in velocity precision and anticipate the detection of Neptune-mass planets in longer-period orbits and even lower-mass planets in short-period orbits, giving us new information on the mass distribution function of exoplanets. Finally, the role of radial-velocity follow-up measurements of transit candidates is emphasized.

  14. SOPHIE velocimetry of Kepler transit candidates. X. KOI-142 c: first radial velocity confirmation of a non-transiting exoplanet discovered by transit timing

    NASA Astrophysics Data System (ADS)

    Barros, S. C. C.; Díaz, R. F.; Santerne, A.; Bruno, G.; Deleuil, M.; Almenara, J.-M.; Bonomo, A. S.; Bouchy, F.; Damiani, C.; Hébrard, G.; Montagnier, G.; Moutou, C.

    2014-01-01

    The exoplanet KOI-142b (Kepler-88b) shows transit timing variations (TTVs) with a semi-amplitude of ~12 h, which earned it the nickname "king of transit variations". Only the transit of planet b was detected in the Kepler data with an orbital period of ~10.92 days and a radius of ~0.36 RJup. The TTVs together with the transit duration variations of KOI-142b were analysed recently, finding a unique solution for a companion-perturbing planet. An outer non-transiting companion was predicted, KOI-142c, with a mass of 0.626 ± 0.03 MJup and a period of 22.3397-0.0018+0.0021 days, which is close to the 2:1 mean-motion resonance with the inner transiting planet. We report an independent confirmation of KOI-142c using radial velocity observations with the SOPHIE spectrograph at the Observatoire de Haute-Provence. We derive an orbital period of 22.10 ± 0.25 days and a minimum planetary mass of 0.760.16+0.32 MJup, both in good agreement with the predictions by previous transit timing analysis. Therefore, this is the first radial velocity confirmation of a non-transiting planet discovered with TTVs, providing an independent validation of the TTVs technique. Based on observations collected with the NASA Kepler satellite and with the SOPHIE spectrograph on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS), France.Tables 2 and 3 are available in electronic form at http://www.aanda.org

  15. Direct detection of exoplanet host star companion γ Cep B and revised masses for both stars and the sub-stellar object

    NASA Astrophysics Data System (ADS)

    Neuhäuser, R.; Mugrauer, M.; Fukagawa, M.; Torres, G.; Schmidt, T.

    2007-02-01

    Context: The star γ Cep is known as a single-lined spectroscopic triple system at a distance of 13.8 pc, composed of a K1 III-IV primary star with V = 3.2 mag, a stellar-mass companion in a 66-67 year orbit (Torres 2007, ApJ, 654, 1095), and a substellar companion with Mp sin i = 1.7 M_Jup that is most likely a planet (Hatzes et al. 2003, ApJ, 599, 1383). Aims: We aim to obtain a first direct detection of the stellar companion, to determine its current orbital position (for comparison with the spectroscopic and astrometric data), its infrared magnitude and, hence, mass. Methods: We use the Adaptive Optics camera CIAO at the Japanese 8 m telescope Subaru on Mauna Kea, Hawaii, with the semi-transparent coronograph to block most of the light from the bright primary γ Cep A, and to detect at the same time the faint companion B. In addition, we also used the IR camera Ω Cass at the Calar Alto 3.5 m telescope, Spain, to image γ Cep A and B by adding up many very short integrations (without AO). Results: γ Cep B is clearly detected on our CIAO and Ω Cass images. We use a photometric standard star to determine the magnitude of B after PSF subtraction in the Subaru image, and the magnitude difference between A and B in the Calar Alto images, and find an average value of K = 7.3 ± 0.2 mag. The separations and position angles between A and B are measured on 15 July 2006 and 11 and 12 Sept. 2006, B is slightly south of west of A. Conclusions: .By combining the radial velocity, astrometric, and imaging data, we have refined the binary orbit and determined the dynamical masses of the two stars in the γ Cep system, namely 1.40 ± 0.12 M⊙ for the primary and 0.409 ± 0.018 M⊙ for the secondary (consistent with being a M4 dwarf). We also determine the minimum mass of the sub-stellar companion to be Mp sin i = 1.60 ± 0.13 M_Jup.

  16. DIRECT IMAGING AND SPECTROSCOPY OF A CANDIDATE COMPANION BELOW/NEAR THE DEUTERIUM-BURNING LIMIT IN THE YOUNG BINARY STAR SYSTEM, ROXs 42B

    SciTech Connect

    Currie, Thayne; Daemgen, Sebastian; Jayawardhana, Ray; Debes, John; Lafreniere, David; Itoh, Yoichi; Ratzka, Thorsten; Correia, Serge

    2014-01-10

    We present near-infrared high-contrast imaging photometry and integral field spectroscopy of ROXs 42B, a binary M0 member of the 1-3 Myr old ρ Ophiuchus star-forming region, from data collected over 7 years. Each data set reveals a faint companion—ROXs 42Bb—located ∼1.''16 (r {sub proj} ≈ 150 AU) from the primaries at a position angle consistent with a point source identified earlier by Ratzka et al.. ROXs 42Bb's astrometry is inconsistent with a background star but consistent with a bound companion, possibly one with detected orbital motion. The most recent data set reveals a second candidate companion at ∼0.''5 of roughly equal brightness, though preliminary analysis indicates it is a background object. ROXs 42Bb's H and K{sub s} band photometry is similar to dusty/cloudy young, low-mass late M/early L dwarfs. K band VLT/SINFONI spectroscopy shows ROXs 42Bb to be a cool substellar object (M8-L0; T {sub eff} ≈ 1800-2600 K), not a background dwarf star, with a spectral shape indicative of young, low surface gravity planet-mass companions. We estimate ROXs 42Bb's mass to be 6-15 M{sub J} , either below the deuterium-burning limit and thus planet mass or straddling the deuterium-burning limit nominally separating planet-mass companions from other substellar objects. Given ROXs 42b's projected separation and mass with respect to the primaries, it may represent the lowest mass objects formed like binary stars or a class of planet-mass objects formed by protostellar disk fragmentation/disk instability, the latter slightly blurring the distinction between non-deuterium-burning planets like HR 8799 bcde and low-mass, deuterium-burning brown dwarfs.

  17. Transiting exoplanets from the CoRoT space mission Resolving the nature of transit candidates for the LRa03 and SRa03 fields

    NASA Astrophysics Data System (ADS)

    Cavarroc, C.; Moutou, C.; Gandolfi, D.; Tingley, B.; Ollivier, M.; Aigrain, S.; Alonso, R.; Almenara, J.-M.; Auvergne, M.; Baglin, A.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Cabrera, J.; Carpano, S.; Carone, L.; Cochran, W. D.; Csizmadia, S.; Deeg, H. J.; Deleuil, M.; Díaz, R. F.; Dvorak, R.; Endl, M.; Erikson, A.; Fridlund, M.; Gillon, M.; Guenther, E. W.; Guillot, T.; Hatzes, A.; Hébrard, G.; Jorda, L.; Léger, A.; Lammer, H.; Lev, T.-O.; Lovis, C.; MacQueen, P. J.; Mazeh, T.; Ofir, A.; Parviainen, H.; Pasternacki, T.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Samuel, B.; Santerne, A.; Schneider, J.; Weingrill, J.; Wuchterl, G.

    2012-02-01

    CoRoT is a space telescope which aims at studying internal structure of stars and detecting extrasolar planets. We present here a list of transits detected in the light curves of stars observed by CoRoT in two fields in the anti-center direction: the LRa03 one observed during 148 days from 3 October 2009 to 1 March 2010 followed by the SRa03 one from the 5 March 2010 to the 29 March 2010 during 25 days. 5329 light curves for the LRa03 field and 4169 for the SRa03 field were analyzed by the detection team of CoRoT. Then some of the selected exoplanetary candidates have been followed up from the ground. In the LRa03 field, 19 exoplanet candidates have been found, 8 remain unsolved. No secured planet has been found yet. In the SRa03 field, there were 11 exoplanetary candidates among which 6 cases remain unsolved and 3 planets have been found: CoRoT-18b, CoRoT-19b, CoRoT-20b.

  18. Dynamical Masses of Young M Dwarfs: Masses and Orbital Parameters of GJ 3305 AB, the Wide Binary Companion to the Imaged Exoplanet Host 51 Eri

    NASA Astrophysics Data System (ADS)

    Montet, Benjamin T.; Bowler, Brendan P.; Shkolnik, Evgenya L.; Deck, Katherine M.; Wang, Ji; Horch, Elliott P.; Liu, Michael C.; Hillenbrand, Lynne A.; Kraus, Adam L.; Charbonneau, David

    2015-11-01

    We combine new high resolution imaging and spectroscopy from Keck/NIRC2, Discovery Channel Telescope/DSSI, and Keck/HIRES with published astrometry and radial velocities to measure individual masses and orbital elements of the GJ 3305 AB system, a young (˜20 Myr) M+M binary (unresolved spectral type M0) member of the β Pictoris moving group comoving with the imaged exoplanet host 51 Eri. We measure a total system mass of 1.11 ± 0.04 {M}⊙ , a period of 29.03 ± 0.50 year, a semimajor axis of 9.78 ± 0.14 AU, and an eccentricity of 0.19 ± 0.02. The primary component has a dynamical mass of 0.67 ± 0.05 {M}⊙ and the secondary has a mass of 0.44 ± 0.05 {M}⊙ . The recently updated BHAC15 models are consistent with the masses of both stars to within 1.5σ . Given the observed masses the models predict an age of the GJ 3305 AB system of 37 ± 9 Myr. Based on the observed system architecture and our dynamical mass measurement, it is unlikely that the orbit of 51 Eri b has been significantly altered by the Kozai-Lidov mechanism. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  19. Dynamical Masses of Young M Dwarfs: Masses and Orbital Parameters of GJ 3305 AB, the Wide Binary Companion to the Imaged Exoplanet Host 51 Eri

    NASA Astrophysics Data System (ADS)

    Montet, Benjamin T.; Bowler, Brendan P.; Shkolnik, Evgenya L.; Deck, Katherine M.; Wang, Ji; Horch, Elliott P.; Liu, Michael C.; Hillenbrand, Lynne A.; Kraus, Adam L.; Charbonneau, David

    2015-11-01

    We combine new high resolution imaging and spectroscopy from Keck/NIRC2, Discovery Channel Telescope/DSSI, and Keck/HIRES with published astrometry and radial velocities to measure individual masses and orbital elements of the GJ 3305 AB system, a young (∼20 Myr) M+M binary (unresolved spectral type M0) member of the β Pictoris moving group comoving with the imaged exoplanet host 51 Eri. We measure a total system mass of 1.11 ± 0.04 {M}ȯ , a period of 29.03 ± 0.50 year, a semimajor axis of 9.78 ± 0.14 AU, and an eccentricity of 0.19 ± 0.02. The primary component has a dynamical mass of 0.67 ± 0.05 {M}ȯ and the secondary has a mass of 0.44 ± 0.05 {M}ȯ . The recently updated BHAC15 models are consistent with the masses of both stars to within 1.5σ . Given the observed masses the models predict an age of the GJ 3305 AB system of 37 ± 9 Myr. Based on the observed system architecture and our dynamical mass measurement, it is unlikely that the orbit of 51 Eri b has been significantly altered by the Kozai–Lidov mechanism. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  20. Synthesizing Exoplanet Demographics: A Single Population of Long-period Planetary Companions to M Dwarfs Consistent with Microlensing, Radial Velocity, and Direct Imaging Surveys

    NASA Astrophysics Data System (ADS)

    Clanton, Christian; Gaudi, B. Scott

    2016-03-01

    We present the first study to synthesize results from five different exoplanet surveys using three independent detection methods: microlensing, radial velocity, and direct imaging. The constraints derived herein represent the most comprehensive picture of the demographics of large-separation (≳2 AU) planets orbiting the most common stars in our Galaxy that has been constructed to date. We assume a simple, joint power-law planet distribution function of the form {d}2{N}{{pl}}/(d{log} {m}p d{log} a)={ A }{({m}p/{M}{{Sat}})}α {(a/2.5{{AU}})}β with an outer cutoff radius of the separation distribution function of aout. Generating populations of planets from these models and mapping them into the relevant observables for each survey, we use actual or estimated detection sensitivities to determine the expected observations for each survey. Comparing with the reported results, we derive constraints on the parameters \\{α ,β ,{ A },{a}{{out}}\\} that describe a single population of planets that is simultaneously consistent with the results of microlensing, radial velocity, and direct imaging surveys. We find median and 68% confindence intervals of α =-{0.86}-0.19+0.21 (-{0.85}-0.19+0.21), β ={1.1}-1.4+1.9 ({1.1}-1.3+1.9), { A }={0.21}-0.15+0.20 {{dex}}-2 ({0.21}-0.15+0.20 {{dex}}-2), and {a}{{out}}={10}-4.7+26 AU ({12}-6.2+50 AU) assuming “hot-start” (“cold-start”) planet evolutionary models. These values are consistent with all current knowledge of planets on orbits beyond ∼2 AU around single M dwarfs.

  1. The search for substellar companions to subdwarf B stars in connection with evolutionary aspects

    NASA Astrophysics Data System (ADS)

    Lutz, Ronny

    2011-09-01

    The formation and evolution of single hot subdwarf B stars is not entirely understood. Enhanced mass loss during the red giant phase is a prerequisite to explain the very existence of these stars, yet its cause is a matter of debate. One hypothesis predicts that substellar companions like brown dwarfs and exoplanets may be able to have a decisive influence on the formation and evolution of single subdwarf B stars. This dissertation investigates two pulsating subdwarf B stars with the goal to search for substellar companions and to directly measure the evolutionary timescales. The long-term multi-site photometric data were taken in the framework of the EXOTIME (EXOplanet search with the TIming MEthod) program and cover a baseline of several tens of months. The secular behaviour of several pulsations in each target is investigated by applying a timing method and constructing O-C (Observed minus Calculated) diagrams. The analysis results in the fundamental insight that both targets are in a phase of global expansion, that their pulsation periods increase on a timescale of several million years and that the two target stars have probably already undergone core Helium exhaustion. Furthermore, the O-C diagrams show evidence for the presence of substellar companions. The star HS0444+0458 has a brown dwarf companion candidate of roughly 31 Jupiter masses in an orbit of 0.27 astronomical units. An exoplanet candidate of 5.6 Jupiter masses is found to orbit its host star HS0702+6043 at a distance of 1.15 astronomical units. These detections provide a direct support for a formation channel of single subdwarf B stars that includes substellar companions as the mass loss trigger.

  2. The NASA Exoplanet Archive

    NASA Astrophysics Data System (ADS)

    Ramirez, Solange; Akeson, R. L.; Ciardi, D.; Kane, S. R.; Plavchan, P.; von Braun, K.; NASA Exoplanet Archive Team

    2013-01-01

    The NASA Exoplanet Archive is an online service that compiles and correlates astronomical information on extra solar planets and their host stars. The data in the archive include exoplanet parameters (such as orbits, masses, and radii), associated data (such as published radial velocity curves, photometric light curves, images, and spectra), and stellar parameters (such as magnitudes, positions, and temperatures). All the archived data are linked to the original literature reference.The archive provides tools to work with these data, including interactive tables (with plotting capabilities), interactive light curve viewer, periodogram service, transit and ephemeris calculator, and application program interface.The NASA Exoplanet Archive is the U.S. portal to the public CoRoT mission data for both the Exoplanet and Asteroseismology data sets. The NASA Exoplanet Archive also serves data related to Kepler Objects of Interest (Planet Candidates and the Kepler False Positives, KOI) in an integrated and interactive table containing stellar and transit parameters. In support of the Kepler Extended Mission, the NASA Exoplanet Archive will host transit modeling parameters, centroid results, several statistical values, and summary and detailed reports for all transit-like events identified by the Kepler Pipeline. To access this information visit us at: http://exoplanetarchive.ipac.caltech.edu

  3. Wide cool and ultracool companions to nearby stars from Pan-STARRS 1

    SciTech Connect

    Deacon, Niall R.; Liu, Michael C.; Magnier, Eugene A.; Aller, Kimberly M.; Best, William M. J.; Bowler, Brendan P.; Burgett, William S.; Chambers, Kenneth C.; Flewelling, H.; Kaiser, Nick; Kudritzki, Rolf-Peter; Morgan, Jeff S.; Tonry, John L.; Dupuy, Trent; Mann, Andrew W.; Redstone, Joshua A.; Draper, Peter W.; Metcalfe, Nigel; Hodapp, Klaus W.; Price, Paul A.; and others

    2014-09-10

    We present the discovery of 57 wide (>5'') separation, low-mass (stellar and substellar) companions to stars in the solar neighborhood identified from Pan-STARRS 1 (PS1) data and the spectral classification of 31 previously known companions. Our companions represent a selective subsample of promising candidates and span a range in spectral type of K7-L9 with the addition of one DA white dwarf. These were identified primarily from a dedicated common proper motion search around nearby stars, along with a few as serendipitous discoveries from our Pan-STARRS 1 brown dwarf search. Our discoveries include 23 new L dwarf companions and one known L dwarf not previously identified as a companion. The primary stars around which we searched for companions come from a list of bright stars with well-measured parallaxes and large proper motions from the Hipparcos catalog (8583 stars, mostly A-K dwarfs) and fainter stars from other proper motion catalogs (79170 stars, mostly M dwarfs). We examine the likelihood that our companions are chance alignments between unrelated stars and conclude that this is unlikely for the majority of the objects that we have followed-up spectroscopically. We also examine the entire population of ultracool (>M7) dwarf companions and conclude that while some are loosely bound, most are unlikely to be disrupted over the course of ∼10 Gyr. Our search increases the number of ultracool M dwarf companions wider than 300 AU by 88% and increases the number of L dwarf companions in the same separation range by 82%. Finally, we resolve our new L dwarf companion to HIP 6407 into a tight (0.''13, 7.4 AU) L1+T3 binary, making the system a hierarchical triple. Our search for these key benchmarks against which brown dwarf and exoplanet atmosphere models are tested has yielded the largest number of discoveries to date.

  4. Wide Cool and Ultracool Companions to Nearby Stars from Pan-STARRS 1

    NASA Astrophysics Data System (ADS)

    Deacon, Niall R.; Liu, Michael C.; Magnier, Eugene A.; Aller, Kimberly M.; Best, William M. J.; Dupuy, Trent; Bowler, Brendan P.; Mann, Andrew W.; Redstone, Joshua A.; Burgett, William S.; Chambers, Kenneth C.; Draper, Peter W.; Flewelling, H.; Hodapp, Klaus W.; Kaiser, Nick; Kudritzki, Rolf-Peter; Morgan, Jeff S.; Metcalfe, Nigel; Price, Paul A.; Tonry, John L.; Wainscoat, Richard J.

    2014-09-01

    We present the discovery of 57 wide (>5'') separation, low-mass (stellar and substellar) companions to stars in the solar neighborhood identified from Pan-STARRS 1 (PS1) data and the spectral classification of 31 previously known companions. Our companions represent a selective subsample of promising candidates and span a range in spectral type of K7-L9 with the addition of one DA white dwarf. These were identified primarily from a dedicated common proper motion search around nearby stars, along with a few as serendipitous discoveries from our Pan-STARRS 1 brown dwarf search. Our discoveries include 23 new L dwarf companions and one known L dwarf not previously identified as a companion. The primary stars around which we searched for companions come from a list of bright stars with well-measured parallaxes and large proper motions from the Hipparcos catalog (8583 stars, mostly A-K dwarfs) and fainter stars from other proper motion catalogs (79170 stars, mostly M dwarfs). We examine the likelihood that our companions are chance alignments between unrelated stars and conclude that this is unlikely for the majority of the objects that we have followed-up spectroscopically. We also examine the entire population of ultracool (>M7) dwarf companions and conclude that while some are loosely bound, most are unlikely to be disrupted over the course of ~10 Gyr. Our search increases the number of ultracool M dwarf companions wider than 300 AU by 88% and increases the number of L dwarf companions in the same separation range by 82%. Finally, we resolve our new L dwarf companion to HIP 6407 into a tight (0.''13, 7.4 AU) L1+T3 binary, making the system a hierarchical triple. Our search for these key benchmarks against which brown dwarf and exoplanet atmosphere models are tested has yielded the largest number of discoveries to date.

  5. Are isolated planetary-mass objects really isolated?. A brown dwarf-exoplanet system candidate in the σ Orionis cluster

    NASA Astrophysics Data System (ADS)

    Caballero, J. A.; Martín, E. L.; Dobbie, P. D.; Barrado Y Navascués, D.

    2006-12-01

    Context: .Free-floating planetary-mass objects have masses below the deuterium burning mass limit at about 13 Jupiter masses, and have mostly been found in very young open clusters. Their origin and relationship to stars and brown dwarfs are still a mystery. Aims: .The recent detection by direct imaging of three giant planets at wide separation (50-250 AU) from their primaries has raised the question about the true "isolation" of planetary-mass objects in clusters. Our goal was to test the possibility that some free-floating planetary-mass objects could in fact be part of wide planetary systems. Methods: .We searched in the literature for stellar and brown-dwarf candidates members of the σ Orionis cluster (~3 Ma, ~360 pc) at small angular separations from published candidate planetary-mass objects. We found one candidate planetary system composed of an X-ray source, SE 70, and a planetary-mass object, S Ori 68, separated by only 4.6 arcsec. In order to assess the cluster membership of the X-ray source, we obtained mid-resolution optical spectroscopy using ISIS on the William Herschel Telescope. We also compiled additional data on the target from available astronomical catalogues. Results: .We have found that SE 70 follows the spectrophotometric sequence of the cluster and displays spectroscopic features of youth, such as lithium in absorption and chromospheric Hα emission. The radial velocity is consistent with cluster membership. Hence, SE 70 is very probably a member of the σ Orionis cluster. The projected physical separation between SE 70 and S Ori 68 is 1700~± 300 AU at the distance of the cluster. If a common proper motion is confirmed in the near future, the system would be composed of an M5-6 brown dwarf with an estimated mass of ~45 M_Jup and an L5 ± 2 giant planet with an estimated mass of ~5 M_Jup. It would be the widest and one of the lowest-mass planetary systems known so far.

  6. THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. II. KOI-1474.01, A CANDIDATE ECCENTRIC PLANET PERTURBED BY AN UNSEEN COMPANION

    SciTech Connect

    Dawson, Rebekah I.; Murray-Clay, Ruth A.; Johnson, John Asher; Morton, Timothy D.; Crepp, Justin R.; Fabrycky, Daniel C.; Howard, Andrew W.

    2012-12-20

    The exoplanets known as hot Jupiters-Jupiter-sized planets with periods of less than 10 days-likely are relics of dynamical processes that shape all planetary system architectures. Socrates et al. argued that high eccentricity migration (HEM) mechanisms proposed for situating these close-in planets should produce an observable population of highly eccentric proto-hot Jupiters that have not yet tidally circularized. HEM should also create failed-hot Jupiters, with periapses just beyond the influence of fast circularization. Using the technique we previously presented for measuring eccentricities from photometry (the ''photoeccentric effect''), we are distilling a collection of eccentric proto- and failed-hot Jupiters from the Kepler Objects of Interest (KOI). Here, we present the first, KOI-1474.01, which has a long orbital period (69.7340 days) and a large eccentricity e 0.81{sup +0.10}{sub -0.07}, skirting the proto-hot Jupiter boundary. Combining Kepler photometry, ground-based spectroscopy, and stellar evolution models, we characterize host KOI-1474 as a rapidly rotating F star. Statistical arguments reveal that the transiting candidate has a low false-positive probability of 3.1%. KOI-1474.01 also exhibits transit-timing variations of the order of an hour. We explore characteristics of the third-body perturber, which is possibly the ''smoking-gun'' cause of KOI-1474.01's large eccentricity. We use the host star's period, radius, and projected rotational velocity to measure the inclination of the stellar spin. Comparing KOI 1474.01's inclination, we find that its orbit is marginally consistent with being aligned with the stellar spin axis, although a reanalysis is warranted with future additional data. Finally, we discuss how the number and existence of proto-hot Jupiters will not only demonstrate that hot Jupiters migrate via HEM, but also shed light on the typical timescale for the mechanism.

  7. The Photoeccentric Effect and Proto-hot Jupiters. II. KOI-1474.01, a Candidate Eccentric Planet Perturbed by an Unseen Companion

    NASA Astrophysics Data System (ADS)

    Dawson, Rebekah I.; Johnson, John Asher; Morton, Timothy D.; Crepp, Justin R.; Fabrycky, Daniel C.; Murray-Clay, Ruth A.; Howard, Andrew W.

    2012-12-01

    The exoplanets known as hot Jupiters—Jupiter-sized planets with periods of less than 10 days—likely are relics of dynamical processes that shape all planetary system architectures. Socrates et al. argued that high eccentricity migration (HEM) mechanisms proposed for situating these close-in planets should produce an observable population of highly eccentric proto-hot Jupiters that have not yet tidally circularized. HEM should also create failed-hot Jupiters, with periapses just beyond the influence of fast circularization. Using the technique we previously presented for measuring eccentricities from photometry (the "photoeccentric effect"), we are distilling a collection of eccentric proto- and failed-hot Jupiters from the Kepler Objects of Interest (KOI). Here, we present the first, KOI-1474.01, which has a long orbital period (69.7340 days) and a large eccentricity e = 0.81+0.10 -0.07, skirting the proto-hot Jupiter boundary. Combining Kepler photometry, ground-based spectroscopy, and stellar evolution models, we characterize host KOI-1474 as a rapidly rotating F star. Statistical arguments reveal that the transiting candidate has a low false-positive probability of 3.1%. KOI-1474.01 also exhibits transit-timing variations of the order of an hour. We explore characteristics of the third-body perturber, which is possibly the "smoking-gun" cause of KOI-1474.01's large eccentricity. We use the host star's period, radius, and projected rotational velocity to measure the inclination of the stellar spin. Comparing KOI 1474.01's inclination, we find that its orbit is marginally consistent with being aligned with the stellar spin axis, although a reanalysis is warranted with future additional data. Finally, we discuss how the number and existence of proto-hot Jupiters will not only demonstrate that hot Jupiters migrate via HEM, but also shed light on the typical timescale for the mechanism.

  8. KEPLER-20: A SUN-LIKE STAR WITH THREE SUB-NEPTUNE EXOPLANETS AND TWO EARTH-SIZE CANDIDATES

    SciTech Connect

    Gautier, Thomas N. III; Rowe, Jason F.; Bryson, Stephen T.; Marcy, Geoffrey W.; Isaacson, Howard; Rogers, Leslie A.; Buchhave, Lars A.; Ciardi, David R.; Ford, Eric B.; Gilliland, Ronald L.; Walkowicz, Lucianne M.; Cochran, William D.; Endl, Michael; and others

    2012-04-10

    We present the discovery of the Kepler-20 planetary system, which we initially identified through the detection of five distinct periodic transit signals in the Kepler light curve of the host star 2MASS J19104752+4220194. From high-resolution spectroscopy of the star, we find a stellar effective temperature T{sub eff} = 5455 {+-} 100 K, a metallicity of [Fe/H] = 0.01 {+-} 0.04, and a surface gravity of log g = 4.4 {+-} 0.1. We combine these estimates with an estimate of the stellar density derived from the transit light curves to deduce a stellar mass of M{sub *} = 0.912 {+-} 0.034 M{sub Sun} and a stellar radius of R{sub *} = 0.944{sup +0.060}{sub -0.095} R{sub Sun }. For three of the transit signals, we demonstrate that our results strongly disfavor the possibility that these result from astrophysical false positives. We accomplish this by first identifying the subset of stellar blends that reproduce the precise shape of the light curve and then using the constraints on the presence of additional stars from high angular resolution imaging, photometric colors, and the absence of a secondary component in our spectroscopic observations. We conclude that the planetary scenario is more likely than that of an astrophysical false positive by a factor of 2 Multiplication-Sign 10{sup 5} (Kepler-20b), 1 Multiplication-Sign 10{sup 5} (Kepler-20c), and 1.1 Multiplication-Sign 10{sup 3} (Kepler-20d), sufficient to validate these objects as planetary companions. For Kepler-20c and Kepler-20d, the blend scenario is independently disfavored by the achromaticity of the transit: from Spitzer data gathered at 4.5 {mu}m, we infer a ratio of the planetary to stellar radii of 0.075 {+-} 0.015 (Kepler-20c) and 0.065 {+-} 0.011 (Kepler-20d), consistent with each of the depths measured in the Kepler optical bandpass. We determine the orbital periods and physical radii of the three confirmed planets to be 3.70 days and 1.91{sup +0.12}{sub -0.21} R{sub Circled-Plus} for Kepler-20b, 10

  9. Wide Companions to Hipparcos Stars within 67 pc of the Sun

    NASA Astrophysics Data System (ADS)

    Tokovinin, Andrei; Lépine, Sébastien

    2012-10-01

    A catalog of common-proper-motion (CPM) companions to stars within 67 pc of the Sun is constructed based on the SUPERBLINK proper-motion survey. It contains 1392 CPM pairs with angular separations 30'' < ρ < 1800'', relative proper motion between the two components less than 25 mas yr-1, and magnitudes and colors of the secondaries consistent with those of dwarfs in the (MV , V - J) diagram. In addition, we list 21 candidate white dwarf CPM companions with separations under 300'', about half of which should be physical. We estimate a 0.31 fraction of pairs with red dwarf companions to be physical systems (about 425 objects), while the rest (mostly wide pairs) are chance alignments. For each candidate companion, the probability of a physical association is evaluated. The distribution of projected separations s of the physical pairs between 2 kAU and 64 kAU follows f(s)vprops -1.5, which decreases faster than Öpik's law. We find that solar-mass dwarfs have no less than 4.4% ± 0.3% companions with separations larger than 2 kAU, or 3.8% ± 0.3% per decade of orbital separation in the 2-16 kAU range. The distribution of mass ratio of those wide companions is approximately uniform in the 0.1 < q < 1.0 range, although we observe a dip at q ~= 0.5 which, if confirmed, could be evidence of bimodal distribution of companion masses. New physical CPM companions to two exoplanet host stars are discovered.

  10. WIDE COMPANIONS TO HIPPARCOS STARS WITHIN 67 pc OF THE SUN

    SciTech Connect

    Tokovinin, Andrei; Lepine, Sebastien E-mail: lepine@amnh.org

    2012-10-01

    A catalog of common-proper-motion (CPM) companions to stars within 67 pc of the Sun is constructed based on the SUPERBLINK proper-motion survey. It contains 1392 CPM pairs with angular separations 30'' < {rho} < 1800'', relative proper motion between the two components less than 25 mas yr{sup -1}, and magnitudes and colors of the secondaries consistent with those of dwarfs in the (M{sub V} , V - J) diagram. In addition, we list 21 candidate white dwarf CPM companions with separations under 300'', about half of which should be physical. We estimate a 0.31 fraction of pairs with red dwarf companions to be physical systems (about 425 objects), while the rest (mostly wide pairs) are chance alignments. For each candidate companion, the probability of a physical association is evaluated. The distribution of projected separations s of the physical pairs between 2 kAU and 64 kAU follows f(s){proportional_to}s {sup -1.5}, which decreases faster than Oepik's law. We find that solar-mass dwarfs have no less than 4.4% {+-} 0.3% companions with separations larger than 2 kAU, or 3.8% {+-} 0.3% per decade of orbital separation in the 2-16 kAU range. The distribution of mass ratio of those wide companions is approximately uniform in the 0.1 < q < 1.0 range, although we observe a dip at q {approx_equal} 0.5 which, if confirmed, could be evidence of bimodal distribution of companion masses. New physical CPM companions to two exoplanet host stars are discovered.

  11. SOPHIE velocimetry of Kepler transit candidates

    NASA Astrophysics Data System (ADS)

    Santerne, A.; Moutou, C.; Bouchy, F.; Hébrard, G.; Deleuil, M.; Díaz, R. F.; Bonomo, A. S.; Almenara, J.-M.

    2011-10-01

    As CoRoT, the Kepler space mission found a large amount of planetary transit candidates for which radial velocity follow-up is necessary in order to establish the planetary nature and then, to characterize the mass of the transiting companion. We are following up some interesting Kepler candidates with the SOPHIE spectrograph mounted at the 1.93-m telescope in Observatoire de Haute Provence (France). More than one year after the first Kepler release, we will present the strategy used to select the most promising Kepler candidates, within reach of a detection with SOPHIE, using the experience of more than 4 years of CoRoT, SWASP and HAT radial velocity follow-up. We will also highlight the results of the first year of observations that led to the discovery of several new transiting exoplanets and help the understanding of the false positive rate of the Kepler mission.

  12. Mass constraints on substellar companion candidates from the re-reduced Hipparcos intermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs

    NASA Astrophysics Data System (ADS)

    Reffert, S.; Quirrenbach, A.

    2011-03-01

    Context. The recently completed re-reduction of the Hipparcos data by van Leeuwen (2007a, Astrophysics and Space Science Library, 350) makes it possible to search for the astrometric signatures of planets and brown dwarfs known from radial velocity surveys in the improved Hipparcos intermediate astrometric data. Aims: Our aim is to put more significant constraints on the orbital parameters which cannot be derived from radial velocities alone, i.e. the inclination and the longitude of the ascending node, than was possible before. The determination of the inclination in particular allows to calculate an unambiguous companion mass, rather than the lower mass limit which can be obtained from radial velocity measurements. Methods: We fitted the astrometric orbits of 310 substellar companions around 258 stars, which were all discovered via the radial velocity method, to the Hipparcos intermediate astrometric data provided by van Leeuwen. Results: Even though the astrometric signatures of the companions cannot be detected in most cases, the Hipparcos data still provide lower limits on the inclination for all but 67 of the investigated companions, which translates into upper limits on the masses of the unseen companions. For nine companions the derived upper mass limit lies in the planetary and for 75 companions in the brown dwarf mass regime, proving the substellar nature of those objects. Two of those objects have minimum masses also in the brown dwarf regime and are thus proven to be brown dwarfs. The confirmed planets are the ones around Pollux (β Gem b), ɛ Eri b, ɛ Ret b, μ Ara b, υ And c and d, 47 UMa b, HD 10647 b and HD 147513 b. The confirmed brown dwarfs are HD 137510 b and HD 168443 c. In 20 cases, the astrometric signature of the substellar companion was detected in the Hipparcos data, resulting in reasonable constraints on inclination and ascending node. Of these 20 companions, three are confirmed as planets or lightweight brown dwarfs (HD 87833 b, ι Dra

  13. Exoplanets: The Hunt Continues!

    NASA Astrophysics Data System (ADS)

    2001-04-01

    Swiss Telescope at La Silla Very Successful Summary The intensive and exciting hunt for planets around other stars ( "exoplanets" ) is continuing with great success in both hemispheres. Today, an international team of astronomers from the Geneva Observatory and other research institutes [1] is announcing the discovery of no less than eleven new, planetary companions to solar-type stars, HD 8574, HD 28185, HD 50554, HD 74156, HD 80606, HD 82943, HD 106252, HD 141937, HD 178911B, HD 141937, among which two new multi-planet systems . The masses of these new objects range from slightly less than to about 10 times the mass of the planet Jupiter [2]. The new detections are based on measured velocity changes of the stars [3], performed with the CORALIE spectrometer on the Swiss 1.2-m Leonard Euler telescope at the ESO La Silla Observatory , as well as with instruments on telescopes at the Haute-Provence Observatory and on the Keck telescopes on Mauna Kea (Hawaii, USA). Some of the new planets are unusual: * a two-planet system (around the star HD 82943) in which one orbital period is nearly exactly twice as long as the other - cases like this (refered to as "orbital resonance") are well known in our own solar system; * another two-planet system (HD 74156), with a Jupiter-like planet and a more massive planet further out; * a planet with the most elongated orbit detected so far (HD 80606), moving between 5 and 127 million kilometers from the central star; * a giant planet moving in an orbit around its Sun-like central star that is very similar to the one of the Earth and whose potential satellites (in theory, at least) might be "habitable". At this moment, there are 63 know exoplanet candidates with minimum masses below 10 Jupiter masses, and 67 known objects with minimum masses below 17 Jupiter masses. The present team of astronomers has detected about half of these. PR Photo 13a/01 : Radial-velocity measurements of HD 82943, a two-planet system . PR Photo 13b/01 : Radial

  14. The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits . III. The frequency of brown dwarfs and giant planets as companions to solar-type stars

    NASA Astrophysics Data System (ADS)

    Reggiani, M.; Meyer, M. R.; Chauvin, G.; Vigan, A.; Quanz, S. P.; Biller, B.; Bonavita, M.; Desidera, S.; Delorme, P.; Hagelberg, J.; Maire, A.-L.; Boccaletti, A.; Beuzit, J.-L.; Buenzli, E.; Carson, J.; Covino, E.; Feldt, M.; Girard, J.; Gratton, R.; Henning, T.; Kasper, M.; Lagrange, A.-M.; Mesa, D.; Messina, S.; Montagnier, G.; Mordasini, C.; Mouillet, D.; Schlieder, J. E.; Segransan, D.; Thalmann, C.; Zurlo, A.

    2016-02-01

    Context. In recent years there have been many attempts to characterize the occurrence and distribution of stellar, brown dwarf (BD), and planetary-mass companions to solar-type stars with the aim of constraining formation mechanisms. From radial velocity observations a dearth of companions with masses between 10-40 MJupiter has been noticed at close separations, suggesting the possibility of a distinct formation mechanism for objects above and below this range. Aims: We present a model for the substellar companion mass function (CMF). This model consists of the superposition of the planet and BD companion mass distributions, assuming that we can extrapolate the radial velocity measured CMF for planets to larger separations and the stellar companion mass-ratio distribution over all separations into the BD mass regime. By using both the results of the VLT/NaCo large program (NaCo-LP) and the complementary archive datasets, which probe the occurrence of planets and BDs on wide orbits around solar-type stars, we place some constraints on the planet and BD distributions. Methods: We developed a Monte Carlo simulation tool to predict the outcome of a given survey, depending on the shape of the orbital parameter distributions (mass, semimajor axis, eccentricity, and inclination). Comparing the predictions with the results of the observations, we calculate the likelihood of different models and which models can be ruled out. Results: Current observations are consistent with the proposed model for the CMF, as long as a sufficiently small outer truncation radius (≲100 AU) is introduced for the planet separation distribution. Some regions of parameter space can be excluded by the observations. Conclusions: We conclude that the results of the direct imaging surveys searching for substellar companions around Sun-like stars are consistent with a combined substellar mass spectrum of planets and BDs. This mass distribution has a minimum between 10 and 50 MJupiter, in agreement

  15. Influence of stellar multiplicity on planet formation. I. Evidence of suppressed planet formation due to stellar companions within 20 au and validation of four planets from the Kepler multiple planet candidates

    SciTech Connect

    Wang, Ji; Fischer, Debra A.; Xie, Ji-Wei; Barclay, Thomas

    2014-03-01

    The planet occurrence rate for multiple stars is important in two aspects. First, almost half of stellar systems in the solar neighborhood are multiple systems. Second, the comparison of the planet occurrence rate for multiple stars to that for single stars sheds light on the influence of stellar multiplicity on planet formation and evolution. We developed a method of distinguishing planet occurrence rates for single and multiple stars. From a sample of 138 bright (K{sub P} < 13.5) Kepler multi-planet candidate systems, we compared the stellar multiplicity rate of these planet host stars to that of field stars. Using dynamical stability analyses and archival Doppler measurements, we find that the stellar multiplicity rate of planet host stars is significantly lower than field stars for semimajor axes less than 20 AU, suggesting that planet formation and evolution are suppressed by the presence of a close-in companion star at these separations. The influence of stellar multiplicity at larger separations is uncertain because of search incompleteness due to a limited Doppler observation time baseline and a lack of high-resolution imaging observation. We calculated the planet confidence for the sample of multi-planet candidates and find that the planet confidences for KOI 82.01, KOI 115.01, KOI 282.01, and KOI 1781.02 are higher than 99.7% and thus validate the planetary nature of these four planet candidates. This sample of bright Kepler multi-planet candidates with refined stellar and orbital parameters, planet confidence estimation, and nearby stellar companion identification offers a well-characterized sample for future theoretical and observational study.

  16. GRO source candidates: (A) Nearby modest-size molecular clouds; (B) Pulsar with Wolf-Rayet companion that has lost its H-envelope

    NASA Technical Reports Server (NTRS)

    Silberberg, R.; Murphy, Ronald J.

    1989-01-01

    Within 100 pc of the sun there are over a hundred cirrus clouds with masses of approx. 60 solar mass and dense molecular clouds with masses of approx. 4 solar mass. If the local interstellar density of cosmic rays is also present in these clouds, the flux of neutral pion from the decay of gamma rays from the core of a cloud at a distance of 20 pc is approx. 13 x 10(exp -8) photons/sq cm/s. The flux from the more extensive cirrus cloud is approx 4 x 10(exp -7) photons/sq cm/s. A relativistic beam of particles generated by a compact stellar object and incident upon a large, close companion can be a strong gamma ray line source if more of the beam energy is used in interactions with C and O and heavier nuclei and less with H and He. This would be the case if the companion has lost its hydrogen envelope and nucleosynthesized much of its He into C, O, and Ne. Such objects are Wolf-Rayet stars and it is believed that some Wolf-Rayet stars do, in fact, have compact companions. For a beam of protons of 10(exp 37) erg/s, the flux at 1 kpc of the 4.4 MeV C-12 line could be as high as 5 x 10(exp -6) photons/sq cm/s. The fluxes of the deexcitation lines from the spallation products of O-16 are also presented.

  17. Two Extremely Hot Exoplanets Caught in Transit

    NASA Astrophysics Data System (ADS)

    2004-05-01

    VLT Measures Properties of New Jupiter-Size Objects in Very Close Orbits Summary A European team of astronomers [1] are announcing the discovery and study of two new extra-solar planets (exoplanets). They belong to the OGLE transit candidate objects and could be characterized in detail. This trebles the number of exoplanets discovered by the transit method; three such objects are now known. The observations were performed in March 2004 with the FLAMES multi-fiber spectrograph on the 8.2-m VLT Kueyen telescope at the ESO Paranal Observatory (Chile). They enabled the astronomers to measure accurate radial velocities for forty-one stars for which a temporary brightness "dip" had been detected by the OGLE survey. This effect might be the signature of the transit in front of the star of an orbiting planet, but may also be caused by a small stellar companion. For two of the stars (OGLE-TR-113 and OGLE-TR-132), the measured velocity changes revealed the presence of planetary-mass companions in extremely short-period orbits. This result confirms the existence of a new class of giant planets, designated "very hot Jupiters" because of their size and very high surface temperature. They are extremely close to their host stars, orbiting them in less than 2 (Earth) days. The transit method for detecting exoplanets will be "demonstrated" for a wide public on June 8, 2004, when planet Venus passes in front of the solar disc, cf. the VT-2004 programme. PR Photo 14a/04: Sky Field with OGLE-TR-113 PR Photo 14b/04: Sky Field with OGLE-TR-132 PR Photo 14c/04: Brightness "Dips" Caused by Two Transiting Exoplanets PR Photo 14d/04: Velocity Variations Caused by Two Transiting Exoplanets PR Photo 14e/04: Properties of Known Transiting Exoplanets Discovering other Worlds During the past decade, astronomers have learned that our Solar System is not unique, as more than 120 giant planets orbiting other stars were discovered by radial-velocity surveys (cf. ESO PR 13/00, ESO PR 07/01, and ESO

  18. Masses of Exoplanets from Doppler Spectroscopy and HST Astrometry

    NASA Astrophysics Data System (ADS)

    Bean, Jacob; McArthur, B. E.; Benedict, G. F.

    2006-12-01

    Mass is the most important physical property to know for extrasolar planets because it is the one property that distinguishes a star's companion as a bona-fide planet rather than a brown dwarf or even a low-mass star. Additionally, planetary masses provide useful boundary conditions for models of planetary formation and evolution as mass is a critical component in determining a planet's instantaneous characteristics and past and future evolution. In order to determine exoplanets' true masses, we currently use the Hubble Space Telescope Fine Guidance Sensors to obtain measurements of the astrometric elements (perturbation semi-major axis and inclination) of nearby stars that host candidate planets. Because of the long perturbation period of our targets, these mass determinations rely on Doppler velocity measurements to establish the planetary orbital parameters. Unknown shorter-period planets can introduce velocity changes that could be misconstrued as noise and lead to deriving incorrect orbital parameters for the known planets. Consequently, we carry out high-cadence Doppler spectroscopy observations subset of our targets with the Hobby-Eberly Telescope at McDonald Observatory. We present here refined orbital parameters and limits on undetected planets for a subset of our target systems from combining our new data with legacy velocities from planet search programs. We also present preliminary three dimensional models and exoplanet masses for some of our targets from combining the astrometric and spectroscopic data. This research is a technique demonstration of direct relevance to the Space Interferometry Mission, which will be able to discover new exoplanets and precisely measure their masses using astrometry alone. Support for this work was provided by NASA through grants GO-10610 and GO-10989 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  19. Direct Imaging of Faint Companions

    NASA Astrophysics Data System (ADS)

    Claudi, Riccardo

    The exoplanets around stars in the solar neighborhood are expected to be bright enough for us to characterize them with direct imaging; however, they are much fainter than their parent stars, and separated by very small angles, so conventional imaging techniques are totally inadequate, and new methods are needed. The direct imaging of exoplanets is extremely challenging. Jupiter is 109 times fainter than our Sun in reflected visible light. A direct imaging instrument for exoplanets must suppress (1) the bright star image and diffraction pattern and (2) the stellar scattered light from imperfections in the telescope. The main goal of high-contrast imaging is primarily to discover and characterize extrasolar planetary systems. High-contrast observations, in optical and infrared astronomy, are defined as any observation requiring a technique to reveal a low mass companion that is so close to the primary, brighter by a factor of at least 105, that optical effects hinder or prevent the collection of photons directly from the target of observation. To overcome this, astronomers combined large telescopes (to reduce the impact of diffraction), adaptive optics (to correct for phase errors induced by atmospheric turbulence), and sophisticated image processing.

  20. 32 New Exoplanets Found

    NASA Astrophysics Data System (ADS)

    2009-10-01

    oday, at an international ESO/CAUP exoplanet conference in Porto, the team who built the High Accuracy Radial Velocity Planet Searcher, better known as HARPS, the spectrograph for ESO's 3.6-metre telescope, reports on the incredible discovery of some 32 new exoplanets, cementing HARPS's position as the world's foremost exoplanet hunter. This result also increases the number of known low-mass planets by an impressive 30%. Over the past five years HARPS has spotted more than 75 of the roughly 400 or so exoplanets now known. "HARPS is a unique, extremely high precision instrument that is ideal for discovering alien worlds," says Stéphane Udry, who made the announcement. "We have now completed our initial five-year programme, which has succeeded well beyond our expectations." The latest batch of exoplanets announced today comprises no less than 32 new discoveries. Including these new results, data from HARPS have led to the discovery of more than 75 exoplanets in 30 different planetary systems. In particular, thanks to its amazing precision, the search for small planets, those with a mass of a few times that of the Earth - known as super-Earths and Neptune-like planets - has been given a dramatic boost. HARPS has facilitated the discovery of 24 of the 28 planets known with masses below 20 Earth masses. As with the previously detected super-Earths, most of the new low-mass candidates reside in multi-planet systems, with up to five planets per system. In 1999, ESO launched a call for opportunities to build a high resolution, extremely precise spectrograph for the ESO 3.6-metre telescope at La Silla, Chile. Michel Mayor, from the Geneva Observatory, led a consortium to build HARPS, which was installed in 2003 and was soon able to measure the back-and-forward motions of stars by detecting small changes in a star's radial velocity - as small as 3.5 km/hour, a steady walking pace. Such a precision is crucial for the discovery of exoplanets and the radial velocity method

  1. Search for exoplanet around northern circumpolar stars. Four planets around HD 11755, HD 12648, HD 24064, and 8 Ursae Minoris

    NASA Astrophysics Data System (ADS)

    Lee, B.-C.; Park, M.-G.; Lee, S.-M.; Jeong, G.; Oh, H.-I.; Han, I.; Lee, J. W.; Lee, C.-U.; Kim, S.-L.; Kim, K.-M.

    2015-12-01

    Aims: This program originated as the north pole region extension of the established exoplanet survey using the 1.8 m telescope at Bohyunsan Optical Astronomy Observatory (BOAO). The aim of our paper is to find exoplanets in northern circumpolar stars with a precise radial velocity (RV) survey. Methods: We selected about 200 northern circumpolar stars with the following criteria: δ ≥ 70°, 0.6 < B - V < 1.6, Hipparcosscat < 0.05 mag, and 5.0 < mv < 7.0. The high-resolution, fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) was used for the RV survey. Chromospheric activities, the Hipparcos photometry, and line bisectors were analyzed to exclude other causes for the RV variations. Results: In 2010, we started to monitor the candidates and have completed initial screening for all stars for the past five years. We present the detection of four new exoplanets. Stars HD 11755, HD 12648, HD 24064, and 8 UMi all show evidence of giant planets in Keplerian motion. The companion to HD 11755 has a minimum mass of 6.5 MJup in a 433-day orbit with an eccentricity of 0.19. HD 12648 is orbited by a companion with a minimum mass of 2.9 MJup, a period of 133 days, and an eccentricity of 0.04. Weak surface activity was suspected in HD 24064. However, no evidence was found to be associated with the RV variations. Its companion has a minimum mass of 9.4 MJup, a period of 535 days, and an eccentricity of 0.35. Finally, 8 UMi has a minimum mass of 1.5 MJup and a period of 93 days with an eccentricity of 0.06. Based on observations made with the BOES instrument on the 1.8 m telescope at Bohyunsan Optical Astronomy Observatory in Korea.

  2. Chandra Pilot Survey of Extrasolar Planet Candidates

    NASA Astrophysics Data System (ADS)

    Tsuboi, Yohko

    2012-09-01

    We propose to detect planetary-mass companion around young nearby stars by X-ray direct imaging observations with Chandra. Our goals are to determine I. if the X-ray band can be a new probe to the exo-planet search, and II. if a planet emit detectable X-rays with a magnetic origin at a young age. This should be a challenging observation but a brand-new discovery space unique to Chandra. The abundant population of YSOs in the same field of view will enable us to obtain complete X-ray catalogues of YSOs with all categories of masses. We will also execute simultaneous deep NIR observations with IRSF/SIRIUS and Nishiharima 2m telescope to search for the other X-ray-emitting very low-mass objects near our aiming planet candidates.

  3. KNOW THE STAR, KNOW THE PLANET. II. SPECKLE INTERFEROMETRY OF EXOPLANET HOST STARS

    SciTech Connect

    Mason, Brian D.; Hartkopf, William I.; Raghavan, Deepak; Subasavage, John P.; Roberts, Lewis C.; Turner, Nils H.; Ten Brummelaar, Theo A. E-mail: wih@usno.navy.mil E-mail: jsubasavage@ctio.noao.edu E-mail: nils@chara-array.org

    2011-11-15

    A study of the host stars to exoplanets is important for understanding their environment. To that end, we report new speckle observations of a sample of exoplanet host primaries. The bright exoplanet host HD 8673 (= HIP 6702) is revealed to have a companion, although at this time we cannot definitively establish the companion as physical or optical. The observing lists for planet searches and for these observations have for the most part been pre-screened for known duplicity, so the detected binary fraction is lower than what would otherwise be expected. Therefore, a large number of double stars were observed contemporaneously for verification and quality control purposes, to ensure that the lack of detection of companions for exoplanet hosts was valid. In these additional observations, 10 pairs are resolved for the first time and 60 pairs are confirmed. These observations were obtained with the USNO speckle camera on the NOAO 4 m telescopes at both KPNO and CTIO from 2001 to 2010.

  4. Lightest exoplanet yet discovered

    NASA Astrophysics Data System (ADS)

    2009-04-01

    at ESO's La Silla Observatory and announced two years ago -- this star was known to harbour a system with a Neptune-sized planet (ESO 30/05) and two super-Earths (ESO 22/07). With the discovery of Gliese 581 e, the planetary system now has four known planets, with masses of about 1.9 (planet e), 16 (planet b), 5 (planet c), and 7 Earth-masses (planet d). The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days. "Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star," says team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. "‘d' could even be covered by a large and deep ocean -- it is the first serious 'water world' candidate," continued Udry. The gentle pull of an exoplanet as it orbits the host star introduces a tiny wobble in the star's motion -- only about 7 km/hour, corresponding to brisk walking speed -- that can just be detected on Earth with today's most sophisticated technology. Low-mass red dwarf stars such as Gliese 581 are potentially fruitful hunting grounds for low-mass exoplanets in the habitable zone. Such cool stars are relatively faint and their habitable zones lie close in, where the gravitational tug of any orbiting planet found there would be stronger, making the telltale wobble more pronounced. Even so, detecting these tiny signals is still a challenge, and the discovery of Gliese 581 e and the refinement of Gliese 581 d's orbit were only possible due to HARPS's unique precision and stability. "It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 -- the one around 51 Pegasi," says Mayor. "The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years." The astronomers are confident that they can still do better. "With similar observing

  5. Planet Hunters. X. Searching for Nearby Neighbors of 75 Planet and Eclipsing Binary Candidates from the K2 Kepler extended mission

    NASA Astrophysics Data System (ADS)

    Schmitt, Joseph R.; Tokovinin, Andrei; Wang, Ji; Fischer, Debra A.; Kristiansen, Martti H.; LaCourse, Daryll M.; Gagliano, Robert; Tan, Arvin Joseff V.; Schwengeler, Hans Martin; Omohundro, Mark R.; Venner, Alexander; Terentev, Ivan; Schmitt, Allan R.; Jacobs, Thomas L.; Winarski, Troy; Sejpka, Johann; Jek, Kian J.; Boyajian, Tabetha S.; Brewer, John M.; Ishikawa, Sascha T.; Lintott, Chris; Lynn, Stuart; Schawinski, Kevin; Schwamb, Megan E.; Weiksnar, Alex

    2016-06-01

    We present high-resolution observations of a sample of 75 K2 targets from Campaigns 1–3 using speckle interferometry on the Southern Astrophysical Research (SOAR) telescope and adaptive optics imaging at the Keck II telescope. The median SOAR I-band and Keck Ks-band detection limits at 1\\prime\\prime were {{Δ }}{m}I=4.4 mag and {{Δ }}{m}{Ks}=6.1 mag, respectively. This sample includes 37 stars likely to host planets, 32 targets likely to be eclipsing binaries (EBs), and 6 other targets previously labeled as likely planetary false positives. We find nine likely physically bound companion stars within 3\\prime\\prime of three candidate transiting exoplanet host stars and six likely EBs. Six of the nine detected companions are new discoveries. One of these new discoveries, EPIC 206061524, is associated with a planet candidate. Among the EB candidates, companions were only found near the shortest period ones (P\\lt 3 days), which is in line with previous results showing high multiplicity near short-period binary stars. This high-resolution data, including both the detected companions and the limits on potential unseen companions, will be useful in future planet vetting and stellar multiplicity rate studies for planets and binaries.

  6. Molecular opacities for exoplanets.

    PubMed

    Bernath, Peter F

    2014-04-28

    Spectroscopic observations of exoplanets are now possible by transit methods and direct emission. Spectroscopic requirements for exoplanets are reviewed based on existing measurements and model predictions for hot Jupiters and super-Earths. Molecular opacities needed to simulate astronomical observations can be obtained from laboratory measurements, ab initio calculations or a combination of the two approaches. This discussion article focuses mainly on laboratory measurements of hot molecules as needed for exoplanet spectroscopy. PMID:24664921

  7. Molecular opacities for exoplanets

    PubMed Central

    Bernath, Peter F.

    2014-01-01

    Spectroscopic observations of exoplanets are now possible by transit methods and direct emission. Spectroscopic requirements for exoplanets are reviewed based on existing measurements and model predictions for hot Jupiters and super-Earths. Molecular opacities needed to simulate astronomical observations can be obtained from laboratory measurements, ab initio calculations or a combination of the two approaches. This discussion article focuses mainly on laboratory measurements of hot molecules as needed for exoplanet spectroscopy. PMID:24664921

  8. Spectroscopically Unlocking Exoplanet Characteristics

    NASA Astrophysics Data System (ADS)

    Lewis, Nikole

    2016-05-01

    Spectroscopy plays a critical role in a number of areas of exoplanet research. The first exoplanets were detected by precisely measuring Doppler shifts in high resolution (R ~ 100,000) stellar spectra, a technique that has become known as the Radial Velocity (RV) method. The RV method provides critical constraints on exoplanet masses, but is currently limited to some degree by robust line shape predictions. Beyond the RV method, spectroscopy plays a critical role in the characterization of exoplanets beyond their mass and radius. The Hubble Space Telescope has spectroscopically observed the atmospheres of exoplanets that transit their host stars as seen from Earth giving us key insights into atmospheric abundances of key atomic and molecular species as well as cloud optical properties. Similar spectroscopic characterization of exoplanet atmospheres will be carried out at higher resolution (R ~ 100-3000) and with broader wavelength coverage with the James Webb Space Telescope. Future missions such as WFIRST that seek to the pave the way toward the detection and characterization of potentially habitable planets will have the capability of directly measuring the spectra of exoplanet atmospheres and potentially surfaces. Our ability to plan for and interpret spectra from exoplanets relies heavily on the fidelity of the spectroscopic databases available and would greatly benefit from further laboratory and theoretical work aimed at optical properties of atomic, molecular, and cloud/haze species in the pressure and temperature regimes relevant to exoplanet atmospheres.

  9. ExELS: an exoplanet legacy science proposal for the ESA Euclid mission - I. Cold exoplanets

    NASA Astrophysics Data System (ADS)

    Penny, M. T.; Kerins, E.; Rattenbury, N.; Beaulieu, J.-P.; Robin, A. C.; Mao, S.; Batista, V.; Calchi Novati, S.; Cassan, A.; Fouqué, P.; McDonald, I.; Marquette, J. B.; Tisserand, P.; Zapatero Osorio, M. R.

    2013-09-01

    to infinity (i.e. the free-floating regime). Recent ground-based microlensing measurements indicate a significant population of free-floating Jupiters, in which case ExELS will detect hundreds of free-floating planets. ExELS will also be sensitive to hot exoplanets and sub-stellar companions through their transit signatures and this is explored in a companion paper.

  10. Dispersed interferometry for infrared exoplanet velocimetry

    NASA Astrophysics Data System (ADS)

    Edelstein, Jerry; Muterspaugh, Matthew W.; Erskine, David; Marckwordt, Mario; Feuerstein, W. Michael; Mercer, Tony; Czeszumska, Agnieszka; Schwer, Jaclyn; Halverson, Sam; Lloyd, James P.; Muirhead, Philip S.; Wright, Jason T.; Herter, Terry

    2008-07-01

    The TEDI (TripleSpec - Exoplanet Discovery Instrument) is the first instrument dedicated to the near infrared radial velocity search for planetary companions to low-mass stars. The TEDI uses Externally Dispersed Interferometry (EDI), a combination of interferometry and multichannel dispersive spectroscopy. We have joined a white-light interferometer with the Cornell TripleSpec (0.9 - 2.4 μm) spectrograph at the Palomar Observatory 200" telescope and begun an experimental program to establish both the experimental and analytical techniques required for precision IR velocimetry and the Doppler-search for planets orbiting low mass stars and brown dwarfs.

  11. Comparative Habitability of Transiting Exoplanets

    NASA Astrophysics Data System (ADS)

    Barnes, Rory; Meadows, Victoria S.; Evans, Nicole

    2015-12-01

    Exoplanet habitability is traditionally assessed by comparing a planet’s semimajor axis to the location of its host star’s “habitable zone,” the shell around a star for which Earth-like planets can possess liquid surface water. The Kepler space telescope has discovered numerous planet candidates near the habitable zone, and many more are expected from missions such as K2, TESS, and PLATO. These candidates often require significant follow-up observations for validation, so prioritizing planets for habitability from transit data has become an important aspect of the search for life in the universe. We propose a method to compare transiting planets for their potential to support life based on transit data, stellar properties and previously reported limits on planetary emitted flux. For a planet in radiative equilibrium, the emitted flux increases with eccentricity, but decreases with albedo. As these parameters are often unconstrained, there is an “eccentricity-albedo degeneracy” for the habitability of transiting exoplanets. Our method mitigates this degeneracy, includes a penalty for large-radius planets, uses terrestrial mass-radius relationships, and, when available, constraints on eccentricity to compute a number we call the “habitability index for transiting exoplanets” that represents the relative probability that an exoplanet could support liquid surface water. We calculate it for Kepler objects of interest and find that planets that receive between 60% and 90% of the Earth’s incident radiation, assuming circular orbits, are most likely to be habitable. Finally, we make predictions for the upcoming TESS and James Webb Space Telescope missions.

  12. THE PHASES DIFFERENTIAL ASTROMETRY DATA ARCHIVE. III. LIMITS TO TERTIARY COMPANIONS

    SciTech Connect

    Muterspaugh, Matthew W.; Lane, Benjamin F.; Kulkarni, S. R.; Konacki, Maciej; Burke, Bernard F.; Colavita, M. M.; Shao, M. E-mail: blane@draper.co

    2010-12-15

    The Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) monitored 51 subarcsecond binary systems to evaluate whether tertiary companions as small as Jovian planets orbited either the primary or secondary stars, perturbing their otherwise smooth Keplerian motions. Twenty-one of those systems were observed 10 or more times and show no evidence of additional companions. A new algorithm is presented for identifying astrometric companions and establishing the (companion mass)-(orbital period) combinations that can be excluded from existence with high confidence based on the PHASES observations, and the regions of mass-period phase space being excluded are presented for 21 PHASES binaries.

  13. Observing Exoplanets with the James Webb Space Telescope

    NASA Technical Reports Server (NTRS)

    Clampin Mark

    2011-01-01

    The search for exoplanets and characterization of their properties has seen increasing success over the last few years. In excess of 500 exoplanets are known and Kepler has approx. 1000 additional candidates. Recently, progress has been made in direct imaging planets, both from the ground and in space. This presentation will discuss the history and current state of technology used for such discoveries, and highlight the new capabilities that will be enabled by the James Webb Space Telescope.

  14. Variable Star and Exoplanet Section of the Czech Astronomical Society

    NASA Astrophysics Data System (ADS)

    Brát, L.; Zejda, M.

    2010-12-01

    We present activities of Czech variable star observers organized in the Variable Star and Exoplanet Section of the Czech Astronomical Society. We work in four observing projects: B.R.N.O. - eclipsing binaries, MEDUZA - intrinsic variable stars, TRESCA - transiting exoplanets and candidates, HERO - objects of high energy astrophysics. Detailed information together with O-C gate (database of eclipsing binaries minima timings) and OEJV (Open European Journal on Variable stars) are available on our internet portal http://var.astro.cz.

  15. Discovery of Low Mass Binary with Super Jupiter Companion

    NASA Astrophysics Data System (ADS)

    Anthes Rich, Evan; Wisniewski, John P.; Hashimoto, Jun; Brandt, Timothy; Kuzuhara, Masayuki; Tamura, Motohide

    2015-12-01

    Transit and radial velocity surveys have been prolific in detecting ~2000 confirmed planets to date. While few directly imaged planets have detected, such systems provide a unique scientific opportunity to probe exoplanets at larger angular separation, younger ages, and study their atmospheres. We present new L- and M-band AO observations, obtained with IRCS on Subaru, of a super Jupiter companion orbiting a cool dwarf. We show that the central object is likely a binary, thereby making this system the first likely directly imaged planetary mass companion surrounding a low mass binary system.

  16. Synthesizing Exoplanet Demographics

    NASA Astrophysics Data System (ADS)

    Clanton, Christian

    2016-01-01

    The discovery of thousands of exoplanets has revealed a large diversity of systems, the majority of which look nothing like our own. On the theoretical side, we are able to make ab initio calculations that make predictions about the properties of exoplanets. However, in order to link these predictions with observations, we must construct a statistical census of exoplanet demographics over as broad a range of parameters as possible. Current constraints on exoplanet demographics are typically constructed using the results of individual surveys using a single detection technique, and thus are incomplete. The only way to derive a statistically-complete census that samples a wide region of exoplanet parameter space is to synthesize the results from surveys employing all of the different discovery methods at our disposal. I present the first studies to demonstrate that this is actually possible, and describe a (mostly) de-biased exoplanet census that is constructed from the synthesis of results from microlensing, radial velocity, and direct imaging surveys. I will also discuss future work that will include the results of transit surveys (in particular, Kepler discoveries) to complete the census of exoplanets in our Galaxy, and describe the application of this census to develop the most comprehensive, observationally-constrained models of planet formation and evolution that have been derived to date.

  17. Glowing Hot Transiting Exoplanet Discovered

    NASA Astrophysics Data System (ADS)

    2003-04-01

    and the fully drawn curve represents a model fit, with the stellar parameters from the analysis of the UVES spectra (1 solar radius and 1 solar mass) and the planetary parameters from the velocity analysis (0.6 Jupiter mass). The best fit allows determination of the planet's size as about 200,000 km (1.4 times the size of Jupiter). The 2 per cent dip in the brightness of OGLE-TR-3 , as observed during the OGLE programme, occurs every 28 hours 33 minutes (1.1899 days), cf. PR Photo 10e/03 . The UVES velocity measurements ( PR Photo 10d/03 ) fit this period well and reveal, with high probability, the presence of an exoplanet orbiting OGLE-TR-3 with this period. In any case, the observations firmly exclude that the well observed brightness variations could be due to a small stellar companion. A red dwarf star would have caused velocity variations of 15 km/s and a brown dwarf star 2.5 km/s; both would have been easy to observe with UVES, and it is clear that such variations can be excluded. Although the available observations are still insufficient to allow an accurate determination of the planetary properties, the astronomers provisionally deduce a true mass of the planet of the order of one half of that of Jupiter . The density is found to be about 250 kg/m 3 , only one-quarter of that of water or one-fifth of that of Jupiter, so the planet is quite big for this mass - a bit "blown up". It is obviously a planet of the gaseous type . A very hot planet The orbital period, 28 hours 33 minutes (1.1899 days), is the shortest known for any exoplanet and the distance between the star and the planet is correspondingly small, only 3.5 million kilometres . The temperature of the side of the planet facing the star must therefore be very high, of the order of 2000 °C . Clearly, the planet must be losing its atmosphere by evaporation. The astronomers also conclude that it might in fact be possible to observe this exoplanet directly because of its comparatively strong infrared

  18. The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits. II. Survey description, results, and performances

    NASA Astrophysics Data System (ADS)

    Chauvin, G.; Vigan, A.; Bonnefoy, M.; Desidera, S.; Bonavita, M.; Mesa, D.; Boccaletti, A.; Buenzli, E.; Carson, J.; Delorme, P.; Hagelberg, J.; Montagnier, G.; Mordasini, C.; Quanz, S. P.; Segransan, D.; Thalmann, C.; Beuzit, J.-L.; Biller, B.; Covino, E.; Feldt, M.; Girard, J.; Gratton, R.; Henning, T.; Kasper, M.; Lagrange, A.-M.; Messina, S.; Meyer, M.; Mouillet, D.; Moutou, C.; Reggiani, M.; Schlieder, J. E.; Zurlo, A.

    2015-01-01

    Context. Young, nearby stars are ideal targets for direct imaging searches for giant planets and brown dwarf companions. After the first-imaged planet discoveries, vast efforts have been devoted to the statistical analysis of the occurence and orbital distributions of giant planets and brown dwarf companions at wide (≥5-6 AU) orbits. Aims: In anticipation of the VLT/SPHERE planet-imager, guaranteed-time programs, we have conducted a preparatory survey of 86 stars between 2009 and 2013 to identify new faint comoving companions to ultimately analyze the occurence of giant planets and brown dwarf companions at wide (10-2000 AU) orbits around young, solar-type stars. Methods: We used NaCo at VLT to explore the occurrence rate of giant planets and brown dwarfs between typically 0.1 and 8''. Diffraction-limited observations in H-band combined with angular differential imaging enabled us to reach primary star-companion brightness ratios as small as 10-6 at 1.5''. Repeated observations at several epochs enabled us to discriminate comoving companions from background objects. Results: During our survey, twelve systems were resolved as new binaries, including the discovery of a new white dwarf companion to the star HD 8049. Around 34 stars, at least one companion candidate was detected in the observed field of view. More than 400 faint sources were detected; 90% of them were in four crowded fields. With the exception of HD 8049 B, we did not identify any new comoving companions. The survey also led to spatially resolved images of the thin debris disk around HD 61005 that have been published earlier. Finally, considering the survey detection limits, we derive a preliminary upper limit on the frequency of giant planets for the semi-major axes of [10, 2000] AU: typically less than 15% between 100 and 500 AU and less than 10% between 50 and 500 AU for exoplanets that are more massive than 5 MJup and 10 MJup respectively, if we consider a uniform input distribution and a

  19. Overlooked wide companions of nearby F stars

    NASA Astrophysics Data System (ADS)

    Scholz, R.-D.

    2016-03-01

    Aims: We checked a sample of 545 F stars within 50 pc for wide companions using existing near-infrared and optical sky surveys. Methods: Applying the common proper motion (CPM) criterion, we detected wide companion candidates with 6-120 arcsec angular separations by visual inspection of multi-epoch finder charts and by searching in proper motion catalogues. Final proper motions were measured by involving positional measurements from up to eleven surveys. Spectral types of red CPM companions were estimated from their absolute J-band magnitudes based on the Hipparcos distances of the primaries. Results: In addition to about 100 known CPM objects, we found 19 new CPM companions and confirmed 31 previously known candidates. A few CPM objects are still considered as candidates according to their level of proper motion agreement. Among the new objects there are nine M0-M4, eight M5-M6, one ≈L3.5 dwarf (HD 3861B), and one white dwarf (WD) (HD 2726B), whereas we confirmed two K, 19 M0-M4, six M5-M6, two early-L dwarfs, and two DA WDs as CPM companions. In a few cases, previous spectral types were available that all agree well with our estimates. Two companions (HD 22879B and HD 49933B) are associated with moderately metal-poor Gaia benchmark stars. One doubtful CPM companion, spectroscopically classified as WD but found to be very bright (J = 11.1) by others, should either be a very nearby foreground WD or a different kind of object associated with HD 165670. Tables A.1, B.1, and C.1 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/587/A51

  20. The Exoplanet Orbit Database

    NASA Astrophysics Data System (ADS)

    Wright, J. T.; Fakhouri, O.; Marcy, G. W.; Han, E.; Feng, Y.; Johnson, John Asher; Howard, A. W.; Fischer, D. A.; Valenti, J. A.; Anderson, J.; Piskunov, N.

    2011-04-01

    We present a database of well-determined orbital parameters of exoplanets, and their host stars' properties. This database comprises spectroscopic orbital elements measured for 427 planets orbiting 363 stars from radial velocity and transit measurements as reported in the literature. We have also compiled fundamental transit parameters, stellar parameters, and the method used for the planets discovery. This Exoplanet Orbit Database includes all planets with robust, well measured orbital parameters reported in peer-reviewed articles. The database is available in a searchable, filterable, and sortable form online through the Exoplanets Data Explorer table, and the data can be plotted and explored through the Exoplanet Data Explorer plotter. We use the Data Explorer to generate publication-ready plots, giving three examples of the signatures of exoplanet migration and dynamical evolution: We illustrate the character of the apparent correlation between mass and period in exoplanet orbits, the different selection biases between radial velocity and transit surveys, and that the multiplanet systems show a distinct semimajor-axis distribution from apparently singleton systems.

  1. A search for companions to irregular variables of type S

    NASA Technical Reports Server (NTRS)

    Peery, B. F., Jr.

    1985-01-01

    IUE archival spectra of S-type stars that may be cool analogues of Ba II stars have been inspected for evidence of hot companions. Although the currently accessible data for 9 stars are of marginal quality, spectra of the brightest candidate, HR 1105, show strong evidence for the presence of a hot companion of low luminosity.

  2. Planets and Brown Dwarfs and Stars, Oh My! --- Companions Along the Road to the Nearest Stars

    NASA Astrophysics Data System (ADS)

    Henry, Todd J.; Davison, C. L.; Dieterich, S. B.; Ianna, P. A.; Jao, W. C.; Koerner, D. W.; Subasavage, J. P.; Tanner, A. M.; White, R. J.; RECONS

    2012-01-01

    RECONS (www.recons.org, REsearch Consortium On Nearby Stars) has been using astrometric techniques since 1999 to search for massive planets orbiting more than 130 nearby red and white dwarfs. Because of their proximity, nearby stars are natural locations to search for other solar systems --- the stars provide increased fluxes, larger astrometric perturbations, and higher probabilities for eventual resolution of planets than similar stars at larger distances. Unlike radial velocity searches, our astrometric effort is most sensitive to Jovian planets in Jovian orbits, i.e. those that span decades. We have discovered stellar companions with masses of a few hundred Jupiters, brown dwarf companions with masses of a few tens of Jupiters, and are now pushing into the realm of planets with masses of a few Jupiters around the nearest red dwarfs. Several previously unknown companions have been imaged via Gemini-AO observations, but we have also detected perturbations caused by enigmatic companions that elude direct detection. As we sweep through the mass regimes of stars to exoplanets for companions, we are now able to assess the various populations --- stars are common as companions, whereas brown dwarfs and massive planets are rare. We outline what we have discovered so far and place our exoplanet search results in context with an overview of the census of more than 60 stars with exoplanets known within 25 pc. This effort is supported by the NSF through grant AST-0908402 and via observations made possible by the SMARTS Consortium.

  3. DETECTABILITY OF EXOPLANETS IN THE {beta} PIC MOVING GROUP WITH THE GEMINI PLANET IMAGER

    SciTech Connect

    Kataria, Tiffany; Simon, Michal

    2010-07-15

    We model the detectability of exoplanets around stars in the {beta} Pic Moving Group (BPMG) using the Gemini Planet Imager (GPI), a coronagraphic instrument designed to detect companions by imaging. Members of the BPMG are considered promising targets for exoplanet searches because of their youth ({approx}12 Myr) and proximity (median distance {approx}35 pc). We wrote a modeling procedure to generate hypothetical companions of given mass, age, eccentricity, and semi-major axis, and place them around BPMG members that fall within the V-band range of the GPI. We count companions lying within the GPI's field of view and H-band fluxes that have a host-companion flux ratio placing them within its sensitivity as possible detections. The fraction of companions that could be detected depends on their brightness at 12 Myr, and hence formation mechanism, and on their distribution of semi-major axes. We used brightness models for formation by disk instability and core-accretion. We considered the two extreme cases of the semi-major axis distribution-the log-normal distribution of the nearby F- and G-type stars and a power-law distribution indicated by the exoplanets detected by the radial velocity technique. We find that the GPI could detect exoplanets of all the F and G spectral type stars in the BPMG sample with a probability that depends on the brightness model and semi-major axis distribution. At spectral type K-M1, exoplanet detectability depends on brightness and hence distance of the host star. GPI will be able to detect the companions of M stars later than M1 only if they are closer than 10 pc. Of the four A stars in the BPMG sample, only one has a V-band brightness in the range of GPI; the others are too bright.

  4. Is This Speck of Light an Exoplanet?

    NASA Astrophysics Data System (ADS)

    2004-09-01

    nature of this intriguing object. Thus, the astronomers refer to it as a "Giant Planet Candidate Companion (GPCC)" [4]. Observations will now be made to ascertain whether the motion in the sky of GPCC is compatible with that of a planet orbiting 2M1207. This should become evident within 1-2 years at the most. PR Photo 26a/04: NACO image of the brown dwarf object 2M1207 and GPCC PR Photo 26b/04: Near-infrared spectrum of the brown dwarf object 2M1207 and GPCC PR Photo 26c/04: Comparison between the possible 2M1207 system and the solar system Just a speck of light ESO PR Photo 26a/04 ESO PR Photo 26a/04 The Brown Dwarf Object 2M1207 and GPCC [Preview - JPEG: 400 x 471 pix - 65k] [Normal - JPEG: 800 x 942 pix - 158k] Caption: ESO PR Photo 26a/04 is a composite image of the brown dwarf object 2M1207 (centre) and the fainter object seen near it, at an angular distance of 778 milliarcsec. Designated "Giant Planet Candidate Companion" by the discoverers, it may represent the first image of an exoplanet. Further observations, in particular of its motion in the sky relative to 2M1207 are needed to ascertain its true nature. The photo is based on three near-infrared exposures (in the H, K and L' wavebands) with the NACO adaptive-optics facility at the 8.2-m VLT Yepun telescope at the ESO Paranal Observatory. Since 1998, a team of European and American astronomers [2] is studying the environment of young, nearby "stellar associations", i.e., large conglomerates of mostly young stars and the dust and gas clouds from which they were recently formed. The stars in these associations are ideal targets for the direct imaging of sub-stellar companions (planets or brown dwarf objects). The leader of the team, ESO astronomer Gael Chauvin notes that "whatever their nature, sub-stellar objects are much hotter and brighter when young - tens of millions of years - and therefore can be more easily detected than older objects of similar mass". The team especially focused on the study of the TW

  5. The history of exoplanet detection.

    PubMed

    Perryman, Michael

    2012-10-01

    I summarize the early developments of the more quantitative aspects of exoplanet detection. After a brief overview of the observational methods currently applied to exoplanet searches and a summary of the first true exoplanet detections resulting from these various techniques, the more relevant historical background is organized according to the observational techniques that are currently most relevant. PMID:23013272

  6. Validating the First Habitable-Zone Planet Candidates Identified by the NASA Kepler Mission

    NASA Astrophysics Data System (ADS)

    Charbonneau, David; Desert, Jean-Michel; Fressin, Francois; Ballard, Sarah; Borucki, William; Latham, David; Gilliland, Ronald; Seager, Sara; Knutson, Heather; Fortney, Jonathan; Brown, Timothy; Ford, Eric; Deming, Drake; Torres, Guillermo

    2011-05-01

    At the beginning of Cycle 8, the NASA Kepler Mission will have completed two years of science observations, the minimum baseline sufficient to identify candidate transiting exoplanets orbiting within the habitable-zones of Sun-like stars. The principal task that lies ahead is to reject from this sample the false positives (blends of eclipsing binaries that precisely mimic the signal of a transiting exoplanet), and to confirm the planetary nature of the remaining candidates. For planets more massive than Neptune, the direct confirmation of their planetary status can be accomplished by radial-velocity measurements. However, such planets possess primordial envelopes of hydrogen and helium that make them unsuitable to life as we know it. The most exciting candidates -- and the ones that Kepler is specifically tasked with finding -- are super-Earth and Earth-sized planets orbiting within their stellar habitable zones. Kepler has just begun to identify such planet candidates, and it will identify many more as its baseline increases throughout the coming year. While the Kepler team has developed powerful tools to weed out the impostors, Spitzer possesses the unique ability to provide the final validation of these candidates as planets, namely by measuring the depth of the transit at infrared wavelengths. By combining the infrared and optical measurements of the transit depth with models of hypothetical stellar blends, we can definitively test the stellar-blend hypothesis. We propose to observe the transits of 20 candidate habitable-zone super-Earths to be identified by the Kepler Mission. The results from this Exploration Science Program will be twofold: First, we will definitively validate the first potentially habitable planets ever identified. Second, we will determine the rate of occurrence of impostors. This rate of false positives can then be applied to the much larger sample of candidates identified by Kepler, to deduce the true rate of planetary companions.

  7. Asteroseismology and Exoplanet Hosts

    NASA Astrophysics Data System (ADS)

    Huber, Daniel

    2015-08-01

    Asteroseismology is among the most powerful observational tools to determine fundamental properties of stars. Space-based photometry has recently enabled the systematic detection of oscillations in exoplanet host stars, allowing a combination of asteroseismology with transit and radial-velocity measurements to precisely characterize planetary systems. In this talk I will review the latest asteroseismic detections in exoplanet host stars spanning from the main sequence to the red-giant branch, focusing in particular on radii and ages of stars hosting small (sub-Neptune sized) planets discovered by the Kepler mission. I will furthermore discuss applications of asteroseismology to measure spin-orbit inclinations in multiplanet systems, and their implications for formation theories of hot Jupiters. Finally I will give an outlook on asteroseismic studies of exoplanet hosts with current and future space- and ground-based facilities such as K2, SONG, TESS, and PLATO.

  8. Uncovering Exoplanets using Polarimetry

    NASA Astrophysics Data System (ADS)

    Stam, D. M.

    2012-12-01

    Since the first discovery of a planet around a solar-type star by Mayor & Queloz in 1995, more than 700 of these exoplanets have been detected. Most of these are giant, gaseous planets, but small, presumably solid, exoplanets, that are much harder to detect, have also been found. Among the latter are even some that orbit in their star's habitable zone, where temperatures could be just right to allow liquid water on a planet's surface. Liquid water is generally considered to be essential for the existence of life. Whether liquid water actually exists on a planet depends strongly on the atmosphere's thickness and characteristics, such as the surface pressure and composition. Famous examples in the Solar System are Venus and the Earth, with similar sizes, inner compositions and orbital radii, but wildly different surface conditions. The characterization of the atmospheres of giant, gaseous exoplanets, and of the atmospheres and/or surfaces of small, solid exoplanets will allow a comparison with Solar System planets and it will open up a treasure trove of knowledge about the formation and evolution of planetary atmospheres and surfaces, thanks to the vast range of orbital distances, planet sizes and ages that can be studied. Characterization will also allow studying conditions for life and ultimately the existence of life around other stars. Some information about the upper atmospheric properties has already been derived for a few close-in, hot, giant exoplanets, whose thermal flux can be derived from measurements of the combined flux of the star and the planet. This method has also provided traces of an atmosphere around a large solid planet orbiting red dwarf star GJ1214. Characterization of the atmosphere and/or surface of exoplanets in wide orbits, resembling the cool planets in our Solar System, and in particular of small, solid, Earth-like planets in the habitable zone of Sun-like stars, is virtually impossible with transit observations. Indeed, polarimetry

  9. NASA's Exoplanet Exploration Program

    NASA Astrophysics Data System (ADS)

    Devirian, Michael

    2009-01-01

    September 24, 2008 NASA has established the Exoplanet Exploration Program (ExEP) to conduct scientific investigations in one of the most exciting new fields of astronomy, the exploration and characterization of planets around other stars in search of those that might show signs of harboring life. In this paper, we will describe that program and how it is expected to work. Key to success in this field is the advancement of optical capabilities to unprecedented levels of precision and stability. The technology program conducted by ExEP will strive to achieve these advancements to enable near-term moderate scale missions and eventually lead to large flagship-class missions that will deeply probe the most promising earth-like planets for signs of biogenic activity. Significant opportunities for community participation in technology development will be available through NASA research solicitations that will call for technology advancements in specific areas. These developments will focus on challenges posed by a strategy for the progression of scientific investigations developed by the science community through bodies such as the Exoplanet Task Force, the Exoplanet Science Forum and ultimately the NRC Decadal Survey. ExEP will be advised in its tactical implementation of this strategy by Exoplanet Program Analysis Group (ExoPAG), which will engage a broad segment of the community in deliberation and then focus its reports through a core group appointed by NASA HQ. The coming decade offers opportunities for continued exoplanet investigations through ground observations, sub-orbital platforms and moderate scale space missions, and the anticipated process and timing of these opportunities will be described. The Exoplanet Exploration Program is managed for NASA at the Jet Propulsion Laboratory, California Institute of Technology.

  10. Hubble space telescope high-resolution imaging of Kepler small and cool exoplanet host stars

    SciTech Connect

    Gilliland, Ronald L.; Cartier, Kimberly M. S.; Wright, Jason T.; Adams, Elisabeth R.; Ciardi, David R.

    2015-01-01

    High-resolution imaging is an important tool for follow-up study of exoplanet candidates found via transit detection with the Kepler mission. We discuss here Hubble Space Telescope imaging with the WFC3 of 23 stars that host particularly interesting Kepler planet candidates based on their small size and cool equilibrium temperature estimates. Results include detections, exclusion of background stars that could be a source of false positives for the transits, and detection of physically associated companions in a number of cases providing dilution measures necessary for planet parameter refinement. For six Kepler objects of interest, we find that there is ambiguity regarding which star hosts the transiting planet(s), with potentially strong implications for planetary characteristics. Our sample is evenly distributed in G, K, and M spectral types. Albeit with a small sample size, we find that physically associated binaries are more common than expected at each spectral type, reaching a factor of 10 frequency excess in M. We document the program detection sensitivities, detections, and deliverables to the Kepler follow-up program archive.

  11. Astronomy: Tycho's mystery companion

    NASA Astrophysics Data System (ADS)

    Branch, David

    2004-10-01

    A famous sixteenth century supernova, seen by Tycho Brahe, is still a hot topic. The stellar explosion might have been initiated by a companion star -- and modern astronomers have at last identified it.

  12. Exoplanet's Atmospheres Characteristics vs. Exoplanet's Orbital Elements

    NASA Astrophysics Data System (ADS)

    Molaverdikhani, Karan

    2009-10-01

    400 years after Galileo Galilei was detected Jovian system, we know about 400 exoplanets in other stellar systems. But we identify just about their major properties like some of orbital elements, planet's radii or density. Also, there are many scientists who interested in searching for life or habitability on these planets. They are working in different ways such as planetary formation, planetary orbital stability or immigration, HabStars, composition of atmospheres, most probable zone in sky for exoplanets detection, etc. In this research we distinct and defined some main characteristics of terrestrial planet's atmospheres with surveying on solar system's planets and matching with current theorems on atmosphere formation. On the other hand, we were modeled Mars, Venus, Titan, single Hadley Earth and virtual Venus with different tilt angel (applying Global Circulation Modeling) to finding a critical limit on Polar Vortex formation in our last research. With extension this method on hypothetical terrestrial planets in constraint mass between 0.7 to 2.5 Earth's mass on Green Belt and applying host stars from 0.5 to 1.5 Sun's mass, we found some limitations on planet's atmosphere formation and estimation values of atmosphere's main characteristics.

  13. Subaru SEEDS Survey of Exoplanets and Disks

    NASA Technical Reports Server (NTRS)

    McElwain, Michael W.

    2012-01-01

    The Strategic Exploration of Exoplanets and Disks at Subaru (SEEDS) is the first strategic observing program (SSOPs) awarded by the National Astronomical Observatory of Japan (NAOJ). SEEDS targets a broad sample of stars that span a wide range of masses and ages to explore the formation and evolution of planetary systems. This survey has been awarded 120 nights over five years time to observe nearly 500 stars. Currently in the second year, SEEDS has already produced exciting new results for the protoplanetary disk AB Aur, transitional disk LkCa15, and nearby companion to GJ 758. We present the survey architecture, performance, recent results, and the projected sample. Finally, we will discuss planned upgrades to the high contrast instrumentation at the Subaru Telescope

  14. Development of Companion Diagnostics

    PubMed Central

    Mankoff, David A.; Edmonds, Christine E.; Farwell, Michael D.; Pryma, Daniel A.

    2016-01-01

    The goal of individualized and targeted treatment and precision medicine requires the assessment of potential therapeutic targets to direct treatment selection. The biomarkers used to direct precision medicine, often termed companion diagnostics, for highly targeted drugs have thus far been almost entirely based on in vitro assay of biopsy material. Molecular imaging companion diagnostics offer a number of features complementary to those from in vitro assay, including the ability to measure the heterogeneity of each patient’s cancer across the entire disease burden and to measure early changes in response to treatment. We discuss the use of molecular imaging methods as companion diagnostics for cancer therapy with the goal of predicting response to targeted therapy and measuring early (pharmacodynamic) response as an indication of whether the treatment has “hit” the target. We also discuss considerations for probe development for molecular imaging companion diagnostics, including both small-molecule probes and larger molecules such as labeled antibodies and related constructs. We then describe two examples where both predictive and pharmacodynamic molecular imaging markers have been tested in humans: endocrine therapy for breast cancer and human epidermal growth factor receptor type 2–targeted therapy. The review closes with a summary of the items needed to move molecular imaging companion diagnostics from early studies into multicenter trials and into the clinic. PMID:26687857

  15. Companion animal adoption study.

    PubMed

    Neidhart, Laura; Boyd, Renee

    2002-01-01

    To better understand the outcomes of companion animal adoptions, Bardsley & Neidhart Inc. conducted a series of 3 surveys over a 1-year period with dog and cat owners who had adopted their pet through either a (a) Luv-A-Pet location, (b) Adopt-a-thon, or (c) traditional shelter. This article suggests opportunities to improve owners' perceptions of their pets and the adoption process through (a) providing more information before adoption about pet health and behaviors, (b) providing counseling to potential adopters to place pets appropriately, and (c) educating adopters to promote companion animal health and retention. Results demonstrate that the pet's relationship to the family unit, such as where the pet sleeps and how much time is spent with the pet, is related to the amount of veterinary care the companion animal receives, and to long-term retention. Satisfaction and retention are attributed to the pet's personality, compatibility, and behavior, rather than demographic differences among adopters or between adoption settings. The age of the companion animal at adoption, the intended recipient, and presence of children in the home also play a role. Health problems were an issue initially for half of all adopted pets, but most were resolved within 12 months. Roughly one fourth of adopters who no longer have their companion animal said their pet died. Characteristics of pets that died support the contention that spaying and neutering profoundly affects a companion animal's life span. Although retention is similar for dogs and cats, mortality is higher among cats in the first year after adoption. PMID:12578739

  16. Understanding Young Exoplanet Analogs with WISE

    NASA Astrophysics Data System (ADS)

    Rice, Emily

    We propose to tackle outstanding questions about the fundamental properties of young brown dwarfs, which are atmospheric analogs to massive gas giant exoplanets, using public archive data from the Wide-field Infrared Survey Explorer (WISE) combined with our extensive dataset of optical and near-infrared observations, including spectra, proper motions, and parallaxes. Using WISE data we will construct color-color diagrams, color- magnitude diagrams, and spectral energy distributions for our sample of candidate young brown dwarfs. We will fully characterize the spectral properties of the candidates and evaluate their membership in nearby young moving groups in order to obtain independent age estimates. The practical outcomes of this project will allow the research community to use observed colors and spectra to reliably constrain the properties - including effective temperature, gravity, and dust/cloud properties - of both brown dwarfs and gas giant exoplanets. We will also search for new young brown dwarfs in the WISE archive using colors and proper motions. The expanded sample of young brown dwarfs will be used to create a self-contained feedback loop to identify and address the shortcomings of cool atmosphere models and low-mass evolutionary tracks, both of which are already being used to infer the properties of massive exoplanets. Disentangling the effects of physical parameters on the observed properties of young brown dwarfs is directly relevant to studies of exoplanets. Direct observations of exoplanets are currently very limited, and young brown dwarfs are the laboratories in which we can solve existing problems before the onslaught of new observations from instruments capable of directly imaging exoplanets, including the Gemini Planet Imager, Project 1640 at the Palomar Observatory, SPHERE on the VLT, and the James Webb Space Telescope. This project addresses the goal of the NASA Science Mission Directorate to discover how the universe works; in particular

  17. Harnessing the Power of the WFIRST-Coronagraph: A Coordinated Plan for Exoplanet and Disk Science

    NASA Astrophysics Data System (ADS)

    Turnbull, Margaret

    We propose to form a WFIRST Coronagraph Science Investigation Team (WFIRST-C SIT) for the purpose of defining the coronagraph scientific performance requirements, designing an exoplanet and debris disk observing program, and developing data analysis techniques including faint source detection and spectral retrieval. Our team will accomplish these tasks by: 1. Providing detailed characterization of the candidate target stars in terms of stellar/substeller companions, circumstellar debris, and astrophysical background in order to inform the final target selection by the community. As part of this effort, we will make a plan for coordination between WFIRST and Large Binocular Telescope Interferometer (LBTI) target selection, to obtain both scattered light and thermal emission observations of exozodiacal dust in the same systems. This will be important precursor science for future exoEarth direct imaging missions. 2. Creating simulated spatial-spectral data cubes representative of what the WFIRST coronagraph may see around the candidate targets, including known and hypothetical exoplanets, dynamically consistent interplanetary dust distributions, and astrophysical background contamination. The code framework to make the high-fidelity input models exists within our team, and we currently have a complete spectral data cube that allows us to generate images at any wavelength between 0.3 microns and 2.5 microns. To generate the simulated datasets for WFIRST, we will make use of instrument simulation tools provided by the coronagraph design team, spanning the range of expected coronagraph performance characteristics. We will also add functionality to these tools, or build our own, as required. 3. Designing and conducting a â€oeblind retrieval challenge― study to distribute these data amongst source detection and spectral modeling teams in the exoplanet and wider astrophysics community. Given the variety of sources expected in each planet-finding field, we expect

  18. Is this a Brown Dwarf or an Exoplanet?

    NASA Astrophysics Data System (ADS)

    2005-04-01

    Since the discovery in 1995 of the first planet orbiting a normal star other than the Sun, there are now more than 150 candidates of these so-called exoplanets known. Most of them are detected by indirect methods, based either on variations of the radial velocity or the dimming of the star as the planet passes in front of it (see ESO PR 06/03, ESO PR 11/04 and ESO PR 22/04). Astronomers would, however, prefer to obtain a direct image of an exoplanet, allowing them to better characterize the object's physical nature. This is an exceedingly difficult task, as the planet is generally hidden in the "glare" of its host star. To partly overcome this problem, astronomers study very young objects. Indeed, sub-stellar objects are much hotter and brighter when young and therefore can be more easily detected than older objects of similar mass. Based on this approach, it might well be that last year's detection of a feeble speck of light next to the young brown dwarf 2M1207 by an international team of astronomers using the ESO Very Large Telescope (ESO PR 23/04) is the long-sought bona-fide image of an exoplanet. A recent report based on data from the Hubble Space Telescope seems to confirm this result. The even more recent observations made with the Spitzer Space Telescope of the warm infrared glows of two previously detected "hot Jupiter" planets is another interesting result in this context. This wealth of new results, obtained in the time span of a few months, illustrates perfectly the dynamic of this field of research. Tiny Companion ESO PR Photo 10a/05 ESO PR Photo 10a/05 The Sub-Stellar Companion to GQ Lupi (NACO/VLT) [Preview - JPEG: 400 x 429 pix - 22k] [Normal - JPEG: 800 x 875 pix - 132k] [Full Res - JPEG: 1042 x 1116 pix - 241k] Caption: ESO PR Photo 10a/05 shows the VLT NACO image, taken in the Ks-band, of GQ Lupi. The feeble point of light to the right of the star is the newly found cold companion. It is 250 times fainter than the star itself and it located 0

  19. Exoplanets, extremophiles and habitability

    NASA Astrophysics Data System (ADS)

    Janot Pacheco, E.; Bernardes, L.

    2012-09-01

    Estimates of the average surface temperature and CO2 partial atmospheric pressure of already discovered exoplanets supposed to be in their Habitable Zone of their stars were surveyed from the Exoplanet Encyclopedia database. Moreover, since planetary surface temperature strongly depends on its albedo and geodynamic conditions, we have been feeding exoplanetary data into a comprehensive model of Earth's atmosphere to get better estimations. We also investigated the possible presence of "exomoons" belonging to giant planets capable of harbour dynamic stability and to retain atmospheric layers and keep geodynamic activity for long time spans. Collected information on biological data of micro-organisms classified as "extremophiles" indicate that such kind of microbial species could dwell in many of them. We thus propose an extension of the more astronomically defined "Habitable Zone" concept into the more astrobiologically "Extremophile Zone", taking into account other refined parameters allowing survival of more robust life forms.

  20. Exoplanet observations with GTC

    NASA Astrophysics Data System (ADS)

    Pallé, Enric

    2015-12-01

    Our group is presently conducting an observational campaign, using the 10-meter Gran Telescopio Canarias (GTC), to obtain the transmission spectrum of several exoplanets during a transit event. The GTC instrument OSIRIS is used in its long-slit spectroscopic mode, covering the spectral range of 520-1040 nm, and observations are taken using a set of custom-built slits of various, broad, widths. We integrate the stellar flux of both stars in different wavelength regions producing several light curves and fit transit models in order to obtain the star-to-planet radius ratio Rp/Rs across wavelength. A Markov Chain Monte Carlo (MCMC) Bayesian approach is used for the transit fitting. We will show that with our instrumental setup, OSIRIS has been able to reach precisions down to 250 ppm (WASP-48b, V=11.06 mag) for each color light curve 10 nm wide, in a single transit. And accuracies of the order of 500ppm can be obtained for objects with V=16. Central transit timing accuracies have been measured down to 6 seconds.Here, we will present refined planet parameters, the detection of planet color signatures, and the transmission spectra of a set of know and unpublished transiting exoplanets. We will also discuss the capabilities and limitations of GTC with current and future instrumentation, and the role of GTC as tool for the follow up of faint exoplanet targets.

  1. Companion Animals. [Information Packet.

    ERIC Educational Resources Information Center

    National Anti-Vivisection Society, Chicago, IL.

    This collection of articles reprinted from other National Anti-Vivisection Society (NAVS) publications was compiled to educate the public on issues of importance to NAVS concerning companion animals. Topics covered include spaying and neutering, animal safety, pet theft, and the use of cats and dogs in research. The article on spaying and…

  2. The Direct Imaging Search of Exoplanets from Ground and Space

    NASA Astrophysics Data System (ADS)

    Dou, Jiangpei; Ren, Deqing; Zhu, Yongtian

    2015-08-01

    Exoplanets search is one of the hottest topics in both modern astronomy and public domain. Until now over 1990 exoplanets have been confirmed mostly by the indirect radial velocity and transiting approaches, yielding several important physical information such as masses and radius. The study of the physics of planet formation and evolution will focus on giant planets through the direct imaging.However, the direct imaging of exoplanets remains challenging, due to the large flux ratio difference and the nearby angular distance. In recent years, the extreme adaptive optics (Ex-AO) coronagraphic instrumentation has been proposed and developed on 8-meter class telescopes, which is optimized for the high-contrast imaging observation from ground, for the giant exoplanets and other faint stellar companions. Gemini Planet Imager (GPI) has recently come to its first light, with a development period over 10 years. The contrast level has been pushed to 10-6. Due to the space limitation or this or other reasons, none professional adaptive optics is available for most of current 3~4 meter class telescopes, which will limit its observation power to some extent, especially in the research of high-contrast imaging of exoplanets.In this presentation, we will report the latest observation results by using our Extreme Adaptive Optics (Ex-AO) as a visiting instrument for high-contrast imaging on ESO’s 3.58-meter NTT telescope at LSO, and on 3.5-meter ARC telescope at Apache Point Observatory, respectively. It has demonstrated the Ex-AO can be used for the scientific research of exoplanets and brown dwarfs. With a update of the currect configuration with critical hardware, the dedicated instrument called as EDICT for imaging research of young giant exoplanets will be presented. Meanwhile, we have fully demonstrated in the lab a contrast on the order of 10-9 in a large detection area, which is a critical technique for future Earth-like exoplanets imaging space missions. And a space

  3. Confirmation of an exoplanet using the transit color signature: Kepler-418b, a blended giant planet in a multiplanet system

    NASA Astrophysics Data System (ADS)

    Tingley, B.; Parviainen, H.; Gandolfi, D.; Deeg, H. J.; Palle, E.; Montañés Rodriguez, P.; Murgas, F.; Alonso, R.; Bruntt, H.; Fridlund, M.

    2014-07-01

    Aims: We announce confirmation of Kepler-418b, one of two proposed planets in this system. This is the first confirmation of an exoplanet based primarily on the transit color signature technique. Methods: We used the Kepler public data archive combined with multicolor photometry from the Gran Telescopio de Canarias and radial velocity follow-up using FIES at the Nordic Optical Telescope for confirmation. Results: We report a confident detection of a transit color signature that can only be explained by a compact occulting body, entirely ruling out a contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing binary. Those findings are corroborated by our radial velocity measurements, which put an upper limit of ~1 MJup on the mass of Kepler-418b. We also report that the host star is significantly blended, confirming the ~10% light contamination suspected from the crowding metric in the Kepler light curve measured by the Kepler team. We report detection of an unresolved light source that contributes an additional ~30% to the target star, which would not have been detected without multicolor photometric analysis. The resulting planet-star radius ratio is 0.110 ± 0.0025, more than 25% more than the 0.087 measured by Kepler leading to a radius of 1.20 ± 0.16 RJup instead of the 0.94 RJup measured by the Kepler team. Conclusions: This is the first confirmation of an exoplanet candidate based primarily on the transit color signature, demonstrating that this technique is viable from ground for giant planets. It is particularly useful for planets with long periods such as Kepler-418b, which tend to have long transit durations. While this technique is limited to candidates with deep transits from the ground, it may be possible to confirm earth-like exoplanet candidates with a few hours of observing time with an instrument like the James Webb Space Telescope. Additionally, multicolor photometric analysis of transits can reveal unknown stellar neighbors

  4. SEEDS - Strategic explorations of exoplanets and disks with the Subaru Telescope -

    NASA Astrophysics Data System (ADS)

    Tamura, M.

    2016-02-01

    The first convincing detection of planets orbiting stars other than the Sun, or exoplanets, was made in 1995. In only 20 years, the number of the exoplanets including promising candidates has already accumulated to more than 5000. Most of the exoplanets discovered so far are detected by indirect methods because the direct imaging of exoplanets needs to overcome the extreme contrast between the bright central star and the faint planets. Using the large Subaru 8.2-m Telescope, a new high-contrast imager, HiCIAO, and second-generation adaptive optics (AO188), the most ambitious high-contrast direct imaging survey to date for giant planets and planet-forming disks has been conducted, the SEEDS project. In this review, we describe the aims and results of the SEEDS project for exoplanet/disk science. The completeness and uniformity of this systematic survey mean that the resulting data set will dominate this field of research for many years.

  5. A Decade of Radial-Velocity Discoveries in the Exoplanet Domain

    NASA Astrophysics Data System (ADS)

    Udry, S.; Fischer, D.; Queloz, D.

    Since the detection of a planetary companion orbiting 51 Peg one decade ago, close to 200 extrasolar planets have been unveiled by radial-velocity measurements. They exhibit a wide variety of characteristics, including large masses with small orbital separations, high eccentricities, multiplanet architectures, and orbital period resonances. Here, we discuss the statistical distributions of orbital parameters and host star properties in the context of constraints they provide for planet-formation models. We expect that radial-velocity surveys will continue to provide important discoveries. Thanks to ongoing instrumental developments and improved observing strategies, Neptune-mass planets in short-period orbits have recently been detected. We foresee continued improvement in radial-velocity precision that will reveal Neptune-mass planets in longer-period orbits and planets down to a few Earth masses in short-period orbits. The next decade of Doppler observations should expand the mass distribution function of exoplanets to lower masses. Finally, the role of radial-velocity followup measurements of transit candidates is emphasized.

  6. Diagnostics of models and observations in the contexts of exoplanets, brown dwarfs, and very low-mass stars.

    NASA Astrophysics Data System (ADS)

    Kopytova, Taisiya

    2016-01-01

    When studying isolated brown dwarfs and directly imaged exoplanets with insignificant orbital motion,we have to rely on theoretical models to determine basic parameters such as mass, age, effective temperature, and surface gravity.While stellar and atmospheric models are rapidly evolving, we need a powerful tool to test and calibrate them.In my thesis, I focussed on comparing interior and atmospheric models with observational data, in the effort of taking into account various systematic effects that can significantly influence the data analysis.As a first step, about 460 candidate member os the Hyades were screened for companions using diffraction limited imaging observation (both our own data and archival data). As a result I could establish the single star sequence for the Hyades comprising about 250 stars (Kopytova et al. 2015, accepted to A&A). Open clusters contain many coeval objects of the same chemical composition and age, and spanning a range of masses. We compare the obtained sequence with a set of theoretical isochrones identifying systematic offsets and revealing probable issues in the models.However, there are many cases when it is impossible to test models before comparing them with observations.As a second step, we apply atmospheric models for constraining parameters of WISE 0855-07, the coolest known Y dwarf(Kopytova et al. 2014, ApJ 797, 3). We demonstrate the limits of constraining effective temperature and the presence/absence of water clouds.As a third step, we introduce a novel method to take into account the above-mentioned systematics. We construct a "systematics vector" that allows us to reveal problematic wavelength ranges when fitting atmospheric models to observed near-infrared spectraof brown dwarfs and exoplanets (Kopytova et al., in prep.). This approach plays a crucial role when retrieving abundances for these objects, in particularly, a C/O ratio. The latter parameter is an important key to formation scenarios of brown dwarf and

  7. Direct Imaging of Exoplanets Living an Exciting Life

    NASA Astrophysics Data System (ADS)

    Chauvin, G.

    2016-01-01

    With the development of high contrast imaging techniques and instruments, vast efforts have been devoted during the past decades to detect and characterize lighter, cooler and closer companions to nearby stars, and ultimately image new planetary systems. Complementary to other planet-hunting techniques, this approach has opened a new astrophysical window to study the physical properties and the formation mechanisms of brown dwarfs and planets. In this review, I will briefly describe the different observing techniques and strategies used, the main samples of targeted nearby stars, finally the main results obtained so far about exoplanet discoveries characterization of their physical properties, and study of their occurrence and possible formation and evolution mechanisms.

  8. The Gemini Planet Imager Exoplanet Survey

    NASA Astrophysics Data System (ADS)

    Macintosh, Bruce

    artifacts and provides accurate and calibrated recovery of exoplanet spectra. We will produce a complete archive of all reduced GPI data products (supplementing the existing Gemini archive of raw data) for use by our collaboration, and release that archive to the public on an 18-month cycle. Most importantly, we will execute the GPI observations, initially through classical telescope visits, transitioning to remote and queue modes as our techniques are refined. As the first direct-imaging planet search with statistical depth comparable to Doppler planet detection and the first to probe into the snow line, the GPI Exoplanet Survey will provide strong constraints on paradigms for planet formation, completing the picture of the giant planet distribution throughout other solar systems, and also illuminating its evolution with stellar age and mass. We will deliver a catalog of detected exoplanets— the principal legacy of this campaign—released for follow-up by the astronomical community within 18 months of observation, as well as searchable archive of fully reduced images and detection limits for all stars surveyed. For each detected planet, we will produce estimated effective temperatures, luminosities, and semi-major axes: for a subset, high-SNR fiducial spectra, orbital eccentricities, and dynamical characterization through polarimetric imaging of attendant debris disks. GPI will complete final acceptance testing this month (May 2013) and is now ready to ship to Chile for first light in September 2013. The GPI survey will provide the best-yet view of the nature of wide-orbit planetary companions, informing our knowledge of solar system formation to guide future NASA planet hunting missions, while simultaneously offering a real- world program using the techniques - from integral field spectroscopy to advanced coronagraphy - that will someday be used to directly image Earthlike planets from space.

  9. Eccentricity of small exoplanets

    NASA Astrophysics Data System (ADS)

    Van Eylen, Vincent; Albrecht, Simon

    2015-12-01

    Solar system planets move on almost circular orbits. In strong contrast, many massive gas giant exoplanets travel on highly elliptical orbits, whereas the shape of the orbits of smaller, more terrestrial, exoplanets remained largely elusive. This is because the stellar radial velocity caused by these small planets is extremely challenging to measure. Knowing the eccentricity distribution in systems of small planets would be important as it holds information about the planet's formation and evolution. Furthermore the location of the habitable zone depends on eccentricity, and eccentricity also influences occurrence rates inferred for these planets because planets on circular orbits are less likely to transit. We make these eccentricity measurements of small planets using photometry from the Kepler satellite and utilizing a method relying on Kepler's second law, which relates the duration of a planetary transit to its orbital eccentricity, if the stellar density is known.I present a sample of 28 multi-planet systems with precise asteroseismic density measurements, which host 74 planets with an average radius of 2.6 R_earth. We find that the eccentricity of planets in these systems is low and can be described by a Rayleigh distribution with sigma = 0.049 +- 0.013. This is in full agreement with solar system eccentricities, but in contrast to the eccentricity distributions previously derived for exoplanets from radial velocity studies. I further report the first results on the eccentricities of over 50 Kepler single-planet systems, and compare them with the multi-planet systems. I close the talk by showing how transit durations help distinguish between false positives and true planets, and present six new planets.

  10. Exoplanet Orbit Database. II. Updates to Exoplanets.org

    NASA Astrophysics Data System (ADS)

    Han, Eunkyu; Wang, Sharon X.; Wright, Jason T.; Feng, Y. Katherina; Zhao, Ming; Fakhouri, Onsi; Brown, Jacob I.; Hancock, Colin

    2014-09-01

    The Exoplanet Orbit Database (EOD) compiles orbital, transit, host star, and other parameters of robustly-detected exoplanets reported in the peer-reviewed literature. The EOD can be navigated through the Exoplanet Data Explorer (EDE) plotter and table, available on the World Wide Web at exoplanets.org. The EOD contains data for 1492 confirmed exoplanets as of 2014 July. The EOD descends from a table provided by Butler and coworkers in 2002 and the Catalog of Nearby Exoplanets (Butler and coworkers in 2006), and the first complete documentation for the EOD and the EDE was presented by Wright and coworkers in 2011. In this work, we describe our work since then. We have expanded the scope of the EOD to include secondary eclipse parameters and asymmetric uncertainties and expanded the EDE to include the sample of over 3000 Kepler Objects of Interest (KOIs) and other real planets without good orbital parameters (such as many of those detected by microlensing and imaging). Users can download the latest version of the entire EOD as a single comma separated value file from the front page of exoplanets.org.

  11. Automatic Classification of Kepler Planetary Transit Candidates

    NASA Astrophysics Data System (ADS)

    McCauliff, Sean D.; Jenkins, Jon M.; Catanzarite, Joseph; Burke, Christopher J.; Coughlin, Jeffrey L.; Twicken, Joseph D.; Tenenbaum, Peter; Seader, Shawn; Li, Jie; Cote, Miles

    2015-06-01

    In the first three years of operation, the Kepler mission found 3697 planet candidates (PCs) from a set of 18,406 transit-like features detected on more than 200,000 distinct stars. Vetting candidate signals manually by inspecting light curves and other diagnostic information is a labor intensive effort. Additionally, this classification methodology does not yield any information about the quality of PCs; all candidates are as credible as any other. The torrent of exoplanet discoveries will continue after Kepler, because a number of exoplanet surveys will have an even broader search area. This paper presents the application of machine-learning techniques to the classification of the exoplanet transit-like signals present in the Kepler light curve data. Transit-like detections are transformed into a uniform set of real-numbered attributes, the most important of which are described in this paper. Each of the known transit-like detections is assigned a class of PC; astrophysical false positive; or systematic, instrumental noise. We use a random forest algorithm to learn the mapping from attributes to classes on this training set. The random forest algorithm has been used previously to classify variable stars; this is the first time it has been used for exoplanet classification. We are able to achieve an overall error rate of 5.85% and an error rate for classifying exoplanets candidates of 2.81%.

  12. E+A and companion galaxies - I. A catalogue and statistics

    NASA Astrophysics Data System (ADS)

    Yamauchi, Chisato; Yagi, Masafumi; Goto, Tomotsugu

    2008-10-01

    Based on our intensive spectroscopic campaign with the GoldCam spectrograph on the Kitt Peak National Observatory (KPNO) 2.1-m telescope, we have constructed the first catalogue of E+A galaxies with spectroscopic companion galaxies, and investigated a probability that an E+A galaxy has close companion galaxies. We selected 660 E+A galaxies with 4.0 Å < Hδ EW at a redshift of <0.167 from the Data Release 5 of the Sloan Digital Sky Survey (SDSS). We selected their companion candidates from the SDSS imaging data, and classified them into true companions, fore/background galaxies and companion candidates using the SDSS and our KPNO spectra. We observed 26 companion candidates of E+A galaxies at the KPNO to measure their redshifts. Their spectra showed that 17 targets are true companion galaxies. The number of spectroscopically confirmed E+A's companions is now 34. This becomes the first catalogue of E+A galaxies with spectroscopic companion systems. We found that E+A galaxies have 54 per cent larger probability of having companion galaxies (7.88 per cent) as compared to the comparison sample of normal galaxies (5.12 per cent). A statistical test shows that the probabilities are different with 99.7 per cent significance. Our results based on spectroscopy tighten the connection between the dynamical merger/interaction and the origin of E+A galaxies.

  13. Chemical modeling of exoplanet atmospheres

    NASA Astrophysics Data System (ADS)

    Venot, O.; Agúndez, M.

    2015-12-01

    The past twenty years have revealed the diversity of planets that exist in the Universe. It turned out that most of exoplanets are different from the planets of our Solar System and thus, everything about them needs to be explored. Thanks to current observational technologies, we are able to determine some information about the atmospheric composition the thermal structure and the dynamics of these exoplanets, but many questions remain still unanswered. To improve our knowledge about exoplanetary systems, more accurate observations are needed and that is why the Exoplanet Characterisation Observatory (EChO) is an essential space mission. Thanks to its large spectral coverage and high spectral resolution, EChO will provide exoplanetary spectra with an unprecedented accuracy, allowing to improve our understanding of exoplanets. In this work, we review what has been done to date concerning the chemical modeling of exoplanet atmospheres and what are the main characteristics of warm exoplanet atmospheres, which are one of the main targets of EChO. Finally we will present the ongoing developments that are necessary for the chemical modeling of exoplanet atmospheres.

  14. Saturn as a Transiting Exoplanet

    NASA Astrophysics Data System (ADS)

    Dalba, Paul A.; Muirhead, Philip S.; Fortney, Jonathan J.; Hedman, Matthew M.; Nicholson, Philip D.; Veyette, Mark J.

    2015-11-01

    Previous investigations of exoplanet atmospheres have not targeted those resembling the gas giant planets in our solar system. These types of exoplanets are too cold to be directly imaged or observed in emission, and their low transit probabilities and frequencies make characterization via transmission spectroscopy a challenging endeavor. However, studies of cold giant exoplanets would be highly valuable to our understanding of planet formation and migration and could place the gas giant members of our own solar system in a greater context. Here, we use solar occultations observed by the Visual and Infrared Mapping Spectrometer aboard the Cassini Spacecraft to extract the 1 to 5 μm transmission spectrum of Saturn, as if it were a transiting exoplanet. We detect absorption features from several molecules despite the presence of ammonia clouds. Self-consistent exoplanet atmosphere models show good agreement with Saturn's transmission spectrum but fail to reproduce the largest feature in the spectrum. We also find that atmospheric refraction determines the minimum altitude that could be probed during mid-transit of a Saturn-twin exoplanet around a Sun-like star. These results suggest that transmission spectroscopy of cold, long-period gaseous exoplanets should be possible with current and future observatories.

  15. NASA's Missions for Exoplanet Exploration

    NASA Astrophysics Data System (ADS)

    Unwin, Stephen

    2014-05-01

    Exoplanets are detected and characterized using a range of observational techniques - including direct imaging, astrometry, transits, microlensing, and radial velocities. Each technique illuminates a different aspect of exoplanet properties and statistics. This diversity of approach has contributed to the rapid growth of the field into a major research area in only two decades. In parallel with exoplanet observations, major efforts are now underway to interpret the physical and atmospheric properties of exoplanets for which spectroscopy is now possible. In addition, comparative planetology probes questions of interest to both exoplanets and solar system studies. In this talk I describe NASA's activities in exoplanet research, and discuss plans for near-future missions that have reflected-light spectroscopy as a key goal. The WFIRST-AFTA concept currently under active study includes a major microlensing survey, and now includes a visible light coronagraph for exoplanet spectroscopy and debris disk imaging. Two NASA-selected community-led teams are studying probe-scale (< 1B) mission concepts for imaging and spectroscopy. These concepts complement existing NASA missions that do exoplanet science (such as transit spectroscopy and debris disk imaging with HST and Spitzer) or are under development (survey of nearby transiting exoplanets with TESS, and followup of the most important targets with transit spectroscopy on JWST), and build on the work of ground-based instruments such as LBTI and observing with HIRES on Keck. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2014. California Institute of Technology. Government sponsorship acknowledged.

  16. Search of Exoplanets - Phase I

    NASA Astrophysics Data System (ADS)

    Vodniza, Alberto Q.; Pereira, M. R.; Lopez, J. P.; Reyes, K.; Chaves, L.

    2008-09-01

    From the Astronomical Observatory at the University of Nariño-COLOMBIA, we have begun a systematic search for exoplanets. Initially we made differential photometry on variable stars weaker than the tenth magnitude to get enough experience on the establishment of stellar transits, so then we could undertake the work with exoplanets. We have already confirmed the transits of two exoplanets with good photometry data: At the exoplanet HAT-P-5b, discovered by Bakos and other investigators and which turns around the GSC 02634-01087, with an orbital period of 2.788491 days according to measurements of the discoverers, and also at the exoplanet TrES-3, discovered by O'Donovan and other investigators and which turns around the GSC 03089-00929, with an orbital period of 1.30619 days, established by its discoverers. Both exoplanets are quite interesting because they have one of the smallest periods found on exoplanets. The TrES-3 also provides a big opportunity for studying the orbital decay and mass loss due to evaporation, caused by the great closeness to its star. We have captured a lot of data to elaborate the lightcurves so we can estimate physical parameters of the bodies. We are getting data on various dates. Actually we are preparing the equipment to develop observations of radial velocities through spectrometry. In a later phase, we expect to verify the presence of other exoplanets which cause less deep transits, and then we can investigate stars with possible exoplanets around them. Besides we hope to design a mathematical model of the studied systems. The equipment we employed is: 14"LX200 GPS MEADE telescope, ST-7XME SBIG camera, STL-1001 SBIG camera, LHIRES III Spectrograph, and SGS-SBIG Spectrograph. On the poster it is explained at length the methodology followed over the search, the data we obtained and the physical- mathematical analysis that was carried out.

  17. PynPoint code for exoplanet imaging

    NASA Astrophysics Data System (ADS)

    Amara, A.; Quanz, S. P.; Akeret, J.

    2015-04-01

    We announce the public release of PynPoint, a Python package that we have developed for analysing exoplanet data taken with the angular differential imaging observing technique. In particular, PynPoint is designed to model the point spread function of the central star and to subtract its flux contribution to reveal nearby faint companion planets. The current version of the package does this correction by using a principal component analysis method to build a basis set for modelling the point spread function of the observations. We demonstrate the performance of the package by reanalysing publicly available data on the exoplanet β Pictoris b, which consists of close to 24,000 individual image frames. We show that PynPoint is able to analyse this typical data in roughly 1.5 min on a Mac Pro, when the number of images is reduced by co-adding in sets of 5. The main computational work, the calculation of the Singular-Value-Decomposition, parallelises well as a result of a reliance on the SciPy and NumPy packages. For this calculation the peak memory load is 6 GB, which can be run comfortably on most workstations. A simpler calculation, by co-adding over 50, takes 3 s with a peak memory usage of 600 MB. This can be performed easily on a laptop. In developing the package we have modularised the code so that we will be able to extend functionality in future releases, through the inclusion of more modules, without it affecting the users application programming interface. We distribute the PynPoint package under GPLv3 licence through the central PyPI server, and the documentation is available online (http://pynpoint.ethz.ch).

  18. VIP: Vortex Image Processing pipeline for high-contrast direct imaging of exoplanets

    NASA Astrophysics Data System (ADS)

    Gomez Gonzalez, Carlos Alberto; Wertz, Olivier; Christiaens, Valentin; Absil, Olivier; Mawet, Dimitri

    2016-03-01

    VIP (Vortex Image Processing pipeline) provides pre- and post-processing algorithms for high-contrast direct imaging of exoplanets. Written in Python, VIP provides a very flexible framework for data exploration and image processing and supports high-contrast imaging observational techniques, including angular, reference-star and multi-spectral differential imaging. Several post-processing algorithms for PSF subtraction based on principal component analysis are available as well as the LLSG (Local Low-rank plus Sparse plus Gaussian-noise decomposition) algorithm for angular differential imaging. VIP also implements the negative fake companion technique coupled with MCMC sampling for rigorous estimation of the flux and position of potential companions.

  19. The First Thousand Exoplanets: Twenty Years of Excitement and Discovery

    NASA Astrophysics Data System (ADS)

    Impey, Chris

    The recent "explosion" in the number of extrasolar planets, or exoplanets, is perhaps the most exciting phenomenon in all of science. Two decades ago, no planets were known beyond the Solar System, and now there are more than 770 confirmed exoplanets and several thousand more candidates, while the mass detection limit has marched steadily downwards from Jupiter mass in 1995 to Neptune mass in the early 2000s to Earth mass now. The vast majority of these exoplanets are detected indirectly, by their gravitational influence on the parent star or the partial eclipse they cause when they periodically pass in front of it. Doppler detection of the planet's reflex motion yields a period and an estimate of the mass, while transits or eclipses yield the size. Exoplanet detection taxes the best observatories in space, yet useful contributions can be made by amateur astronomers armed with 6-inch telescopes. The early discoveries were surprising; no one predicted "hot Jupiters" or the wild diversity of exoplanet properties that has been seen. It is still unclear if the Solar System is "typical" or not, but at current detection limits at least 10 % of Sun-like stars harbor planets and architectures similar to the Solar System are now being found. Over a hundred multiple planet systems are known and the data are consistent with every star in the Milky Way having at least one planet, with an implication of millions of habitable, Earth-like planets, and of which could harbor life. Doppler and transit data can be combined to give average density, and additional methods are beginning to give diagnostics of atmospheric composition. When this work can be extended to rocky and low mass exoplanets, and the imprint of biology on a global atmosphere can be measured, this might be the way that life beyond Earth is finally detected for the first time.

  20. The Architecture of Exoplanets

    NASA Astrophysics Data System (ADS)

    Hatzes, Artie P.

    2016-05-01

    Prior to the discovery of exoplanets our expectations of their architecture were largely driven by the properties of our solar system. We expected giant planets to lie in the outer regions and rocky planets in the inner regions. Planets should probably only occupy orbital distances 0.3-30 AU from the star. Planetary orbits should be circular, prograde and in the same plane. The reality of exoplanets have shattered these expectations. Jupiter-mass, Neptune-mass, Superearths, and even Earth-mass planets can orbit within 0.05 AU of the stars, sometimes with orbital periods of less than one day. Exoplanetary orbits can be eccentric, misaligned, and even in retrograde orbits. Radial velocity surveys gave the first hints that the occurrence rate increases with decreasing mass. This was put on a firm statistical basis with the Kepler mission that clearly demonstrated that there were more Neptune- and Superearth-sized planets than Jupiter-sized planets. These are often in multiple, densely packed systems where the planets all orbit within 0.3 AU of the star, a result also suggested by radial velocity surveys. Exoplanets also exhibit diversity along the main sequence. Massive stars tend to have a higher frequency of planets ( ≈ 20-25 %) that tend to be more massive ( M≈ 5-10 M_{Jup}). Giant planets around low mass stars are rare, but these stars show an abundance of small (Neptune and Superearth) planets in multiple systems. Planet formation is also not restricted to single stars as the Kepler mission has discovered several circumbinary planets. Although we have learned much about the architecture of planets over the past 20 years, we know little about the census of small planets at relatively large ( a>1 AU) orbital distances. We have yet to find a planetary system that is analogous to our own solar system. The question of how unique are the properties of our own solar system remains unanswered. Advancements in the detection methods of small planets over a wide range

  1. Weird Warm Spot on Exoplanet

    NASA Video Gallery

    This animation illustrates an unexpected warm spot on the surface of a gaseous exoplanet. NASA's Spitzer Space Telescope discovered that the hottest part of the planet, shown here as bright, orange...

  2. A Cloudy View of Exoplanets

    NASA Technical Reports Server (NTRS)

    Deming, Drake

    2010-01-01

    The lack of absorption features in the transmission spectrum of exoplanet GJ1214b rules out a hydrogen-rich atmosphere for the planet. It is consistent with an atmosphere rich in water vapour or abundant in clouds.

  3. Exoplanet Clouds in the Laboratory

    NASA Astrophysics Data System (ADS)

    Johnson, Alexandria; Cziczo, Daniel J.; Seager, Sara; Charbonneau, David; Bauer, Amy J. R.

    2015-12-01

    The lack of strong spectral features of some exoplanet atmospheres may suggest the presence of a cloud layer and poses great challenges for atmospheric characterization. We aim to address these observations and the challenges by leveraging lab-based terrestrial cloud particle instrumentation as a means of investigating how particles representative of those in exoplanet atmospheres interact with incoming radiation. In the end we hope to achieve two goals - First, to better understand the observable properties of cloud particles in exoplanet atmospheres. Second, to determine how these clouds might directly limit our ability to observe and characterize the atmosphere below.In this presentation I will discuss the cloud chamber used for this work, how we leverage terrestrial based cloud knowledge, our initial investigation of the light scattered by ammonium nitrate (NH4NO3) across temperature and relative humidity dependent phase changes, and future work with suspected exoplanet atmospheric condensates under various atmospheric compositions, pressures, and temperatures.

  4. DEBRIS DISKS IN KEPLER EXOPLANET SYSTEMS

    SciTech Connect

    Lawler, S. M.; Gladman, B.

    2012-06-10

    The Kepler mission recently identified 997 systems hosting candidate extrasolar planets, many of which are super-Earths. Realizing these planetary systems are candidates to host extrasolar asteroid belts, we use mid-infrared data from the Wide-field Infrared Survey Explorer (WISE) to search for emission from dust in these systems. We find excesses around eight stars, indicating the presence of warm to hot dust ({approx}100-500 K), corresponding to orbital distances of 0.1-10 AU for these solar-type stars. The strongest detection, KOI 1099, demands {approx}500 K dust interior to the orbit of its exoplanet candidate. One star, KOI 904, may host very hot dust ({approx}1200 K, corresponding to 0.02 AU). Although the fraction of these exoplanet-bearing stars with detectable warm excesses ({approx}3%) is similar to that found by Spitzer surveys of solar-type field stars, the excesses detectable in the WISE data have much higher fractional luminosities (L{sub dust}/L{sub *}) than most known debris disks, implying that the fraction with debris disks of comparable luminosity may actually be significantly higher. It is difficult to explain the presence of dust so close to the host stars, generally corresponding to dust rings at radii <0.3 AU; both the collisional and Poynting-Robertson drag timescales to remove dust from the system are hundreds of years or less at these distances. Assuming a steady state for these systems implies large mass consumption rates with these short removal timescales, meaning that the dust production mechanism in these systems must almost certainly be episodic in nature.

  5. Observations of Exoplanet Atmospheres

    NASA Astrophysics Data System (ADS)

    Crossfield, Ian J. M.

    2015-10-01

    Detailed characterization of an extrasolar planet's atmosphere provides the best hope for distinguishing the makeup of its outer layers, and the only hope for understanding the interplay between initial composition, chemistry, dynamics and circulation, and disequilibrium processes. In recent years, some areas have seen rapid progress, while developments in others have come more slowly and/or have been hotly contested. This article gives an observer's perspective on the current understanding of extrasolar planet atmospheres prior to the considerable advances expected from the next generation of observing facilities. Atmospheric processes of both transiting and directly imaged planets are discussed, including molecular and atomic abundances, cloud properties, thermal structure, and planetary energy budgets. In the future we can expect a continuing and accelerating stream of new discoveries, which will fuel the ongoing exoplanet revolution for many years to come.

  6. Structure of exoplanets.

    PubMed

    Spiegel, David S; Fortney, Jonathan J; Sotin, Christophe

    2014-09-01

    The hundreds of exoplanets that have been discovered in the past two decades offer a new perspective on planetary structure. Instead of being the archetypal examples of planets, those of our solar system are merely possible outcomes of planetary system formation and evolution, and conceivably not even especially common outcomes (although this remains an open question). Here, we review the diverse range of interior structures that are both known and speculated to exist in exoplanetary systems--from mostly degenerate objects that are more than 10× as massive as Jupiter, to intermediate-mass Neptune-like objects with large cores and moderate hydrogen/helium envelopes, to rocky objects with roughly the mass of Earth. PMID:24379369

  7. Geoengineering on exoplanets

    NASA Astrophysics Data System (ADS)

    Lockley, Andrew

    2015-04-01

    Solar radiation management (SRM) geoengineering can be used to deliberately alter the Earth's radiation budget, by reflecting sunlight to space. SRM has been suggested as a response to Anthropogenic Global Warming (AGW), to partly or fully balance radiative forcing from AGW [1]. Approximately 22% of sun-like stars have Earth-like exoplanets[2]. Advanced civilisations may exist on these, and may use geoengineering for positive or negative radiative forcing. Additionally, terraforming projects [e.g. 3], may be used to expand alien habitable territory, or for resource management or military operations on non-home planets. Potential observations of alien geoengineering and terraforming may enable detection of technologically advanced alien civilisations, and may help identify widely-used and stable geoengineering technologies. This knowledge may assist the development of safe and stable geoengineering methods for Earth. The potential risks and benefits of possible alien detection of Earth-bound geoengineering schemes must be considered before deployment of terrestrial geoengineering schemes.

  8. Visualising Astronomy: Visualising Exoplanets

    NASA Astrophysics Data System (ADS)

    Wyatt, R.

    2012-05-01

    In my previous column1, I described some of the varied means of diagramming the data about exoplanets and exoplanetary systems. Frankly, however, those methods don't do justice to the bigger picture: we need a wider range of tools to help people grok2 (to understand intuitively) what astronomical observations have revealed. (Normally, I use the term "visualisation" to refer to the visual representation of data, but I'm going to relax that a little in this context; instead, I'll interpret the word in its more commonplace usage of creating a mental image.) How can we help people comprehend the scope, the breadth, and the impact of the spectacular observations of planets around other stars?

  9. Structure of exoplanets

    PubMed Central

    Spiegel, David S.; Fortney, Jonathan J.; Sotin, Christophe

    2014-01-01

    The hundreds of exoplanets that have been discovered in the past two decades offer a new perspective on planetary structure. Instead of being the archetypal examples of planets, those of our solar system are merely possible outcomes of planetary system formation and evolution, and conceivably not even especially common outcomes (although this remains an open question). Here, we review the diverse range of interior structures that are both known and speculated to exist in exoplanetary systems—from mostly degenerate objects that are more than 10× as massive as Jupiter, to intermediate-mass Neptune-like objects with large cores and moderate hydrogen/helium envelopes, to rocky objects with roughly the mass of Earth. PMID:24379369

  10. Kepler mission exoplanet transit data analysis using fractal imaging

    NASA Astrophysics Data System (ADS)

    Dehipawala, S.; Tremberger, G.; Majid, Y.; Holden, T.; Lieberman, D.; Cheung, T.

    2012-10-01

    The Kepler mission is designed to survey a fist-sized patch of the sky within the Milky Way galaxy for the discovery of exoplanets, with emphasis on near Earth-size exoplanets in or near the habitable zone. The Kepler space telescope would detect the brightness fluctuation of a host star and extract periodic dimming in the lightcurve caused by exoplanets that cross in front of their host star. The photometric data of a host star could be interpreted as an image where fractal imaging would be applicable. Fractal analysis could elucidate the incomplete data limitation posed by the data integration window. The fractal dimension difference between the lower and upper halves of the image could be used to identify anomalies associated with transits and stellar activity as the buried signals are expected to be in the lower half of such an image. Using an image fractal dimension resolution of 0.04 and defining the whole image fractal dimension as the Chi-square expected value of the fractal dimension, a p-value can be computed and used to establish a numerical threshold for decision making that may be useful in further studies of lightcurves of stars with candidate exoplanets. Similar fractal dimension difference approaches would be applicable to the study of photometric time series data via the Higuchi method. The correlated randomness of the brightness data series could be used to support inferences based on image fractal dimension differences. Fractal compression techniques could be used to transform a lightcurve image, resulting in a new image with a new fractal dimension value, but this method has been found to be ineffective for images with high information capacity. The three studied criteria could be used together to further constrain the Kepler list of candidate lightcurves of stars with possible exoplanets that may be planned for ground-based telescope confirmation.

  11. Search for wide, ultracool companions of nearby T dwarfs

    NASA Astrophysics Data System (ADS)

    Osorio, M. R. Zapatero; Béjar, V. J. S.; Goldman, B.; Rebolo, R.; Bihain, G.; Bouy, H.

    2009-02-01

    We report on our on-going proper motion survey of very low-mass (>=5 MJup), ultracool (Teff>=350 K) companions of nearby, field T-type brown dwarfs in the Solar neighborhood. Our project is intended to provide seeing-limited images of the targets to find companion candidates at wide separations (>=15 AU) and within an area of 3'×3' around the primaries, thus complementing previous searches that explored the inner-most regions. Data are collected in the J-band with 2-4-m class telescopes; the completeness magnitude of our survey goes from ~19.5 to ~21 mag (depending on seeing and transparency conditions). So far we have studied 11 late-L and T-type brown dwarfs located at d<=16 pc of the Sun. Only one faint, proper motion companion candidate is found; its definitive confirmation highly requires third epoch data.

  12. The Unseen Companion of HD 114762

    NASA Astrophysics Data System (ADS)

    Latham, David W.

    2014-01-01

    I have told the story of the discovery of the unseen companion of HD114762 (Latham et al. 1989, Nature, 389, 38-40) in a recent publication (Latham 2012, New Astronomy Reviews 56, 16-18). The discovery was enabled by a happy combination of some thinking outside the box by Tsevi Mazeh at Tel Aviv University and the development of new technology for measuring stellar spectra at the Harvard-Smithsonian Center for Astrophysics. Tsevi's unconventional idea was that giant exoplanets might be found much closer to their host stars than Jupiter and Saturn are to the Sun, well inside the snow line. Our instrument was a high-resolution echelle spectrograph optimized for measuring radial velocities of stars similar to the Sun. The key technological developments were an intensified Reticon photon-counting detector under computer control combined with sophisticated analysis of the digital spectra. The detector signal-processing electronics eliminated persistence, which had plagued other intensified systems. This allowed bright Th-Ar calibration exposures before and after every stellar observation, which in turn enabled careful correction for spectrograph drifts. We built three of these systems for telescopes in Massachusetts and Arizona and christened them the "CfA Digital Speedometers". The discovery of HD 114762-b was serendipitous, but not accidental.

  13. Exoplanet Caught on the Move

    NASA Astrophysics Data System (ADS)

    2010-06-01

    observations, taken during autumn 2009, revealed the object on the other side of the disc after a period of hiding either behind or in front of the star (in which case it is hidden in the glare of the star). This confirmed that the source indeed was an exoplanet and that it was orbiting its host star. It also provided insights into the size of its orbit around the star. Images are available for approximately ten exoplanets, and the planet around Beta Pictoris (designated "Beta Pictoris b") has the smallest orbit known so far. It is located at a distance between 8 and 15 times the Earth-Sun separation - or 8-15 Astronomical Units - which is about the distance of Saturn from the Sun. "The short period of the planet will allow us to record the full orbit within maybe 15-20 years, and further studies of Beta Pictoris b will provide invaluable insights into the physics and chemistry of a young giant planet's atmosphere," says student researcher Mickael Bonnefoy. The planet has a mass of about nine Jupiter masses and the right mass and location to explain the observed warp in the inner parts of the disc. This discovery therefore bears some similarity to the prediction of the existence of Neptune by astronomers Adams and Le Verrier in the 19th century, based on observations of the orbit of Uranus. "Together with the planets found around the young, massive stars Fomalhaut and HR8799, the existence of Beta Pictoris b suggests that super-Jupiters could be frequent byproducts of planet formation around more massive stars," explains Gael Chauvin, a member of the team. Such planets disturb the discs around their stars, creating structures that should be readily observable with the Atacama Large Millimeter/submillimeter Array (ALMA), the revolutionary telescope being built by ESO together with international partners. A few other planetary candidates have been imaged, but they are all located further from their host star than Beta Pictoris b. If located in the Solar System, they all would

  14. Clandestine Companions of Nearby Red Dwarfs

    NASA Astrophysics Data System (ADS)

    Henry, Todd J.; Koerner, D. W.; Jao, W. C.; Subasavage, J. P.; Ianna, P. A.; RECONS

    2006-12-01

    During the RECONS parallax program at the CTIO 0.9m, we have accumulated more than six years of astrometric data on red dwarfs in the southern sky. Eighty red dwarfs within 10 pc, including more than two dozen new discoveries by our team, are being followed to reveal the telltale perturbations caused by unseen companions. The advent of modern CCD technology yields substantial improvement in the detection of low mass companions over the classic studies done using photographic plates. The current ASPENS (Astrometric Search for Planets Encircling Nearby Stars) program is capable of finding hidden companions with masses as low as 10 Jupiters. Here we report the first results of the ASPENS effort, including a few intriguing systems with orbital periods of several years. Nearby red dwarfs are prime candidates for NASA's Space Interferometry Mission (SIM) because the astrometric perturbations are largest for planets orbiting nearby stars of low mass. In addition, new multiple red dwarf systems can be targeted for mass determinations, thereby providing points on a comprehensive mass-luminosity relation for the most populous members of the Galaxy. These long-term observations began in 1999 as an NOAO Surveys program, and are continuing via the SMARTS Consortium. This work has been supported by the National Science Foundation (AST 98-20711 and 05-07711), NASA's Space Interferometry Mission, Georgia State University, and Northern Arizona University.

  15. Immunocontraception in companion animals.

    PubMed

    Purswell, B J; Kolster, Kara A

    2006-08-01

    There is real need worldwide to control the population growth of companion animals. Throughout the world and particularly in the United States, overpopulation of unwanted dogs and cats is a concern for many reasons. Feral populations pose risk to native species by spread of disease and predation. That unwanted animals are humanely eradicated is of concern to many persons. The need to control population growth has led to various approaches to contraception, including immunocontraception. Concerns regarding efficacy, duration of action, harm to the individual, and species specificity are among the issues being addressed. As new technologies emerge, ethical, political, and safety issues evoke differing opinions. It is hoped that in the near future, different strategies will be developed to solve this disturbing problem. PMID:16837035

  16. Exoplanet Yield Estimation for Decadal Study Concepts using EXOSIMS

    NASA Astrophysics Data System (ADS)

    Morgan, Rhonda; Lowrance, Patrick; Savransky, Dmitry; Garrett, Daniel

    2016-01-01

    The anticipated upcoming large mission study concepts for the direct imaging of exo-earths present an exciting opportunity for exoplanet discovery and characterization. While these telescope concepts would also be capable of conducting a broad range of astrophysical investigations, the most difficult technology challenges are driven by the requirements for imaging exo-earths. The exoplanet science yield for these mission concepts will drive design trades and mission concept comparisons.To assist in these trade studies, the Exoplanet Exploration Program Office (ExEP) is developing a yield estimation tool that emphasizes transparency and consistent comparison of various design concepts. The tool will provide a parametric estimate of science yield of various mission concepts using contrast curves from physics-based model codes and Monte Carlo simulations of design reference missions using realistic constraints, such as solar avoidance angles, the observatory orbit, propulsion limitations of star shades, the accessibility of candidate targets, local and background zodiacal light levels, and background confusion by stars and galaxies. The python tool utilizes Dmitry Savransky's EXOSIMS (Exoplanet Open-Source Imaging Mission Simulator) design reference mission simulator that is being developed for the WFIRST Preliminary Science program. ExEP is extending and validating the tool for future mission concepts under consideration for the upcoming 2020 decadal review. We present a validation plan and preliminary yield results for a point design.

  17. Imaginary Companions of Preschool Children.

    ERIC Educational Resources Information Center

    Gleason, Tracy R.; Sebanc, Anne M.; Hartup, Willard W.

    2000-01-01

    Interviewed mothers to examine the developmental significance of preschoolers' imaginary companions. Found that relationships with invisible companions were described as sociable and friendly, whereas personified objects were usually nurtured. Object personification frequently occurred as a result of acquiring a toy; invisible friends were viewed…

  18. The Kepler-454 System: A Small, Not-rocky Inner Planet, a Jovian World, and a Distant Companion

    NASA Astrophysics Data System (ADS)

    Gettel, Sara; Charbonneau, David; Dressing, Courtney D.; Buchhave, Lars A.; Dumusque, Xavier; Vanderburg, Andrew; Bonomo, Aldo S.; Malavolta, Luca; Pepe, Francesco; Collier Cameron, Andrew; Latham, David W.; Udry, Stéphane; Marcy, Geoffrey W.; Isaacson, Howard; Howard, Andrew W.; Davies, Guy R.; Silva Aguirre, Victor; Kjeldsen, Hans; Bedding, Timothy R.; Lopez, Eric; Affer, Laura; Cosentino, Rosario; Figueira, Pedro; Fiorenzano, Aldo F. M.; Harutyunyan, Avet; Johnson, John Asher; Lopez-Morales, Mercedes; Lovis, Christophe; Mayor, Michel; Micela, Giusi; Molinari, Emilio; Motalebi, Fatemeh; Phillips, David F.; Piotto, Giampaolo; Queloz, Didier; Rice, Ken; Sasselov, Dimitar; Ségransan, Damien; Sozzetti, Alessandro; Watson, Chris; Basu, Sarbani; Campante, Tiago L.; Christensen-Dalsgaard, Jørgen; Kawaler, Steven D.; Metcalfe, Travis S.; Handberg, Rasmus; Lund, Mikkel N.; Lundkvist, Mia S.; Huber, Daniel; Chaplin, William J.

    2016-01-01

    Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like star that hosts a transiting planet candidate in a 10.6 day orbit. From spectroscopy, we estimate the stellar temperature to be 5687 ± 50 K, its metallicity to be [m/H] = 0.32 ± 0.08, and the projected rotational velocity to be v sin i < 2.4 km s-1. We combine these values with a study of the asteroseismic frequencies from short cadence Kepler data to estimate the stellar mass to be {1.028}-0.03+0.04{M}⊙ , the radius to be 1.066 ± 0.012 R⊙, and the age to be {5.25}-1.39+1.41 Gyr. We estimate the radius of the 10.6 day planet as 2.37 ± 0.13 R⊕. Using 63 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 36 observations made with the HIRES spectrograph at the Keck Observatory, we measure the mass of this planet to be 6.8 ± 1.4 M⊕. We also detect two additional non-transiting companions, a planet with a minimum mass of 4.46 ± 0.12 MJ in a nearly circular 524 day orbit and a massive companion with a period >10 years and mass >12.1 MJ. The 12 exoplanets with radii <2.7 R⊕ and precise mass measurements appear to fall into two populations, with those <1.6 R⊕ following an Earth-like composition curve and larger planets requiring a significant fraction of volatiles. With a density of 2.76 ± 0.73 g cm-3, Kepler-454b lies near the mass transition between these two populations and requires the presence of volatiles and/or H/He gas.

  19. Exoplanet Caught on the Move

    NASA Astrophysics Data System (ADS)

    2010-06-01

    observations, taken during autumn 2009, revealed the object on the other side of the disc after a period of hiding either behind or in front of the star (in which case it is hidden in the glare of the star). This confirmed that the source indeed was an exoplanet and that it was orbiting its host star. It also provided insights into the size of its orbit around the star. Images are available for approximately ten exoplanets, and the planet around Beta Pictoris (designated "Beta Pictoris b") has the smallest orbit known so far. It is located at a distance between 8 and 15 times the Earth-Sun separation - or 8-15 Astronomical Units - which is about the distance of Saturn from the Sun. "The short period of the planet will allow us to record the full orbit within maybe 15-20 years, and further studies of Beta Pictoris b will provide invaluable insights into the physics and chemistry of a young giant planet's atmosphere," says student researcher Mickael Bonnefoy. The planet has a mass of about nine Jupiter masses and the right mass and location to explain the observed warp in the inner parts of the disc. This discovery therefore bears some similarity to the prediction of the existence of Neptune by astronomers Adams and Le Verrier in the 19th century, based on observations of the orbit of Uranus. "Together with the planets found around the young, massive stars Fomalhaut and HR8799, the existence of Beta Pictoris b suggests that super-Jupiters could be frequent byproducts of planet formation around more massive stars," explains Gael Chauvin, a member of the team. Such planets disturb the discs around their stars, creating structures that should be readily observable with the Atacama Large Millimeter/submillimeter Array (ALMA), the revolutionary telescope being built by ESO together with international partners. A few other planetary candidates have been imaged, but they are all located further from their host star than Beta Pictoris b. If located in the Solar System, they all would

  20. The NASA Exoplanet Exploration Program

    NASA Astrophysics Data System (ADS)

    Hudgins, Douglas M.; Blackwood, Gary H.; Gagosian, John S.

    2015-12-01

    The NASA Exoplanet Exploration Program (ExEP) is chartered to implement the NASA space science goals of detecting and characterizing exoplanets and to search for signs of life. The ExEP manages space missions, future studies, technology investments, and ground-based science that either enables future missions or completes mission science. The exoplanet science community is engaged by the Program through Science Definition Teams and through the Exoplanet Program Analysis Group (ExoPAG). The ExEP includes the space science missions of Kepler, K2 , and the proposed WFIRST-AFTA that includes dark energy science, a widefield infrared survey, a microlensing survey for outer-exoplanet demographics, and a coronagraph for direct imaging of cool outer gas- and ice-giants around nearby stars. Studies of probe-scale (medium class) missions for a coronagraph (internal occulter) and starshade (external occulter) explore the trades of cost and science and provide motivation for a technology investment program to enable consideration of missions at the next decadal survey for NASA Astrophysics. Program elements include follow-up observations using the Keck Observatory, which contribute to the science yield of Kepler and K2, and include mid-infrared observations of exo-zodiacal dust by the Large Binocular Telescope Interferometer which provide parameters critical to the design and predicted science yield of the next generation of direct imaging missions. ExEP includes the NASA Exoplanet Science Institute which provides archives, tools, and professional education for the exoplanet community. Each of these program elements contribute to the goal of detecting and characterizing earth-like planets orbiting other stars, and seeks to respond to rapid evolution in this discovery-driven field and to ongoing programmatic challenges through engagement of the scientific and technical communities.

  1. The NASA Exoplanet Exploration Program

    NASA Astrophysics Data System (ADS)

    Hudgins, Douglas M.; Blackwood, Gary; Gagosian, John

    2014-11-01

    The NASA Exoplanet Exploration Program (ExEP) is chartered to implement the NASA space science goals of detecting and characterizing exoplanets and to search for signs of life. The ExEP manages space missions, future studies, technology investments, and ground-based science that either enables future missions or completes mission science. The exoplanet science community is engaged by the Program through Science Definition Teams and through the Exoplanet Program Analysis Group. The ExEP includes the space science missions of Kepler, K2, and the proposed WFIRST-AFTA that includes dark energy science, a widefield infrared survey, a microlensing survey for outer-exoplanet demographics, and a coronagraph for direct imaging of cool outer gas- and ice-giants around nearby stars. Studies of probe-scale (medium class) missions for a coronagraph (internal occulter) and starshade (external occulter) explore the trades of cost and science and provide motivation for a technology investment program to enable consideration of missions at the next decadal survey for NASA Astrophysics. Program elements include follow-up observations using the Keck Observatory which contribute to the science yield of Kepler and K2, and include mid-infrared observations of exo-zodiacal dust by the Large Binocular Telescope Interferometer which provide parameters critical to the design and predicted science yield of the next generation of direct imaging missions. ExEP includes the NASA Exoplanet Science Institute which provides archives, tools, and professional education for the exoplanet community. Each of these program elements contribute to the goal of detecting and characterizing earth-like planets orbiting other stars, and seeks to respond to rapid evolution in this discovery-driven field and to ongoing programmatic challenges through engagement of the scientific and technical communities.

  2. Exceptional Stars Origins, Companions, Masses and Planets

    NASA Technical Reports Server (NTRS)

    Kulkarni, Shrinivas R.; Hansen, Bradley M. S.; Phinney, Sterl; vanKerkwijk, Martin H.; Vasisht, Gautam

    2004-01-01

    As SIM Interdisciplinary Scientist, we will study the formation, nature and planetary companions of the exotic endpoints of stellar evolution. Our science begins with stars evolving from asymptotic branch giants into white dwarfs. We will determine the parallax and orbital inclination of several iron-deficient post-AGB stars, who peculiar abundances and infrared excesses are evidence that they are accreting gas depleted of dust from a circumbinary disk. Measurement of the orbital inclination, companion mass arid parallax will provide critical constraints. One of these stars is a prime candidate for trying nulling observations, which should reveal light reflected from both the circumbinary and Roche disks. The circumbinary disks seem favorable sites for planet formation. Next, we will search for planets around white dwarfs, both survivors froni the main-sequence stage, and ones newly formed from the circumbinary disks of post-AGB binaries or in white dwarf mergers. Moving up in mass, we will measure the orbital reflex of OB/Be companions to pulsars, determine natal kicks and presupernova orbits, and expand the sample of well-determined neutron star masses. We will obtain the parallax of a transient X-ray binary, whose quiescent emission may be thermal emission from the neutron star, aiming for precise measurement of the neutron star radius. Finally, black holes. We will measure the reflex motions of the companion of what appear to be the most massive stellar black holes. The visual orbits will determine natal kicks, and test the assumptions underlying mass estimates made from the radial velocity curves, projected rotation, and ellipsoidal variations. In addition, we will attempt to observe the visual orbit of SS 433, as well as the proper motion of the emission line clumps in its relativistic jets. Additional information is included in the original document.

  3. Imaging exoplanets with the WFIRST Coronagraph: A background check of high priority targets

    NASA Astrophysics Data System (ADS)

    Fu, Guangwei; Turnbull, Margaret C.; Gallagher, John S.; Kotulla, Ralf C.; Merrelli, Aronne; L'Ecuyer, Tristan; Hu, Renyu

    2016-01-01

    The WFIRST coronagraph is envisioned to achieve a limiting contrast for exoplanet detection of 10e-9. This revolutionary mission will enable the direct detection of known and newly discovered exoplanets amongst the nearest stars, from super-Earths to giants. However, at this contrast the coronagraph will essentially see a Hubble Ultra Deep Field (HUDF) in every image. For targets near the Galactic Plane on the sky, distant stars with varying levels of extinction and reddening will dominate the background. Away from the plane, we then expect extragalactic sources to dominate. What impact will these background sources have on the WFIRST exoplanet imaging program? How can we efficiently distinguish background sources from exoplanet targets in a single image? To have a comprehensive understanding of the distribution of background sources across the sky, we have used the HUDF to model extragalactic faint sources, and "Trilegal" simulations to model galactic background sources. Through some preliminary color and point source analysis, we offer a statistical estimation of expected background contamination and the probability of false positive background sources. In this poster we show plots relating number of extragalactic sources versus magnitude in HUDF and "Trilegal" simulation. We present a table of high priority WFIRST exoplanet imaging targets, with an assessment of the "background threat" due to background stars, galaxies, and binary companions.

  4. Minerva: Big Exoplanet Science from Small Telescopes

    NASA Astrophysics Data System (ADS)

    McCrady, Nate

    2012-10-01

    The Kepler mission has identified over 2300 candidate planets in the past two years, adding to the over 500 confirmed exoplanets from radial velocity (RV) surveys. One of the most striking results of these surveys is that the number of planets increases rapidly with decreasing size. There may in fact be more Earth-like planets in the Galaxy than stars. There must be terrestrial planets around nearby stars, though few have yet been discovered. Finding these planets requires high precision RV observations and high cadence transit observing to densely sample the orbital phase. Minerva will surmount these obstacles with a dedicated observatory for detection of super-Earths and close-in Earth-like planets. Our array of four 0.7-m telescopes will operate in two modes: jointly with a high precision fiber-fed spectrometer capable of detecting the RV signal of an Earth orbiting a low mass star, and independently for photometric transit detection surveys.

  5. Taking the Galactic Exoplanet Census with K2

    NASA Astrophysics Data System (ADS)

    Christiansen, Jessie; CHAI (California/Hawaii/Arizona/Indiana) K2 Follow-up Consortium

    2016-06-01

    The NASA Kepler mission was designed and executed with the goal of measuring planet occurrence rates. The stellar sample, the science pipeline, and the planet candidate sample have all been chosen and characterised with an eye to generating uniform, robust statistical measurements. The subsequent K2 mission, however, has been much more open to all science goals, and subsequently the target selection, planet candidate generation and catalogue assembly have been substantially more ad hoc. Here we discuss the pathway forward to using the Galactic latitude coverage of K2 to begin the Galactic exoplanet census that will be continued by the NASA TESS mission.

  6. "Some Like it Hot” - Evidence for the Shrinking Orbit of the 2.2-day Transiting Hot Jupiter Exoplanet HD 189733b - Evidence of Transfer of Planet Orbital Momentum to its Host Star

    NASA Astrophysics Data System (ADS)

    Santapaga, Thomas; Guinan, E. F.; Ballouz, R.; Engle, S. G.; Dewarf, L.

    2011-01-01

    HD189733A is a K2V star that has attracted much attention because it hosts a transiting, hot Jupiter-exoplanet. HD189733b has one of the shortest known orbital-periods (P = 2.22-days) and is only 0.031AU from its host star (Buchy et al. 2005). Based on measurements of the K2V star's P(rot) from starspot-modulations of 12-d, coronal Lx 1028 ergs/s, and chromospheric Ca II-HK emission, indicate an age 0.6 -1.0 Gyr - inferred from our rotation-age-activity relations. However, this age is discrepant with an older-age inferred from the star's low Lithium-abundance ( 1/10 Solar.). However, the age-rotation-activity determination assumes no tidal-effects from close companions- such as close planet. Recently Gaspar et al. (2006) discovered a dM4 companion star (HD 189733 B: 12'' distance to the K-dwarf). X MM-Newton observations of the HD 189733 A&B carried out recently by Pilliteri et al. (2010), surprisingly revealed that HD 189733B shows no X-ray emission, with an upper limit of 9*1026 ergs/s. Using activity-age relationships for dM-stars, we expected a Lx of an order of magnitude higher for age <1.0 Ga. This apparent discrepancy can be resolved by the supposition that the K2V-star has been spun-up by its nearby planetary companion, and that its age determined from activity-rotation relationships is invalid. This supposition is supported by the recent photometry by the Kepler for 300+ exoplanet candidate systems discovered thus far (Borucki et al. 2010). The analysis these data have reveal that tidal locking between the planet and host star has occurred for a significant number of exoplanet with short orbital periods. We explain the fast rotation of the K2 star via the transfer of the planet's orbital angular momentum to the star via tidal interactions. The significance of these finding with respect to the evolution of planetary systems is discussed. This work is partially supported by NSF/RUI grant AST-1009903.

  7. Exoplanet Equilibrium Chemistry Calculations

    NASA Astrophysics Data System (ADS)

    Blumenthal, Sarah; Harrington, J.; Bowman, M.; Blecic, J.

    2013-10-01

    Recently, Agundez et al. (2012, A&A 548, A73) used a chemical kinetics code to study a model HD 209458b (equilibrium temperature of 1450 K, assuming full redistribution and 0 albedo). They found that thermochemistry dominates most of the dayside, but that significant compositional gradients may exist across the dayside. We calculate equilibrium-chemistry molecular abundances for several model exoplanets, using NASA's open-source Chemical Equilibrium Abundances code (McBride and Gordon 1996). We vary the degree of radiation redistribution to the dark side, ranging from total redistribution to instantaneous reradiation. Atomically, both the solar abundance multiple and the carbon fraction vary. Planet substellar temperatures range from just above 1200 K, where photochemistry should no longer be important, to those of hot planets (3000 K). We present synthetic abundance images for the key spectroscopic molecules CO, CH4, and H2O for several hot-Jupiter model planets. This work was supported by the NASA Planetary Atmospheres grant NNX12AI69G.

  8. Direct imaging of exoplanets.

    PubMed

    Lagrange, Anne-Marie

    2014-04-28

    Most of the exoplanets known today have been discovered by indirect techniques, based on the study of the host star radial velocity or photometric temporal variations. These detections allowed the study of the planet populations in the first 5-8 AU from the central stars and have provided precious information on the way planets form and evolve at such separations. Direct imaging on 8-10 m class telescopes allows the detection of giant planets at larger separations (currently typically more than 5-10 AU) complementing the indirect techniques. So far, only a few planets have been imaged around young stars, but each of them provides an opportunity for unique dedicated studies of their orbital, physical and atmospheric properties and sometimes also on the interaction with the 'second-generation', debris discs. These few detections already challenge formation theories. In this paper, I present the results of direct imaging surveys obtained so far, and what they already tell us about giant planet (GP) formation and evolution. Individual and emblematic cases are detailed; they illustrate what future instruments will routinely deliver for a much larger number of stars. I also point out the limitations of this approach, as well as the needs for further work in terms of planet formation modelling. I finally present the progress expected in direct imaging in the near future, thanks in particular to forthcoming planet imagers on 8-10 m class telescopes. PMID:24664924

  9. Exoplanet Science with TMT

    NASA Astrophysics Data System (ADS)

    Crossfield, Ian

    2014-07-01

    TMT will have unparalleled capabilities for characterizing the composition of extrasolar planets and their atmospheres, and for probing the complex interplay between planet formation, evolution, and migration. In this plenary talk I will summarize these science cases and discuss their synergy with other observing facilities. High-resolution imaging with IRIS and PFI/SEIT will study young, hot planets in nearby star-forming regions, complementing JWST and WFIRST/AFTA coronagraphic efforts at larger semimajor axes. The same instruments will flesh out planets detected by radial velocity (RV) by measuring the albedos and bolometric radii of old, cold Jovian planets and a few ~300 K super-Earths. Complementing JWST and HST studies of short-period transiting planets, NIRES and IRMS spectroscopy will reveal atmospheric composition, dynamics, and thermal structure for dozens of hot Jupiters and Neptunes; NIRES will also produce 2D global maps and movies of a few exoplanets and dozens of brown dwarfs. HROS high-dispersion spectroscopy will precisely measure the composition of extrasolar planetesimals in polluted white dwarfs, and RV followup will continue to exploit the legacies of Kepler, K2, TESS, and PLATO to measure the masses, orbits, and bulk compositions of Earth analogues. Most exciting of all, TMT may facilitate the next major step in the study of exobiology by allowing the detection of biosignature gases around the closest habitable transiting planets.

  10. The Gemini Planet Imager Exoplanet Survey (GPIES) Campaign Initial Results

    NASA Astrophysics Data System (ADS)

    Patience, Jennifer; Macintosh, Bruce; Graham, James R.; Barman, Travis; De Rosa, Robert; Konopacky, Quinn; Marley, Mark; Marois, Christian; Nielsen, Eric Ludwig; Pueyo, Laurent; Rajan, Abhijith; Rameau, Julien; Saumon, Didier; Wang, Jason

    2015-12-01

    The Gemini Planet Imager (GPI) is a next-generation coronagraphic integral field unit with the sensitivity and resolution to detect planetary companions with separations of 0”.2 to 1”.0 around a large set of stars. An 890-hour GPI survey of 600 young, nearby stars commenced in late-2014, and approximately 100 stars have been observed thus far. The central aims of the program are: (1) the discovery of a population of giant planets with orbital radii of 5-50 AU comparable to Solar System gas giant orbits, (2) the characterization of the atmospheric properties of young planetary companions, and (3) the exploration of planet-disk interactions. Initial results from GPI exoplanet observations include the discovery of a new planetary companion to a young F-star; the planet spectrum shows a strong signature of methane absorption, indicating a cooler temperature than previously imaged young planets. An overview of the survey scope, current detection limits, and initial results will be presented.

  11. The Close Stellar Companions to Intermediate-mass Black Holes

    NASA Astrophysics Data System (ADS)

    MacLeod, Morgan; Trenti, Michele; Ramirez-Ruiz, Enrico

    2016-03-01

    When embedded in dense cluster cores, intermediate-mass black holes (IMBHs) acquire close stellar or stellar-remnant companions. These companions are not only gravitationally bound, but also tend to hierarchically isolate from other cluster stars through series of multibody encounters. In this paper we study the demographics of IMBH companions in compact star clusters through direct N-body simulations. We study clusters initially composed of 105 or 2 × 105 stars with IMBHs of 75 and 150 solar masses, and we follow their evolution for 6-10 Gyr. A tight, innermost binary pair of IMBH and stellar object rapidly forms. The IMBH has a companion with an orbital semimajor axis at least three times tighter than the second-most-bound object over 90% of the time. These companionships have typical periods on the order of years and are subject to cycles of exchange and destruction. The most frequently observed, long-lived pairings persist for ˜107 years. The demographics of IMBH companions in clusters are diverse: they include both main-sequence, giant stars and stellar remnants. Companion objects may reveal the presence of an IMBH in a cluster in one of several ways. The most-bound companion stars routinely suffer grazing tidal interactions with the IMBH, offering a dynamical mechanism to produce repeated flaring episodes like those seen in the IMBH candidate HLX-1. The stellar winds of companion stars provide a minimum quiescent accretion rate for IMBHs, with implications for radio searches for IMBH accretion in globular clusters. Finally, gravitational wave inspirals of compact objects occur with promising frequency.

  12. Asteroseismology of Exoplanet Host Stars

    NASA Astrophysics Data System (ADS)

    Kayhan, Cenk; Çelik Orhan, Zeynep; Yildiz, Mutlu

    2016-07-01

    Exoplanet studies are one of the most interesting and attractive topics in astrophysics. Besides of ground-based observations, Kepler and CoRoT space missions improved our knowledge by providing unprecedented data of exoplanets and host stars. Precise determination of basic properties of planets depends on how we accurately determine fundamental properties of host stars. Asteroseismology is a powerful tool to study stellar structure and evolution and provides us radius, mass and age of the host stars. In this study, we construct stellar interior models of these stars with the MESA evolution code and compare model frequencies with the oscillation frequencies derived from Kepler data. Then, we obtain fundamental parameters of the host stars. Finally, fundamental parameters of exoplanets are reevaluated.

  13. A SEARCH FOR ADDITIONAL PLANETS IN THE NASA EPOXI OBSERVATIONS OF THE EXOPLANET SYSTEM GJ 436

    SciTech Connect

    Ballard, Sarah; Christiansen, Jessie L.; Charbonneau, David; Holman, Matthew J.; Fabrycky, Daniel; Deming, Drake; Barry, Richard K.; Kuchner, Marc J.; Livengood, Timothy A.; Hewagama, Tilak; A'Hearn, Michael F.; Wellnitz, Dennis D.; Sunshine, Jessica M.; Hampton, Don L.; Lisse, Carey M.; Seager, Sara; Veverka, Joseph F.

    2010-06-20

    We present time series photometry of the M dwarf transiting exoplanet system GJ 436 obtained with the Extrasolar Planet Observation and Characterization (EPOCh) component of the NASA EPOXI mission. We conduct a search of the high-precision time series for additional planets around GJ 436, which could be revealed either directly through their photometric transits or indirectly through the variations these second planets induce on the transits of the previously known planet. In the case of GJ 436, the presence of a second planet is perhaps indicated by the residual orbital eccentricity of the known hot Neptune companion. We find no candidate transits with significance higher than our detection limit. From Monte Carlo tests of the time series, we rule out transiting planets larger than 1.5 R{sub +} interior to GJ 436b with 95% confidence and larger than 1.25 R{sub +} with 80% confidence. Assuming coplanarity of additional planets with the orbit of GJ 436b, we cannot expect that putative planets with orbital periods longer than about 3.4 days will transit. However, if such a planet were to transit, we would rule out planets larger than 2.0 R{sub +} with orbital periods less than 8.5 days with 95% confidence. We also place dynamical constraints on additional bodies in the GJ 436 system, independent of radial velocity measurements. Our analysis should serve as a useful guide for similar analyses of transiting exoplanets for which radial velocity measurements are not available, such as those discovered by the Kepler mission. From the lack of observed secular perturbations, we set upper limits on the mass of a second planet as small as 10 M{sub +} in coplanar orbits and 1 M{sub +} in non-coplanar orbits close to GJ 436b. We present refined estimates of the system parameters for GJ 436. We find P = 2.64389579 {+-} 0.00000080 d, R{sub *} = 0.437 {+-} 0.016 R{sub sun}, and R{sub p} = 3.880 {+-} 0.147 R{sub +}. We also report a sinusoidal modulation in the GJ 436 light curve

  14. The Orbital Design of Alpha Centauri Exoplanet Satellite (ACESat)

    NASA Technical Reports Server (NTRS)

    Weston, Sasha; Belikov, Rus; Bendek, Eduardo

    2015-01-01

    Exoplanet candidates discovered by Kepler are too distant for biomarkers to be detected with foreseeable technology. Alpha Centauri has high separation from other stars and is of close proximity to Earth, which makes the binary star system 'low hanging fruit' for scientists. Alpha Centauri Exoplanet Satellite (ACESat) is a mission proposed to Small Explorer Program (SMEX) that will use a coronagraph to search for an orbiting planet around one of the stars of Alpha Centauri. The trajectory design for this mission is presented here where three different trajectories are considered: Low Earth Orbit (LEO), Geosynchronous Orbit (GEO) and a Heliocentric Orbit. Uninterrupted stare time to Alpha Centauri is desirable for meeting science requirements, or an orbit that provides 90% stare time to the science target. The instrument thermal stability also has stringent requirements for proper function, influencing trajectory design.

  15. A Statistical Analysis of Exoplanets in Their Habitable Zones

    NASA Astrophysics Data System (ADS)

    Adams, Arthur; Kane, S. R.

    2014-01-01

    The Kepler mission has detected a wealth of planets through planetary transits since its launch in 2009. An important step in the continued study of exoplanets is to characterize planets based on their orbital properties and compositions. As the Kepler mission has progressed the data sensitivity to planetary transits at longer orbital periods has increased. This allows for an enhanced probability of detecting planets which lie in the Habitable Zones (HZs) of their host stars. We present the results of statistical analyses of Kepler planetary candidates to study the percentage of orbital time spent in the HZ as a function of planetary parameters, including planetary mass, radius, and orbital eccentricity. We compare these results to the confirmed exoplanet population.

  16. Habitable zone lifetimes of exoplanets around main sequence stars.

    PubMed

    Rushby, Andrew J; Claire, Mark W; Osborn, Hugh; Watson, Andrew J

    2013-09-01

    The potential habitability of newly discovered exoplanets is initially assessed by determining whether their orbits fall within the circumstellar habitable zone of their star. However, the habitable zone (HZ) is not static in time or space, and its boundaries migrate outward at a rate proportional to the increase in luminosity of a star undergoing stellar evolution, possibly including or excluding planets over the course of the star's main sequence lifetime. We describe the time that a planet spends within the HZ as its "habitable zone lifetime." The HZ lifetime of a planet has strong astrobiological implications and is especially important when considering the evolution of complex life, which is likely to require a longer residence time within the HZ. Here, we present results from a simple model built to investigate the evolution of the "classic" HZ over time, while also providing estimates for the evolution of stellar luminosity over time in order to develop a "hybrid" HZ model. These models return estimates for the HZ lifetimes of Earth and 7 confirmed HZ exoplanets and 27 unconfirmed Kepler candidates. The HZ lifetime for Earth ranges between 6.29 and 7.79×10⁹ years (Gyr). The 7 exoplanets fall in a range between ∼1 and 54.72 Gyr, while the 27 Kepler candidate planets' HZ lifetimes range between 0.43 and 18.8 Gyr. Our results show that exoplanet HD 85512b is no longer within the HZ, assuming it has an Earth analog atmosphere. The HZ lifetime should be considered in future models of planetary habitability as setting an upper limit on the lifetime of any potential exoplanetary biosphere, and also for identifying planets of high astrobiological potential for continued observational or modeling campaigns. PMID:24047111

  17. Infrared spectrum and proper motion of the brown dwarf companion of HR 7329 in Tucanae

    NASA Astrophysics Data System (ADS)

    Guenther, E. W.; Neuhäuser, R.; Huélamo, N.; Brandner, W.; Alves, J.

    2001-01-01

    Up to now only four brown dwarf companions to normal stars have been found and confirmed by both spectroscopy and proper motion (namely Gl 229 B, G 196-3 B, Gl 570 D, and CoD-33 deg 7795 B). On the basis of an optical spectrum taken with HST/STIS Lowrance et al. (2000) recently pointed out another possible candidate companion. The companion candidate is located at a distance of 4{' '} from the A0-star HR 7329, which is considered as a member of a moving group of young stars in Tucanae located at a distance of only ~ 48 pc. In order to confirm or disregard the companion nature of the candidate, we have determined the proper motion of the brown dwarf candidate with an epoch difference of 1.8 years, and found that it is consistent with a co-moving companion of HR 7329. Additional to the proper motion measurement, we have also taken an H-band spectrum using ISAAC on the ESO-VLT. From this spectrum, we conclude that the companion candidate has spectral type M 7 to M 8, which is in agreement with the optical spectrum. We thus conclude that HR 7329 B is most likely a brown dwarf companion. The mass ratio of this pair (A0 to M 7-8, i.e. ~ 100:1) is the largest known among brown dwarf companions, which is relevant for studying the formation of brown dwarfs as companions. Based on observations obtained at the European Southern Observatory on Cerro Paranal and La Silla in program\\break 65.L-0144.

  18. Point Source Polarimetry with the Gemini Planet Imager: Sensitivity Characterization with T5.5 Dwarf Companion HD 19467 B

    NASA Technical Reports Server (NTRS)

    Jensen-Clem, Rebecca; Millar-Blanchaer, Max; Mawet, Dimitri; Graham, James R.; Wallace, J. Kent; Macintosh, Bruce; Hinkley, Sasha; Wiktorowicz, Sloane J.; Perrin, Marshall D.; Marley, Mark S.; Fitzgerald, Michael P.; Oppenheimer, Rebecca; Ammons, S. Mark; Rantakyro, Fredrik T.; Marchis, Franck

    2016-01-01

    Detecting polarized light from self-luminous exoplanets has the potential to provide key information about rotation, surface gravity, cloud grain size, and cloud coverage. While field brown dwarfs with detected polarized emission are common, no exoplanet or substellar companion has yet been detected in polarized light. With the advent of high contrast imaging spectro-polarimeters such as GPI and SPHERE, such a detection may now be possible with careful treatment of instrumental polarization. In this paper, we present 28 minutes of H-band GPI polarimetric observations of the benchmark T5.5 companion HD 19467 B. We detect no polarization signal from the target, and place an upper limit on the degree of linear polarization of pCL99:73% less than 1:7%. We discuss our results in the context of T dwarf cloud models and photometric variability.

  19. Point Source Polarimetry with the Gemini Planet Imager: Sensitivity Characterization with T5.5 Dwarf Companion HD 19467 B

    NASA Astrophysics Data System (ADS)

    Jensen-Clem, Rebecca; Millar-Blanchaer, Max; Mawet, Dimitri; Graham, James R.; Wallace, J. Kent; Macintosh, Bruce; Hinkley, Sasha; Wiktorowicz, Sloane J.; Perrin, Marshall D.; Marley, Mark S.; Fitzgerald, Michael P.; Oppenheimer, Rebecca; Ammons, S. Mark; Rantakyrö, Fredrik T.; Marchis, Franck

    2016-04-01

    Detecting polarized light from self-luminous exoplanets has the potential to provide key information about rotation, surface gravity, cloud grain size, and cloud coverage. While field brown dwarfs with detected polarized emission are common, no exoplanet or substellar companion has yet been detected in polarized light. With the advent of high contrast imaging spectro-polarimeters such as GPI and SPHERE, such a detection may now be possible with careful treatment of instrumental polarization. In this paper, we present 28 minutes of H-band GPI polarimetric observations of the benchmark T5.5 companion HD 19467 B. We detect no polarization signal from the target, and place an upper limit on the degree of linear polarization of {p}{CL99.73%}≤slant 2.4%. We discuss our results in the context of T dwarf cloud models and photometric variability.

  20. The LEECH Exoplanet Imaging Survey: Characterization of the Coldest Directly Imaged Exoplanet, GJ 504 b, and Evidence for Superstellar Metallicity

    NASA Astrophysics Data System (ADS)

    Skemer, Andrew J.; Morley, Caroline V.; Zimmerman, Neil T.; Skrutskie, Michael F.; Leisenring, Jarron; Buenzli, Esther; Bonnefoy, Mickael; Bailey, Vanessa; Hinz, Philip; Defrére, Denis; Esposito, Simone; Apai, Dániel; Biller, Beth; Brandner, Wolfgang; Close, Laird; Crepp, Justin R.; De Rosa, Robert J.; Desidera, Silvano; Eisner, Josh; Fortney, Jonathan; Freedman, Richard; Henning, Thomas; Hofmann, Karl-Heinz; Kopytova, Taisiya; Lupu, Roxana; Maire, Anne-Lise; Males, Jared R.; Marley, Mark; Morzinski, Katie; Oza, Apurva; Patience, Jenny; Rajan, Abhijith; Rieke, George; Schertl, Dieter; Schlieder, Joshua; Stone, Jordan; Su, Kate; Vaz, Amali; Visscher, Channon; Ward-Duong, Kimberly; Weigelt, Gerd; Woodward, Charles E.

    2016-02-01

    As gas giant planets and brown dwarfs radiate away the residual heat from their formation, they cool through a spectral type transition from L to T, which encompasses the dissipation of cloud opacity and the appearance of strong methane absorption. While there are hundreds of known T-type brown dwarfs, the first generation of directly imaged exoplanets were all L type. Recently, Kuzuhara et al. announced the discovery of GJ 504 b, the first T dwarf exoplanet. GJ 504 b provides a unique opportunity to study the atmosphere of a new type of exoplanet with a ˜500 K temperature that bridges the gap between the first directly imaged planets (˜1000 K) and our own solar system's Jupiter (˜130 K). We observed GJ 504 b in three narrow L-band filters (3.71, 3.88, and 4.00 μm), spanning the red end of the broad methane fundamental absorption feature (3.3 μm) as part of the LBTI Exozodi Exoplanet Common Hunt (LEECH) exoplanet imaging survey. By comparing our new photometry and literature photometry with a grid of custom model atmospheres, we were able to fit GJ 504 b's unusual spectral energy distribution for the first time. We find that GJ 504 b is well fit by models with the following parameters: Teff = 544 ± 10 K, g < 600 m s-2, [M/H] = 0.60 ± 0.12, cloud opacity parameter of fsed = 2-5, R = 0.96 ± 0.07 RJup, and log(L) = -6.13 ± 0.03 L⊙, implying a hot start mass of 3-30 Mjup for a conservative age range of 0.1-6.5 Gyr. Of particular interest, our model fits suggest that GJ 504 b has a superstellar metallicity. Since planet formation can create objects with nonstellar metallicities, while binary star formation cannot, this result suggests that GJ 504 b formed like a planet, not like a binary companion. The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are the University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrophisica, Italy; LBT

  1. Polarimetry for rocky exoplanet characterization

    NASA Astrophysics Data System (ADS)

    Stam, Daphne; Karalidi, Theodora

    2013-04-01

    Since the first discovery of a planet around a solar-type star by Mayor & Queloz in 1995, several hundreds of exoplanets have been detected. Indeed, it appears that practically all Sun-like stars have planets. Inevitable, Earth-sized, rocky planets that orbit in their star's habitable zone, where temperatures could be just right to allow liquid water on a planet's surface, will be found. Liquid water is generally considered to be essential for the existence of life. Whether liquid water actually exists on a planet depends strongly on the atmosphere's thickness and characteristics, such as the surface pressure and composition. Famous examples in the Solar System are Venus and the Earth, with similar sizes, inner compositions and orbital radii, but wildly different surface conditions. The characterization of the atmospheres and/or surfaces of exoplanets will allow a comparison with Solar System planets and it will open up a treasure trove of knowledge about the formation and evolution of planetary atmospheres and surfaces, thanks to the vast range of orbital distances, planet sizes and ages that can be studied. Characterization will also allow studying conditions for life and ultimately the existence of life around other stars. Information about the upper atmospheres of close-in, hot, giant exoplanets, can be derived from measurements of the combined flux of the star and the planet, in particular when the planet is transiting its star. This method has also provided traces of an atmosphere around a large solid planet orbiting red dwarf star GJ1214. Detection and characterization of the atmospheres and/or surfaces of small, solid, Earth-like exoplanets in the habitable zones of Sun-like stars, is virtually impossible with transit observations. For these exiting planets, polarimetry appears to be a strong tool. Polarimetry helps the detection of exoplanets, because direct starlight is usually unpolarized, while starlight that has been reflected by a planet is usually

  2. NPOI Observations of the Exoplanet Host Kappa Coronae Borealis

    NASA Astrophysics Data System (ADS)

    Baines, Ellyn K.; Armstrong, J. T.; van Belle, G.

    2014-01-01

    Kappa Coronae Borealis is a "retired A star", otherwise known as a former A-type dwarf that is now a K-type subgiant. It is a particularly fascinating target because of its unusual configuration of companions and dust rings. It hosts at least one exoplanet and perhaps two, and features a single wide dust ring or two narrow ones. We observed the star interferometrically in order to characterize the main star and the environment in which the planet(s) and dust ring(s) reside. We determined a variety of fundamental parameters for kappa CrB: the limb-darkened angular diameter, physical size, effective temperature, luminosity, mass, age, and the extent of the habitable zone range. We combined our mass with the orbital parameters from four sources from the literature to calculate the planet's mass as well.

  3. Dynamical Measurements of the Interior Structure of Exoplanets

    NASA Astrophysics Data System (ADS)

    Becker, Juliette; Batygin, K.

    2013-10-01

    Giant gaseous planets often reside on orbits in sufficient proximity to their host stars for the planetary quadrupole gravitational field to become non-negligible. In presence of an additional planetary companion, a precise characterization of the system’s orbital state can yield meaningful constraints on the transiting planet’s interior structure. However, the applicability of this type of analysis can be limited by the configuration of the target system. Here, we explore the dynamical range in which these methods are valid while using HAT-P-13 as a case study. We determine that the interior structure determination method, despite being indirect, is surprisingly robust. As a result, we conclude that future efforts aimed at characterizing the interiors of giant exoplanets are likely to be fruitful.

  4. Cloud Driven Variability on Young Brown Dwarfs and Giant Exoplanets

    NASA Astrophysics Data System (ADS)

    Biller, Beth

    2016-01-01

    Variability has now been robustly observed in a range of L and T type field brown dwarfs, primarily at near-IR and mid-IR wavelengths. The probable cause of this variability is surface inhomogeneities in the clouds of these objects, causing a semi-periodic variability signal when combined with the rotational modulation from the 3-12 hour period expected for these objects. Variability at similar or even higher amplitudes may be expected for young brown dwarfs and giant exoplanets, which share similar Teff as field brown dwarfs, but have considerably lower surface gravities. Variability studies of these objects relative to old field objects is then a direct probe of the effects of surface gravity on atmospheric structure. Here I discuss ongoing efforts to detect variability from these young objects, both for free-floating objects and companions to stars, including preliminary results from an ongoing survey of young, low surface gravity objects with NTT SOFI.

  5. [Companion diagnostics and reimbursement system].

    PubMed

    Tazawa, Yoshiaki

    2013-05-01

    Recently, Companion Diagnostics (CoDx) have been gaining importance to promote personalized medicine in order to improve the safety and cost effectiveness of therapy. In July 2011, the FDA published draft guidance for the development of CoDx, which recommends the co-development of CoDx and new drugs as the best practice, and then the FDA approved vemurafenib and the BRAF-V600-E gene mutation assay simultaneously as a typical example of the co-development of a new drug and its CoDx. Considering medical needs for multiple biomarker assays to select the right assay from various therapeutic candidates, more complicated assay technologies such as DNA sequencing will be required for CoDx in the near future. However, since it is quite difficult to standardize the validation process and manage test quality under the current regulatory criteria of in-vitro diagnostics using advanced and/or complicated assay technologies, the clinical use of laboratory-developed tests (LDT) should be recommended in order to avoid biomarker test lag. On the other hand, the current reimbursement system is not always suitable to assess the clinical and technological value of CoDx and it should be revised to encourage the development of CoDx. Although Health Technology Assessment (HTA) is a potential method to assess the value of CoDx, it is not easy to define appropriate indicators for CoDx because its clinical utility and cost effectiveness are completely dependent on the performance and value of available therapy. It is also suggested that the price and/or insurance rate of CoDx should be included in the price of the drug; however, there is no good solution to how to pay for CoDx with negative results for all therapies. It is said that the concept of personalized medicine with advanced technologies is a destructive innovation that could markedly change the current structure and system of medications; therefore, it is essential to create a quite new regulatory and reimbursement system to

  6. Faint Companions in the Close Environment of Starforming Dwarf Galaxies: possible overlooked starburst triggers? (Oral Contribution)

    NASA Astrophysics Data System (ADS)

    Noeske, K. G.; Iglesias-Páramo, J.; Vílchez, J. M.; Papaderos, P.; Fricke, K. J.

    Using the NASA Extragalactic Database, we have searched the close environment of 98 star-forming dwarf galaxies (SFDGs) from field- and low density environments for companion galaxies. Most of the found companions are dwarf galaxies, previously disregarded in environmental studies of SFDGs. Using a subsample at low redshifts, cz < 2000 km/s, i.e. less biased against dwarf companions, we find that 30% of the SFDGs have close companions within a projected linear separation s_p < 100 kpc and a redshift difference of (Delta cz) < 500 km/s. This fraction must be considered a lower limit, given the incompleteness of the available data sets and the non-negligible frequency of HI clouds in the vicinity of SFDGs, so that the majority of SFDGs should not be considered isolated. The redshift differences between companion candidates and sample SFDGs are typically smaller than ~250 km/s and concentrated towards lower values. This is similarly observed for dwarf satellites of spiral galaxies and suggests a physical association between the companion candidates and the sample SFDGs. SFDGs with a close companion do not show significant differences in their H(beta) equivalent widths and B-V colours as compared to isolated ones. However, the available data do not allow to rule out close dwarf companions as an influencing factor for star formation activity.

  7. Climates of Oblique Exoplanets

    NASA Astrophysics Data System (ADS)

    Dobrovolskis, A. R.

    2008-12-01

    A previous paper (Dobrovolskis 2007; Icarus 192, 1-23) showed that eccentricity can have profound effects on the climate, habitability, and detectability of extrasolar planets. This complementary study shows that obliquity can have comparable effects. The known exoplanets exhibit a wide range of orbital eccentricities, but those within several million km of their suns are generally in near-circular orbits. This fact is widely attributed to the dissipation of tides in the planets, which is particularly effective for solid/liquid bodies like "Super-Earths". Along with friction between a solid mantle and a liquid core, tides also are expected to despin a planet until it is captured in the synchronous resonance, so that its rotation period is identical to its orbital period. The canonical example of synchronous spin is the way that our Moon always keeps nearly the same hemisphere facing the Earth. Tides also tend to reduce the planet's obliquity (the angle between its spin and orbital angular velocities). However, orbit precession can cause the rotation to become locked in a "Cassini state", where it retains a nearly constant non-zero obliquity. For example, our Moon maintains an obliquity of about 6.7° with respect to its orbit about the Earth. For comparison, stable Cassini states can exist for practically any obliquity up to 180° for planets of binary stars, or in multi-planet systems with high mutual inclinations, such as are produced by scattering or by the Kozai mechanism. This work considers planets in synchronous rotation with circular orbits. For obliquities greater than 90°, the ground track of the sub-solar point wraps around all longitudes on the surface of such a planet. For smaller obliquities, the sub-solar track takes the figure-8 shape of an analemma. This can be visualized as the intersection of the planet's spherical surface with a right circular cylinder, parallel to the spin axis and tangent to the equator from the inside. The excursion of the

  8. Be stars with white dwarf companions

    NASA Astrophysics Data System (ADS)

    Orio, Marina; Luna, Gerardo; Zemko, Polina; Kotulla, Ralf; Gallagher, Jay; Harbeck, Daniel

    2016-07-01

    A handful of supersoft X-ray sources in the Magellanic Clouds that could not be identified with transient nova outbursts turned out to be mainly massive close binaries. Recently, we have clearly identified a Be binary in M31, and are currently collecting data for another candidate in that galaxy. Work is in progress to assess whether the compact object companion really is a hydrogen burning white dwarf (the alternative being a massive stellar-mass black hole). If we can prove that Be+white dwarf interacting close binaries are common, and that hydrogen is often ignited on the white dwarf in these systems, we have discovered a new promising channel towards the explosion of supernovae of type Ia in star forming regions, without invoking double degenerate systems

  9. LOW-MASS TERTIARY COMPANIONS TO SPECTROSCOPIC BINARIES. I. COMMON PROPER MOTION SURVEY FOR WIDE COMPANIONS USING 2MASS

    SciTech Connect

    Allen, Peter R.; Burgasser, Adam J.; Faherty, Jacqueline K.; Kirkpatrick, J. Davy

    2012-08-15

    We report the first results of a multi-epoch search for wide (separations greater than a few tens of AU), low-mass tertiary companions of a volume-limited sample of 118 known spectroscopic binaries within 30 pc of the Sun, using the Two Micron All Sky Survey Point Source Catalog and follow-up observations with the KPNO and CTIO 4 m telescopes. Note that this sample is not volume complete but volume limited, and, thus, there is incompleteness in our reported companion rates. We are sensitive to common proper motion companions with separations from roughly 200 AU to 10,000 AU ({approx}10'' {yields} {approx} 10'). From 77 sources followed-up to date, we recover 11 previously known tertiaries, 3 previously known candidate tertiaries, of which 2 are spectroscopically confirmed and 1 rejected, and 3 new candidates, of which 2 are confirmed and 1 rejected. This yields an estimated wide tertiary fraction of 19.5{sup +5.2}{sub -3.7}%. This observed fraction is consistent with predictions set out in star formation simulations where the fraction of wide, low-mass companions to spectroscopic binaries is >10%.

  10. First Estimate of the Exoplanet Population from Kepler Observations

    NASA Astrophysics Data System (ADS)

    Borucki, William J.; Koch, D. G.; Batalha, N.; Caldwell, D.; Dunham, E. W.; Gautier, T. N., III; Howell, S. B.; Jenkins, J. M.; Marcy, G. W.; Rowe, J.; Charbonneau, D.; Ciardi, D.; Ford, E. B.; Christiansen, J. L.; Kolodziejczak, J.; Prsa, A.

    2011-05-01

    William J. Borucki, David G. Koch, Natalie Batalha, Derek Buzasi , Doug Caldwell, David Charbonneau, Jessie L. Christiansen, David R. Ciardi, Edward Dunham, Eric B. Ford, Steve Thomas N. Gautier III, Steve Howell, Jon M. Jenkins, Jeffery Kolodziejczak, Geoffrey W. Marcy, Jason Rowe, and Andrej Prsa A model was developed to provide a first estimate of the intrinsic frequency of planetary candidates based on the number of detected planetary candidates and the measured noise for each of the 156,000 observed stars. The estimated distributions for the exoplanet frequency are presented with respect to the semi-major axis and the stellar effective temperature and represent values appropriate only to short-period candidates. Improved estimates are expected after a Monte Carlo study of the sensitivity of the data analysis pipeline to transit signals injected at the pixel level is completed.

  11. Stable regions around Exoplanets: the search for Exomoons

    NASA Astrophysics Data System (ADS)

    Fernandes Guimaraes, Ana Helena; Moretto Tusnski, Luis Ricardo; Vieira-Neto, Ernesto; Silva Valio, Adriana

    2015-08-01

    There are hundreds of exoplanets which the data are available to a dynamical investigation. We extracted from the data base (exoplanets.org) all planets and candidates which have the necessary data available for the numerical investigation of the orbital stability of a body around a exoplanet in a total of 2749 of those.There is a wealth diversity of exoplanets types and the expectation in find our Earth-living conditions in another planet motivates the search for extra-solar planets, and a satellite around a planet would, in addiction, help to keep a favorable climate.Using the planets class according to PHL@Arecibo, those planets were sorted out in groups. Analyses of density, distance from the primary body, and mass ratios were done beside the suggested classification to fit some no-classified planets into one of the groups.The aim of this work is to derive the upper stability limit (or upper critical orbit) of fictitious direct satellites around exoplanets of any density, or size, orbiting single stars. Our search is for stable regions around the planet, the called S-type orbits. This orbit type determines if there is any chance to exist (or not) bodies around the planets. The investigation is limited to single stars, excluding binaries.We derived such limit purely through numerical simulations. Our proposal involved long-term integration of the circular restricted three bodies problem . Basically, the cut off of the stability zone determined in the previous work by Domingos et al. (2006) were confirmed for any planet type. However, the limitation due the Roche limit of the own satellite showed to be lower. We used this to determined possible size and to adjust orbital range were a third body could orbit the exoplanet.Independently of densities, distance, and sizes of the objects involved, the idea was to delimit where to find celestial bodies in any given system around single stars. Furthermore, we aim to provide tracks to the search for exomoons using

  12. Enabling Technologies for Characterizing Exoplanet Systems with Exo-C

    NASA Astrophysics Data System (ADS)

    Cahoy, Kerri Lynn; Belikov, Ruslan; Stapelfeldt, Karl R.; Chakrabarti, Supriya; Trauger, John T.; Serabyn, Eugene; McElwain, Michael W.; Pong, Christopher M.; Brugarolas, Paul

    2015-01-01

    requirements) and to integrate these subsystems together for a hardware-in-the-loop end-to-end demonstration, the overall readiness of the suite of enabling technologies makes a compelling case for Exo-C among the exoplanet direct imaging mission candidates.

  13. Variability of Kepler Solar-like Stars Harboring Small Exoplanets

    NASA Astrophysics Data System (ADS)

    Howell, Steve B.; Ciardi, David R.; Giampapa, Mark S.; Everett, Mark E.; Silva, David R.; Szkody, Paula

    2016-02-01

    We examine Kepler light-curve variability on habitable zone transit timescales for a large uniform sample of spectroscopically studied Kepler exoplanet host stars. The stars, taken from Everett et al., are solar-like in their properties and each harbors at least one exoplanet (or candidate) of radius ≤2.5 {R}{{e}}. The variability timescale examined is typical for habitable zone planets orbiting solar-like stars and we note that the discovery of the smallest exoplanets (≤1.2 {R}{{e}}) with corresponding transit depths of less than ∼0.18 mmag occur for the brightest and photometrically quietest stars. Thus, these detections are quite rare in Kepler observations. Some brighter and more evolved stars (subgiants), the latter of which often show large radial velocity jitter, are found to be among the photometrically quietest solar-like stars in our sample and the most likely small planet transit hunting grounds. The Sun is discussed as a solar-like star proxy to provide insight into the nature and cause of photometric variability. It is shown that Kepler’s broad, visible light observations are insensitive to variability caused by chromospheric activity that may be present in the observed stars.

  14. Hot subdwarfs with degenerate companions

    NASA Astrophysics Data System (ADS)

    Mereghetti, Sandro

    2010-10-01

    Stellar evolutionary models predict that most of the hot sub-dwarfs in close binary systems have white dwarf companions. In a few cases even more massive compact objects (neutron stars or black holes) are suggested by the optical mass functions. The X-ray emission expected from accretion of the sub-dwarf's wind can reveal the nature of the compact companions and be used to derive other important information on these post-common envelope systems, as recently demonstrated by the discovery of a massive WD in HD 49798. We selected 3 promising targets from a sample of hot subdwarfs suspected to have degenerate companions. This proposal was accepted in AO9 with C priority.

  15. Polarimetry, Exoplanets and Biosignatures

    NASA Astrophysics Data System (ADS)

    Sparks, W. B.

    2011-12-01

    A fundamental topic in astronomy is the study of extrasolar planets, the ultimate goal of which is to image and characterize Earth-like planets around other stars and determine whether they host life. Polarization and spectropolarization observations provide unique diagnostic information and can contribute to both the detection and characterization phases of extasolar planet astronomy. Ultimately polarization may even be able to help us to determine whether life is present. Polarimetry can be used in several ways to facilitate planetary detection, and can influence mission design by providing an effective discriminant for true companions shining by reflected light against background objects. This may be particularly effective when coupled to other differential methods such as integral field spectroscopy (Sparks and Ford 2002). Spectropolarimetry can play an important role in the characterization phase of extrasolar planets in general, probing aerosols and surface and atmospheric scattering. In the search for life, time resolved spectropolarimetry can be used to seek evidence of special features such as a strongly polarized specular reflection, "glint", that would arise from the liquid surface of an extrasolar ocean, or rainbows from liquid droplets (Bailey 2007; Zugger et al 2010; Karalidi et al 2011). Looking further into the future, precision circular spectropolarimetry may offer a direct probe of the presence of microbial photosynthesis or vegetation. The unique homochirality of biological material coupled to the optical activity of biological compounds means that biological matter can influence the polarization, circular polarization in particular, of reflected light. Homochirality arises as a consequence of self-replication hence is likely to be generic to all forms of biological life and has the potential to produce a macroscopic signature. We have shown that a variety of photosynthetic microbial organisms, as well as macroscopic vegetation, yield significant

  16. A SEARCH FOR GIANT PLANET COMPANIONS TO T TAURI STARS

    SciTech Connect

    Crockett, Christopher J.; Mahmud, Naved I.; Johns-Krull, Christopher M.; Hartigan, Patrick M.; Prato, L.; Jaffe, Daniel T.; Beichman, Charles A. E-mail: lprato@lowell.edu E-mail: cmj@rice.edu

    2012-12-20

    We present results from an ongoing multiwavelength radial velocity (RV) survey of the Taurus-Auriga star-forming region as part of our effort to identify pre-main-sequence giant planet hosts. These 1-3 Myr old T Tauri stars present significant challenges to traditional RV surveys. The presence of strong magnetic fields gives rise to large, cool star spots. These spots introduce significant RV jitter which can mimic the velocity modulation from a planet-mass companion. To distinguish between spot-induced and planet-induced RV modulation, we conduct observations at {approx}6700 A and {approx}2.3 {mu}m and measure the wavelength dependence (if any) in the RV amplitude. CSHELL observations of the known exoplanet host Gl 86 demonstrate our ability to detect not only hot Jupiters in the near-infrared but also secular trends from more distant companions. Observations of nine very young stars reveal a typical reduction in RV amplitude at the longer wavelengths by a factor of {approx}2-3. While we cannot confirm the presence of planets in this sample, three targets show different periodicities in the two wavelength regions. This suggests different physical mechanisms underlying the optical and the K-band variability.

  17. Glowing Hot Transiting Exoplanet Discovered

    NASA Astrophysics Data System (ADS)

    2003-04-01

    VLT Spectra Indicate Shortest-Known-Period Planet Orbiting OGLE-TR-3 Summary More than 100 exoplanets in orbit around stars other than the Sun have been found so far. But while their orbital periods and distances from their central stars are well known, their true masses cannot be determined with certainty, only lower limits. This fundamental limitation is inherent in the common observational method to discover exoplanets - the measurements of small and regular changes in the central star's velocity, caused by the planet's gravitational pull as it orbits the star. However, in two cases so far, it has been found that the exoplanet's orbit happens to be positioned in such a way that the planet moves in front of the stellar disk, as seen from the Earth. This "transit" event causes a small and temporary dip in the star's brightness, as the planet covers a small part of its surface, which can be observed. The additional knowledge of the spatial orientation of the planetary orbit then permits a direct determination of the planet's true mass. Now, a group of German astronomers [1] have found a third star in which a planet, somewhat larger than Jupiter, but only half as massive, moves in front of the central star every 28.5 hours . The crucial observation of this solar-type star, designated OGLE-TR-3 [2] was made with the high-dispersion UVES spectrograph on the Very Large Telescope (VLT) at the ESO Paranal Observatory (Chile). It is the exoplanet with the shortest period found so far and it is very close to the star, only 3.5 million km away. The hemisphere that faces the star must be extremely hot, about 2000 °C and the planet is obviously losing its atmosphere at high rate . PR Photo 10a/03 : The star OGLE-TR-3 . PR Photo 10b/03 : VLT UVES spectrum of OGLE-TR-3. PR Photo 10c/03 : Relation between stellar brightness and velocity (diagram). PR Photo 10d/03 : Observed velocity variation of OGLE-TR-3. PR Photo 10e/03 : Observed brightness variation of OGLE-TR-3. The search

  18. Exoplanet Science from NASA’s Kepler Mission

    SciTech Connect

    Steffen, Jason

    2012-09-12

    NASA's exoplanet mission is the world's premier instrument for the discovery and study of planets orbiting distant stars. As the nominal mission comes to a close, Kepler has discovered nearly 2500 planet candidates, confirmed dozens of multi-planet systems, provided important insights into the orbital architectures of planetary systems, identified specific systems that challenge theories of planet formation and dynamical evolution, has revolutionized our understanding of stellar interiors, and is gearing to measure the frequency of Earth-like planets in the habitable zones of Sun-like stars in its extended mission phase. I present the most recent results from the Kepler mission.

  19. OPTICAL PHASE CURVES OF KEPLER EXOPLANETS

    SciTech Connect

    Esteves, Lisa J.; De Mooij, Ernst J. W.; Jayawardhana, Ray E-mail: demooij@astro.utoronto.ca

    2013-07-20

    We conducted a comprehensive search for optical phase variations of all close-in (a/R{sub *} < 10) planet candidates in 15 quarters of Kepler space telescope data. After correcting for systematics, we found eight systems that show secondary eclipses as well as phase variations. Of these, five (Kepler-5, Kepler-6, Kepler-8, KOI-64, and KOI-2133) are new and three (TrES-2, HAT-P-7, and KOI-13) have published phase curves, albeit with many fewer observations. We model the full phase curve of each planet candidate, including the primary and secondary transits, and derive their albedos, dayside and nightside temperatures, ellipsoidal variations, and Doppler beaming. We find that KOI-64 and KOI-2133 have nightside temperatures well above their equilibrium values (while KOI-2133 also has an albedo, >1), so we conclude that they are likely to be self-luminous objects rather than planets. The other six candidates have characteristics consistent with their being planets with low geometric albedos (<0.3). For TrES-2 and KOI-13, the Kepler bandpass appears to probe atmospheric layers hotter than the planet's equilibrium temperature. For KOI-13, we detect a never-before-seen third cosine harmonic with an amplitude of 6.7 {+-} 0.3 ppm and a phase shift of -1.1 {+-} 0.1 rad in the phase curve residual, possibly due to its spin-orbit misalignment. We report derived planetary parameters for all six planets, including masses from ellipsoidal variations and Doppler beaming, and compare our results to published values when available. Our results nearly double the number of Kepler exoplanets with measured phase curve variations, thus providing valuable constraints on the properties of hot Jupiters.

  20. Analysis of Exoplanet Light Curves

    NASA Astrophysics Data System (ADS)

    Erdem, A.; Budding, E.; Rhodes, M. D.; Püsküllü, Ç.; Soydugan, F.; Soydugan, E.; Tüysüz, M.; Demircan, O.

    2015-07-01

    We have applied the close binary system analysis package WINFITTER to a variety of exoplanet transiting light curves taken both from the NASA Exoplanet Archive and our own ground-based observations. WINFitter has parameter options for a realistic physical model, including gravity brightening and structural parameters derived from Kopal's applications of the relevant Radau equation, and it includes appropriate tests for determinacy and adequacy of its best fitting parameter sets. We discuss a number of issues related to empirical checking of models for stellar limb darkening, surface maculation, Doppler beaming, microvariability, and transit time variation (TTV) effects. The Radau coefficients used in the light curve modeling, in principle, allow structural models of the component stars to be tested.

  1. ARIEL: Atmospheric Remote-Sensing Infrared Exoplanet Large-survey

    NASA Astrophysics Data System (ADS)

    Tinetti, Giovanna

    2015-11-01

    More than 1,000 extrasolar systems have been discovered, hosting nearly 2,000 exoplanets. Ongoing and planned ESA and NASA missions from space such as GAIA, Cheops, PLATO, K2 and TESS will increase the number of known systems to tens of thousands.Of all these exoplanets we know very little, i.e. their orbital data and, for some of these, their physical parameters such as their size and mass. In the past decade, pioneering results have been obtained using transit spectroscopy with Hubble, Spitzer and ground-based facilities, enabling the detection of a few of the most abundant ionic, atomic and molecular species and to constrain the planet’s thermal structure. Future general purpose facilities with large collecting areas will allow the acquisition of better exoplanet spectra, compared to the currently available, especially from fainter targets. A few tens of planets will be observed with JWST and E-ELT in great detail.A breakthrough in our understanding of planet formation and evolution mechanisms will only happen through the observation of the planetary bulk and atmospheric composition of a statistically large sample of planets. This requires conducting spectroscopic observations covering simultaneously a broad spectral region from the visible to the mid-IR. It also requires a dedicated space mission with the necessary photometric stability to perform these challenging measurements and sufficient agility to observe multiple times ~500 exoplanets over mission life-time.The ESA-M4 mission candidate ARIEL is designed to accomplish this goal and will provide a complete, statistically significant sample of gas-giants, Neptunes and super-Earths with temperatures hotter than 600K, as these types of planets will allow direct observation of their bulk properties, enabling us to constrain models of planet formation and evolution.The ARIEL consortium currently includes academic institutes and industry from eleven countries in Europe; the consortium is open and invites new

  2. Discriminating between Cloudy, Hazy, and Clear Sky Exoplanets Using Refraction

    NASA Astrophysics Data System (ADS)

    Misra, Amit K.; Meadows, Victoria S.

    2014-11-01

    We propose a method to distinguish between cloudy, hazy, and clear sky (free of clouds and hazes) exoplanet atmospheres that could be applicable to upcoming large aperture space- and ground-based telescopes such as the James Webb Space Telescope (JWST) and the European Extremely Large Telescope (E-ELT). These facilities will be powerful tools for characterizing transiting exoplanets, but only after a considerable amount of telescope time is devoted to a single planet. A technique that could provide a relatively rapid means of identifying haze-free targets (which may be more valuable targets for characterization) could potentially increase the science return for these telescopes. Our proposed method utilizes broadband observations of refracted light in the out-of-transit spectrum. Light refracted through an exoplanet atmosphere can lead to an increase of flux prior to ingress and subsequent to egress. Because this light is transmitted at pressures greater than those for typical cloud and haze layers, the detection of refracted light could indicate a cloud- or haze-free atmosphere. A detection of refracted light could be accomplished in <10 hr for Jovian exoplanets with JWST and <5 hr for super-Earths/mini-Neptunes with E-ELT. We find that this technique is most effective for planets with equilibrium temperatures between 200 and 500 K, which may include potentially habitable planets. A detection of refracted light for a potentially habitable planet would strongly suggest the planet was free of a global cloud or haze layer, and therefore a promising candidate for follow-up observations.

  3. DISCRIMINATING BETWEEN CLOUDY, HAZY, AND CLEAR SKY EXOPLANETS USING REFRACTION

    SciTech Connect

    Misra, Amit K.; Meadows, Victoria S.

    2014-11-01

    We propose a method to distinguish between cloudy, hazy, and clear sky (free of clouds and hazes) exoplanet atmospheres that could be applicable to upcoming large aperture space- and ground-based telescopes such as the James Webb Space Telescope (JWST) and the European Extremely Large Telescope (E-ELT). These facilities will be powerful tools for characterizing transiting exoplanets, but only after a considerable amount of telescope time is devoted to a single planet. A technique that could provide a relatively rapid means of identifying haze-free targets (which may be more valuable targets for characterization) could potentially increase the science return for these telescopes. Our proposed method utilizes broadband observations of refracted light in the out-of-transit spectrum. Light refracted through an exoplanet atmosphere can lead to an increase of flux prior to ingress and subsequent to egress. Because this light is transmitted at pressures greater than those for typical cloud and haze layers, the detection of refracted light could indicate a cloud- or haze-free atmosphere. A detection of refracted light could be accomplished in <10 hr for Jovian exoplanets with JWST and <5 hr for super-Earths/mini-Neptunes with E-ELT. We find that this technique is most effective for planets with equilibrium temperatures between 200 and 500 K, which may include potentially habitable planets. A detection of refracted light for a potentially habitable planet would strongly suggest the planet was free of a global cloud or haze layer, and therefore a promising candidate for follow-up observations.

  4. Galactic cosmic ray-induced radiation dose on terrestrial exoplanets.

    PubMed

    Atri, Dimitra; Hariharan, B; Grießmeier, Jean-Mathias

    2013-10-01

    This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground- and space-based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets that reside in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Planetary systems around M dwarfs are considered to be prime candidates to search for life beyond the Solar System. Such planets are likely to be tidally locked and have close-in habitable zones. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in the case of super-Earths. Such exoplanets are subjected to a high flux of galactic cosmic rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin that strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another factor governing the radiation dose is the depth of the planetary atmosphere. The higher the depth of the planetary atmosphere, the lower the flux of secondary particles will be on the surface. If the secondary particles are energetic enough, and their flux is sufficiently high, the radiation from muons can also impact the subsurface regions, such as in the case of Mars. If the radiation dose is too high, the chances of sustaining a long-term biosphere on the planet are very low. We have examined the dependence of the GCR-induced radiation dose on the strength of the planetary magnetic field and its atmospheric depth, and found that the latter is the decisive factor for the protection of a planetary biosphere. PMID:24143867

  5. In the Search of Exoplanets

    NASA Astrophysics Data System (ADS)

    Crespo, Luis Cuesta

    The Spanish Instituto Nacional de Técnica Aeroespacial has a network of three telescopes located in some of the best places for Astronomy in Spain: the Observatory of Calar Alto, in Almería, near Calatayud, in Zaragoza, at the summit of a 1,400m high mountain, and at the campus of INTA, in Madrid. The three telescopes have diameters between 40 and 50cm, and are equipped with instrumentation very adequate to identify exoplanets.

  6. Phase Curves of Eccentric Exoplanets

    NASA Astrophysics Data System (ADS)

    Lewis, Nikole K.; de Wit, Julien; Laughlin, Gregory P.; Knutson, Heather

    2016-01-01

    Nearly 15% of the known exoplanet population have significantly eccentric orbits (e > 0.25). Systems with planets on highly eccentric orbits provide natural laboratories to test theories of orbital evolution, tidal forcing, and atmospheric response. The two best studied eccentric exoplanets are HAT-P-2b (e~0.5) and HD 80606 b (e~0.9). Both of these eccentric planets have full or partial orbit phase curve observations taken with the 3.6, 4.5, and 8.0 micron channels of the Spitzer IRAC instrument. These phase-curve observations of HAT-P-2b and HD 80606 b have given us important insights into atmospheric radiative timescales, planetary rotation rates and orbital evolution, and planet-star tidal interactions. Here I will overview the key results from the Spitzer observational campaigns for HAT-P-2b and HD 80606 b and look toward the future of phase curve observations of eccentric exoplanets in the era of JWST.

  7. Transiting Exoplanet Survey Satellite (TESS)

    NASA Technical Reports Server (NTRS)

    Ricker, G. R.; Clampin, M.; Latham, D. W.; Seager, S.; Vanderspek, R. K.; Villasenor, J. S.; Winn, J. N.

    2012-01-01

    The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey, TESS will monitor more than 500,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. No ground-based survey can achieve this feat. A large fraction of TESS target stars will be 30-100 times brighter than those observed by Kepler satellite, and therefore TESS . planets will be far easier to characterize with follow-up observations. TESS will make it possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. TESS will provide prime targets for observation with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future. TESS data will be released with minimal delay (no proprietary period), inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the very nearest and brightest main-sequence stars hosting transiting exoplanets, thus providing future observers with the most favorable targets for detailed investigations.

  8. First Temperate Exoplanet Sized Up

    NASA Astrophysics Data System (ADS)

    2010-03-01

    Combining observations from the CoRoT satellite and the ESO HARPS instrument, astronomers have discovered the first "normal" exoplanet that can be studied in great detail. Designated Corot-9b, the planet regularly passes in front of a star similar to the Sun located 1500 light-years away from Earth towards the constellation of Serpens (the Snake). "This is a normal, temperate exoplanet just like dozens we already know, but this is the first whose properties we can study in depth," says Claire Moutou, who is part of the international team of 60 astronomers that made the discovery. "It is bound to become a Rosetta stone in exoplanet research." "Corot-9b is the first exoplanet that really does resemble planets in our solar system," adds lead author Hans Deeg. "It has the size of Jupiter and an orbit similar to that of Mercury." "Like our own giant planets, Jupiter and Saturn, the planet is mostly made of hydrogen and helium," says team member Tristan Guillot, "and it may contain up to 20 Earth masses of other elements, including water and rock at high temperatures and pressures." Corot-9b passes in front of its host star every 95 days, as seen from Earth [1]. This "transit" lasts for about 8 hours, and provides astronomers with much additional information on the planet. This is fortunate as the gas giant shares many features with the majority of exoplanets discovered so far [2]. "Our analysis has provided more information on Corot-9b than for other exoplanets of the same type," says co-author Didier Queloz. "It may open up a new field of research to understand the atmospheres of moderate- and low-temperature planets, and in particular a completely new window in our understanding of low-temperature chemistry." More than 400 exoplanets have been discovered so far, 70 of them through the transit method. Corot-9b is special in that its distance from its host star is about ten times larger than that of any planet previously discovered by this method. And unlike all such

  9. Astrometric exoplanet detection with Gaia

    SciTech Connect

    Perryman, Michael; Hartman, Joel; Bakos, Gáspár Á.; Lindegren, Lennart

    2014-12-10

    We provide a revised assessment of the number of exoplanets that should be discovered by Gaia astrometry, extending previous studies to a broader range of spectral types, distances, and magnitudes. Our assessment is based on a large representative sample of host stars from the TRILEGAL Galaxy population synthesis model, recent estimates of the exoplanet frequency distributions as a function of stellar type, and detailed simulation of the Gaia observations using the updated instrument performance and scanning law. We use two approaches to estimate detectable planetary systems: one based on the signal-to-noise ratio of the astrometric signature per field crossing, easily reproducible and allowing comparisons with previous estimates, and a new and more robust metric based on orbit fitting to the simulated satellite data. With some plausible assumptions on planet occurrences, we find that some 21,000 (±6000) high-mass (∼1-15M {sub J}) long-period planets should be discovered out to distances of ∼500 pc for the nominal 5 yr mission (including at least 1000-1500 around M dwarfs out to 100 pc), rising to some 70,000 (±20, 000) for a 10 yr mission. We indicate some of the expected features of this exoplanet population, amongst them ∼25-50 intermediate-period (P ∼ 2-3 yr) transiting systems.

  10. Overcoming Degeneracies in Exoplanet Spectra

    NASA Astrophysics Data System (ADS)

    Benneke, Björn

    2015-08-01

    Spectroscopic observations of exoplanets can provide invaluable insights into the planets’ compositions, their formation and evolution histories, and even their habitability. Obtaining exoplanet spectra is observationally challenging; however, and we are generally limited to relatively low signal-to-noise, low spectral resolution, disk-integrated observations , often with relatively narrow wavelength coverage. This low data situation results in strong correlations and degeneracies between the different planet and atmospheric parameters of interest. In this talk, I will present a conceptual picture of how vital information about the planet is encoded in its observable spectrum. I will then give an overview about the wide range of correlations and degeneracies relevant to today’s exoplanet observations. Finally, I will demonstrate how some degeneracies can be overcome and improved constraints can be obtained by including prior knowledge of atmospheric chemistry and physics in the retrieval. I present a new atmospheric retrieval framework, SCARLET, that combines observational data and our prior (limited) knowledge of atmospheric processes in a statistical robust Bayesian framework. New results for hot Jupiters will be presented.

  11. The Routledge Companion to Education

    ERIC Educational Resources Information Center

    Arthur, James, Ed.; Peterson, Andrew, Ed.

    2011-01-01

    "The Routledge Companion to Education" presents the most comprehensive, up-to-date guide available to the key theories, themes and topics in education. Forty specially commissioned chapters, covering all aspects of education, introduce you to the ideas, research and issues that have shaped this most diverse, dynamic and fluid field. Part one…

  12. Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids

    NASA Astrophysics Data System (ADS)

    Evans, Nancy Remage; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Tingle, Evan; Karovska, Margarita; Pillitteri, Ignazio

    2016-05-01

    We have conducted an imaging survey with the Hubble Space Telescope Wide Field Camera 3 (WFC3) of 70 Galactic Cepheids, typically within 1 kpc, with the aim of finding resolved physical companions. The WFC3 field typically covers the 0.1 pc area where companions are expected. In this paper, we identify 39 Cepheids having candidate companions, based on their positions in color-magnitude diagrams, and having separations ⩾ 5'' from the Cepheids. We use follow-up observations of 14 of these candidates with XMM-Newton, and of one of them with ROSAT, to separate X-ray-active young stars (probable physical companions) from field stars (chance alignments). Our preliminary estimate, based on the optical and X-ray observations, is that only 3% of the Cepheids in the sample have wide companions. Our survey easily detects resolved main-sequence companions as faint as spectral type K. Thus the fact that the two most probable companions (those of FF Aql and RV Sco) are earlier than type K is not simply a function of the detection limit. We find no physical companions having separations larger than 4000 au in the X-ray survey. Two Cepheids are exceptions in that they do have young companions at significantly larger separations (δ Cep and S Nor), but both belong to a cluster or a loose association, so our working model is that they are not gravitationally bound binary members, but rather cluster/association members. All of these properties provide constraints on both star formation and subsequent dynamical evolution. The low frequency of true physical companions at separations > 5'' is confirmed by examination of the subset of the nearest Cepheids and also the density of the fields. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  13. Search for transiting exoplanets and variable stars in the open cluster NGC 7243

    NASA Astrophysics Data System (ADS)

    Garai, Z.; Pribulla, T.; Hambálek, Ľ.; Errmann, R.; Adam, Ch.; Buder, S.; Butterley, T.; Dhillon, V. S.; Dincel, B.; Gilbert, H.; Ginski, Ch.; Hardy, L. K.; Kellerer, A.; Kitze, M.; Kundra, E.; Littlefair, S. P.; Mugrauer, M.; Nedoroščík, J.; Neuhäuser, R.; Pannicke, A.; Raetz, S.; Schmidt, J. G.; Schmidt, T. O. B.; Seeliger, M.; Vaňko, M.; Wilson, R. W.

    2016-03-01

    We report results of the first five observing campaigns for the open stellar cluster NGC 7243 in the frame of project Young Exoplanet Transit Initiative (YETI). The project focuses on the monitoring of young and nearby stellar clusters, with the aim to detect young transiting exoplanets and to study other variability phenomena on time-scales from minutes to years. After five observing campaigns and additional observations during 2013 and 2014, a clear and repeating transit-like signal was detected in the light curve of J221550.6+495611. Furthermore, we detected and analysed 37 new eclipsing binary stars in the studied region. The best fit parameters and light curves of all systems are given. Finally, we detected and analysed 26 new, presumably pulsating variable stars in the studied region. The follow-up investigation of these objects, including spectroscopic measurements of the exoplanet candidate, is currently planned.

  14. Memory for Companions in Preschool Children.

    ERIC Educational Resources Information Center

    Delfosse, Patricia; Smith, Peter K.

    1979-01-01

    Memory of preschool children (four years of age) for companions was investigated by comparing interview data using a picture sociometric technique with observational data on actual play companions. Subjects were 15 boys and girls. (Author/MP)

  15. Extreme Planet-Like Systems: Brown Dwarfs at the Exoplanet Mass Boundary

    NASA Astrophysics Data System (ADS)

    Faherty, Jacqueline Kelly

    2015-12-01

    Brown dwarfs have long been the observational anchors for our theoretical understanding of giant gas planets. Recent studies have uncovered a population of nearby young sources that rival the age and mass of many planetary mass companions. From detailed observations, we postulate that objects in this young population have dynamic atmospheres ripe with exotic, thick condensate cloud species that drive extreme photometric and spectroscopic characteristics. In this talk I will review how we are using these so-called exoplanet analogs to establish luminosity, temperature, age, and mass relations for brown dwarf into planetary mass objects.

  16. Exoplanet Community Report on Direct Infrared Imaging of Exoplanets

    NASA Technical Reports Server (NTRS)

    Danchi, William C.; Lawson, Peter R.

    2009-01-01

    Direct infrared imaging and spectroscopy of exoplanets will allow for detailed characterization of the atmospheric constituents of more than 200 nearby Earth-like planets, more than is possible with any other method under consideration. A flagship mission based on larger passively cooled infrared telescopes and formation flying technologies would have the highest angular resolution of any concept under consideration. The 2008 Exoplanet Forum committee on Direct Infrared Imaging of Exoplanets recommends: (1) a vigorous technology program including component development, integrated testbeds, and end-to-end modeling in the areas of formation flying and mid-infrared nulling; (2) a probe-scale mission based on a passively cooled structurally connected interferometer to be started within the next two to five years, for exoplanetary system characterization that is not accessible from the ground, and which would provide transformative science and lay the engineering groundwork for the flagship mission with formation flying elements. Such a mission would enable a complete exozodiacal dust survey (<1 solar system zodi) in the habitable zone of all nearby stars. This information will allow for a more efficient strategy of spectral characterization of Earth-sized planets for the flagship missions, and also will allow for optimization of the search strategy of an astrometric mission if such a mission were delayed due to cost or technology reasons. (3) Both the flagship and probe missions should be pursued with international partners if possible. Fruitful collaboration with international partners on mission concepts and relevant technology should be continued. (4) Research and Analysis (R&A) should be supported for the development of preliminary science and mission designs. Ongoing efforts to characterize the the typical level of exozodiacal light around Sun-like stars with ground-based nulling technology should be continued.

  17. SEEDS — Strategic explorations of exoplanets and disks with the Subaru Telescope —

    PubMed Central

    TAMURA, Motohide

    2016-01-01

    The first convincing detection of planets orbiting stars other than the Sun, or exoplanets, was made in 1995. In only 20 years, the number of the exoplanets including promising candidates has already accumulated to more than 5000. Most of the exoplanets discovered so far are detected by indirect methods because the direct imaging of exoplanets needs to overcome the extreme contrast between the bright central star and the faint planets. Using the large Subaru 8.2-m Telescope, a new high-contrast imager, HiCIAO, and second-generation adaptive optics (AO188), the most ambitious high-contrast direct imaging survey to date for giant planets and planet-forming disks has been conducted, the SEEDS project. In this review, we describe the aims and results of the SEEDS project for exoplanet/disk science. The completeness and uniformity of this systematic survey mean that the resulting data set will dominate this field of research for many years. PMID:26860453

  18. SEEDS - Strategic explorations of exoplanets and disks with the Subaru Telescope.

    PubMed

    Tamura, Motohide

    2016-01-01

    The first convincing detection of planets orbiting stars other than the Sun, or exoplanets, was made in 1995. In only 20 years, the number of the exoplanets including promising candidates has already accumulated to more than 5000. Most of the exoplanets discovered so far are detected by indirect methods because the direct imaging of exoplanets needs to overcome the extreme contrast between the bright central star and the faint planets. Using the large Subaru 8.2-m Telescope, a new high-contrast imager, HiCIAO, and second-generation adaptive optics (AO188), the most ambitious high-contrast direct imaging survey to date for giant planets and planet-forming disks has been conducted, the SEEDS project. In this review, we describe the aims and results of the SEEDS project for exoplanet/disk science. The completeness and uniformity of this systematic survey mean that the resulting data set will dominate this field of research for many years. PMID:26860453

  19. Biosignature Gases in H2-dominated Atmospheres on Rocky Exoplanets

    NASA Astrophysics Data System (ADS)

    Seager, S.; Bains, W.; Hu, R.

    2013-11-01

    Super-Earth exoplanets are being discovered with increasing frequency and some will be able to retain stable H2-dominated atmospheres. We study biosignature gases on exoplanets with thin H2 atmospheres and habitable surface temperatures, using a model atmosphere with photochemistry and a biomass estimate framework for evaluating the plausibility of a range of biosignature gas candidates. We find that photochemically produced H atoms are the most abundant reactive species in H2 atmospheres. In atmospheres with high CO2 levels, atomic O is the major destructive species for some molecules. In Sun-Earth-like UV radiation environments, H (and in some cases O) will rapidly destroy nearly all biosignature gases of interest. The lower UV fluxes from UV-quiet M stars would produce a lower concentration of H (or O) for the same scenario, enabling some biosignature gases to accumulate. The favorability of low-UV radiation environments to accumulate detectable biosignature gases in an H2 atmosphere is closely analogous to the case of oxidized atmospheres, where photochemically produced OH is the major destructive species. Most potential biosignature gases, such as dimethylsulfide and CH3Cl, are therefore more favorable in low-UV, as compared with solar-like UV, environments. A few promising biosignature gas candidates, including NH3 and N2O, are favorable even in solar-like UV environments, as these gases are destroyed directly by photolysis and not by H (or O). A more subtle finding is that most gases produced by life that are fully hydrogenated forms of an element, such as CH4 and H2S, are not effective signs of life in an H2-rich atmosphere because the dominant atmospheric chemistry will generate such gases abiologically, through photochemistry or geochemistry. Suitable biosignature gases in H2-rich atmospheres for super-Earth exoplanets transiting M stars could potentially be detected in transmission spectra with the James Webb Space Telescope.

  20. First Temperate Exoplanet Sized Up

    NASA Astrophysics Data System (ADS)

    2010-03-01

    Combining observations from the CoRoT satellite and the ESO HARPS instrument, astronomers have discovered the first "normal" exoplanet that can be studied in great detail. Designated Corot-9b, the planet regularly passes in front of a star similar to the Sun located 1500 light-years away from Earth towards the constellation of Serpens (the Snake). "This is a normal, temperate exoplanet just like dozens we already know, but this is the first whose properties we can study in depth," says Claire Moutou, who is part of the international team of 60 astronomers that made the discovery. "It is bound to become a Rosetta stone in exoplanet research." "Corot-9b is the first exoplanet that really does resemble planets in our solar system," adds lead author Hans Deeg. "It has the size of Jupiter and an orbit similar to that of Mercury." "Like our own giant planets, Jupiter and Saturn, the planet is mostly made of hydrogen and helium," says team member Tristan Guillot, "and it may contain up to 20 Earth masses of other elements, including water and rock at high temperatures and pressures." Corot-9b passes in front of its host star every 95 days, as seen from Earth [1]. This "transit" lasts for about 8 hours, and provides astronomers with much additional information on the planet. This is fortunate as the gas giant shares many features with the majority of exoplanets discovered so far [2]. "Our analysis has provided more information on Corot-9b than for other exoplanets of the same type," says co-author Didier Queloz. "It may open up a new field of research to understand the atmospheres of moderate- and low-temperature planets, and in particular a completely new window in our understanding of low-temperature chemistry." More than 400 exoplanets have been discovered so far, 70 of them through the transit method. Corot-9b is special in that its distance from its host star is about ten times larger than that of any planet previously discovered by this method. And unlike all such

  1. DISCOVERY OF A PLANETARY-MASS COMPANION TO A BROWN DWARF IN TAURUS

    SciTech Connect

    Todorov, K.; Luhman, K. L.; McLeod, K. K.

    2010-05-01

    We have performed a survey for substellar companions to young brown dwarfs in the Taurus star-forming region using the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. In these data, we have discovered a candidate companion at a projected separation of 0.''105 from one of the brown dwarfs, corresponding to 15 AU at the distance of Taurus. To determine if this object is a companion, we have obtained images of the pair at a second epoch with the adaptive optics system at Gemini Observatory. The astrometry from the Hubble and Gemini data indicates that the two objects share similar proper motions and thus are likely companions. We estimate a mass of 5-10 M {sub Jup} for the secondary based on a comparison of its bolometric luminosity to the predictions of theoretical evolutionary models. This object demonstrates that planetary-mass companions to brown dwarfs can form on a timescale of {tau} {approx}< 1 Myr. Companion formation on such a rapid timescale is more likely to occur via gravitational instability in a disk or fragmentation of a cloud core than through core accretion. The Gemini images also reveal a possible substellar companion ({rho} = 0.''23) to a young low-mass star that is 12.''4 from the brown dwarf targeted by Hubble. If these four objects comprise a quadruple system, then its hierarchical configuration would suggest that the fragmentation of molecular cloud cores can produce companions below 10 M {sub Jup}.

  2. Direct Exoplanet Imaging around Sun-like Stars: Beating the Speckle Noise with Innovative Imaging Techniques

    NASA Astrophysics Data System (ADS)

    Marois, Christian; Doyon, R.; Racine, R.; Nadeau, D.; Lafreniere, D.; Vallee, P.; Riopel, M.; Macintosh, B.

    2005-08-01

    Indirect surveys have now uncovered more than 150 exoplanets, but are limited to planets close to the star and measure only the projected mass and orbital parameters. Both photometry and spectroscopy of exoplanets are required to derive their physical characteristics. The star to exoplanet intensity ratio (>108 in the near infrared) and the relative separation (< 0.5 arcseconds) significantly complicate this endeavour. Current ground- and space-based direct imaging surveys achieve an intensity ratio up to 104 at 0.5. separation, a factor 10,000 from the desired goal. These surveys are limited by uncorrected atmospheric turbulence and optical surface imperfections that produce quasi-static speckles that look like exoplanets, but much brighter. Two techniques will be discussed to attenuate this speckle noise. The first is the Simultaneous Spectral Differential Imaging technique (SSDI), acquiring a number of images simultaneously at different adjacent narrowband wavelengths and combining them to attenuate speckles. The second is the Angular Differential Imaging technique (ADI), taking multiple observations while rotating the telescope or waiting for sufficient field rotation to subtract static speckles and to preserve the companion flux. Results from a dedicated SSDI camera "TRIDENT" that was mounted under PUEO/CFHT and from an ongoing ADI survey at Gemini with Altair/NIRI will be presented. Future work involving a new type of detector, the Multi-Color Detector Assembly (MCDA), will also be discussed. Combining these observation strategies and new detectors are of particular interest for specialized exoplanet finder instruments for 10-m telescopes that are currently under study, like ExAOC at Gemini, and future space-based observatories like TPF.

  3. The Companion's Role in the Doctor-Elderly Patient-Companion Interaction.

    ERIC Educational Resources Information Center

    Beisecker, Analee E.; Fuemmeler, Elizabeth F.

    Based on Beisecker's earlier finding that patients over age 60 brought companions to their medical appointments more often than did patients aged 25-59, a study was conducted to examine the role of the companion. Eleven of 21 patients aged 60-85 brought companions. Companions were either spouses or adult children of the patients. Within this…

  4. Wide Low-Mass Tertiary Companions of Binary Star Systems as a Test of Star Formation Theories

    NASA Astrophysics Data System (ADS)

    Douglas, Stephanie; Allen, P.

    2012-01-01

    We will present the status of a common proper motion search for wide low-mass stellar and sub-stellar companions to known white dwarf-M dwarf binary systems. I-band observations were made using the 31" NURO telescope at Lowell Observatory. Candidate companions are selected using astrometry from our own data and 2MASS photometry. We have begun to spectroscopically confirm candidates that pass our selection criteria. The ultimate goal of the search is to test star formation theories which predict that close binary systems form by transferring angular momentum to a third companion. To this end, we will model the physical companion population and perform Bayesian statistical analysis to determine the best-fit population model to our data. Here we will present our spectroscopically confirmed companions as well as the preliminary results of our population models and statistical analysis.

  5. Insolation patterns on eccentric exoplanets

    NASA Astrophysics Data System (ADS)

    Dobrovolskis, Anthony R.

    2015-04-01

    Several studies have found that synchronously-rotating Earth-like planets in the habitable zones of M-dwarf stars should exhibit an "eyeball" climate pattern, with a pupil of open ocean facing the parent star, and ice everywhere else. Recent work on eccentric exoplanets by Wang et al. (Wang, Y., Tian, F., Hu, Y. [2014b] Astrophys. J. 791, L12) has extended this conclusion to the 2:1 spin-orbit resonance as well, where the planet rotates twice during one orbital period. However, Wang et al. also found that the 3:2 and 5:2 half-odd resonances produce a zonally-striped climate pattern with polar icecaps instead. Unfortunately, they used incorrect insolation functions for the 3:2 and 5:2 resonances whose long-term time averages are essentially independent of longitude. This paper presents the correct insolation patterns for eccentric exoplanets with negligible obliquities in the 0:1, 1:2, 1:1, 3:2, 2:1, 5:2, 3:1, 7:2, and 4:1 spin-orbit resonances. I confirm that the mean insolation is distributed in an eyeball pattern for integer resonances; but for half-odd resonances, the mean insolation takes a "double-eyeball" pattern, identical over the "eastern" and "western" hemispheres. Presuming that liquids, ices, clouds, albedo, and thermal emission are similarly distributed, this has significant implications for the observation and interpretation of potentially habitable exoplanets. Finally, whether a striped ball, eyeball, or double-eyeball pattern emerges, the possibility exists that long-term build-up of ice (or liquid) away from the hot spots may alter the planet's inertia tensor and quadrupole moments enough to re-orient the planet, ultimately changing the distribution of liquid and ice.

  6. Time Domain Challenges for Exoplanets

    NASA Astrophysics Data System (ADS)

    Dawson, Rebekah Ilene

    2016-01-01

    Over the past couple decades, thousands of extra-solar planets have been discovered orbiting other stars. Most have been detected and characterized using transit and/or radial velocity time series, and these techniques have undergone huge improvements in instrumental precision. However, the improvements in precision have brought to light new statistical challenges in detecting and characterizing exoplanets in the presence of correlated noise caused by stellar activity (transits and radial velocities) and gaps in the time sampling (radial velocities). These challenges have afflicted many of the most interesting exoplanets, from Earth-like planets to planetary systems whose orbital dynamics place important constraints on how planetary systems form and evolve. In the first part of the talk, I will focus on the problem of correlated noise for characterizing transiting exoplanets using transit timing variations. I will present a comparison of several techniques using wavelets, Gaussian processes, and polynomial splines to account for correlated noise in the likelihood function when inferring planetary parameters. I will also present results on the characteristics of correlated noise that cause planets to be missed by the Kepler and homegrown pipelines despite high nominal signal-to-noise. In the second part of the talk, I will focus on the problem of aliasing caused by gaps in the radial-velocity time series on yearly, daily, and monthly timescales. I will present results on identifying aliases in the Fourier domain by taking advantage of aliasing on multiple timescales and discuss the interplay between aliasing and stellar activity for several habitable-zone "planets" that have recently been called into question as possible spurious signals caused by activity. As we push toward detecting and characterizing lower mass planets, it is essential that astrostatistical advances keep pace with advances in instrumentation.

  7. Enabling Participation In Exoplanet Science

    NASA Astrophysics Data System (ADS)

    Taylor, Stuart F.

    2015-08-01

    Determining the distribution of exoplanets has required the contributions of a community of astronomers, who all require the support of colleagues to finish their projects in a manner to enable them to enter new collaborations to continue to contribute to understanding exoplanet science.The contributions of each member of the astronomy community are to be encouraged and must never be intentionally obstructed.We present a member’s long pursuit to be a contributing part of the exoplanet community through doing transit photometry as a means of commissioning the telescopes for a new observatory, followed by pursuit of interpreting the distributions in exoplanet parameter data.We present how the photometry projects have been presented as successful by the others who have claimed to have completed them, but how by requiring its employees to present results while omitting one member has been obstructive against members working together and has prevented the results from being published in what can genuinely be called a peer-reviewed fashion.We present how by tolerating one group to obstruct one member from finishing participation and then falsely denying credit is counterproductive to doing science.We show how expecting one member to attempt to go around an ostracizing group by starting something different is destructive to the entire profession. We repeat previously published appeals to help ostracized members to “go around the observatory” by calling for discussion on how the community must act to reverse cases of shunning, bullying, and other abuses. Without better recourse and support from the community, actions that do not meet standard good collegial behavior end up forcing good members from the community. The most important actions are to enable an ostracized member to have recourse to participating in group papers by either working through other authors or through the journal. All journals and authors must expect that no co-author is keeping out a major

  8. Validation of Kepler's multiple planet candidates. II. Refined statistical framework and descriptions of systems of special interest

    SciTech Connect

    Lissauer, Jack J.; Bryson, Stephen T.; Rowe, Jason F.; Jontof-Hutter, Daniel; Borucki, William J.; Marcy, Geoffrey W.; Kolbl, Rea; Agol, Eric; Carter, Joshua A.; Torres, Guillermo; Ford, Eric B.; Gilliland, Ronald L.; Star, Kimberly M.; Steffen, Jason H.

    2014-03-20

    We extend the statistical analysis performed by Lissauer et al. in 2012, which demonstrates that the overwhelming majority of Kepler candidate multiple transiting systems (multis) represents true transiting planets, and we develop therefrom a procedure to validate large numbers of planet candidates in multis as bona fide exoplanets. We show that this statistical framework correctly estimates the abundance of false positives already identified around Kepler targets with multiple sets of transit-like signatures based on their abundance around targets with single sets of transit-like signatures. We estimate the number of multis that represent split systems of one or more planets orbiting each component of a binary star system. We use the high reliability rate for multis to validate more than one dozen particularly interesting multi-planet systems herein. Hundreds of additional multi-planet systems are validated in a companion paper by Rowe et al. We note that few very short period (P < 1.6 days) planets orbit within multiple transiting planet systems and discuss possible reasons for their absence. There also appears to be a shortage of planets with periods exceeding a few months in multis.

  9. Hidden in Starlight: A Search for Widely Separated Substellar-Mass Companions

    NASA Astrophysics Data System (ADS)

    Hulsebus, Alan; Marengo, Massimo; Carson, Joseph; Stapelfeldt, Karl R.

    2014-06-01

    Relatively few widely separated substellar-mass companions of planetary systems are known. These companions can alter the dynamics of planets through Kozai-mechanism-style secular perturbations, and may be a cause of the high mean eccentricity of exoplanets. The orbital periods of such companions are expected to be of the order of tens to thousands of years, making them undetectable by time-domain observations such as transit- and radial velocity searches. We have conducted a Spitzer/Infrared Array Camera (IRAC) 3.6 and 4.5 µm imaging search for widely separated substellar-mass companions with projected separation between 5 to 40 arcsec from their parent star. The 36 stars in my sample range from 4 to 15 pc from the sun, giving a typical sensitivity of 10 MJ for objects with an orbital radius in the range of 50 to 300 au. This search required advanced PSF-subtraction techniques in order to minimize the inner working angle and increase sensitivity. In this talk I present the results of this search and discuss the data analysis methods we developed for it.

  10. SUB-STELLAR COMPANIONS AND STELLAR MULTIPLICITY IN THE TAURUS STAR-FORMING REGION

    SciTech Connect

    Daemgen, Sebastian; Bonavita, Mariangela; Jayawardhana, Ray; Lafrenière, David; Janson, Markus

    2015-02-01

    We present results from a large, high-spatial-resolution near-infrared imaging search for stellar and sub-stellar companions in the Taurus-Auriga star-forming region. The sample covers 64 stars with masses between those of the most massive Taurus members at ∼3 M {sub ☉} and low-mass stars at ∼0.2 M {sub ☉}. We detected 74 companion candidates, 34 of these reported for the first time. Twenty-five companions are likely physically bound, partly confirmed by follow-up observations. Four candidate companions are likely unrelated field stars. Assuming physical association with their host star, estimated companion masses are as low as ∼2 M {sub Jup}. The inferred multiplicity frequency within our sensitivity limits between ∼10-1500 AU is 26.3{sub −4.9}{sup +6.6}%. Applying a completeness correction, 62% ± 14% of all Taurus stars between 0.7 and 1.4 M {sub ☉} appear to be multiple. Higher order multiples were found in 1.8{sub −1.5}{sup +4.2}% of the cases, in agreement with previous observations of the field. We estimate a sub-stellar companion frequency of ∼3.5%-8.8% within our sensitivity limits from the discovery of two likely bound and three other tentative very low-mass companions. This frequency appears to be in agreement with what is expected from the tail of the stellar companion mass ratio distribution, suggesting that stellar and brown dwarf companions share the same dominant formation mechanism. Further, we find evidence for possible evolution of binary parameters between two identified sub-populations in Taurus with ages of ∼2 Myr and ∼20 Myr, respectively.

  11. Three Red Giants With Substellar-Mass Companions

    NASA Astrophysics Data System (ADS)

    Niedzielski, A.; Wolszczan, A.; Nowak, G.; Adamów, M.; Kowalik, K.; Maciejewski, G.; Deka-Szymankiewicz, B.; Adamczyk, M.

    2015-04-01

    We present three giant stars from the ongoing Penn State-Toruń Planet Search with the Hobby-Eberly Telescope, which exhibit radial velocity (RV) variations that point to the presence of planetary-mass companions around them. BD+49 828 is a M=1.52+/- 0.22 {{M}⊙ } K0 giant with a m sin i=1.6-0.2+0.4 {{M}J} minimum mass companion in a = 4.2+0.32-0.2 AU (2590+300-180d), e = 0.35+0.24-0.10 orbit. HD 95127, a log L/{{L}⊙ }=2.28+/- 0.38, R=20+/- 9 {{R}⊙ }, M=1.20+/- 0.22 {{M}⊙ } K0 giant, has a m sin i = 5.01-0.44+0.61 {{M}J} minimum mass companion in a = 1.28+0.01-0.01 AU (482+5-5d), e = 0.11+0.15-0.06 orbit. Finally, HD 216536 is a M=1.36+/- 0.38 {{M}⊙ } K0 giant with a msin i=1.47-0.12+0.20 {{M}J} minimum mass companion in a=0.609-0.002+0.002 AU (148.6-0.7+0.7d), e = 0.38+0.12-0.10 orbit. Both HD 95127 b and HD 216536 b in their compact orbits are very close to the engulfment zone and hence prone to ingestion in the near future. BD+49 828 b is among the longest-period planets detected with the RV technique until now and it will remain unaffected by stellar evolution up to a very late stage of its host. We discuss general properties of planetary systems around evolved stars and planet survivability using existing data on exoplanets in more detail. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  12. Preferred Hosts for Short-Period Exoplanets

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-12-01

    In an effort to learn more about how planets form around their host stars, a team of scientists has analyzed the population of Kepler-discovered exoplanet candidates, looking for trends in where theyre found.Planetary OccurrenceSince its launch in 2009, Kepler has found thousands of candidate exoplanets around a variety of star types. Especially intriguing is the large population of super-Earths and mini-Neptunes planets with masses between that of Earth and Neptune that have short orbital periods. How did they come to exist so close to their host star? Did they form in situ, or migrate inwards, or some combination of both processes?To constrain these formation mechanisms, a team of scientists led by Gijs Mulders (University of Arizona and NASAs NExSS coalition) analyzed the population of Kepler planet candidates that have orbital periods between 2 and 50 days.Mulders and collaborators used statistical reconstructions to find the average number of planets, within this orbital range, around each star in the Kepler field. They then determined how this planet occurrence rate changed for different spectral types and therefore the masses of the host stars: do low-mass M-dwarf stars host more or fewer planets than higher-mass, main-sequence F, G, or K stars?Challenging ModelsAuthors estimates for the occurrence rate for short-period planets of different radii around M-dwarfs (purple) and around F, G, and K-type stars (blue). [Mulders et al. 2015]The team found that M dwarfs, compared to F, G, or K stars, host about half as many large planets with orbital periods of P 50 days. But, surprisingly, they host significantly more small planets, racking up an average of 3.5 times the number of planets in the size range of 12.8 Earth-radii.Could it be that M dwarfs have a lower total mass of planets, but that mass is distributed into more, smaller planets? Apparently not: the authors show that the mass of heavy elements trapped in short-orbital-period planets is higher for M

  13. Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wyttenbach, Aurélien; Ehrenreich, David

    2015-12-01

    The field of exoplanet atmospheres is booming thanks to (low-resolution) space-borne spectrographs and high-resolution (narrow-ranged) NIR spectrographs on ground-based 8m-class telescopes. Atmospheres are important because they are our observing window on the physical, chemical, and evolutionary processes occurring on exoplanets. Transiting exoplanets are the best suitable targets for atmospheric studies. Observing a transit in different filters or with a spectrograph reveals the transmission spectrum of the planet atmosphere. More than one decade of such observations allowed the exploration of these remote words by detecting some constituents of their atmospheres, but revealing also the presence of scattering hazes and clouds in several exoplanets preventing the detection of major chemical constituents at low to medium resolution even from space.Transit observations from the ground with stabilised high-resolution spectrograph, such HARPS, have key roles to play in this context. Observation of the hot-jupiter HD 189733b with HARPS allow the detection of sodium in the planet atmosphere. The high-resolution transmission spectra allowed to probe a new region high in the atmosphere and revealed rapid winds and a heating thermosphere. This new use of the famous planet hunter turned HARPS into a powerful exoplanet characterisation machine. It has the precision level of the Hubble Space Telescope, albeit at 20 higher resolution.A survey of a large set of known hot transiting exoplanets with HARPS and later with ESPRESSO will allow the detection of key tracers of atmospheric physics, chemistry, and evolution, above the scattering haze layers known to dominate low-resolution visible spectra of exoplanets.Such observation, in total sinergy with other technics, will rmly establish stabilised, high-resolution spectrographs on 4m telescopes as corner-stones for the characterisation of exoplanets. This is instrumental considering the upcoming surveys (NGTS,K2, CHEOPS, TESS

  14. YETI observations of the young transiting planet candidate CVSO 30 b

    NASA Astrophysics Data System (ADS)

    Raetz, St.; Schmidt, T. O. B.; Czesla, S.; Klocová, T.; Holmes, L.; Errmann, R.; Kitze, M.; Fernández, M.; Sota, A.; Briceño, C.; Hernández, J.; Downes, J. J.; Dimitrov, D. P.; Kjurkchieva, D.; Radeva, V.; Wu, Z.-Y.; Zhou, X.; Takahashi, H.; Henych, T.; Seeliger, M.; Mugrauer, M.; Adam, Ch.; Marka, C.; Schmidt, J. G.; Hohle, M. M.; Ginski, Ch.; Pribulla, T.; Trepl, L.; Moualla, M.; Pawellek, N.; Gelszinnis, J.; Buder, S.; Masda, S.; Maciejewski, G.; Neuhäuser, R.

    2016-08-01

    CVSO 30 is a unique young low-mass system, because, for the first time, a close-in transiting and a wide directly imaged planet candidates are found around a common host star. The inner companion, CVSO 30 b, is the first possible young transiting planet orbiting a previously known weak-lined T-Tauri star. With five telescopes of the 'Young Exoplanet Transit Initiative' (YETI) located in Asia, Europe and South America we monitored CVSO 30 over three years in a total of 144 nights and detected 33 fading events. In two more seasons we carried out follow-up observations with three telescopes. We can confirm that there is a change in the shape of the fading event between different observations and that the fading event even disappears and reappears. A total of 38 fading event light curves were simultaneously modelled. We derived the planetary, stellar, and geometrical properties of the system and found them slightly smaller but in agreement with the values from the discovery paper. The period of the fading event was found to be 1.36 s shorter and 100 times more precise than the previous published value. If CVSO 30 b would be a giant planet on a precessing orbit, which we cannot confirm, yet, the precession period may be shorter than previously thought. But if confirmed as a planet it would be the youngest transiting planet ever detected and will provide important constraints on planet formation and migration time-scales.

  15. YETI observations of the young transiting planet candidate CVSO 30 b

    NASA Astrophysics Data System (ADS)

    Raetz, St.; Schmidt, T. O. B.; Czesla, S.; Klocová, T.; Holmes, L.; Errmann, R.; Kitze, M.; Fernández, M.; Sota, A.; Briceño, C.; Hernández, J.; Downes, J. J.; Dimitrov, D. P.; Kjurkchieva, D.; Radeva, V.; Wu, Z.-Y.; Zhou, X.; Takahashi, H.; Henych, T.; Seeliger, M.; Mugrauer, M.; Adam, Ch.; Marka, C.; Schmidt, J. G.; Hohle, M. M.; Ginski, Ch.; Pribulla, T.; Trepl, L.; Moualla, M.; Pawellek, N.; Gelszinnis, J.; Buder, S.; Masda, S.; Maciejewski, G.; Neuhäuser, R.

    2016-08-01

    CVSO 30 is a unique young low-mass system, because, for the first time, a close-in transiting and a wide directly imaged planet candidates are found around a common host star. The inner companion, CVSO 30 b, is the first possible young transiting planet orbiting a previously known weak-lined T Tauri star. With five telescopes of the `Young Exoplanet Transit Initiative' located in Asia, Europe and South America, we monitored CVSO 30 over three years in a total of 144 nights and detected 33 fading events. In two more seasons we carried out follow-up observations with three telescopes. We can confirm that there is a change in the shape of the fading event between different observations and that the fading event even disappears and reappears. A total of 38 fading event light curves were simultaneously modelled. We derived the planetary, stellar and geometrical properties of the system and found them slightly smaller but in agreement with the values from the discovery paper. The period of the fading event was found to be 1.36 s shorter and 100 times more precise than the previous published value. If CVSO 30 b would be a giant planet on a precessing orbit, which we cannot confirm, yet, the precession period may be shorter than previously thought. But if confirmed as a planet it would be the youngest transiting planet ever detected and will provide important constraints on planet formation and migration time-scales.

  16. Ultraviolet emission from main-sequence companions of AGB stars

    NASA Astrophysics Data System (ADS)

    Ortiz, Roberto; Guerrero, Martín A.

    2016-09-01

    Although the majority of known binary asymptotic giant branch (AGB) stars are symbiotic systems (i.e. with a white dwarf as a secondary star), main-sequence companions of AGB stars can be more numerous, even though they are more difficult to find because the primary high luminosity hampers the detection of the companion at visual wavelengths. However, in the ultraviolet the flux emitted by a secondary with Teff > 5500 ˜ 6000 K may prevail over that of the primary, and then it can be used to search for candidates to binary AGB stars. In this work, theoretical atmosphere models are used to calculate the UV excess in the GALEX near- and far-UV bands due to a main-sequence companion. After analysing a sample of confirmed binary AGB stars, we propose as a criterium for binarity: (1) the detection of the AGB star in the GALEX far-UV band and/or (2) a GALEX near-UV observed-to-predicted flux ratio >20. These criteria have been applied to a volume-limited sample of AGB stars within 500 pc of the Sun; 34 out of the sample of 58 AGB stars (˜60 per cent) fulfill them, implying to have a main-sequence companion of spectral type earlier than K0. The excess in the GALEX near- and far-UV bands cannot be attributed to a single temperature companion star, thus suggesting that the UV emission of the secondary might be absorbed by the extended atmosphere and circumstellar envelope of the primary or that UV emission is produced in accretion flows.

  17. Highlights in the study of exoplanet atmospheres.

    PubMed

    Burrows, Adam S

    2014-09-18

    Exoplanets are now being discovered in profusion. To understand their character, however, we require spectral models and data. These elements of remote sensing can yield temperatures, compositions and even weather patterns, but only if significant improvements in both the parameter retrieval process and measurements are made. Despite heroic efforts to garner constraining data on exoplanet atmospheres and dynamics, reliable interpretation has frequently lagged behind ambition. I summarize the most productive, and at times novel, methods used to probe exoplanet atmospheres; highlight some of the most interesting results obtained; and suggest various broad theoretical topics in which further work could pay significant dividends. PMID:25230656

  18. Highlights in the study of exoplanet atmospheres

    NASA Astrophysics Data System (ADS)

    Burrows, Adam S.

    2014-09-01

    Exoplanets are now being discovered in profusion. To understand their character, however, we require spectral models and data. These elements of remote sensing can yield temperatures, compositions and even weather patterns, but only if significant improvements in both the parameter retrieval process and measurements are made. Despite heroic efforts to garner constraining data on exoplanet atmospheres and dynamics, reliable interpretation has frequently lagged behind ambition. I summarize the most productive, and at times novel, methods used to probe exoplanet atmospheres; highlight some of the most interesting results obtained; and suggest various broad theoretical topics in which further work could pay significant dividends.

  19. PYNPOINT: an image processing package for finding exoplanets

    NASA Astrophysics Data System (ADS)

    Amara, Adam; Quanz, Sascha P.

    2012-12-01

    We present the scientific performance results of PYNPOINT, our Python-based software package that uses principal component analysis to detect and estimate the flux of exoplanets in two-dimensional imaging data. Recent advances in adaptive optics and imaging technology at visible and infrared wavelengths have opened the door to direct detections of planetary companions to nearby stars, but image processing techniques have yet to be optimized. We show that the performance of our approach gives a marked improvement over what is presently possible using existing methods such as LOCI. To test our approach, we use real angular differential imaging (ADI) data taken with the adaptive optics-assisted high resolution near-infrared camera NACO at the VLT. These data were taken during the commissioning of the apodizing phase plate (APP) coronagraph. By inserting simulated planets into these data, we test the performance of our method as a function of planet brightness for different positions on the image. We find that in all cases PYNPOINT has a detection threshold that is superior to that given by our LOCI analysis when assessed in a common statistical framework. We obtain our best improvements for smaller inner working angles (IWAs). For an IWA of ˜0.29 arcsec we find that we achieve a detection sensitivity that is a factor of 5 better than LOCI. We also investigate our ability to correctly measure the flux of planets. Again, we find improvements over LOCI, with PYNPOINT giving more stable results. Finally, we apply our package to a non-APP data set of the exoplanet β Pictoris b and reveal the planet with high signal-to-noise. This confirms that PYNPOINT can potentially be applied with high fidelity to a wide range of high-contrast imaging data sets.

  20. PULSE: the Palomar Ultraviolet Laser for the Study of Exoplanets

    NASA Astrophysics Data System (ADS)

    Bottom, Michael; Dekany, R.; Bowler, B. P.; Baranec, C.; Burruss, R.

    2014-01-01

    PULSE is a project to augment the currently operating 5.1-m Hale PALM-3000 exoplanet adaptive optics system with an ultraviolet Rayleigh laser and associated wavefront sensor. By using a bright (U ~ 7) ultraviolet laser to measure the high spatial and temporal order turbulence near the telescope aperture, where it dominates, one can extend the faintness limit of natural guide stars needed by PALM-3000. Initial simulations indicate that very-high infrared contrast ratios and good visible-light adaptive optics performance will be achieved by such an upgraded system on stars as faint as mV = 16-17 using an optimized low-order NGS sensor. This will enable direct imaging searches for, and subsequent characterization of, companions around cool, low-mass stars for the first time, as well as routine visible-light imaging twice as sharp as HST for fainter targets. PULSE will reuse the laser and wavefront sensor technology developed for the automated Robo-AO laser system currently operating at the Palomar 60-inch telescope, as well as take advantage of pending optimization of low-order NGS wavefront sensing and planned new interfaces to the PALM-3000 real-time reconstruction computer. PULSE will dramatically extend the AO sky coverage of the telescope from 1% to 50%. More specifically, this will boost the yield from a number of operational exoplanet instruments at Palomar including PHARO, a NIR imager, spectrograph, and coronagraph; a fiber nulling interferometer; and Project 1640, a coronagraph and IFS. Two additional funded instruments expected to benefit from PULSE in the coming years are the SDC; a NIR/visible self-calibrating vector vortex coronagraph, and DARKNESS; an energy-resolving, photon counting MKIDS camera.

  1. MODELING THE INFRARED SPECTRUM OF THE EARTH-MOON SYSTEM: IMPLICATIONS FOR THE DETECTION AND CHARACTERIZATION OF EARTHLIKE EXTRASOLAR PLANETS AND THEIR MOONLIKE COMPANIONS

    SciTech Connect

    Robinson, Tyler D.

    2011-11-01

    The Moon maintains large surface temperatures on its illuminated hemisphere and can contribute significant amounts of flux to spatially unresolved thermal infrared (IR) observations of the Earth-Moon system, especially at wavelengths where Earth's atmosphere is absorbing. In this paper we investigate the effects of an unresolved companion on IR observations of Earthlike exoplanets. For an extrasolar twin Earth-Moon system observed at full phase at IR wavelengths, the Moon consistently comprises about 20% of the total signal, approaches 30% of the signal in the 9.6 {mu}m ozone band and the 15 {mu}m carbon dioxide band, makes up as much as 80% of the signal in the 6.3 {mu}m water band, and more than 90% of the signal in the 4.3 {mu}m carbon dioxide band. These excesses translate to inferred brightness temperatures for Earth that are too large by 20-40 K and demonstrate that the presence of undetected satellites can have significant impacts on the spectroscopic characterization of exoplanets. The thermal flux contribution from an airless companion depends strongly on phase, implying that observations of exoplanets should be taken when the star-planet-observer angle (i.e., phase angle) is as large as feasibly possible if contributions from companions are to be minimized. We show that, by differencing IR observations of an Earth twin with a companion taken at both gibbous and crescent phases, Moonlike satellites may be detectable by future exoplanet characterization missions for a wide range of system inclinations.

  2. APIC: Absolute Position Interfero Coronagraph for direct exoplanet detection: first laboratory results

    NASA Astrophysics Data System (ADS)

    Allouche, Fatmé; Glindemann, Andreas; Aristidi, Eric; Vakili, Farrokh

    2010-07-01

    For the detection and direct imaging of exoplanets, when the intensity ratio between a star and its orbiting planet can largely exceed 106, coronagraphic methods are mandatory. In 1996, a concept of achromatic interferocoronagraph (AIC) was presented by J. Gay and Y. Rabbia for the detection of very faint stellar companions, such as exoplanets. In an earlier paper, we presented a modified version of the AIC permitting to determine the relative position of these faint companions with respect to the parent star, a problem unsolved in the original design of the AIC. Our modification lied in the use of cylindrical lens doublets as field rotator. By placing two of them in one arm of the interferometric set-up of AIC, we destroyed the axis of symmetry induced by the AIC's original design. Our theoretical study, along with the numerical computations, presented then, and the preliminary test bench results aiming at validating the cylindrical lens doublet field rotation capability, presented in this paper, show that the axis of symmetry is destroyed when one of the cylindrical doublets is rotated around the optic axis.

  3. Substellar companions to white dwarves

    NASA Astrophysics Data System (ADS)

    Mullally, Fergal Robert

    2007-08-01

    We search for planets and brown dwarves around white dwarves (WDs). Finding extra-solar planets is the first step toward establishing the existence and abundance of life in the Universe. The low mass and luminosity of WDs make them ideal stars to search for low mass companion objects. Theoretical predictions generally agree that a star will consume and destroy close-in, low mass planets as it ascends the red giant and asymptotic giant branch evolutionary tracks, but larger mass objects and those further out will survive. The matter ejected from the star as it evolves into a white dwarf may also be accreted onto daughter planets, or may coalesce into a disk from which planets can then form. We employ two techniques to search for planets and brown dwarves (BDs) around WDs. A subset of pulsating white dwarf stars have a pulsational stability that rivals pulsars and atomic clocks. When a planet is in orbit around a such a star the orbital motion of the star around the centre of mass is detectable as a change in arrival times of the otherwise stable pulsations. We search for, and find, a sample of suitable pulsators, monitor them for between three and four years, and place limits on companions by constraining the variation in the pulse arrival times. For one star, we detect a variation consistent with a 2.4M J planet in a 4.6 year orbit. We also observe a large sample of WDs to search for a mid-infrared excess caused by the presence of sub-stellar companions. We present evidence for a potential binary system consisting of a WD and a BD on the basis of an observed excess flux at near and mid-infrared wavelengths. We also place limits on the presence of planetary mass companions around these stars and compare our results to predictions of planetary survival theories. Our findings do not support suggestions of planet formation or accretion of extra mass during stellar death.

  4. Lightning and Life on Exoplanets

    NASA Astrophysics Data System (ADS)

    Rimmer, Paul; Ardaseva, Aleksandra; Hodosan, Gabriella; Helling, Christiane

    2016-07-01

    Miller and Urey performed a ground-breaking experiment, in which they discovered that electric discharges through a low redox ratio gas of methane, ammonia, water vapor and hydrogen produced a variety of amino acids, the building blocks of proteins. Since this experiment, there has been significant interest on the connection between lightning chemistry and the origin of life. Investigation into the atmosphere of the Early Earth has generated a serious challenge for this project, as it has been determined both that Earth's early atmosphere was likely dominated by carbon dioxide and molecular nitrogen with only small amounts of hydrogen, having a very high redox ratio, and that discharges in gases with high redox ratios fail to yield more than trace amounts of biologically relevant products. This challenge has motivated several origin of life researchers to abandon lightning chemistry, and to concentrate on other pathways for prebiotic synthesis. The discovery of over 2000 exoplanets includes a handful of rocky planets within the habitable zones around their host stars. These planets can be viewed as remote laboratories in which efficient lightning driven prebiotic synthesis may take place. This is because many of these rocky exoplanets, called super-Earths, have masses significantly greater than that of Earth. This higher mass would allow them to more retain greater amounts hydrogen within their atmosphere, reducing the redox ratio. Discharges in super-Earth atmospheres can therefore result in a significant yield of amino acids. In this talk, I will discuss new work on what lightning might look like on exoplanets, and on lightning driven chemistry on super-Earths. Using a chemical kinetics model for a super-Earth atmosphere with smaller redox ratios, I will show that in the presence of lightning, the production of the amino acid glycine is enhanced up to a certain point, but with very low redox ratios, the production of glycine is again inhibited. I will conclude

  5. No Timing Variations Observed in Third Transit of Snow-line Exoplanet Kepler-421b

    NASA Astrophysics Data System (ADS)

    Dalba, Paul A.; Muirhead, Philip S.

    2016-07-01

    We observed Kepler-421 during the anticipated third transit of the snow-line exoplanet Kepler-421b in order to constrain the existence and extent of transit timing variations (TTVs). Previously, the Kepler spacecraft only observed two transits of Kepler-421b, leaving the planet’s transit ephemeris unconstrained. Our visible light, time-series observations from the 4.3 m Discovery Channel Telescope were designed to capture pre-transit baseline and the partial transit of Kepler-421b, barring significant TTVs. We use the light curves to assess the probabilities of various transit models using both the posterior odds ratio and the Bayesian Information Criterion, and find that a transit model with no TTVs is favored to 3.6σ confidence. These observations suggest that Kepler-421b is either alone in its system or is only experiencing minor dynamic interactions with an unseen companion. With the Kepler-421b ephemeris constrained, we calculate future transit times and discuss the opportunity to characterize the atmosphere of this cold, long-period exoplanet via transmission spectroscopy. Our investigation emphasizes the difficulties associated with observing long-period exoplanet transits and the consequences that arise from failing to refine transit ephemerides.

  6. Increasing the sensitivity of Kepler to Earth-like exoplanets

    NASA Astrophysics Data System (ADS)

    Foreman-Mackey, Daniel; Hogg, David W.; Schölkopf, Bernhard; Wang, Dun

    2015-01-01

    Many transiting exoplanets have been discovered using photometry from the Kepler mission but the results are still very incomplete in some of the most interesting parts of parameter space: small planetary radius and long orbital period. We have developed a method for detecting transiting exoplanet signals in stellar light curves that is more sensitive to small planets on long orbits than previously published procedures. It is standard practice to start by "de-trending" the light curves—by filtering—to remove the instrumental systematics and stellar variability from the time series. Instead, we build an flexible model for these effects using a Gaussian Process. We use as inputs to the Gaussian Process not just time but also the light curves of dozens of other stars. This exploits the causal structure of the problem: permitting the noise model to capture spacecraft-induced covariability. Since we know a priori that the other stars are causally unrelated to the star of interest, any information that they share must be due to systematics. A key motivation for our work is that any filtering—no matter how robust—reduces the amplitude of the signals of interest. By marginalizing over the stellar and instrumental variability while simultaneously fitting for the transits, we maintain sensitivity to transit signals and reduce contamination. We apply our method to light curves from the Kepler mission. Using synthetic transits generated by realistic planetary systems injected into raw aperture photometry from the pipeline, we determine the detection efficiency of our method and train a supervised classification algorithm to weed out false signals. Our pipeline returns all of the ingredients needed for studies of exoplanet populations: a catalog of planet candidates, posterior samples for the physical parameters of these planets and their host stars, and an empirical measurement of the detection efficiency as a function of all of these parameters.

  7. An Orbital Stability Study of the Proposed Companions of SW Lyncis

    NASA Astrophysics Data System (ADS)

    Hinse, T. C.; Horner, Jonathan; Wittenmyer, Robert A.

    2014-09-01

    We have investigated the dynamical stability of the proposed companions orbiting the Algol type short-period eclipsing binary SW Lyncis (Kim et al. 2010). The two candidate companions are of stellar to substellar nature, and were inferred from timing measurements of the system's primary and secondary eclipses. We applied well-tested numerical techniques to accurately integrate the orbits of the two companions and to test for chaotic dynamical behavior. We carried out the stability analysis within a systematic parameter survey varying both the geometries and orientation of the orbits of the companions, as well as their masses. In all our numerical integrations we found that the proposed SW Lyn multi-body system is highly unstable on time-scales on the order of 1000 years. Our results cast doubt on the interpretation that the timing variations are caused by two companions. This work demonstrates that a straightforward dynamical analysis can help to test whether a best-fit companion-based model is a physically viable explanation for measured eclipse timing variations. We conclude that dynamical considerations reveal that the proposed SW Lyncis multi-body system most likely does not exist or the companions have significantly different orbital properties from those conjectured in Kim et al. (2010).

  8. NEW M, L, AND T DWARF COMPANIONS TO NEARBY STARS FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER

    SciTech Connect

    Luhman, Kevin L.; Loutrel, Nicholas P.; McCurdy, Nicholas S.; Melso, Nicole D.; Star, Kimberly M.; Terrien, Ryan C.; Mace, Gregory N.; McLean, Ian S.; Young, Michael D.; Rhode, Katherine L.; Davy Kirkpatrick, J.

    2012-12-01

    We present 11 candidate late-type companions to nearby stars identified with data from the Wide-field Infrared Survey Explorer (WISE) and the Two Micron All Sky Survey (2MASS). Eight of the candidates are likely to be companions based on their common proper motions with the primaries. The remaining three objects are rejected as companions, one of which is a free-floating T7 dwarf. Spectral types are available for five of the companions, which consist of M2V, M8.5V, L5, T8, and T8. Based on their photometry, the unclassified companions are probably two mid-M dwarfs and one late-M/early-L dwarf. One of the T8 companions, WISE J142320.84+011638.0, has already been reported by Pinfield and coworkers. The other T8 companion, ULAS J095047.28+011734.3, was discovered by Burningham and coworkers through the United Kingdom Infrared Telescope Infrared Deep Sky Survey, but its companionship has not been previously recognized in the literature. The L5 companion, 2MASS J17430860+8526594, is a new member of a class of L dwarfs that exhibit unusually blue near-IR colors. Among the possible mechanisms that have been previously proposed for the peculiar colors of these L dwarfs, low metallicity does not appear to be a viable explanation for 2MASS J17430860+8526594 since our spectrum of the primary suggests that its metallicity is not significantly subsolar.

  9. A search for eclipses of HD 114762 by a low-mass companion

    SciTech Connect

    Robinson, E.L.; Cochran, A.L.; Cochran, W.D.; Shafter, A.W.; Zhang, Erho Beijing Observatory )

    1990-02-01

    HD 114762 has an unseen companion with a dynamical mass that satisfies the constraint mass sin i = 2.5 x 10 to the 31st gm. The companion is a good candidate for a planetary-mass object, but the inclination of its orbit is unknown and its mass is indeterminate. Tests were conducted for the specific case of a nearly edge-on orbit by looking for eclipses of HD 114762 by the companion. Although the a priori probability of an eclipse is low, this is a crucial case because the companion has its minimum mass if the orbit is edge on. No eclipses were found with a depth greater than 0.01 mag and, therefore, the inclination of the orbit of HD 114762 is less than 89 deg. 12 refs.

  10. Spectra as windows into exoplanet atmospheres.

    PubMed

    Burrows, Adam S

    2014-09-01

    Understanding a planet's atmosphere is a necessary condition for understanding not only the planet itself, but also its formation, structure, evolution, and habitability. This requirement puts a premium on obtaining spectra and developing credible interpretative tools with which to retrieve vital planetary information. However, for exoplanets, these twin goals are far from being realized. In this paper, I provide a personal perspective on exoplanet theory and remote sensing via photometry and low-resolution spectroscopy. Although not a review in any sense, this paper highlights the limitations in our knowledge of compositions, thermal profiles, and the effects of stellar irradiation, focusing on, but not restricted to, transiting giant planets. I suggest that the true function of the recent past of exoplanet atmospheric research has been not to constrain planet properties for all time, but to train a new generation of scientists who, by rapid trial and error, are fast establishing a solid future foundation for a robust science of exoplanets. PMID:24613929

  11. Walking on Exoplanets: Is Star Wars Right?

    NASA Astrophysics Data System (ADS)

    Ballesteros, Fernando J.; Luque, B.

    2016-05-01

    As the number of detected extrasolar planets increases, exoplanet databases become a valuable resource, confirming some details about planetary formation, but also challenging our theories with new unexpected properties.

  12. Spectra as windows into exoplanet atmospheres

    NASA Astrophysics Data System (ADS)

    Burrows, Adam S.

    2014-09-01

    Understanding a planet's atmosphere is a necessary condition for understanding not only the planet itself, but also its formation, structure, evolution, and habitability. This requirement puts a premium on obtaining spectra and developing credible interpretative tools with which to retrieve vital planetary information. However, for exoplanets, these twin goals are far from being realized. In this paper, I provide a personal perspective on exoplanet theory and remote sensing via photometry and low-resolution spectroscopy. Although not a review in any sense, this paper highlights the limitations in our knowledge of compositions, thermal profiles, and the effects of stellar irradiation, focusing on, but not restricted to, transiting giant planets. I suggest that the true function of the recent past of exoplanet atmospheric research has been not to constrain planet properties for all time, but to train a new generation of scientists who, by rapid trial and error, are fast establishing a solid future foundation for a robust science of exoplanets.

  13. Balloon Exoplanet Nulling Interferometer (BENI)

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Ford, Holland; Petro, Larry; Herman, Jay; Rinehart, Stephen; Carpenter, Kenneth; Marzouk, Joe

    2009-01-01

    We evaluate the feasibility of using a balloon-borne nulling interferometer to detect and characterize exosolar planets and debris disks. The existing instrument consists of a 3-telescope Fizeau imaging interferometer with 3 fast steering mirrors and 3 delay lines operating at 800 Hz for closed-loop control of wavefront errors and fine pointing. A compact visible nulling interferometer is under development which when coupled to the imaging interferometer would in-principle allow deep suppression of starlight. We have conducted atmospheric simulations of the environment above 100,000 feet and believe balloons are a feasible path forward towards detection and characterization of a limited set of exoplanets and their debris disks. Herein we will discuss the BENI instrument, the balloon environment and the feasibility of such as mission.

  14. Exoplanet Forecast: Hot and Wet

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on image for larger poster version

    This plot of data from NASA's Spitzer Space Telescope tells astronomers that a toasty gas exoplanet, or a planet beyond our solar system, contains water vapor.

    Spitzer observed the planet, called HD 189733b, cross in front of its star at three different infrared wavelengths: 3.6 microns; 4.5 microns and 8 microns (see lime-colored dots). For each wavelength, the planet's atmosphere absorbed different amounts of the starlight that passed through it. The pattern by which this absorption varies with wavelength matches known signatures of water, as shown by the theoretical model in blue.

  15. Exoplanets and their Host Stars

    NASA Astrophysics Data System (ADS)

    Schmitt, J.

    2016-06-01

    Among the most fundamental astrophysical discoveries are clearly the detections of many thousands of ``extrasolar'' planets orbiting their hosts. The majority of these new planetary systems have properties dramatically different from those in our solar system. The large distances to extrasolar planets imply that they can only be observed together with their hosts. Modern observations have shown that stars and planets are not merely accidental celestial neighbors bound by the force of gravity, rather they influence each other in a variety of ways. This also and specifically applies to the X-ray properties of exoplanet systems which I will review in my talk and give some ideas for future work in this area.

  16. A METAL-RICH LOW-GRAVITY COMPANION TO A MASSIVE MILLISECOND PULSAR

    SciTech Connect

    Kaplan, D. L.; Bhalerao, V. B.; Van Kerkwijk, M. H.; Koester, D.; Kulkarni, S. R.; Stovall, K. E-mail: mhvk@astro.utoronto.ca

    2013-03-10

    Most millisecond pulsars with low-mass companions are in systems with either helium-core white dwarfs or non-degenerate (''black widow'' or ''redback'') stars. A candidate counterpart to PSR J1816+4510 was identified by Kaplan et al. whose properties were suggestive of both types of companions although identical to neither. We have assembled optical spectroscopy of the candidate companion and confirm that it is part of the binary system with a radial velocity amplitude of 343 {+-} 7 km s{sup -1}, implying a high pulsar mass, M{sub psr}sin {sup 3} i = 1.84 {+-} 0.11 M{sub Sun }, and a companion mass M{sub c} sin {sup 3} i = 0.193 {+-} 0.012 M{sub Sun }, where i is the inclination of the orbit. The companion appears similar to proto-white dwarfs/sdB stars, with a gravity log{sub 10}(g) = 4.9 {+-} 0.3, and effective temperature 16, 000 {+-} 500 K. The strongest lines in the spectrum are from hydrogen, but numerous lines from helium, calcium, silicon, and magnesium are present as well, with implied abundances of roughly 10 times solar (relative to hydrogen). As such, while from the spectrum the companion to PSR J1816+4510 is superficially most similar to a low-mass white dwarf, it has much lower gravity, is substantially larger, and shows substantial metals. Furthermore, it is able to produce ionized gas eclipses, which had previously been seen only for low-mass, non-degenerate companions in redback or black widow systems. We discuss the companion in relation to other sources, but find that we understand neither its nature nor its origins. Thus, the system is interesting for understanding unusual stellar products of binary evolution, as well as, independent of its nature, for determining neutron-star masses.

  17. VizieR Online Data Catalog: Overlooked wide companions of nearby F stars (Scholz, 2016)

    NASA Astrophysics Data System (ADS)

    Scholz, R.-D.

    2016-02-01

    We checked a sample of 545 F stars within 50pc for wide companions using existing near-infrared and optical sky surveys. Applying the common proper motion (CPM) criterion, we detected wide companion candidates with 6-120arcsec angular separations by visual inspection of multi-epoch finder charts and by searching in proper motion catalogues. Final proper motions were measured by involving positional measurements from up to eleven surveys. Spectral types of red CPM companions were estimated from their absolute J-band magnitudes based on the Hipparcos distances of the primaries. In addition to about 100 known CPM objects, we found 19 new CPM companions and confirmed 31 previously known candidates. A few CPM objects are still considered as candidates according to their level of proper motion agreement. Among the new objects there are nine M0-M4, eight M5-M6, one ~L3.5 dwarf (HD 3861B), and one white dwarf (WD) (HD 2726B), whereas we confirmed two K, 19 M0-M4, six M5-M6, two early-L dwarfs, and two DA WDs as CPM companions. In a few cases, previous spectral types were available that all agree well with our estimates. Two companions (HD 22879B and HD 49933B) are associated with moderately metal-poor Gaia benchmark stars. One doubtful CPM companion, spectroscopically classified as WD but found to be very bright (J=11.1) by others, should either be a very nearby foreground WD or a different kind of object associated with HD 165670. The main results of this research note, data on new, confirmed, and rejected CPM pairs, are listed in tablea1.dat, tableb1.dat, and tablec1.dat, respectively. (4 data files).

  18. DISCOVERY OF A LOW-MASS COMPANION TO A METAL-RICH F STAR WITH THE MARVELS PILOT PROJECT

    SciTech Connect

    Fleming, Scott W.; Ge Jian; Mahadevan, Suvrath; Lee, Brian; Cuong Nguyen, Duy; Morehead, Robert C.; Wan Xiaoke; Zhao Bo; Liu Jian; Guo Pengcheng; Kane, Stephen R.; Eastman, Jason D.; Siverd, Robert J.; Scott Gaudi, B.; Niedzielski, Andrzej; Sivarani, Thirupathi; Stassun, Keivan G.; Gary, Bruce; Wolszczan, Alex; Barnes, Rory

    2010-08-01

    We report the discovery of a low-mass companion orbiting the metal-rich, main sequence F star TYC 2949-00557-1 during the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS) pilot project. The host star has an effective temperature T{sub eff} = 6135 {+-} 40 K, logg = 4.4 {+-} 0.1, and [Fe/H] = 0.32 {+-} 0.01, indicating a mass of M = 1.25 {+-} 0.09 M{sub sun} and R = 1.15 {+-} 0.15 R{sub sun}. The companion has an orbital period of 5.69449 {+-} 0.00023 days and straddles the hydrogen burning limit with a minimum mass of 64 M{sub J} , and thus may be an example of the rare class of brown dwarfs orbiting at distances comparable to those of 'Hot Jupiters'. We present relative photometry that demonstrates that the host star is photometrically stable at the few millimagnitude level on time scales of hours to years, and rules out transits for a companion of radius {approx}>0.8 R{sub J} at the 95% confidence level. Tidal analysis of the system suggests that the star and companion are likely in a double synchronous state where both rotational and orbital synchronization have been achieved. This is the first low-mass companion detected with a multi-object, dispersed, fixed-delay interferometer.

  19. The moving group targets of the seeds high-contrast imaging survey of exoplanets and disks: Results and observations from the first three years

    SciTech Connect

    Brandt, Timothy D.; Turner, Edwin L.; Janson, M.; Knapp, G. R.; Kuzuhara, Masayuki; McElwain, Michael W.; Schlieder, Joshua E.; Carson, J.; Biller, B.; Bonnefoy, M.; Brandner, W.; Wisniewski, John P.; Hashimoto, J.; Matsuo, T.; Dressing, C.; Moro-Martín, A.; Kudo, T.; Kusakabe, N.; Abe, L.; and others

    2014-05-01

    We present results from the first three years of observations of moving group (MG) targets in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of ∼10{sup 5} at 1'' and ∼10{sup 6} beyond 2'' around 63 proposed members of nearby kinematic MGs. We review each of the kinematic associations to which our targets belong, concluding that five, β Pictoris (∼20 Myr), AB Doradus (∼100 Myr), Columba (∼30 Myr), Tucana-Horogium (∼30 Myr), and TW Hydrae (∼10 Myr), are sufficiently well-defined to constrain the ages of individual targets. Somewhat less than half of our targets are high-probability members of one of these MGs. For all of our targets, we combine proposed MG membership with other age indicators where available, including Ca II HK emission, X-ray activity, and rotation period, to produce a posterior probability distribution of age. SEEDS observations discovered a substellar companion to one of our targets, κ And, a late B star. We do not detect any other substellar companions, but do find seven new close binary systems, of which one still needs to be confirmed. A detailed analysis of the statistics of this sample, and of the companion mass constraints given our age probability distributions and exoplanet cooling models, will be presented in a forthcoming paper.

  20. The Moving Group Targets of the Seeds High-Contrast Imaging Survey of Exoplanets and Disks: Results and Observations from the First Three Years

    NASA Technical Reports Server (NTRS)

    Brandt, Timothy D.; Kuzuhara, Masayuki; McElwain, Michael W.; Schlieder, Joshua E.; Wisniewski, John P.; Turner, Edwin L.; Carson, J.; Matsuo, T.; Biller, B.; Bonnefoy, M.; Dressing, C.; Janson, M.; Knapp, G. R.; Moro-Martin, A.; Thalmann, C.; Kudo, T.; Kusakabe, N.; Hashimoto, J.; Abe, L.; Brandner, W.; Currie, T.; Egner, S.; Feldt, M.; Golota, T.; Goto, M.; Brady, C. A.; Guyon, O.; Hayano, Y.; Hyashi, M.; Hayashi, S.; Henning, T.; Hodapp, W.; Ishi, M.; Iye, M.; Kandori, R.

    2014-01-01

    We present results from the first three years of observations of moving group (MG) targets in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of (is) approximately10(exp 5) at 1" and (is) approximately 10(exp 6) beyond 2" around 63 proposed members of nearby kinematic MGs. We review each of the kinematic associations to which our targets belong, concluding that five, beta Pictoris ((is) approximately 20 Myr), AB Doradus ((is) approximately 100 Myr), Columba ((is) approximately 30 Myr), Tucana-Horogium ((is) approximately 30 Myr), and TW Hydrae ((is) approximately 10 Myr), are sufficiently well-defined to constrain the ages of individual targets. Somewhat less than half of our targets are high-probability members of one of these MGs. For all of our targets, we combine proposed MG membership with other age indicators where available, including Ca ii HK emission, X-ray activity, and rotation period, to produce a posterior probability distribution of age. SEEDS observations discovered a substellar companion to one of our targets, kappa And, a late B star. We do not detect any other substellar companions, but do find seven new close binary systems, of which one still needs to be confirmed. A detailed analysis of the statistics of this sample, and of the companion mass constraints given our age probability distributions and exoplanet cooling models, will be presented in a forthcoming paper.

  1. The Moving Group Targets of the SEEDS High-contrast Imaging Survey of Exoplanets and Disks: Results and Observations from the First Three Years

    NASA Astrophysics Data System (ADS)

    Brandt, Timothy D.; Kuzuhara, Masayuki; McElwain, Michael W.; Schlieder, Joshua E.; Wisniewski, John P.; Turner, Edwin L.; Carson, J.; Matsuo, T.; Biller, B.; Bonnefoy, M.; Dressing, C.; Janson, M.; Knapp, G. R.; Moro-Martín, A.; Thalmann, C.; Kudo, T.; Kusakabe, N.; Hashimoto, J.; Abe, L.; Brandner, W.; Currie, T.; Egner, S.; Feldt, M.; Golota, T.; Goto, M.; Grady, C. A.; Guyon, O.; Hayano, Y.; Hayashi, M.; Hayashi, S.; Henning, T.; Hodapp, K. W.; Ishii, M.; Iye, M.; Kandori, R.; Kwon, J.; Mede, K.; Miyama, S.; Morino, J.-I.; Nishimura, T.; Pyo, T.-S.; Serabyn, E.; Suenaga, T.; Suto, H.; Suzuki, R.; Takami, M.; Takahashi, Y.; Takato, N.; Terada, H.; Tomono, D.; Watanabe, M.; Yamada, T.; Takami, H.; Usuda, T.; Tamura, M.

    2014-05-01

    We present results from the first three years of observations of moving group (MG) targets in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of ~105 at 1'' and ~106 beyond 2'' around 63 proposed members of nearby kinematic MGs. We review each of the kinematic associations to which our targets belong, concluding that five, β Pictoris (~20 Myr), AB Doradus (~100 Myr), Columba (~30 Myr), Tucana-Horogium (~30 Myr), and TW Hydrae (~10 Myr), are sufficiently well-defined to constrain the ages of individual targets. Somewhat less than half of our targets are high-probability members of one of these MGs. For all of our targets, we combine proposed MG membership with other age indicators where available, including Ca II HK emission, X-ray activity, and rotation period, to produce a posterior probability distribution of age. SEEDS observations discovered a substellar companion to one of our targets, κ And, a late B star. We do not detect any other substellar companions, but do find seven new close binary systems, of which one still needs to be confirmed. A detailed analysis of the statistics of this sample, and of the companion mass constraints given our age probability distributions and exoplanet cooling models, will be presented in a forthcoming paper.

  2. Astrometric exoplanet surveys in practice: challenges, opportunities, and results

    NASA Astrophysics Data System (ADS)

    Sahlmann, Johannes

    2015-08-01

    Conversely to the transit photometry and radial velocity methods, the astrometric discovery of exoplanets is still limited by the sensitivity of available instruments. Furthermore, the signature of a planet (described by 7 free parameters) is orders of magnitude smaller than the standard motion of a star (5 free parameters), which has to be solved for first. This has important implications in the design and implementation of astrometric planet search surveys and the large parameter space to be explored calls for efficient fitting algorithms. I will present results of the so-far most precise astrometric planet search from the ground, targeting 20 very low-mass stars and brown dwarfs with an accuracy of 100 micro-arcseconds, which include the discovery of binaries with components in the planetary mass regime and several planet candidates with Neptune-to-Jupiter masses. The employed genetic and MCMC algorithms were shown to be efficient in constraining all astrometric parameters, which makes them important tools for the exploitation of the data currently collected by the Gaia satellite. Gaia is expected to astrometrically discover thousands of giant exoplanets and I will report on several ongoing projects in preparation of this unique harvest, including the expected yield of circumbinary planets.

  3. Planetary companions in K giants β Cancri, μ Leonis, and β Ursae Minoris

    NASA Astrophysics Data System (ADS)

    Lee, B.-C.; Han, I.; Park, M.-G.; Mkrtichian, D. E.; Hatzes, A. P.; Kim, K.-M.

    2014-06-01

    Aims: The aim of our paper is to investigate the low-amplitude and long-period variations in evolved stars with a precise radial velocity survey. Methods: The high-resolution, the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) was used from 2003 to 2013 for a radial velocity survey of giant stars as part of the exoplanet search program at Bohyunsan Optical Astronomy Observatory (BOAO). Results: We report the detection of three new planetary companions orbiting the K giants β Cnc, μ Leo, and β UMi. The planetary nature of the radial velocity variations is supported by analyzes of ancillary data. The Hipparcos photometry shows no variations with periods close to those in radial velocity variations and there is no strong correlation between the bisector velocity span (BVS) and the radial velocities for each star. Furthermore, the stars show weak or no core reversal in Ca II H lines indicating that they are inactive stars. The companion to β Cnc has a minimum mass of 7.8 MJup in a 605-day orbit with an eccentricity of 0.08. The giant μ Leo is orbited by a companion of minimum mass of 2.4 MJup having a period of 357 days and an eccentricity of 0.09. The giant β UMi is a known barium star and is suspected of harboring a white dwarf or substellar mass companion. Its companion has a minimum mass of 6.1 MJup, a period of 522 days, and an eccentricity e = 0.19. Based on observations made with the BOES instrument on the 1.8 m telescope at Bohyunsan Optical Astronomy Observatory in Korea.Tables 4-6 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/566/A67

  4. Tidal synchronization of close-in satellites and exoplanets: II. Spin dynamics and extension to Mercury and exoplanet host stars

    NASA Astrophysics Data System (ADS)

    Ferraz-Mello, Sylvio

    2015-08-01

    This paper deals with the application of the creep tide theory (Ferraz-Mello, Celest Mech Dyn Astron 116:109, 2013a) to the rotation of close-in satellites, Mercury, close-in exoplanets, and their host stars. The solutions show different behaviors with two extreme cases: close-in giant gaseous planets with fast relaxation (low viscosity) and satellites and Earth-like planets with slow relaxation (high viscosity). The rotation of close-in gaseous planets follows the classical Darwinian pattern: it is tidally driven toward a stationary solution that is synchronized with the orbital motion when the orbit is circular, but if the orbit is elliptical, it has a frequency larger than the orbital mean motion. The rotation of rocky bodies, however, may be driven to several attractors whose frequencies are times the mean motion. The number of attractors increases with the viscosity of the body and with the orbital eccentricity. The final stationary state depends on the initial conditions. The classical example is Mercury, whose rotational period is 2/3 of the orbital period (3/2 attractor). The planet behaves as a molten body with a relaxation that allowed it to cross the 2/1 attractor without being trapped but not to escape being trapped in the 3/2 one. In that case, the relaxation is estimated to lie in the interval (equivalent to a quality factor roughly constrained to the interval ). The stars have a relaxation similar to the hot Jupiters, and their rotation is also driven to the only stationary solution existing in these cases. However, solar-type stars may lose angular momentum due to stellar wind, braking the rotation and displacing the attractor toward larger periods. Old, active host stars with big close-in companions generally have rotational periods larger than the orbital periods of the companions. The paper also includes a study of energy dissipation and the evolution of orbital eccentricity.

  5. First supernova companion star found

    NASA Astrophysics Data System (ADS)

    2004-01-01

    Supernova 1993J exploding hi-res Size hi-res: 222 kb Credits: ESA and Justyn R. Maund (University of Cambridge) Supernova 1993J exploding (artist’s impression) New observations with the Hubble Space Telescope allow a look into a supernova explosion under development. In this artist’s view the red supergiant supernova progenitor star (left) is exploding after having transferred about 10 solar masses of hydrogen gas to the blue companion star (right). This interaction process happened over about 250 years and affected the supernova explosion to such an extent that SN 1993J was later known as one of the most peculiar supernovae ever seen. Supernova 1993J exploding hi-res Size hi-res: 4200 kb Credits: ESA and Justyn R. Maund (University of Cambridge) The site of the Supernova 1993J explosion A virtual journey into one of the spiral arms of the grand spiral Messier 81 (imaged with the Isaac Newton Telescope on La Palma, left) reveals the superb razor-sharp imaging power of the NASA/ESA Hubble Space Telescope (Hubble’s WFPC2 instrument, below). The close-up (with Hubble’s ACS, to the right) is centred on the newly discovered companion star to Supernova 1993J that itself is no longer visible. The quarter-circle around the supernova companion is a so-called light echo originating from sheets of dust in the galaxy reflecting light from the original supernova explosion. Supernova 1993J explosing site hi-res Size hi-res: 1502 kb Credits: ESA and Justyn R. Maund (University of Cambridge) Close-up of the Supernova 1993J explosion site (ACS/HRC image) This NASA/ESA Hubble Space Telescope image shows the area in Messier 81 where Supernova 1993J exploded. The companion to the supernova ‘mother star’ that remains after the explosion is seen in the centre of the image. The image is taken with Hubble’s Advanced Camera for Surveys and is a combination of four exposures taken with ACS’ High Resolution Camera. The exposures were taken through two near-UV filters (250W

  6. MAGNETIC ACTIVITY CYCLES IN THE EXOPLANET HOST STAR {epsilon} ERIDANI

    SciTech Connect

    Metcalfe, T. S.; Mathur, S.; Buccino, A. P.; Mauas, P. J. D.; Petrucci, R.; Brown, B. P.; Soderblom, D. R.; Henry, T. J.; Hall, J. C.; Basu, S.

    2013-02-01

    The active K2 dwarf {epsilon} Eri has been extensively characterized both as a young solar analog and more recently as an exoplanet host star. As one of the nearest and brightest stars in the sky, it provides an unparalleled opportunity to constrain stellar dynamo theory beyond the Sun. We confirm and document the 3-year magnetic activity cycle in {epsilon} Eri originally reported by Hatzes and coworkers, and we examine the archival data from previous observations spanning 45 years. The data show coexisting 3-year and 13-year periods leading into a broad activity minimum that resembles a Maunder minimum-like state, followed by the resurgence of a coherent 3-year cycle. The nearly continuous activity record suggests the simultaneous operation of two stellar dynamos with cycle periods of 2.95 {+-} 0.03 years and 12.7 {+-} 0.3 years, which, by analogy with the solar case, suggests a revised identification of the dynamo mechanisms that are responsible for the so-called 'active' and 'inactive' sequences as proposed by Boehm-Vitense. Finally, based on the observed properties of {epsilon} Eri, we argue that the rotational history of the Sun is what makes it an outlier in the context of magnetic cycles observed in other stars (as also suggested by its Li depletion), and that a Jovian-mass companion cannot be the universal explanation for the solar peculiarities.

  7. The Gemini NICI planet-finding campaign: The companion detection pipeline

    SciTech Connect

    Wahhaj, Zahed; Liu, Michael C.; Nielsen, Eric L.; Chun, Mark; Ftaclas, Christ; Biller, Beth A.; Close, Laird M.; Hayward, Thomas L.; Hartung, Markus

    2013-12-10

    We present high-contrast image processing techniques used by the Gemini NICI Planet-Finding Campaign to detect faint companions to bright stars. The Near-Infrared Coronographic Imager (NICI) is an adaptive optics instrument installed on the 8 m Gemini South telescope, capable of angular and spectral difference imaging and specifically designed to image exoplanets. The Campaign data pipeline achieves median contrasts of 12.6 mag at 0.''5 and 14.4 mag at 1'' separation, for a sample of 45 stars (V = 4.3-13.9 mag) from the early phase of the campaign. We also present a novel approach to calculating contrast curves for companion detection based on 95% completeness in the recovery of artificial companions injected into the raw data, while accounting for the false-positive rate. We use this technique to select the image processing algorithms that are more successful at recovering faint simulated point sources. We compare our pipeline to the performance of the Locally Optimized Combination of Images (LOCI) algorithm for NICI data and do not find significant improvement with LOCI.

  8. Direct imaging of the cold jovian (?) companion GJ504b with VLT/SPHERE

    NASA Astrophysics Data System (ADS)

    Bonnefoy, Mickaël

    2015-12-01

    In 2008, the Subaru/SEEDS survey reported the direct imaging discovery of a Jovian exoplanet around the Sun-like star GJ 504. With a mass of 3-10 MJup and projected separation of 43.5 AU, this object challenges the core-accretion paradigm. This is the only known nearly mature (age ≫ 50 Myr) gas giant planet imaged so far. The very low (500 K) estimated temperature of the object makes it a benchmark for the study of the physical and chemical processes at play into the non-irradiated atmospheres of gas giants.We will present new SPHERE dual-band imaging data on the system gathered from 0.95 to 2.25 microns. The data enable to detect the companion and complete its spectral energy distribution. We use them to refine the effective temperature, surface gravity, and metallicity estimates for the object. This in turns enables to discuss the nature of the companion. We also set constraints on additional companions in the system.

  9. The possible false-detection of a transiting brown dwarf candidate in the overlapping fields of Kepler and MARVELS

    NASA Astrophysics Data System (ADS)

    Reyes, Alan; Ge, Jian; Thomas, Neil; Ma, Bo; Heslar, Michael Francis; SDSS-III MARVELS Team

    2016-01-01

    While searching for exoplanets via the transit method, it has been documented that the periodicity of an unresolved background eclipsing binary (BEB) can be misinterpreted as the orbital companion of a target star. We explore the possibility that this false-positive contamination method can also occur in Doppler surveys if the angular separation between a BEB and a selected primary is under a certain threshold, dependent on the fiber diameter of the spectrometer instrument. The case example of this investigation is a K2 giant in the constellation Cygnus, in the region of overlap of the Kepler and MARVELS surveys. This star was originally flagged for potentially having a 5.56d period companion as per the Kepler transit photometry. It was also imbricated with radial velocity (RV) observations performed by the SDSS-III MARVELS survey, in which Doppler information was extracted from along the dispersion direction of the fiducially-calibrated, post-pipeline-rendered spectra. The 5.56d period was corroborated after testing its probability against that of others via a Lomb-Scargle periodogram analysis. The pipeline mass determination yielded a ~17 MJupiter companion, within the characteristic mass-range of brown dwarfs. The MARVELS results seem to constitute an independent discovery, and hence confirmation, of the brown dwarf candidate. However, a later investigation conducted by EXPERT, intent upon refining the system's physical parameters, failed to identify the RV signal of any companion whatsoever. EXPERT, with its superior resolving power (R=30,000 vs R=11,000 in MARVELS), finer fiber width (1.2 vs 1.9 arcsec), and higher degree of precision (~10 m/s), was expected to finalize the confirmation, but now offers a major challenge to previous models of the system. Additionally, high-resolution adaptive optics imaging reveals the presence of a distinct, close-in object. The object may itself be an unbound BEB, and thus the source of the period signals reported by Kepler

  10. The NASA Exoplanet Archive: Data Inventory Service

    NASA Astrophysics Data System (ADS)

    Ramirez, Solange; Akeson, Rachel L.; Ciardi, David R.; Chen, Xi; Christiansen, Jessie; Plavchan, Peter

    2014-06-01

    We present here the latest addition to the NASA Exoplanet Archive - the Data Inventory Service, a tool aimed to provide the user with all the data available within the archive (exoplanet and stellar parameters, time series from ground-based transit surveys (such as Super WASP, XO, HAT-P, KELT), Kepler Pipeline products, CoRoT light curves, etc.) at or near the location of an astronomical object. The NASA Exoplanet Archive is an online service dedicated to compile and to serve public astronomical data sets involved in the search for and characterization of extrasolar planets and their host stars. The data in the archive include stellar parameters (e.g., positions, magnitudes, temperatures, etc.), exoplanet parameters (such as masses and orbital parameters) and discovery/characterization data (e.g., published radial velocity curves, photometric light curves, spectra, etc.). In support of the Kepler Extended Mission, the NASA Exoplanet Archive also hosts data related to Kepler Objects of Interest (KOI), Kepler Pipeline products such as Threshold Crossing Events (TCE) and Data Validation Reports, and Kepler Stellar parameters as used by the Kepler Pipeline. The archive provides tools to work with these data, including interative tables (with plotting capabilities), interactive light curve viewer, periodogram service, transit and ephemeris calculator, and application program interface. To access this information visit us at: http://exoplanetarchive.ipac.caltech.edu

  11. Frontiers of Exoplanet Atmosphere Characterization

    NASA Astrophysics Data System (ADS)

    Kreidberg, Laura

    2016-01-01

    Exoplanet atmosphere characterization has the potential to reveal the origins, nature, and even habitability of distant worlds. In this dissertation talk, I will present work that is a step toward realizing that potential for a diverse group of four extrasolar planets. I will discuss the results of intensive observational campaigns with the Hubble and Spitzer Space Telescopes to study the atmospheres of the super-Earth GJ 1214b and the hot Jupiters WASP-43b, WASP-12b, and WASP-103b. For GJ 1214b, I measured an unprecedentedly precise near-infrared transmission spectrum that definitively reveals the presence of clouds in the planet's atmosphere. For WASP-43b and WASP-12b, I also obtained very precise spectra. These exhibit water features at high confidence (>7 sigma). The retrieved water abundance for WASP-43b extends the well-known Solar System trend of decreasing atmospheric metallicity with increasing planet mass. The detection of water for WASP-12b marks the first spectroscopic identification of a molecule in the planet's atmosphere and implies that it has solar composition, ruling out carbon-to-oxygen ratios greater than unity. For WASP-103b, I will present preliminary results from the new technique of phase-resolved spectroscopy that constrain the planet's temperature structure, dynamics, and energy budget. Taken together, these results provide a foundation for comparative planetology beyond the Solar System and the investigation of Earth-like, potentially habitable planets with future observing facilities.

  12. Observed Exoplanets and Intelligent Life

    NASA Astrophysics Data System (ADS)

    Cole, G. H. A.

    2006-05-01

    If intelligent life were common in the Universe, should we not be aware of it on Earth through contact with advanced space ships and automatic probes? Would we not at least expect to intercept communication signals between space travellers? That this is not found has led to much speculation in the past. Recent discoveries of planets around other stars (called here exoplanets) and, separately, recent discoveries in the evolution of life on Earth, including Homo sapiens, allow this question to be considered again but now with more information than before. This is the subject of the present paper. The study involves aspects of physics and chemistry in combination with biological studies. It is concluded here that the places where technologically capable intelligent life might be expected to be found in our Galaxy are so few that any such “centres of civilisation” must be separated by large distances, probably in excess of 50 light years. If true, this would make the different centres essentially isolated and would suggest that each manifestation of advanced intelligent life is a purely local development. This would agree with our experience of aloneness. Nevertheless, the number of centres throughout the Universe would still be astronomically large, even if each galaxy had only one centre. An hypothesis is proposed which could account for the existence of such centres in this form.

  13. TRANSMISSION SPECTROSCOPY OF EXOPLANET XO-2b OBSERVED WITH HUBBLE SPACE TELESCOPE NICMOS

    SciTech Connect

    Crouzet, N.; McCullough, P. R.; Long, D.; Burke, C.

    2012-12-10

    Spectroscopy during planetary transits is a powerful tool to probe exoplanet atmospheres. We present the near-infrared transit spectroscopy of XO-2b obtained with Hubble Space Telescope NICMOS. Uniquely for NICMOS transit spectroscopy, a companion star of similar properties to XO-2 is present in the field of view. We derive improved star and planet parameters through a photometric white-light analysis. We show a clear correlation of the spectrum noise with instrumental parameters, in particular the angle of the spectral trace on the detector. An MCMC method using a decorrelation from instrumental parameters is used to extract the planetary spectrum. Spectra derived independently from each of the three visits have an rms of 430, 510, and 1000 ppm, respectively. The same analysis is performed on the companion star after numerical injection of a transit with a depth constant at all wavelengths. The extracted spectra exhibit residuals of similar amplitude as for XO-2, which represent the level of remaining NICMOS systematics. This shows that extracting planetary spectra is at the limit of NICMOS's capability. We derive a spectrum for the planet XO-2b using the companion star as a reference. The derived spectrum can be represented by a theoretical model including atmospheric water vapor or by a flat spectrum model. We derive a 3{sigma} upper limit of 1570 ppm on the presence of water vapor absorption in the atmosphere of XO-2b. In the Appendix, we perform a similar analysis for the gas giant planet XO-1b.

  14. Exoplanet Transit Database. Reduction and processing of the photometric data of exoplanet transits

    NASA Astrophysics Data System (ADS)

    Poddaný, Stanislav; Brát, Luboš; Pejcha, Ondřej

    2010-03-01

    We demonstrate the newly developed resource for exoplanet researchers - The Exoplanet Transit Database. This database is designed to be a web application and it is open for any exoplanet observer. It came on-line in September 2008. The ETD consists of three individual sections. One serves for predictions of the transits, the second one for processing and uploading new data from the observers. We use a simple analytical model of the transit to calculate the central time of transit, its duration and the depth of the transit. These values are then plotted into the observed-computed diagrams (O-C), that represent the last part of the application.

  15. Transit spectroscopy of exoplanets from space: how to optimize the wavelength coverage and spectral resolving power

    NASA Astrophysics Data System (ADS)

    Encrenaz, T.; Tinetti, G.; Tessenyi, M.; Drossart, P.; Hartogh, P.; Coustenis, A.

    2015-12-01

    The study of exoplanets is an exploding field in astronomy. Recent discoveries have made possible the development of a new research field, the spectroscopic characterization of the exoplanetary atmospheres, using both primary and eclipse transits. A dedicated space mission will make possible the characterization of many classes of exoplanets, from the hot Jupiters to the temperate super-Earths. In this paper, we discuss how the spectral range and the spectral resolving power can be optimized for identifying a maximum number of candidate atmospheric species. Spectral modeling shows that the simultaneous observation of the whole spectral range, from 0.55 to 16 μm is ideal for (1) capturing all types of planets at different temperatures, (2) detecting the variety of chemical atmospheric compounds with some redundancy, and (3) enabling an optimal retrieval of the chemical abundances and thermal profile. Limiting the spectral interval to 11 μm would make the retrieval more difficult in the case of cold exoplanets. In the visible range, the extension down to 0.4 s at different temperatures, (2) detecting the variety of chemical atmospheric compounds with some redundancy, and (3) enabling an optimal retrieval of the chemical abundances andst candidate molecules.

  16. vsini observations of potential exoplanet parent stars

    NASA Astrophysics Data System (ADS)

    Stankov, A.; Schulz, R.; Erd, C.; Ho, T.; Stüwe, J.; Smit, H.

    2013-09-01

    We present spectroscopic measurements for a sample of 19 stars with spectral types F, G, and K, suitable to host exoplanets. The relative strengths of the Ca II H and K emission lines were measured and from these the projected rotational velocities, v sin i, will be determined. Theory states that the v sin i value is smaller if the observed star hosts exoplanets [1]. This is valid for stars later than spectreal type F 5 [2]. The v sin i information can be used to prioritize a target star catalog for a project that is aiming at discovering new exoplanets. Here we describe this project in more detail and show first results for selected target stars.

  17. TMT and Exoplanet Radial Velocity Surveys

    NASA Astrophysics Data System (ADS)

    Tanner, Angelle; Crossfield, Ian

    2014-07-01

    With echelle spectrometers on the verge of crossing over the 0.1 m/s radial velocity (RV) measurement precision threshold needed to detect habitable Earth mass planets around Sun-like stars, conducing such surveys on state-of-the-art telescopes is an imperative. RV exoplanets surveys conducted with the optical and infrared echelle spectrometers being built for the TMT have the potential to complete a census of the population of Earth-mass planets in our local stellar neighborhood. The detection of such systems will provide a valuable stellar sample for follow-up exoplanet studies which would characterize the atmospheres of these or additional planets found in these nearby solar systems. Here, we will further discuss the impact of the TMT on radial velocity exoplanet surveys.

  18. Constraining exoplanet mass from transmission spectroscopy.

    PubMed

    de Wit, Julien; Seager, Sara

    2013-12-20

    Determination of an exoplanet's mass is a key to understanding its basic properties, including its potential for supporting life. To date, mass constraints for exoplanets are predominantly based on radial velocity (RV) measurements, which are not suited for planets with low masses, large semimajor axes, or those orbiting faint or active stars. Here, we present a method to extract an exoplanet's mass solely from its transmission spectrum. We find good agreement between the mass retrieved for the hot Jupiter HD 189733b from transmission spectroscopy with that from RV measurements. Our method will be able to retrieve the masses of Earth-sized and super-Earth planets using data from future space telescopes that were initially designed for atmospheric characterization. PMID:24357312

  19. [Companion Diagnostics for Solid Tumors].

    PubMed

    Watanabe, Atsushi

    2015-11-01

    Companion diagnostics (CoDx) will likely continue to rapidly increase in number and application to disease areas including solid tumors, for example EGFR for gefitinib and ALK fusion gene for crizotinib in non-small-cell lung cancer; KRAS against the use of cetuximab and panitumumab in colorectal cancer; HER2 for trastuzumab in breast cancer. CoDx are an indispensable part of personalized medicine and pharmacogenomics. In CoDx development, there are still many challenges, such as the business model promoting cooperation between diagnostics and pharmaceutical companies, and also the regulations related to CoDx. The FDA notice on the development of CoDx in 2011 recommended the co-development of a new drug and CoDx as the best practice, and the Ministry of Health, Labour and Welfare in Japan also issued a statement in 2013. In addition, the recent discovery of many novel variants in the DNA sequence, advances in sequencing and genomic technology, and improved analytic methods have enabled the impact of germline and somatic mutations to be determined using multiplex diagnosis. The complex challenges to develop CoDx necessitate a close collaboration among academic institutions, regulatory authorities, and pharmaceutical companies. [Review]. PMID:26995877

  20. Companion Diagnostics and Molecular Imaging.

    PubMed

    Puranik, Ameya D; Kulkarni, Harshad R; Baum, Richard P

    2015-01-01

    Companion diagnostics (CDx) is a positive attempt in the direction of improving the drug development process, especially in the field of oncology, with the advent of newer targeted therapies. It helps the oncologist in deciding the choice of treatment for the individual patient. The role of CDx assays has attracted the attention of regulators, and especially the US Food and Drug Administration developed regulatory strategies for CDx and the drug-diagnostic codevelopment project. For an increasing number of cancer patients, the treatment selection will depend on the result generated by a CDx assay, and consequently this type of assay has become critical for the care and safety of the patients. In addition to the assay-based approach, molecular imaging with its ability to image at the genetic and receptor level has made foray into the field of drug development and personalized medicine. We shall review these aspects of CDx, with special focus on molecular imaging and the upcoming concept of Theranostics. PMID:26049701

  1. Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids

    NASA Astrophysics Data System (ADS)

    Remage Evans, Nancy; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Tingle, Evan; Karovska, Margarita; Pillitteri, Ignazio

    2016-05-01

    We have conducted an imaging survey with the Hubble Space Telescope Wide Field Camera 3 (WFC3) of 70 Galactic Cepheids, typically within 1 kpc, with the aim of finding resolved physical companions. The WFC3 field typically covers the 0.1 pc area where companions are expected. In this paper, we identify 39 Cepheids having candidate companions, based on their positions in color–magnitude diagrams, and having separations ≥slant 5\\prime\\prime from the Cepheids. We use follow-up observations of 14 of these candidates with XMM-Newton, and of one of them with ROSAT, to separate X-ray-active young stars (probable physical companions) from field stars (chance alignments). Our preliminary estimate, based on the optical and X-ray observations, is that only 3% of the Cepheids in the sample have wide companions. Our survey easily detects resolved main-sequence companions as faint as spectral type K. Thus the fact that the two most probable companions (those of FF Aql and RV Sco) are earlier than type K is not simply a function of the detection limit. We find no physical companions having separations larger than 4000 au in the X-ray survey. Two Cepheids are exceptions in that they do have young companions at significantly larger separations (δ Cep and S Nor), but both belong to a cluster or a loose association, so our working model is that they are not gravitationally bound binary members, but rather cluster/association members. All of these properties provide constraints on both star formation and subsequent dynamical evolution. The low frequency of true physical companions at separations \\gt 5\\prime\\prime is confirmed by examination of the subset of the nearest Cepheids and also the density of the fields. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  2. Cepheid Companions and the Masses of Cepheids

    NASA Astrophysics Data System (ADS)

    Bohm-Vitense, E.; Borutzki, S.; Harris, H.

    The authors have observed in the ultraviolet the hot companions of the Cepheids SV Per, RW Cam, SY Nor and KN Cen. The study of the absolute and relative intensities reveals that all, except the companion for KN Cen are evolved stars which should fit on almost the same mass track as the Cepheid. The authors find however that with generally accepted reddening values the companions of at least SV Per and RW Cam are too faint. Either the Cepheid loops are more luminous than presently calculated or the reddening is larger than presently accepted.

  3. Exoplanet Characterization With Spitzer Eclipses

    NASA Astrophysics Data System (ADS)

    Harrington, Joseph

    We will analyze our existing Spitzer eclipse data for 11 exoplanets (GJ 436b, WASP-8b, WASP-29b, WASP-11b, TrES-1, WASP-34b, WASP-43b, HD 209458b, HAT-P-30b, HAT-P-13b, and WASP-12b) along with all other Spitzer eclipse and transit data for these systems (723 hours of total data). In combination with transit results, these measurements reveal the surface fluxes emitted by the planets' atmospheres in the six Spitzer bandpasses (3.6, 4.5, 5.8, 8.0, 16, and 24 1-4m), as well as orbital eccentricity and in a few cases possibly even precession rate. The fluxes, in turn, can constrain atmospheric composition and thermal profiles. We propose here to analyze data for these planets using Monte Carlo-driven, radiative-transfer, model-fitting codes; to conduct aggregate analyses; and to develop and share statistical modeling tools. Secondary eclipses provide us with a unique way to characterize exoplanetary atmospheres. Since other techniques like spectroscopy divide the planetary signal into many channels, they require very high signal-to-noise ratio (S/N) and are only possible for a few planets. Broadband eclipse photometry is thus the only technique that can measure dozens of atmospheres and identify the mechanisms that cause planets at a given irradiation level to behave so differently from one another. Until JWST becomes available, the broad variety of Spitzer data that we already have in hand, along with observations from the Hubble Space Telescope and possibly SOFIA, are our best way to understand the wide diversity of exoplanetary atmospheres. Since 2010, the team has produced six papers from a new, highly modular pipeline that implements optimal methods for analysis of Spitzer photometric time series, and our efficiency is increasing. The sensitivity needed for these measurements is up to 100 times better than Spitzer's design criteria, so careful treatment of systematic error is critically important and first-order approximations rarely work. The new pipeline

  4. PLANETESIMAL COMPOSITIONS IN EXOPLANET SYSTEMS

    SciTech Connect

    Johnson, Torrence V.; Mousis, Olivier; Lunine, Jonathan I.; Madhusudhan, Nikku

    2012-10-01

    We have used recent surveys of the composition of exoplanet host stars to investigate the expected composition of condensed material in planetesimals formed beyond the snow line in the circumstellar nebulae of these systems. Of the major solid-forming elements, C and O abundances (and particularly the C/O abundance ratio) strongly affect the amounts of volatile ices and refractory phases in icy planetesimals formed in these systems. This results from these elements' effects on the partitioning of O among gas, refractory solid and ice phases in the final condensate. The calculations use a self-consistent model for the condensation sequence of volatile ices from the nebula gas after refractory (silicate and metal) phases have condensed. The resultant mass fractions (compared to the total condensate) of refractory phases and ices were calculated for a range of nebular temperature structures and redox conditions. Planetesimals in systems with sub-solar C/O should be water ice-rich, with lower than solar mass fractions of refractory materials, while in super-solar C/O systems planetesimals should have significantly higher mass fractions of refractories, in some cases having little or no water ice. C-bearing volatile ices and clathrates also become increasingly important with increasing C/O depending on the assumed nebular temperatures. These compositional variations in early condensates in the outer portions of the nebula will be significant for the equivalent of the Kuiper Belt in these systems, icy satellites of giant planets, and the enrichment (over stellar values) of volatiles and heavy elements in giant planet atmospheres.

  5. Possible climates on terrestrial exoplanets.

    PubMed

    Forget, F; Leconte, J

    2014-04-28

    What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, for instance, to optimize future telescopic observations or to assess the probability of habitable worlds. To begin with, climate primarily depends on (i) the atmospheric composition and the volatile inventory; (ii) the incident stellar flux; and (iii) the tidal evolution of the planetary spin, which can notably lock a planet with a permanent night side. The atmospheric composition and mass depends on complex processes, which are difficult to model: origins of volatiles, atmospheric escape, geochemistry, photochemistry, etc. We discuss physical constraints, which can help us to speculate on the possible type of atmosphere, depending on the planet size, its final distance for its star and the star type. Assuming that the atmosphere is known, the possible climates can be explored using global climate models analogous to the ones developed to simulate the Earth as well as the other telluric atmospheres in the solar system. Our experience with Mars, Titan and Venus suggests that realistic climate simulators can be developed by combining components, such as a 'dynamical core', a radiative transfer solver, a parametrization of subgrid-scale turbulence and convection, a thermal ground model and a volatile phase change code. On this basis, we can aspire to build reliable climate predictors for exoplanets. However, whatever the accuracy of the models, predicting the actual climate regime on a specific planet will remain challenging because climate systems are affected by strong positive feedbacks. They can drive planets with very similar forcing and volatile inventory to completely different states. For instance, the coupling among temperature, volatile phase changes and radiative properties results in instabilities, such as runaway glaciations and runaway greenhouse effect. PMID:24664919

  6. VizieR Online Data Catalog: CANDID code for interferometric observations (Gallenne+, 2015)

    NASA Astrophysics Data System (ADS)

    Gallenne, A.; Merand, A.; Kervella, P.; Monnier, J. D.; Schaefer, G. H.; Baron, F.; Breitfelder, J.; Le Bouquin, J. B.; Roettenbacher, R. M.; Gieren, W.; Pietrzynski, G.; McAlister, H.; Ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Ridgway, S.; Kraus, S.

    2015-07-01

    This is a suite of Python2.7 tools to find faint companion around star in interferometric data in the OIFITS format. This tool allows to systematically search for faint companions in OIFITS data, and if not found, estimates the detection limit. All files are also available at https://github.com/amerand/CANDID . (3 data files).

  7. Characterising exoplanet atmospheres with EChO: Updated results for a new payload design

    NASA Astrophysics Data System (ADS)

    Tessenyi, M.; Beaulieu, J.-P.; Ollivier, M.; Tinetti, G.; Coudé du Foresto, V.; Reess, J.-M.

    2012-12-01

    The field of exoplanets is one of the fastest growing and most novel in astrophysics, with hundreds of planetary discoveries and thousands of candidates waiting to be confirmed. Many of these planets are very different from the planets in our Solar System, yet at present we do not have an explanation nor a clear understanding of this diversity. The atmospheric composition of these remote worlds may provide a key to interpreting this diversity. Spectroscopic measurement of transiting exoplanets is the only viable technique we can use today to sound these exotic atmospheres. EChO, the Exoplanet Characterization Observatory is a Medium class ESA mission candidate, currently being assessed as part of the COSMIC VISION programme. EChO will be the first mission fully dedicated to the systematic study of the physics and chemistry of a large portfolio of exoplanet atmospheres. The targets will cover a wide range of planets: from hot planets to temperate ones, from large, gaseous Jupiter-like planets to small telluric planets. The baseline mission design is a 1.2 m off axis telescope with one instrument composed of several channels covering the spectral range 0.4-16 μm with a spectral resolution in the 300-30 range. The satellite is optimised for stability and is based on the legacy of previous successful ESA missions. EChO will observe primary transits and secondary eclipses, and also phase curves of some non-transiting planets. We present updated results for secondary eclipses, based on methods from previous studies and incorporating the evolution of the payload design.

  8. Imaginary Play Companions: Characteristics and Functions.

    ERIC Educational Resources Information Center

    Kalyan-Masih, V.

    1986-01-01

    Investigates some of the following characteristics associated with young children playing with imaginary play companions (IPCs): intelligence, parental and socioeconomic and educational background, family size, and birth order. Compares these children to those without IPCs. (HOD)

  9. Single transit candidates from K2: detection and period estimation

    NASA Astrophysics Data System (ADS)

    Osborn, H. P.; Armstrong, D. J.; Brown, D. J. A.; McCormac, J.; Doyle, A. P.; Louden, T. M.; Kirk, J.; Spake, J. J.; Lam, K. W. F.; Walker, S. R.; Faedi, F.; Pollacco, D. L.

    2016-04-01

    Photometric surveys such as Kepler have the precision to identify exoplanet and eclipsing binary candidates from only a single transit. K2, with its 75 d campaign duration, is ideally suited to detect significant numbers of single-eclipsing objects. Here we develop a Bayesian transit-fitting tool (`Namaste: An Mcmc Analysis of Single Transit Exoplanets') to extract orbital information from single transit events. We achieve favourable results testing this technique on known Kepler planets, and apply the technique to seven candidates identified from a targeted search of K2 campaigns 1, 2 and 3. We find EPIC203311200 to host an excellent exoplanet candidate with a period, assuming zero eccentricity, of 540 ^{+410}_{-230} d and a radius of 0.51 ± 0.05RJup. We also find six further transit candidates for which more follow-up is required to determine a planetary origin. Such a technique could be used in the future with TESS, PLATO and ground-based photometric surveys such as NGTS, potentially allowing the detection of planets in reach of confirmation by Gaia.

  10. Video Otoscopy in Exotic Companion Mammals.

    PubMed

    Jekl, Vladimir; Hauptman, Karel; Knotek, Zdenek

    2015-09-01

    Ear disease is a common disorder seen in exotic companion mammals, especially in ferrets, rabbits, and rats. This article describes patient preparation, equipment, and video otoscopy technique in exotic companion mammals. This noninvasive technique facilitates accurate diagnosis of diseases affecting the external ear canal or middle ear. Moreover, therapeutic otoscopic evaluation of the external ear facilitates foreign body removal, external ear canal flushing, intralesional drug administration, myringotomy, and middle ear cavity flushing. PMID:26117517

  11. Microphysics of Exoplanet Clouds and Hazes

    NASA Astrophysics Data System (ADS)

    Gao, Peter; Benneke, Björn; Knutson, Heather; Yung, Yuk

    2015-12-01

    Clouds and hazes are ubiquitous in the atmospheres of exoplanets. However, as most of these planets have temperatures between 600 and 2000 K, their clouds and hazes are likely composed of exotic condensates such as silicates, metals, and salts. We currently lack a satisfactory understanding of the microphysical processes that govern the distribution of these clouds and hazes, thus creating a gulf between the cloud properties retrieved from observations and the cloud composition predictions from condensation equilibrium models. In this work we present a 1D microphysical cloud model that calculates, from first principles, the rates of condensation, evaporation, coagulation, and vertical transport of chemically mixed cloud and haze particles in warm and hot exoplanet atmospheres. The model outputs the equilibrium number density of cloud particles with altitude, the particle size distribution, and the chemical makeup of the cloud particles as a function of altitude and particle mass. The model aims to (1) explain the observed variability in “cloudiness” of individual exoplanets, (2) assess whether the proposed cloud materials are capable of forming the observed particle distributions, and (3) examine the role clouds have in the transport of (cloud-forming) heavy elements in exoplanet atmospheres.

  12. Microphysics of Exoplanet Clouds and Hazes

    NASA Astrophysics Data System (ADS)

    Gao, Peter; Benneke, Björn; Knutson, Heather; Yung, Yuk

    2016-01-01

    Clouds and hazes are ubiquitous in the atmospheres of exoplanets. However, as most of these planets have temperatures between 600 and 2000 K, their clouds and hazes are likely composed of exotic condensates such as silicates, metals, and salts. We currently lack a satisfactory understanding of the microphysical processes that govern the distribution of these clouds and hazes, thus creating a gulf between the cloud properties retrieved from observations and the cloud composition predictions from condensation equilibrium models. In this work we present a 1D microphysical cloud model that calculates, from first principles, the rates of condensation, evaporation, coagulation, and vertical transport of chemically mixed cloud and haze particles in warm and hot exoplanet atmospheres. The model outputs the equilibrium number density of cloud particles with altitude, the particle size distribution, and the chemical makeup of the cloud particles as a function of altitude and particle mass. The model aims to (1) explain the observed variability in "cloudiness" of individual exoplanets, (2) assess whether the proposed cloud materials are capable of forming the observed particle distributions, and (3) examine the role clouds have in the transport of (cloud-forming) heavy elements in exoplanet atmospheres.

  13. Microphysics of Exoplanet Clouds and Hazes

    NASA Astrophysics Data System (ADS)

    Gao, Peter; Benneke, Björn; Knutson, Heather A.; Yung, Yuk L.

    2015-11-01

    Clouds and hazes are ubiquitous in the atmospheres of exoplanets. However, as most of these planets have temperatures between 600 and 2000 K, their clouds and hazes are likely composed of exotic condensates such as silicates, metals, and salts. We currently lack a satisfactory understanding of the microphysical processes that govern the distribution of these clouds and hazes, thus creating a gulf between the cloud properties retrieved from observations and the cloud composition predictions from condensation equilibrium models. In this work we present a 1D microphysical cloud model that calculates, from first principles, the rates of condensation, evaporation, coagulation, and vertical transport of chemically mixed cloud and haze particles in warm and hot exoplanet atmospheres. The model outputs the equilibrium number density of cloud particles with altitude, the particle size distribution, and the chemical makeup of the cloud particles as a function of altitude and particle mass. The model aims to (1) explain the observed variability in “cloudiness” of individual exoplanets, (2) assess whether the proposed cloud materials are capable of forming the observed particle distributions, and (3) examine the role clouds have in the transport of (cloud-forming) heavy elements in exoplanet atmospheres.

  14. Deformable Mirrors Capture Exoplanet Data, Reflect Lasers

    NASA Technical Reports Server (NTRS)

    2014-01-01

    To image and characterize exoplanets, Goddard Space Flight Center turned to deformable mirrors (DMs). Berkeley, California-based Iris AO, Inc. worked with Goddard through the SBIR program to improve the company’s microelectromechanical DMs, which are now being evaluated and used for biological research, industrial applications, and could even be used by drug manufacturers.

  15. Hubble Exoplanet Pro/Am Collaboration (Abstract)

    NASA Astrophysics Data System (ADS)

    Conti, D. M.

    2016-06-01

    (Abstract only) A collaborative effort is being organized between a world-wide network of amateur astronomers and a Hubble Space Telescope (HST) science team. The purpose of this collaboration is to supplement an HST near-infrared spectroscopy survey of some 15 exoplanets with ground-based observations in the visible range.

  16. New Measurements of Polarised Light from Exoplanets

    NASA Astrophysics Data System (ADS)

    Bott, Kimberly Marie; Cotton, Daniel; Kedziora-Chudczer, Lucyna; Bailey, Jeremy

    2015-08-01

    Detections of polarised light from exoplanets are an important expansion of exoplanet studies, as they provide a complimentary and advantageous diagnostic to the other characterisation methods. However some of the earliest claimed detections of polarised light from exoplanets are disputed.The High Precision Polarimetric Instrument (HIPPI) is currently the highest sensitivity astronomical polarimeter (Bailey 2015) in the world at 4.3 ppm or better precision, and has been used to observe exoplanet systems including the disputed first detection source (Berdyugina 2008, Wiktorowicz 2009, Berdyugina 2011), HD189733b. HIPPI is designed for best sensitivity in blue light where Rayleigh scattering would produce a strong signal for hot Jupiter planets (Burrows 2008). These observations, taken at the Anglo-Australian Telescope in 2014 and 2015, are compared to models from a polarised light adaptation of the Versatile Software for the Transfer of Atmospheric Radiation (VSTAR).Our new, independent Hot Jupiter polarised light detections are discussed, including the physical sources of the detected polarised light, as well as additional contributing factors (e.g. debris, ISM anomalies). For HD 189733b we use available visible and near infrared transit and polarimetric data to create and interpret a planetary portrait using VSTAR.

  17. LEECH: LBTI Exozodi Exoplanet Common Hunt

    NASA Astrophysics Data System (ADS)

    Skemer, A.

    2014-03-01

    In Spring 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began its 100-night campaign from the Large Binocular Telescope (LBT) atop Mt Graham, Arizona. This survey benefits from the many technological achievements of the LBT, including two 8.4- meter mirrors on a single fixed mount, dual adaptive secondary mirrors for high Strehl performance, and a cold beam combiner to dramatically reducing the telescope's overall background emissivity. LEECH neatly complements other high-contrast planet imaging efforts by observing stars at L' (3.8 microns) with LMIRcam, as opposed to the shorter wavelength near-infrared bands (1-2.4 microns) of other similar surveys. This portion of the spectrum offers deeper mass sensitivity for intermediate age (several hundred Myr-old) systems, since their Jovian-mass planets radiate predominantly in the mid-infrared. The goals of LEECH are to (1) discover new exoplanets, (2) characterize the atmospheres of newly discovered exoplanets, (3) characterize the architectures of nearby planetary systems, and (4) establish meaningful constraints on the prevalence of wideseparation exoplanets.

  18. Exoplanet environments to harbour extremophile life

    NASA Astrophysics Data System (ADS)

    Janot-Pacheco, Eduardo; Lage, Claudia A. S.; Lima, Ivan G. P.

    2010-02-01

    In this contribution, we estimate the temperature at the surface of known exoplanets and of their putative satellites for two albedo extreme cases (Venus and Mars) and present a selection of extremophiles living on Earth that can live under those conditions. We examine also the possibility of survival of microorganisms in planetary systems of variable stars.

  19. Exoplanet magnetic field: possible marker of habitability

    NASA Astrophysics Data System (ADS)

    Mogilevsky, Mikhail; Skalsky, Alexandre; Gotlib, Vladimir; Rothkaehl, Hanna; Gurvits, Leonid; Korepanov, Valeriy; Romantsova, Tatiana

    2013-04-01

    The intrinsic magnetic field shielding the planetary surface from most of space radiation is one of indicator on possible habitability of exoplanet. A search of exosolar terrestrial-like planets possessing the magnetic fields and developed magnetospheres seems to be the most intriguing objective of exoplanet studies. The interaction of planetary magnetosphere with the star wind results in generation of radioemissions (similar to AKR radiation of the terrestrial magnetosphere) which allows remote sensing of exoplanet magnetic field. However, frequency range of waves expected from terrestrial-like exoplanet is below, roughly, 10 MHz and, thus, these radioemissions can be hardly investigated by ground facilities due to conducting Earth's ionosphere. The Moon possessing a week atmosphere/ionosphere around its surface seems to be a perfect base for carrying out measurements of low frequency radio emissions originated from the space. The paper presents approaches to antenna design and a scenario of radio facility deployment at Moon's surface which is aimed on terrestrial-like planet search in exosolar system.

  20. Spectra as windows into exoplanet atmospheres

    PubMed Central

    Burrows, Adam S.

    2014-01-01

    Understanding a planet’s atmosphere is a necessary condition for understanding not only the planet itself, but also its formation, structure, evolution, and habitability. This requirement puts a premium on obtaining spectra and developing credible interpretative tools with which to retrieve vital planetary information. However, for exoplanets, these twin goals are far from being realized. In this paper, I provide a personal perspective on exoplanet theory and remote sensing via photometry and low-resolution spectroscopy. Although not a review in any sense, this paper highlights the limitations in our knowledge of compositions, thermal profiles, and the effects of stellar irradiation, focusing on, but not restricted to, transiting giant planets. I suggest that the true function of the recent past of exoplanet atmospheric research has been not to constrain planet properties for all time, but to train a new generation of scientists who, by rapid trial and error, are fast establishing a solid future foundation for a robust science of exoplanets. PMID:24613929

  1. An infrared search for low-mass companions of stars near the sun

    NASA Technical Reports Server (NTRS)

    Skrutskie, M. F.; Forrest, W. J.; Shure, Mark

    1989-01-01

    Using a CCD camera on the IRTF telescope on Mauna Kea, a search was conducted for low-mass companions to stars in the solar neighborhood. The K band (2.2 microns) survey includes 55 condidates closer than 12 pc, as well as eight stars in the Pleiades star cluster. Due to the saturation of the primary star image, the survey was insensitive to companions within about 2 arcsec of the primary star. The survey detected a single low-mass candidate object, a companion to the star Gliese 569, which lies near or below the hydrogen-burning mass limit and resembles extremely low-mass stars similar to VB 10 and LHS 2924.

  2. DISCOVERY OF THE COLDEST IMAGED COMPANION OF A SUN-LIKE STAR

    SciTech Connect

    Thalmann, C.; Carson, J.; Goto, M.; Feldt, M.; Henning, T.; Klahr, H.; Mordasini, C.; Janson, M.; McElwain, M.; Egner, S.; Hayano, Y.; Suzuki, R.; Hashimoto, J.; Kandori, R.; Kudo, T.; Kusakabe, N.; Morino, J.-I.; Suto, H.; Tamura, M.; Hodapp, K. W.

    2009-12-20

    We present the discovery of a brown dwarf or possible planet at a projected separation of 1.''9 = 29 AU around the star GJ 758, placing it between the separations at which substellar companions are expected to form by core accretion (approx5 AU) or direct gravitational collapse (typically approx>100 AU). The object was detected by direct imaging of its thermal glow with Subaru/HiCIAO. At 10-40 times the mass of Jupiter and a temperature of 550-640 K, GJ 758 B constitutes one of the few known T-type companions, and the coldest ever to be imaged in thermal light around a Sun-like star. Its orbit is likely eccentric and of a size comparable to Pluto's orbit, possibly as a result of gravitational scattering or outward migration. A candidate second companion is detected at 1.''2 at one epoch.

  3. MAPPING DIRECTLY IMAGED GIANT EXOPLANETS

    SciTech Connect

    Kostov, Veselin; Apai, Daniel

    2013-01-01

    With the increasing number of directly imaged giant exoplanets, the current atmosphere models are often not capable of fully explaining the spectra and luminosity of the sources. A particularly challenging component of the atmosphere models is the formation and properties of condensate cloud layers, which fundamentally impact the energetics, opacity, and evolution of the planets. Here we present a suite of techniques that can be used to estimate the level of rotational modulations these planets may show. We propose that the time-resolved observations of such periodic photometric and spectroscopic variations of extrasolar planets due to their rotation can be used as a powerful tool to probe the heterogeneity of their optical surfaces. In this paper, we develop simulations to explore the capabilities of current and next-generation ground- and space-based instruments for this technique. We address and discuss the following questions: (1) what planet properties can be deduced from the light curve and/or spectra, and in particular can we determine rotation periods, spot coverage, spot colors, and spot spectra?; (2) what is the optimal configuration of instrument/wavelength/temporal sampling required for these measurements?; and (3) can principal component analysis be used to invert the light curve and deduce the surface map of the planet? Our simulations describe the expected spectral differences between homogeneous (clear or cloudy) and patchy atmospheres, outline the significance of the dominant absorption features of H{sub 2}O, CH{sub 4}, and CO, and provide a method to distinguish these two types of atmospheres. Assuming surfaces with and without clouds for most currently imaged planets the current models predict the largest variations in the J band. Simulated photometry from current and future instruments is used to estimate the level of detectable photometric variations. We conclude that future instruments will be able to recover not only the rotation periods

  4. An astrometric search for a stellar companion to the sun

    SciTech Connect

    Perlmutter, S.

    1986-11-25

    A companion star within 0.8 pc of the Sun has been postulated to explain a possible 26 Myr periodicity in mass extinctions of species on the Earth. Such a star would already be catalogued in the Yale Bright Star catalogue unless it is fainter than m/sub nu/ = 6.5; this limits the possible stellar types for an unseen companion to red dwarfs, brown dwarfs, or compact objects. Red dwarfs account for about 75% of these possible stars. We describe here the design and development of an astrometric search for a nearby red dwarf companion with a six-month peak-to-peak parallax of greater than or equal to2.5 arcseconds. We are measuring the parallax of 2770 candidate faint red stars selected from the Dearborn Observatory catalogue. An automated 30-inch telescope and CCD camera system collect digitized images of the candidate stars, along with a 13' x 16' surrounding field of background stars. Second-epoch images, taken a few months later, are registered to the first epoch images using the background stars as fiducials. An apparent motion, m/sub a/, of the candidate stars is found to a precision of sigma/sub m//sub a/ approx. = 0.08 pixel approx. = 0.2 arcseconds for fields with N/sub fiducial/ greater than or equal to 10 fiducial stars visible above the background noise. This precision is sufficient to detect the parallactic motion of a star at 0.8 pc with a two month interval between the observation epochs. Images with fewer fiducial stars above background noise are observed with a longer interval between epochs. If a star is found with high parallactic motion, we will confirm its distance with further parallax measurements, photometry, and spectral studies, and will measure radial velocity and proper motion to establish its orbit. We have demonstrated the search procedure with observations of 41 stars, and have shown that none of these is a nearby star. 37 refs., 16 figs., 3 tabs.

  5. DAVE: Discovery and Vetting of K2 Exoplanets

    NASA Astrophysics Data System (ADS)

    Coughlin, Jeffrey; Mullally, Fergal; Mullally, Susan; Colón, Knicole D.; Barentsen, Geert; Quintana, Elisa V.; Burke, Christopher J.; Barclay, Thomas

    2016-06-01

    NASA's K2 mission is capable of finding planets as small as the Earth around bright, nearby stars. These targets are well-suited for JWST follow-up to study their density and atmospheric composition. Such observations will yield a better understanding of the difference between rocky and gaseous planets, particularly how composition varies as a function of radius. K2 observes over 10,000 stars every 90 days, which coupled with significant systematics due to spacecraft pointing jitter, presents a challenge in rapidly detecting high-quality planet candidates. In this talk, we present results from our Discovery and Vetting of K2 Exoplanets (DAVE) team. DAVE focuses on applying robotic vetting techniques, formulated as part of the prime Kepler mission, to possible K2 planets detected by both DAVE and other teams. We highlight these robotic vetting techniques and the types of false positives they eliminate, and present examples of well-vetted candidates. We make the DAVE pipeline, including the vetting tools, publicly available at http://github.com/barentsen/dave. This work is funded by a K2 Guest Observer Cycle 2 grant.

  6. Dancing in the Dark --- Unseen Companions of Nearby Stars

    NASA Astrophysics Data System (ADS)

    Henry, Todd J.; Koerner, D. W.; Jao, W. C.; Subasavage, J. P.; Ianna, P. A.; Bean, J. L.; Benedict, G. F.; McArthur, B. E.; RECONS

    2007-12-01

    We are carrying out the ASPENS (Astrometric Search for Planets Encircling Nearby Stars) program using the CTIO 0.9m telescope in an effort to discover unseen companions to 100 nearby stars. The CCD camera used yields substantial improvement in the detection of low mass companions over the classic studies done using photographic plates. We have accumulated up to 8 years of astrometric data on 85 red dwarfs and 14 white dwarfs, primarily at southern declinations and within 10 parsecs. The target list includes 39 new solar neighbors revealed to be closer than 10 parsecs by the RECONS team. With consistent (and significant) observing time as part of the SMARTS Consortium, we have been able to discover new companions with masses between 0.20 Msun and 4 Mjup. The latter is the first confirmed discovery of an extrasolar planet via astrometry. We have also detected the planet through HET iodine cell radial velocity work. Nearby red dwarfs are prime candidates for NASA's SIM PlanetQuest because the astrometric perturbations are largest for planets orbiting nearby stars of low mass. In addition, new multiple red dwarf systems can be targeted for mass determinations, thereby providing points on a comprehensive mass-luminosity relation for the most populous members of the Galaxy. These long-term observations began in 1999 as an NOAO Surveys program, and are continuing via the SMARTS Consortium. This work has been supported by the National Science Foundation (AST 98-20711 and 05-07711), NASA's SIM PlanetQuest, Georgia State University, and Northern Arizona University.

  7. Structures induced by companions in galactic discs

    NASA Astrophysics Data System (ADS)

    Kyziropoulos, P. E.; Efthymiopoulos, C.; Gravvanis, G. A.; Patsis, P. A.

    2016-09-01

    Using N-body simulations we study the structures induced on a galactic disc by repeated flybys of a companion in decaying eccentric orbit around the disc. Our system is composed by a stellar disc, bulge and live dark matter halo, and we study the system's dynamical response to a sequence of a companion's flybys, when we vary i) the disc's temperature (parameterized by Toomre's Q-parameter) and ii) the companion's mass and initial orbit. We use a new 3D Cartesian grid code: MAIN (Mesh-adaptive Approximate Inverse N-body solver). The main features of MAIN are reviewed, with emphasis on the use of a new Symmetric Factored Approximate Sparse Inverse (SFASI) matrix in conjunction with the multigrid method that allows the efficient solution of Poisson's equation in three space variables. We find that: i) companions need to be assigned initial masses in a rather narrow window of values in order to produce significant and more long-standing non-axisymmetric structures (bars and spirals) in the main galaxy's disc by the repeated flyby mechanism. ii) a crucial phenomenon is the antagonism between companion-excited and self-excited modes on the disc. Values of Q > 1.5 are needed in order to allow for the growth of the companion-excited modes to prevail over the the growth of the disc's self-excited modes. iii) We give evidence that the companion-induced spiral structure is best represented by a density wave with pattern speed nearly constant in a region extending from the ILR to a radius close to, but inside, corotation.

  8. Zoonotic Poxviruses Associated with Companion Animals

    PubMed Central

    Tack, Danielle M.; Reynolds, Mary G.

    2011-01-01

    Simple Summary Contemporary enthusiasm for the ownership of exotic animals and hobby livestock has created an opportunity for the movement of poxviruses—such as monkeypox, cowpox, and orf—outside their traditional geographic range bringing them into contact with atypical animal hosts and groups of people not normally considered at risk. It is important that pet owners and practitioners of human and animal medicine develop a heightened awareness for poxvirus infections and understand the risks that can be associated with companion animals and livestock. This article reviews the epidemiology and clinical features of zoonotic poxviruses that are most likely to affect companion animals. Abstract Understanding the zoonotic risk posed by poxviruses in companion animals is important for protecting both human and animal health. The outbreak of monkeypox in the United States, as well as current reports of cowpox in Europe, point to the fact that companion animals are increasingly serving as sources of poxvirus transmission to people. In addition, the trend among hobbyists to keep livestock (such as goats) in urban and semi-urban areas has contributed to increased parapoxvirus exposures among people not traditionally considered at high risk. Despite the historic notoriety of poxviruses and the diseases they cause, poxvirus infections are often missed. Delays in diagnosing poxvirus-associated infections in companion animals can lead to inadvertent human exposures. Delays in confirming human infections can result in inappropriate treatment or prolonged recovery. Early recognition of poxvirus-associated infections and application of appropriate preventive measures can reduce the spread of virus between companion animals and their owners. This review will discuss the epidemiology and clinical features associated with the zoonotic poxvirus infections most commonly associated with companion animals. PMID:26486622

  9. Synthesizing exoplanet demographics from radial velocity and microlensing surveys. I. Methodology

    SciTech Connect

    Clanton, Christian; Gaudi, B. Scott

    2014-08-20

    Motivated by the order of magnitude difference in the frequency of giant planets orbiting M dwarfs inferred by microlensing and radial velocity (RV) surveys, we present a method for comparing the statistical constraints on exoplanet demographics inferred from these methods. We first derive the mapping from the observable parameters of a microlensing-detected planet to those of an analogous planet orbiting an RV-monitored star. Using this mapping, we predict the distribution of RV observables for the planet population inferred from microlensing surveys, taking care to adopt reasonable priors for, and properly marginalize over, the unknown physical parameters of microlensing-detected systems. Finally, we use simple estimates of the detection limits for a fiducial RV survey to predict the number and properties of analogs of the microlensing planet population such an RV survey should detect. We find that RV and microlensing surveys have some overlap, specifically for super-Jupiter mass planets (m{sub p} ≳ 1 M {sub Jup}) with periods between ∼3-10 yr. However, the steeply falling planetary mass function inferred from microlensing implies that, in this region of overlap, RV surveys should infer a much smaller frequency than the overall giant planet frequency (m{sub p} ≳ 0.1 M {sub Jup}) inferred by microlensing. Our analysis demonstrates that it is possible to statistically compare and synthesize data sets from multiple exoplanet detection techniques in order to infer exoplanet demographics over wider regions of parameter space than are accessible to individual methods. In a companion paper, we apply our methodology to several representative microlensing and RV surveys to derive the frequency of planets around M dwarfs with orbits of ≲ 30 yr.

  10. Subaru Direct Imaging Survey of Wide-Orbit Exoplanets and Solar-System-Scale Disks

    NASA Astrophysics Data System (ADS)

    Tamura, Motohide

    2015-08-01

    SEEDS (Strategic Explorations of Exoplanets and Disks with Subaru) is the first Subaru Strategic Program, whose aim is to conduct a direct imaging survey for giant planets as well as protoplanetary/debris disks at a few to a few tens of AU region around 500 nearby solar-type or more massive young stars devoting 120 Subaru nights for 5 years from 2009. The targets are composed of five categories spanning the ages of ~1 Myr to ~1 Gyr. Some RV-planet targets with older ages are also observed. We describe this survey and present its main results. The topics include (1) statistic of wide-orbit planets, (2) detection and characterization of one of the most lowest-mass planet via direct imaging. (3) detection of a super-Jupiter around the most massive star ever imaged, (4) detection of companions around retrograde exoplanet, (5) the discovery of unprecedentedly detailed structures of more than a dozen of protoplanetary disks and some debris disks. The detected structures such as wide gaps and spirals arms of a Solar-system scale could be signpost of planet.

  11. Binary pulsars studies with multiwavelength sky surveys - I. Companion star identification

    NASA Astrophysics Data System (ADS)

    Mignani, R. P.; Corongiu, A.; Pallanca, C.; Oates, S. R.; Yershov, V. N.; Breeveld, A. A.; Page, M. J.; Ferraro, F. R.; Possenti, A.; Jackson, A. C.

    2014-09-01

    The identification of the stellar companions to binary pulsars is key to studying the evolution of the binary system and how this is influenced by the interactions between the two stars. For only a fraction of the known binary pulsars, the stellar companions have been identified. Here, we used 11 source catalogues available from multiwavelength (ultraviolet, optical, infrared) imaging sky surveys to search for the stellar companions of a sample of 144 field binary pulsars (i.e. not in globular clusters) selected from the Australia Telescope National Facility data base (version 1.48) and from the public list of γ-ray pulsars detected by Fermi. We found positional associations in at least one source catalogue for 22 pulsars, of which 10 are detected in γ-rays by Fermi, including 15 millisecond pulsars. For six pulsars in our compilation, we confirm their identifications. For another seven pulsars that had yet not been identified, we examine potential identifications. In particular, we identified a likely companion star candidate to PSR J2317+1439, whereas for both PSR B1953+29 and PSR J1935+1726 the companion star identification is more uncertain. Follow-up observations of these three pulsars are needed to settle the proposed identifications. For the remaining nine pulsars that had been already identified, we provide additional spectral information in at least one of the surveys' spectral bands, which we will use to better constrain the stars' spectral energy distributions.

  12. A SUBSTELLAR COMMON PROPER-MOTION COMPANION TO THE PLEIAD H II 1348

    SciTech Connect

    Geissler, Kerstin; Metchev, Stanimir A.; Pham, Alfonse; Larkin, James E.; McElwain, Michael; Hillenbrand, Lynne A.

    2012-02-10

    We announce the identification of a proper-motion companion to the star H II 1348, a K5 V member of the Pleiades open cluster. The existence of a faint point source 1.''1 away from H II 1348 was previously known from adaptive optics imaging by Bouvier et al. However, because of a high likelihood of background star contamination and in the absence of follow-up astrometry, Bouvier et al. tentatively concluded that the candidate companion was not physically associated with H II 1348. We establish the proper-motion association of the pair from adaptive optics imaging with the Palomar 5 m telescope. Adaptive optics spectroscopy with the integral field spectrograph OSIRIS on the Keck 10 m telescope reveals that the companion has a spectral type of M8 {+-} 1. According to substellar evolution models, the M8 spectral type resides within the substellar mass regime at the age of the Pleiades. The primary itself is a known double-lined spectroscopic binary, which makes the resolved companion, H II 1348B, the least massive and widest component of this hierarchical triple system and the first substellar companion to a stellar primary in the Pleiades.

  13. Three Wide Planetary-mass Companions to FW Tau, ROXs 12, and ROXs 42B

    NASA Astrophysics Data System (ADS)

    Kraus, Adam L.; Ireland, Michael J.; Cieza, Lucas A.; Hinkley, Sasha; Dupuy, Trent J.; Bowler, Brendan P.; Liu, Michael C.

    2014-01-01

    We report the discovery of three planetary-mass companions (M = 6-20 M Jup) in wide orbits (ρ ~ 150-300 AU) around the young stars FW Tau (Taurus-Auriga), ROXs 12 (Ophiuchus), and ROXs 42B (Ophiuchus). All three wide planetary-mass companions (PMCs) were reported as candidate companions in previous binary survey programs, but then were neglected for >10 yr. We therefore obtained followup observations that demonstrate that each candidate is comoving with its host star. Based on the absolute M_{K^{\\prime }} magnitudes, we infer masses (from hot-start evolutionary models) and projected separations of 10 ± 4 M Jup and 330 ± 30 AU for FW Tau b, 16 ± 4 M Jup and 210 ± 20 AU for ROXs 12, and 10 ± 4 M Jup and 140 ± 10 AU for ROXs 42B b. We also present similar observations for 10 other candidates that show that they are unassociated field stars, as well as multicolor JHK'L' near-infrared photometry for our new PMCs and for five previously identified substellar or planetary-mass companions. The near-infrared photometry for our sample of eight known and new companions generally parallels the properties of free-floating, low-mass brown dwarfs in these star-forming regions. However, five of the seven objects with M < 30 M Jup are redder in K' - L' than the distribution of young free-floating counterparts of similar J - K' color. We speculate that this distinction could indicate a structural difference in circumplanetary disks, perhaps tied to higher disk mass since at least two of the objects in our sample are known to be accreting more vigorously than typical free-floating counterparts.

  14. Three wide planetary-mass companions to FW Tau, ROXs 12, and ROXs 42B

    SciTech Connect

    Kraus, Adam L.; Ireland, Michael J.; Cieza, Lucas A.; Bowler, Brendan P.; Liu, Michael C.; Hinkley, Sasha; Dupuy, Trent J.

    2014-01-20

    We report the discovery of three planetary-mass companions (M = 6-20 M {sub Jup}) in wide orbits (ρ ∼ 150-300 AU) around the young stars FW Tau (Taurus-Auriga), ROXs 12 (Ophiuchus), and ROXs 42B (Ophiuchus). All three wide planetary-mass companions (PMCs) were reported as candidate companions in previous binary survey programs, but then were neglected for >10 yr. We therefore obtained followup observations that demonstrate that each candidate is comoving with its host star. Based on the absolute M{sub K{sup ′}} magnitudes, we infer masses (from hot-start evolutionary models) and projected separations of 10 ± 4 M {sub Jup} and 330 ± 30 AU for FW Tau b, 16 ± 4 M {sub Jup} and 210 ± 20 AU for ROXs 12, and 10 ± 4 M {sub Jup} and 140 ± 10 AU for ROXs 42B b. We also present similar observations for 10 other candidates that show that they are unassociated field stars, as well as multicolor JHK'L' near-infrared photometry for our new PMCs and for five previously identified substellar or planetary-mass companions. The near-infrared photometry for our sample of eight known and new companions generally parallels the properties of free-floating, low-mass brown dwarfs in these star-forming regions. However, five of the seven objects with M < 30 M {sub Jup} are redder in K' – L' than the distribution of young free-floating counterparts of similar J – K' color. We speculate that this distinction could indicate a structural difference in circumplanetary disks, perhaps tied to higher disk mass since at least two of the objects in our sample are known to be accreting more vigorously than typical free-floating counterparts.

  15. Reading Aloud: Companion Reader vs. No Companion Reader--An Experimental Research Study

    ERIC Educational Resources Information Center

    Ruivo, Paula

    2006-01-01

    This study has been done to gather data as to whether there is improvement in vocabulary development, reading comprehension and reading fluency when a child is reading aloud and he or she has a reading companion as opposed to not having a reading companion. As this literature review indicates there has been a lot of research on the benefits of…

  16. Design of the CHARIS integral field spectrograph for exoplanet imaging

    NASA Astrophysics Data System (ADS)

    Groff, Tyler D.; Peters, Mary Anne; Kasdin, N. Jeremy; Knapp, Gillian; Galvin, Michael; Carr, Michael; McElwain, Michael W.; Brandt, Timothy; Janson, Markus; Gunn, James E.; Lupton, Robert; Guyon, Olivier; Martinache, Frantz; Jovanovic, Nemanja; Hayashi, Masahiko; Takato, Naruhisa

    2013-09-01

    Princeton University is building an integral field spectrograph (IFS), the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS), for integration with the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system and the AO188 adaptive optics system on the Subaru telescope. CHARIS and SCExAO will measure spectra of hot, young Jovian planets in a coronagraphic image across J, H, and K bands down to an 80 milliarcsecond inner working angle. SCExAO's coronagraphs and wavefront control system will make it possible to detect companions five orders of magnitude dimmer than their parent star. However, quasi-static speckles in the image contaminate the signal from the planet. In an IFS this also causes uncertainty in the spectra due to diffractive cross-contamination, commonly referred to as crosstalk. Post-processing techniques can subtract these speckles, but they can potentially skew spectral measurements, become less effective at small angular separation, and at best can only reduce the crosstalk down to the photon noise limit of the contaminating signal. CHARIS will address crosstalk effects of a high contrast image through hardware design, which drives the optical and mechanical design of the assembly. The work presented here sheds light on the optical and mechanical considerations taken in designing the IFS to provide high signal-to-noise spectra in a coronagraphic image from and extreme adaptive optics image. The design considerations and lessons learned are directly applicable to future exoplanet instrumentation for extremely large telescopes and space observatories capable of detecting rocky planets in the habitable zone.

  17. VLT Captures First Direct Spectrum of an Exoplanet

    NASA Astrophysics Data System (ADS)

    2010-01-01

    By studying a triple planetary system that resembles a scaled-up version of our own Sun's family of planets, astronomers have been able to obtain the first direct spectrum - the "chemical fingerprint" [1] - of a planet orbiting a distant star [2], thus bringing new insights into the planet's formation and composition. The result represents a milestone in the search for life elsewhere in the Universe. "The spectrum of a planet is like a fingerprint. It provides key information about the chemical elements in the planet's atmosphere," says Markus Janson, lead author of a paper reporting the new findings. "With this information, we can better understand how the planet formed and, in the future, we might even be able to find tell-tale signs of the presence of life." The researchers obtained the spectrum of a giant exoplanet that orbits the bright, very young star HR 8799. The system is at about 130 light-years from Earth. The star has 1.5 times the mass of the Sun, and hosts a planetary system that resembles a scaled-up model of our own Solar System. Three giant companion planets were detected in 2008 by another team of researchers, with masses between 7 and 10 times that of Jupiter. They are between 20 and 70 times as far from their host star as the Earth is from the Sun; the system also features two belts of smaller objects, similar to our Solar System's asteroid and Kuiper belts. "Our target was the middle planet of the three, which is roughly ten times more massive than Jupiter and has a temperature of about 800 degrees Celsius," says team member Carolina Bergfors. "After more than five hours of exposure time, we were able to tease out the planet's spectrum from the host star's much brighter light." This is the first time the spectrum of an exoplanet orbiting a normal, almost Sun-like star has been obtained directly. Previously, the only spectra to be obtained required a space telescope to watch an exoplanet pass directly behind its host star in an "exoplanetary

  18. Genomic Analysis of Companion Rabbit Staphylococcus aureus

    PubMed Central

    Holmes, Mark A.; Harrison, Ewan M.; Fisher, Elizabeth A.; Graham, Elizabeth M.; Parkhill, Julian; Foster, Geoffrey; Paterson, Gavin K.

    2016-01-01

    In addition to being an important human pathogen, Staphylococcus aureus is able to cause a variety of infections in numerous other host species. While the S. aureus strains causing infection in several of these hosts have been well characterised, this is not the case for companion rabbits (Oryctolagus cuniculus), where little data are available on S. aureus strains from this host. To address this deficiency we have performed antimicrobial susceptibility testing and genome sequencing on a collection of S. aureus isolates from companion rabbits. The findings show a diverse S. aureus population is able to cause infection in this host, and while antimicrobial resistance was uncommon, the isolates possess a range of known and putative virulence factors consistent with a diverse clinical presentation in companion rabbits including severe abscesses. We additionally show that companion rabbit isolates carry polymorphisms within dltB as described as underlying host-adaption of S. aureus to farmed rabbits. The availability of S. aureus genome sequences from companion rabbits provides an important aid to understanding the pathogenesis of disease in this host and in the clinical management and surveillance of these infections. PMID:26963381

  19. Genomic Analysis of Companion Rabbit Staphylococcus aureus.

    PubMed

    Holmes, Mark A; Harrison, Ewan M; Fisher, Elizabeth A; Graham, Elizabeth M; Parkhill, Julian; Foster, Geoffrey; Paterson, Gavin K

    2016-01-01

    In addition to being an important human pathogen, Staphylococcus aureus is able to cause a variety of infections in numerous other host species. While the S. aureus strains causing infection in several of these hosts have been well characterised, this is not the case for companion rabbits (Oryctolagus cuniculus), where little data are available on S. aureus strains from this host. To address this deficiency we have performed antimicrobial susceptibility testing and genome sequencing on a collection of S. aureus isolates from companion rabbits. The findings show a diverse S. aureus population is able to cause infection in this host, and while antimicrobial resistance was uncommon, the isolates possess a range of known and putative virulence factors consistent with a diverse clinical presentation in companion rabbits including severe abscesses. We additionally show that companion rabbit isolates carry polymorphisms within dltB as described as underlying host-adaption of S. aureus to farmed rabbits. The availability of S. aureus genome sequences from companion rabbits provides an important aid to understanding the pathogenesis of disease in this host and in the clinical management and surveillance of these infections. PMID:26963381

  20. ESA M3 mission candidate EChO

    NASA Astrophysics Data System (ADS)

    Puig, L.; Isaak, K. G.; Escudero, I.; Martin, D.; Crouzet, P.-E.; Rando, N.

    2011-09-01

    The Exoplanet Characterisation Observatory (EChO) is a medium class mission candidate within the science program Cosmic Vision 2015-2025 of the European Space Agency. It was selected in February 2011 as one of 4 M3 mission candidates to enter an assessment phase. The assessment activities start with the definition of science and mission requirements as well as of a preliminary model payload, followed by an internal Concurrent Design Facility (CDF) study. Parallel industrial studies will follow in 2012, after which the 4 missions will be reviewed to identify candidates entering definition phase studies in 2013. EChO aims at characterising the atmosphere of known transiting exoplanets, potentially from giant Hot Jupiters down to Super-Earths orbiting in the habitable zone of M-dwarf stars. It will use a 1 m class telescope, feeding a spectrometer covering the wave lengths from 0.4 to 11 microns with a potential extension to 16 microns. While spatial differentiation of the exoplanet and its host star is not necessary, spectral differentiation will be achieved by making differential measurements of in- and out- of transit frames to cancel the star signal. This paper describes critical requirements, and gives an overview of the model payload design. It also reports on the results of the CDF.

  1. New M, L, and T Dwarf Companions to Nearby Stars from the Wide-field Infrared Survey Explorer

    NASA Astrophysics Data System (ADS)

    Luhman, Kevin L.; Loutrel, Nicholas P.; McCurdy, Nicholas S.; Mace, Gregory N.; Melso, Nicole D.; Star, Kimberly M.; Young, Michael D.; Terrien, Ryan C.; McLean, Ian S.; Kirkpatrick, J. Davy; Rhode, Katherine L.

    2012-12-01

    We present 11 candidate late-type companions to nearby stars identified with data from the Wide-field Infrared Survey Explorer (WISE) and the Two Micron All Sky Survey (2MASS). Eight of the candidates are likely to be companions based on their common proper motions with the primaries. The remaining three objects are rejected as companions, one of which is a free-floating T7 dwarf. Spectral types are available for five of the companions, which consist of M2V, M8.5V, L5, T8, and T8. Based on their photometry, the unclassified companions are probably two mid-M dwarfs and one late-M/early-L dwarf. One of the T8 companions, WISE J142320.84+011638.0, has already been reported by Pinfield and coworkers. The other T8 companion, ULAS J095047.28+011734.3, was discovered by Burningham and coworkers through the United Kingdom Infrared Telescope Infrared Deep Sky Survey, but its companionship has not been previously recognized in the literature. The L5 companion, 2MASS J17430860+8526594, is a new member of a class of L dwarfs that exhibit unusually blue near-IR colors. Among the possible mechanisms that have been previously proposed for the peculiar colors of these L dwarfs, low metallicity does not appear to be a viable explanation for 2MASS J17430860+8526594 since our spectrum of the primary suggests that its metallicity is not significantly subsolar. Based on data from the Wide-field Infrared Survey Explorer, 2MASS, the W.M. Keck Observatory, the NASA Infrared Telescope Facility, the Hobby-Eberly Telescope, the WIYN Observatory at Kitt Peak National Observatory, the Spitzer Space Telescope, the Canada-France-Hawaii Telescope, and the European Southern Observatory New Technology Telescope.

  2. New prospects for observing and cataloguing exoplanets in well-detached binaries

    NASA Astrophysics Data System (ADS)

    Schwarz, R.; Funk, B.; Zechner, R.; Bazsó, Á.

    2016-08-01

    This paper is devoted to study the circumstances favourable to detect circumstellar and circumbinary planets in well detached binary-star-systems using eclipse timing variations (ETVs). We investigated the dynamics of well detached binary star systems with a star separation from 0.5 to 3~AU, to determine the probability of the detection of such variations with ground based telescopes and space telescopes (like former missions CoRoT and Kepler and future space missions Plato, Tess and Cheops). For the chosen star separations both dynamical configurations (circumstellar and circumbinary) may be observable. We performed numerical simulations by using the full three-body problem as dynamical model. The dynamical stability and the ETVs are investigated by computing ETV maps for different masses of the secondary star and the exoplanet (Earth, Neptune and Jupiter size). In addition we changed the planet's and binary's eccentricities. We conclude that many amplitudes of ETVs are large enough to detect exoplanets in binary star systems. As an application, we prepared statistics of the catalogue of exoplanets in binary star systems which we introduce in this article and compared the statistics with our parameter-space which we used for our calculations. In addition to these statistics of the catalogue we enlarged them by the investigation of well detached binary star systems from several catalogues and discussed the possibility of further candidates.

  3. New prospects for observing and cataloguing exoplanets in well-detached binaries

    NASA Astrophysics Data System (ADS)

    Schwarz, R.; Funk, B.; Zechner, R.; Bazsó, Á.

    2016-08-01

    This paper is devoted to study the circumstances favourable to detect circumstellar and circumbinary planets in well-detached binary-star systems using eclipse timing variations (ETVs). We investigated the dynamics of well-detached binary star systems with a star separation from 0.5 to 3 au, to determine the probability of the detection of such variations with ground-based telescopes and space telescopes (like former missions CoRoT and Kepler and future space missions Plato, Tess and Cheops). For the chosen star separations both dynamical configurations (circumstellar and circumbinary) may be observable. We performed numerical simulations by using the full three-body problem as dynamical model. The dynamical stability and the ETVs are investigated by computing ETV maps for different masses of the secondary star and the exoplanet (Earth, Neptune and Jupiter size). In addition we changed the planet's and binary's eccentricities. We conclude that many amplitudes of ETVs are large enough to detect exoplanets in binary-star systems. As an application, we prepared statistics of the catalogue of exoplanets in binary star systems which we introduce in this article and compared the statistics with our parameter-space which we used for our calculations. In addition to these statistics of the catalogue we enlarged them by the investigation of well-detached binary star systems from several catalogues and discussed the possibility of further candidates.

  4. Companion cropping to manage parasitic plants.

    PubMed

    Pickett, John A; Hamilton, Mary L; Hooper, Antony M; Khan, Zeyaur R; Midega, Charles A O

    2010-01-01

    Parasitic plants, through a range of infestation strategies, can attack crop plants and thereby require management. Because such problems often occur in resource-poor farming systems, companion cropping to manage parasitic plants is an appropriate approach. Many examples of companion cropping for this purpose have been reported, but the use of cattle forage legumes in the genus Desmodium as intercrops has been shown to be particularly successful in controlling the parasitic witchweeds (Striga spp.) that afflict approximately one quarter of sub-Saharan African cereal production. Through the use of this example, the development of effective companion crops is described, together with developments toward widespread adoption and understanding the underlying mechanisms, both for sustainability and ensuring food security, and also for exploitation beyond the cropping systems described here. PMID:20429664

  5. Massive Stars and their Siblings: the Extreme End of the Companion Mass Function

    NASA Astrophysics Data System (ADS)

    de Mink, Selma

    2014-10-01

    The gold-rush for detecting exoplanets has lead to an exponential improvement of optimization algorithms for high-contrast imaging optimized for HST. We propose to exploit these to probe the virtually unexplored population of low mass stars in the very close vicinity of young massive stars in order to I. progress our understanding of how low-mass stars form and survive under the influence of the ionizing radiation of their massive host and II. provide urgently needed constraints on competing theories of massive star formation by measuring their multiplicity. The high spatial and temporal stability of HST's point spread function is essential for the detection of very faint companions down to sub-arcsecond separations even in crowded regions at contrast up to delta-mag ~ 10, i.e. flux ratios up to 10,000. Furthermore the characterization of the low mass companions calls for wavelength bands largely affected by absorption by H2O in the earth's atmosphere. To achieve this goal we propose to use WFC3/IR to observe two adjacent fields in the center of the very young, nearby star cluster Trumpler 14, which harbors a rich population of massive stars.

  6. Massive Stars and their Siblings: the Extreme End of the Companion Mass Function

    NASA Astrophysics Data System (ADS)

    de Mink, Selma

    2013-10-01

    The gold-rush for detecting exoplanets has lead to an exponential improvement of optimization algorithms for high-contrast imaging optimized for HST. We propose to exploit these to probe the virtually unexplored population of low mass stars in the very close vicinity of young massive stars in order to I. progress our understanding of how low-mass stars form and survive under the influence of the ionizing radiation of their massive host and II. provide urgently needed constraints on competing theories of massive star formation by measuring their multiplicity. The high spatial and temporal stability of HST's point spread function is essential for the detection of very faint companions down to sub-arcsecond separations even in crowded regions at contrast up to delta-mag ~ 10, i.e. flux ratios up to 10,000. Furthermore the characterization of the low mass companions calls for wavelength bands largely affected by absorption by H2O in the earth's atmosphere. To achieve this goal we propose to use WFC3/IR to observe two adjacent fields in the center of the very young, nearby star cluster Trumpler 14, which harbors a rich population of massive stars.

  7. Contributions of the Pulkovo and Kharkiv Scientific Schools to the search for exoplanets and low-mass dark satellites of stars

    NASA Astrophysics Data System (ADS)

    Zakhozhay, V. A.; Gnedin, Yu. N.; Shakht, N. A.

    2010-12-01

    This article is devoted to the Pulkovo astronomer, Prof. Aleksandr Nikolaevich Deich (Deutsch) (1899-1986), on the 110-th anniversary of his birth. Deich is known as the founder of the Pulkovo program for observing stars with invisible companions, as well as for his research on the star 61 Cyg, which was suspected, in his time, of having invisible companions with the masses of planets. Astrometric observations on the long focus astrograph and searches for exoplanets of nearby stars are reviewed. Modern methods of searching for exoplanets are summarized briefly. Instrument designs proposed by astronomers at Kharkiv (Scientific Research Institute of Astronomy at Kharkiv National University, NIIA KhNU) and Kazan (Institute of Astronomy, Kazan State University, AO KGU) for use in the search for low-mass dark components of stars are discussed. Examples are given of confirmations of invisible companions of stars which were first discovered by observation. A number of theoretical results on this topic from Kharkiv National University (Scientific Research Institute of Astronomy at Kharkiv and the Dept. of Astronomy) are noted.

  8. Doppler follow-up of OGLE planetary transit candidates in Carina

    NASA Astrophysics Data System (ADS)

    Pont, F.; Bouchy, F.; Melo, C.; Santos, N. C.; Mayor, M.; Queloz, D.; Udry, S.

    2005-08-01

    We present the results of our high-resolution spectroscopic follow-up of 42 planetary transit candidates in Carina from the OGLE survey. This follow-up has already allowed the discovery of three new transiting exoplanets, OGLE-TR-111, 113 and 132. Here we analyse the data for the remaining 39 candidates. The radial velocity data show that most of them are eclipsing binaries, in very varied configurations. Precise radial velocity orbits were derived for 15 binaries, revealing 9 transits of small stars (generally M-dwarfs) in front of F-G dwarfs, 1 grazing equal-mass eclipsing binary, 4 triple and 1 quadruple systems. A further 14 systems appear binary, but the exact orbit is uncertain or was not determined. 2 objects do not show any radial velocity variations in phase with the transit signal, and 6 do not possess spectral lines strong enough for a reliable cross-correlation function to be measured. Among these last two categories, up to 6 objects are suspected false positives of the photometric transit detection. 2 objects are unsolved cases that deserve further observations. Our study illustrates the wide variety of cases that can mimic photometric planetary transits, and the importance of spectroscopic follow-up. Multi-fiber capacities and an optimized follow-up strategy, which we present here, can help deal with the high number of candidates that are likely to be found in the near future. An important by-product of this study is the determination of exact masses and radii for five very low-mass stars, including two at the very edge of the stellar domain, OGLE-TR-106 (M=0.116± 0.021 {M}_⊙) and OGLE-TR-122 (M=0.092 ± 0.009 {M}_⊙). The radius of these objects is consistent with theoretical expectations. Two further objects, OGLE-TR-123 and OGLE-TR-129, may harbour transiting companions near the brown-dwarf/stellar limit (M≃ 0.07 {M}_⊙), whose confirmation requires further high-resolution spectroscopic monitoring. No transiting massive planets (M=2{-}10 {M

  9. Habitability constraints on water-rich exoplanets

    NASA Astrophysics Data System (ADS)

    Noack, Lena; Höning, Dennis; Rivoldini, Attilio; Heistracher, Clemens; Zimov, Nastasia; Journaux, Baptiste; Lammer, Helmut; Van Hoolst, Tim; Hendrik Bredehöft, Jan

    2016-04-01

    This research addresses the characterization, modelling, thermal evolution and possible habitability of water-rich exoplanets. Water is necessary for the origin and survival of life as we know it. In the search for habitable worlds, water-rich planets therefore seem obvious candidates. The water layer on such planets could be hundreds of kilometers deep. Depending on the temperature profile and the pressure gradient, it is likely that at great depths a significant part of the water layer is solid high pressure ice. Whether the solid ice layer extends to the bottom of the water layer, or if a shallow lower ocean forms above the silicate mantle, depends amongst others on the thermal state of the planet. We therefore model the thermal evolution of water-rich planets with a 1D parameterized model. Depth-dependent profiles for thermodynamic properties as well as pressure and gravity are obtained by solving the Poisson equation for the gravity and the hydrostatic pressure equation for pre-defined mass and composition (in terms of iron, silicates and water) [1]. For density, equations of state are applied. For the simulation of the thermal evolution of water-rich planets, several parameters (as initial temperatures or layer thicknesses) are unknown. We therefore employ a quantitatve study with more than 20'000 simulations, where we investigated which parameters have the largest influence on the appearance of a lower ocean, i.e. the possible melting of high-pressure ice by heat flowing out of the silicate mantle [2]. We find that the surface temperature has the largest influence on the thickness of water layers, for which a lower ocean can still form between the high-pressure ice layer and the silicate mantle. For higher surface temperatures, not only entirely liquid oceans are possible for deeper water shells, also a liquid ocean can form under high-pressure ice layers of hundreds of kilometer thickness (for a 1 Earth-mass planet). Deeper down, the lower ocean can still

  10. Dispatch Scheduling to Maximize Exoplanet Detection

    NASA Astrophysics Data System (ADS)

    Johnson, Samson; McCrady, Nate; MINERVA

    2016-01-01

    MINERVA is a dedicated exoplanet detection telescope array using radial velocity measurements of nearby stars to detect planets. MINERVA will be a completely robotic facility, with a goal of maximizing the number of exoplanets detected. MINERVA requires a unique application of queue scheduling due to its automated nature and the requirement of high cadence observations. A dispatch scheduling algorithm is employed to create a dynamic and flexible selector of targets to observe, in which stars are chosen by assigning values through a weighting function. I designed and have begun testing a simulation which implements the functions of a dispatch scheduler and records observations based on target selections through the same principles that will be used at the commissioned site. These results will be used in a larger simulation that incorporates weather, planet occurrence statistics, and stellar noise to test the planet detection capabilities of MINERVA. This will be used to heuristically determine an optimal observing strategy for the MINERVA project.

  11. Exoplanet Observations in SOFIA's Cycle 1

    NASA Astrophysics Data System (ADS)

    Angerhausen, Daniel

    2013-06-01

    The NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA), a 2.5-meter infrared telescope on board a Boeing 747-SP, will conduct 0.3 - 1,600 micron photometric, spectroscopic, and imaging observations from altitudes as high as 45,000 ft. The airborne-based platform has unique advantages in comparison to ground- and space-based observatories in the field of characterization of the physical properties of exoplanets: parallel optical and near-infrared photometric and spectrophotometric follow-up observations during planetary transits and eclipses will be feasible with SOFIA's instrumentation, in particular the HIPO-FLITECAM optical/NIR instruments and possible future dedicated instrumentation. Here we present spectrophotometric exoplanet observations that were or will be conducted in SOFIA's cycle 1.

  12. Observing Exoplanets in the Mid-Ultraviolet

    NASA Technical Reports Server (NTRS)

    Heap. Sara

    2008-01-01

    There are good reasons for pushing the spectral range of observation to shorter wavelengths than currently envisaged for terrestrial planet-finding missions utilizing with a 4-m, diffraction-limited, optical telescope: (1) The angular resolution is higher, so the image of an exoplanet is better separated from that of the much brighter star. (2) The exozodiacal background per resolution element is smaller, so exposure times are reduced for the same incident flux. (3) Most importantly, the sensitivity to the ozone biomarker is increased by several hundred-fold by access to the ozone absorption band at 250-300 nm. These benefits must be weighed against challenges arising from the faintness of exoplanets in the mid-UV. We will evaluate both the technical and cost challenges including image quality of large telescopes, advanced mirror coatings and innovative designs for enhanced optical throughput, and CCD detectors optimized for 250-400 nm.

  13. Exoplanets in the M2K Survey

    NASA Astrophysics Data System (ADS)

    Boyajian, Tabetha; Fischer, Debra; Gaidos, Eric; Giguere, Matt

    2013-07-01

    Late type stars are ideal targets for the detection of low-mass planets residing in habitable zones. In such systems, not only is the stellar noise a minimum, but the lower stellar mass affords larger reflex velocities and the lower stellar luminosity moves the habitable zone inward. The M2K program is a high precision Doppler survey monitoring a couple hundred late-type stars over the past few years in search for such important exoplanetary systems. We present updated orbits of known exoplanet systems and newly detected exoplanet systems that have resulted from this program. We also advertise the Planethunters.org "Guest Scientist" program as well as our survey to measure stellar diameters and temperatures with long baseline optical interferometry.

  14. Infrared spectroscopy of exoplanets: observational constraints.

    PubMed

    Encrenaz, Thérèse

    2014-04-28

    The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations. PMID:24664918

  15. Statistical Signatures of Panspermia in Exoplanet Surveys

    NASA Astrophysics Data System (ADS)

    Lin, Henry W.; Loeb, Abraham

    2015-09-01

    A fundamental astrobiological question is whether life can be transported between extrasolar systems. We propose a new strategy to answer this question based on the principle that life which arose via spreading will exhibit more clustering than life which arose spontaneously. We develop simple statistical models of panspermia to illustrate observable consequences of these excess correlations. Future searches for biosignatures in the atmospheres of exoplanets could test these predictions: a smoking gun signature of panspermia would be the detection of large regions in the Milky Way where life saturates its environment interspersed with voids where life is very uncommon. In a favorable scenario, detection of as few as ∼25 biologically active exoplanets could yield a 5σ detection of panspermia. Detectability of position-space correlations is possible unless the timescale for life to become observable once seeded is longer than the timescale for stars to redistribute in the Milky Way.

  16. Infrared spectroscopy of exoplanets: observational constraints

    PubMed Central

    Encrenaz, Thérèse

    2014-01-01

    The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations. PMID:24664918

  17. Instrumentation for the detection and characterization of exoplanets.

    PubMed

    Pepe, Francesco; Ehrenreich, David; Meyer, Michael R

    2014-09-18

    In no other field of astrophysics has the impact of new instrumentation been as substantial as in the domain of exoplanets. Before 1995 our knowledge of exoplanets was mainly based on philosophical and theoretical considerations. The years that followed have been marked, instead, by surprising discoveries made possible by high-precision instruments. Over the past decade, the availability of new techniques has moved the focus of research from the detection to the characterization of exoplanets. Next-generation facilities will produce even more complementary data that will lead to a comprehensive view of exoplanet characteristics and, by comparison with theoretical models, to a better understanding of planet formation. PMID:25230658

  18. Instrumentation for the detection and characterization of exoplanets

    NASA Astrophysics Data System (ADS)

    Pepe, Francesco; Ehrenreich, David; Meyer, Michael R.

    2014-09-01

    In no other field of astrophysics has the impact of new instrumentation been as substantial as in the domain of exoplanets. Before 1995 our knowledge of exoplanets was mainly based on philosophical and theoretical considerations. The years that followed have been marked, instead, by surprising discoveries made possible by high-precision instruments. Over the past decade, the availability of new techniques has moved the focus of research from the detection to the characterization of exoplanets. Next-generation facilities will produce even more complementary data that will lead to a comprehensive view of exoplanet characteristics and, by comparison with theoretical models, to a better understanding of planet formation.

  19. Evidence for a solar companion star

    SciTech Connect

    Muller, R.A.

    1984-08-01

    Periodicity seen in both the mass extinctions and large impact cratering on earth can be explained if one postulates that the sun has a companion star, orbiting in a moderately eccentric orbit with a major axis of 2.8 light-years. No other explanations that have been suggested are compatible with known facts of physics and astronomy. If the companion is a red dwarf star, the most common kind in the galaxy, then no previous astronomical observations would have found it. A search for red objects with large parallax is now underway at Berkeley, and has a good chance of identifying the star in the near future.

  20. ARIEL - The Atmospheric Remote-sensing Infrared Exoplanet Large-survey

    NASA Astrophysics Data System (ADS)

    Eccleston, P.; Tinetti, G.

    2015-10-01

    More than 1,000 extrasolar systems have been discovered, hosting nearly 2,000 exoplanets. Ongoing and planned ESA and NASA missions from space such as GAIA, Cheops, PLATO, K2 and TESS, plus ground based surveys, will increase the number of known systems to tens of thousands. Of all these exoplanets we know very little; i.e. their orbital data and, for some of these, their physical parameters such as their size and mass. In the past decade, pioneering results have been obtained using transit spectroscopy with Hubble, Spitzer and ground-based facilities, enabling the detection of a few of the most abundant ionic, atomic and molecular species and to constrain the planet's thermal structure. Future general purpose facilities with large collecting areas will allow the acquisition of better exoplanet spectra, compared to the currently available, especially from fainter targets. A few tens of planets will be observed with JWST and E-ELT in great detail. A breakthrough in our understanding of planet formation and evolution mechanisms will only happen through the observation of the planetary bulk and atmospheric composition of a statistically large sample of planets. This requires conducting spectroscopic observations covering simultaneously a broad spectral region from the visible to the mid-IR. It also requires a dedicated space mission with the necessary photometric stability to perform these challenging measurements and sufficient agility to observe multiple times ~500 exoplanets over 3.5 years. The ESA Cosmic Vision M4 mission candidate ARIEL is designed to accomplish this goal and will provide a complete, statistically significant sample of gas-giants, Neptunes and super-Earths with temperatures hotter than 600K, as these types of planets will allow direct observation of their bulk properties, enabling us to constrain models of planet formation and evolution. The ARIEL consortium currently includes academic institutes and industry from eleven countries in Europe; the

  1. Calibration of surface temperature on rocky exoplanets

    NASA Astrophysics Data System (ADS)

    Kashyap Jagadeesh, Madhu

    2016-07-01

    Study of exoplanets and the search for life elsewhere has been a very fascinating area in recent years. Presently, lots of efforts have been channelled in this direction in the form of space exploration and the ultimate search for the habitable planet. One of the parametric methods to analyse the data available from the missions such as Kepler, CoRoT, etc, is the Earth Similarity Index (ESI), defined as a number between zero (no similarity) and one (identical to Earth), introduced to assess the Earth likeness of exoplanets. A multi-parameter ESI scale depends on the radius, density, escape velocity and surface temperature of exoplanets. Our objective is to establish how exactly the individual parameters, entering the interior ESI and surface ESI, are contributing to the global ESI, using the graphical analysis. Presently, the surface temperature estimates are following a correction factor of 30 K, based on the Earth's green-house effect. The main objective of this work in calculations of the global ESI using the HabCat data is to introduce a new method to better estimate the surface temperature of exoplanets, from theoretical formula with fixed albedo factor and emissivity (Earth values). From the graphical analysis of the known data for the Solar System objects, we established the calibration relation between surface and equilibrium temperatures for the Solar System objects. Using extrapolation we found that the power function is the closest description of the trend to attain surface temperature. From this we conclude that the correction term becomes very effective way to calculate the accurate value of the surface temperature, for further analysis with our graphical methodology.

  2. The Transiting Exoplanet Survey Satellite Mission

    NASA Astrophysics Data System (ADS)

    Ricker, G. R.

    2014-03-01

    The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey of the solar neighborhood, TESS will monitor more than 500,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. TESS stars will typically be 30-100 times brighter than those surveyed by the Kepler satellite; thus, TESS planets will be far easier to characterize with follow-up observations. For the first time it will be possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. Full frame images with a cadence of 30 minutes or less will provide precise photometric information for several million stars during observation sessions of several weeks. The brighter TESS stars will potentially yield valuable asteroseismic information as a result of monitoring at a rapid cadence of 1 minute or less. An extended survey by TESS of the Ecliptic caps will provide prime exoplanet targets for characterization with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future. TESS will serve as the "People's Telescope," with data releases every 4 months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest main-sequence stars hosting transiting exoplanets, which will endure as the most favorable targets for detailed future investigations. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission.

  3. The Transiting Exoplanet Survey Satellite Mission

    NASA Astrophysics Data System (ADS)

    Ricker, G. R.

    2014-06-01

    (Abstract only) The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey of the solar neighborhood, TESS will monitor more than 500,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. TESS stars will typically be 30 to 100 times brighter than those surveyed by the Kepler satellite; thus,TESS planets will be far easier to characterize with follow-up observations. For the first time it will be possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. All of the half-million plus TESS targets will be observed at a rapid cadence (1 minute or less). Hence, the brighter TESS stars will potentially yield valuable asteroseismic information. TESS will provide prime exoplanet targets for characterization with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future. TESS will serve as the "People's Telescope," with data releases every 4 months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest main-sequence stars hosting transiting exoplanets, which will endure as the most favorable targets for detailed future investigations. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission.

  4. The Transiting Exoplanet Survey Satellite: Mission Status

    NASA Astrophysics Data System (ADS)

    Ricker, George R.; TESS Team

    2015-01-01

    The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey of the solar neighborhood, TESS will monitor more than 200,000 bright stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances.TESS stars will typically be 30-100 times brighter than those surveyed by the Kepler satellite; thus, TESS planets will be far easier to characterize with follow-up observations. For the first time it will be possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. Full frame images with a cadence of 30 minutes or less will provide precise photometric information for more than 20 million stars during observation sessions of several weeks. The brighter TESS stars will potentially yield valuable asteroseismic information as a result of monitoring at a rapid cadence of 2 minute or less. An extended survey by TESS of regions surrounding the North and South Ecliptic Poles will provide prime exoplanet targets for characterization with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future.TESS will issue data releases every 4 months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest main-sequence stars hosting transiting exoplanets, which will endure as the most favorable targets for detailed future investigations.TESS has a planned launch date in 2017 as a NASA Astrophysics Explorer mission.

  5. The Transiting Exoplanet Survey Satellite Mission

    NASA Astrophysics Data System (ADS)

    Ricker, George R.; Vanderspek, Roland Kraft; Latham, David W.; Winn, Joshua N.

    2014-06-01

    The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey of the solar neighborhood, TESS will monitor more than 200,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. TESS stars will typically be 30-100 times brighter than those surveyed by the Kepler satellite; thus, TESS planets will be far easier to characterize with follow-up observations. For the first time it will be possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. Full frame images with a cadence of 30 minutes or less will provide precise photometric information for several million stars during observation sessions of several weeks. The brighter TESS stars will potentially yield valuable asteroseismic information as a result of monitoring at a rapid cadence of 1 minute or less. An extended survey by TESS of regions surrounding the North and South Ecliptic Poles will provide prime exoplanet targets for characterization with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future. TESS will serve as the “People’s Telescope,” with data releases every 4 months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest main-sequence stars hosting transiting exoplanets, which will endure as the most favorable targets for detailed future investigations.TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission.

  6. THEORETICAL SPECTRA OF TERRESTRIAL EXOPLANET SURFACES

    SciTech Connect

    Hu Renyu; Seager, Sara; Ehlmann, Bethany L.

    2012-06-10

    We investigate spectra of airless rocky exoplanets with a theoretical framework that self-consistently treats reflection and thermal emission. We find that a silicate surface on an exoplanet is spectroscopically detectable via prominent Si-O features in the thermal emission bands of 7-13 {mu}m and 15-25 {mu}m. The variation of brightness temperature due to the silicate features can be up to 20 K for an airless Earth analog, and the silicate features are wide enough to be distinguished from atmospheric features with relatively high resolution spectra. The surface characterization thus provides a method to unambiguously identify a rocky exoplanet. Furthermore, identification of specific rocky surface types is possible with the planet's reflectance spectrum in near-infrared broad bands. A key parameter to observe is the difference between K-band and J-band geometric albedos (A{sub g}(K) - A{sub g}(J)): A{sub g}(K) - A{sub g}(J) > 0.2 indicates that more than half of the planet's surface has abundant mafic minerals, such as olivine and pyroxene, in other words primary crust from a magma ocean or high-temperature lavas; A{sub g}(K) - A{sub g}(J) < -0.09 indicates that more than half of the planet's surface is covered or partially covered by water ice or hydrated silicates, implying extant or past water on its surface. Also, surface water ice can be specifically distinguished by an H-band geometric albedo lower than the J-band geometric albedo. The surface features can be distinguished from possible atmospheric features with molecule identification of atmospheric species by transmission spectroscopy. We therefore propose that mid-infrared spectroscopy of exoplanets may detect rocky surfaces, and near-infrared spectrophotometry may identify ultramafic surfaces, hydrated surfaces, and water ice.

  7. The ASIAGO exo-planet transits search

    NASA Astrophysics Data System (ADS)

    Claudi, R. U.; Desidera, S.; Gratton, R.; Bruno, P.

    2004-01-01

    The ASIAGO project is a search for giant exo-planets with the photometric transit method, exploiting the 67/92 Schmidt Telescope at Mount Ekar near the town of Asiago, in Italy. The telescope is equipped with the SCAM-1 camera of DLR (Berlin) (Barbieri et al. 2003) and in the summer of 2002 underwent a refurbishment and automation phase. We describe the status of the first phase of the project (telescope refurbishment) and the telescope capability for transit searches.

  8. Radial Velocity Eclipse Mapping of Exoplanets

    NASA Astrophysics Data System (ADS)

    Nikolov, Nikolay; Sainsbury-Martinez, Felix

    2015-07-01

    Planetary rotation rates and obliquities provide information regarding the history of planet formation, but have not yet been measured for evolved extrasolar planets. Here we investigate the theoretical and observational perspective of the Rossiter-McLaughlin effect during secondary eclipse (RMse) ingress and egress for transiting exoplanets. Near secondary eclipse, when the planet passes behind the parent star, the star sequentially obscures light from the approaching and receding parts of the rotating planetary surface. The temporal block of light emerging from the approaching (blueshifted) or receding (redshifted) parts of the planet causes a temporal distortion in the planet’s spectral line profiles resulting in an anomaly in the planet’s radial velocity curve. We demonstrate that the shape and the ratio of the ingress-to-egress radial velocity amplitudes depends on the planetary rotational rate, axial tilt, and impact factor (i.e., sky-projected planet spin-orbital alignment). In addition, line asymmetries originating from different layers in the atmosphere of the planet could provide information regarding zonal atmospheric winds and constraints on the hot spot shape for giant irradiated exoplanets. The effect is expected to be most-pronounced at near-infrared wavelengths, where the planet-to-star contrasts are large. We create synthetic near-infrared, high-dispersion spectroscopic data and demonstrate how the sky-projected spin axis orientation and equatorial velocity of the planet can be estimated. We conclude that the RMse effect could be a powerful method to measure exoplanet spins.

  9. Archaeology and direct imaging of exoplanets

    NASA Astrophysics Data System (ADS)

    Campbell, John B.

    The search for extraterrestrial technology effectively began 45 years ago with Frank Drake's Project Ozma and a radioastronomy start to the search for extraterrestrial intelligence (SETI). Eventually searches began for possible interstellar probes in stable orbits in the Solar System, as well as for infrared excesses from possible Dyson spheres round Sun-like stars. Whilst the Cold War was still underway, some scientists looked for evidence of nuclear waste dumps and nuclear wars elsewhere in the Milky Way. None of this work was carried out by archaeologists, even though by their very nature archaeologists are experts in the detection of ancient technologies. The technologies being searched for would have been partly ancient in age though advanced in techniques and science. The development of ESA's Darwin and NASA's TPF for detection and imaging of Earth-like exoplanets in our galactic neighbourhood represents an opportunity for the testing of techniques for detecting signatures of technological activities. Ideally, both Darwin and TPF might be able to provide spectroscopic data on the chemistry and biochemistry of the atmospheres of Earth-like exoplanets, and thus to detect some of the signs of life. If this can be accomplished successfully, then in theory evidence for pollution and nuclear accidents and wars should be detectable. Some infrared signatures of ETT on or round exoplanets might be detectable. Direct visual imaging of ETT structures will probably not be feasible till we have extremely powerful interstellar telescopes or actually send orbital craft.

  10. CHEOPS: CHaracterising ExOPlanet Satellite

    NASA Astrophysics Data System (ADS)

    Isaak, K. G.

    2015-10-01

    CHEOPS (CHaracterising ExOPlanet Satellite) is the first exoplanet mission dedicated to the search for transits of exoplanets by means of ultrahigh precision photometry of bright stars already known to host planets. CHEOPS will provide the unique capability of determining radii to ~10% accuracy for a subset of those planets in the super-Earth to Neptune mass range. The high photometric precision of CHEOPS will be achieved using a photometer covering the 0.4 - 1.1um waveband and designed around a single frame-transfer CCD which is mounted in the focal plane of a 30 cm equivalent aperture diameter, f/5 on-axis Ritchey-Chretien telescope. Key to reaching the required performance is rejection of straylight from the Earth that is achieved using a specially designed optical baffle. CHEOPS is the first S-class mission in ESA's Cosmic Vision 2015-2025, and is currently planned to be launch-ready by the end of 2017. The mission is a partnership between Switzerland and ESA's science programme, with important contributions from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden and the United Kingdom. In this presentation I will give a scientific and technical overview of the mission, as well as an update on the status of the project.

  11. THE FREQUENCY OF LOW-MASS EXOPLANETS

    SciTech Connect

    O'Toole, S. J.; Jones, H. R. A.; Tinney, C. G.; Bailey, J.; Wittenmyer, R. A.; Butler, R. P.; Marcy, G. W.; Carter, B.

    2009-08-20

    We report first results from the Anglo-Australian Telescope Rocky Planet Search-an intensive, high-precision Doppler planet search targeting low-mass exoplanets in contiguous 48 night observing blocks. On this run, we targeted 24 bright, nearby and intrinsically stable Sun-like stars selected from the Anglo-Australian Planet Search's main sample. These observations have already detected one low-mass planet reported elsewhere (HD 16417b), and here we reconfirm the detection of HD 4308b. Further, we have Monte Carlo simulated data from this run on a star-by-star basis to produce robust detection constraints. These simulations demonstrate clear differences in the exoplanet detectability functions from star to star due to differences in sampling, data quality and intrinsic stellar stability. They reinforce the importance of star-by-star simulation when interpreting the data from Doppler planet searches. These simulations indicate that for some of our target stars we are sensitive to close-orbiting planets as small as a few Earth masses. The two low-mass planets present in our 24-star sample indicate that the exoplanet minimum mass function at low masses is likely to be a flat {alpha} {approx} -1 (for dN/dM {proportional_to} M {sup {alpha}}) and that between 15% {+-} 10% (at {alpha} = -0.3) and 48% {+-} 34% (at {alpha} = -1.3) of stars host planets with orbital periods of less than 16 days and minimum masses greater than 3 M {sub +}.

  12. Observational constraints on the composition of exoplanets

    NASA Astrophysics Data System (ADS)

    Griffith, C. A.; Tinetti, G.; Swain, M. R.; Deroo, P.; Cunha, K.; Schuler, S.; Freedman, R.

    2011-10-01

    Two forms of exoplanetary spectra can be measured. The primary eclipse provides a transmission spectra of the exoplanet's limb as the planet passes in front of the star. The secondary eclipse measures the emission of mainly the planet's dayside atmosphere from the planet plus star's emission minus the emission of star alone, when it eclipses the planet. In the past 3 years, infrared transmission and emission spectroscopy have revealed the presence of the primary carbon and oxygen species (CH4, CO2, CO, and H2O). Yet, efforts to constrain the abundances of these molecules are hindered by degenerate effects of the temperature and composition in the emission spectra, and the composition and assumed radius in the transmission spectrum. These degeneracies lead to derived mixing ratios that span several orders of magnitude. This talk will discuss the correlations in the degenerate solutions that result from the radiative transfer analyses of both emission and transmission spectroscopy. We present an analysis of primary and secondary transit observations of HD209458b's optical to infrared spectra, and correlate the degenerate effects of the atmospheric parameters using a principal components analysis to better constrain the atmospheric composition of the exoplanet. The derived oxygen and carbon composition of the HD209458b's atmosphere are considered in conjunction with the primary star's composition in order to start to address questions regarding the evolution of the exoplanet.

  13. TWO EXOPLANETS DISCOVERED AT KECK OBSERVATORY

    SciTech Connect

    Valenti, Jeff A.; Fischer, Debra; Giguere, Matt; Isaacson, Howard; Marcy, Geoffrey W.; Howard, Andrew W.; Johnson, John A.; Henry, Gregory W.; Wright, Jason T.

    2009-09-10

    We present two exoplanets detected at Keck Observatory. HD 179079 is a G5 subgiant that hosts a hot Neptune planet with M sin i = 27.5 M{sub +} in a 14.48 days, low-eccentricity orbit. The stellar reflex velocity induced by this planet has a semiamplitude of K = 6.6 m s{sup -1}. HD 73534 is a G5 subgiant with a Jupiter-like planet of M sin i = 1.1 M{sub Jup} and K = 16 m s{sup -1} in a nearly circular 4.85 yr orbit. Both stars are chromospherically inactive and metal-rich. We discuss a known, classical bias in measuring eccentricities for orbits with velocity semiamplitudes, K, comparable to the radial velocity uncertainties. For exoplanets with periods longer than 10 days, the observed exoplanet eccentricity distribution is nearly flat for large amplitude systems (K > 80 m s{sup -1}), but rises linearly toward low eccentricity for lower amplitude systems (K > 20 m s{sup -1})

  14. The Gemini NICI Planet-Finding Campaign: The Companion Detection Pipeline

    NASA Astrophysics Data System (ADS)

    Wahhaj, Zahed; Liu, Michael C.; Biller, Beth A.; Nielsen, Eric L.; Close, Laird M.; Hayward, Thomas L.; Hartung, Markus; Chun, Mark; Ftaclas, Christ; Toomey, Douglas W.

    2013-12-01

    We present high-contrast image processing techniques used by the Gemini NICI Planet-Finding Campaign to detect faint companions to bright stars. The Near-Infrared Coronographic Imager (NICI) is an adaptive optics instrument installed on the 8 m Gemini South telescope, capable of angular and spectral difference imaging and specifically designed to image exoplanets. The Campaign data pipeline achieves median contrasts of 12.6 mag at 0.''5 and 14.4 mag at 1'' separation, for a sample of 45 stars (V = 4.3-13.9 mag) from the early phase of the campaign. We also present a novel approach to calculating contrast curves for companion detection based on 95% completeness in the recovery of artificial companions injected into the raw data, while accounting for the false-positive rate. We use this technique to select the image processing algorithms that are more successful at recovering faint simulated point sources. We compare our pipeline to the performance of the Locally Optimized Combination of Images (LOCI) algorithm for NICI data and do not find significant improvement with LOCI. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  15. RADIO INTERFEROMETRIC PLANET SEARCH. II. CONSTRAINTS ON SUB-JUPITER-MASS COMPANIONS TO GJ 896A

    SciTech Connect

    Bower, Geoffrey C.; Bolatto, Alberto; Ford, Eric B.; Fries, Adam; Kalas, Paul; Sanchez, Karol; Viscomi, Vincent; Sanderbeck, Phoebe

    2011-10-10

    We present results from the Radio Interferometric Planet search for companions to the nearby star GJ 896A. We present 11 observations over 4.9 yr. Fitting astrometric parameters to the data reveals a residual with peak-to-peak amplitude of {approx}3 mas in right ascension. This residual is well fit by an acceleration term of 0.458 {+-} 0.032 mas yr{sup -2}. The parallax is fit to an accuracy of 0.2 mas and the proper motion terms are fit to accuracies of 0.01 mas yr{sup -1}. After fitting astrometric and acceleration terms, residuals are 0.26 mas in each coordinate, demonstrating that stellar jitter does not limit the ability to carry out radio astrometric planet detection and characterization. The acceleration term originates in part from the companion GJ 896B, but the amplitude of the acceleration in declination is not accurately predicted by the orbital model. The acceleration sets a mass upper limit of 0.15 M{sub J} at a semimajor axis of 2 AU for a planetary companion to GJ 896A. For semimajor axes between 0.3 and 2 AU upper limits are determined by the maximum angular separation; the upper limits scale from the minimum value in proportion to the inverse of the radius. Upper limits at larger radii are set by the acceleration and scale as the radius squared. An improved solution for the stellar binary system could improve the exoplanet mass sensitivity by an order of magnitude.

  16. Coronagraphic search for wide substellar companions among members of the Ursa Major moving group

    NASA Astrophysics Data System (ADS)

    Ammler-von Eiff, M.; Bedalov, A.; Kranhold, C.; Mugrauer, M.; Schmidt, T. O. B.; Neuhäuser, R.; Errmann, R.

    2016-06-01

    Context. We present the results of a survey to detect low-mass companions of Ursa Major (UMa) group members, carried out in 2003-2006 with NACO at the ESO VLT. While many extra-solar planets and planetary candidates have been found in close orbits around stars by the radial velocity and the transit methods, direct detections at wider orbits are rare. The UMa group, a young nearby stellar association at an age of about 200-600 Myr, has not yet been addressed as a whole although its members represent a very interesting sample to search for and characterize substellar companions by direct imaging. Aims: Our goal was to find or to provide detection limits on wide substellar companions around nearby UMa group members using high-resolution imaging. Methods: We searched for faint companions around 20 UMa group members within 30 pc. The primaries were placed below a semi-transparent coronagraph, a rarely used mode of NACO, to increase the dynamic range of the images. In most cases, second epoch images of companion candidates were taken to check whether they share common proper motion with the primary. Results: Our coronagraphic images rule out substellar companions around the stars of the sample. A typical dynamical range of 13-15 mag in the Ks band was achieved at separations beyond 3'' from the star. Candidates as faint as Ks ≈ 20 were securely identified and measured. The survey is most sensitive between separations of 100 and 200 au but only on average because of the very different target distance. Field coverage reaches about 650 au for the most distant targets. Most of the 200 candidates detected in the covered fields are visible in two epochs and were rejected because they are distant background objects. Based on observations collected at the European Southern Observatory, Chile, in programmes 72.C-0485, 73.C-0225, 76.C-0777, 77.C-0268, 384.C-0245A.Table D.1 is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via

  17. Kepler Mission Discovers Trove of Extrasolar Planet Candidates

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2011-02-01

    NASA's Kepler discovery mission is collecting more than just pennies from heaven. Results from the first 4 months of science operations of the Kepler space telescope, announced on 2 February, include the discovery of 1235 candidate planets orbiting 997 stars in a small portion of the Milky Way galaxy examined by the telescope. Follow-up observations likely could confirm about 80% of the candidates as actual planets rather than false positives, according to researchers. This new trove of possible exoplanets could greatly expand the number of known planets outside of our solar system.

  18. Integrated Wavefront Correction and Bias Estimation for the High-Contrast Imaging of Exoplanets

    NASA Astrophysics Data System (ADS)

    Riggs, A. J. Eldorado

    Just over two decades ago the first planet outside our solar system was found, and thousands more have been discovered since. Nearly all these exoplanets were indirectly detected by sensing changes in their host stars' light. However, exoplanets must be directly imaged to determine their atmospheric compositions and the orbital parameters unavailable from only indirect detections. The main challenge of direct imaging is to observe stellar companions much fainter than the star and at small angular separations. Coronagraphy is one method of suppressing stellar diffraction to provide high star-to-planet contrast, but coronagraphs are extremely sensitive to quasi-static aberrations in the optical system. Active correction of the stellar wavefront is performed with deformable mirrors to recover high-contrast regions in the image. Estimation and control of the stellar electric field is performed iteratively in the camera's focal plane to avoid non-common path aberrations arising from a separate pupil sensor. Estimation can thus be quite time consuming because it requires several high-contrast intensity images per correction iteration. This thesis focuses on efficient focal plane wavefront correction (FPWC) for coronagraphy. Time is a precious commodity for a space telescope, so there is a strong incentive to reduce the total exposure time required for focal plane wavefront estimation. Much of our work emphasizes faster, more robust estimation via Kalman filtering, which optimally combines prior data with new measurements. The other main contribution of this thesis is a paradigm shift in the use of estimation images. Time for FPWC has generally been considered to be lost overhead, but we demonstrate that estimation images can be used for the detection and characterization of exoplanets and disks. These science targets are incoherent with their host stars, so we developed and implemented an iterated extended Kalman filter (IEKF) for simultaneous estimation of the stellar

  19. When Toddlers Provide Care: Infants Companion Space.

    ERIC Educational Resources Information Center

    Braten, Stein

    1996-01-01

    Hypothesizes regarding factors that enhance prosociality in children, implying that the quality of childrearing and early companionship have profound impact on toddlers' social behavior. Discusses observation space versus companion space, prosocial behavior across cultures, when toddlers abuse, and the implications of a circular reenactment of…

  20. Asteroidal companions in the visible: HST data

    NASA Astrophysics Data System (ADS)

    Storrs, Alex; Vilas, Faith; Landis, Rob; Gaffey, Michael J.; Makhoul, Khaldoun; Davis, MIke; Richmond, Mike

    2016-01-01

    We present a reanalysis of HST images of five asteroids with known companions (45 Eugenia, 87 Sylvia, 93 Minerva, 107 Camilla, 121 Hermione). It is remarkable that all of these companion bodies are much redder in the visible region than their primary bodies. Storrs et al. (2009, BAAS vol. 41, no. 4, p 189) attributed this to space weathering, however, all of these bodies belong to dark C- or X-type groups. Current modeling of space weathering effects are limited to bright asteroids (e.g. Cloutis et al., Icarus 252, pp. 39-82, 2015) and show little change on the scale reported here. We suggest that the interaction of dark, possibly organic-rich surfaces with the solar wind produces reddening on a much greater scale than is observed in bright, silica-rich surfaces, and that this effect is easily reset by collisions. Thus, while both the parent and companion object accumulate the effects, the parent is much more likely to be "reset" by small collisions than the companion, due to the differences in their cross-sections.

  1. Polaris: Amplitude, Period Change, and Companions

    NASA Astrophysics Data System (ADS)

    Evans, N. R.; Sasselov, D. D.; Short, C. I.

    2000-12-01

    Amplitude: Polaris has presented us with the rare phenomenon of a Cepheid with a pulsation amplitude which has decreased over the last 50 years. In this study we investigate whether the amplitude decrease during the last 15 years has had any effect on upper atmosphere heating. We obtained IUE high and low resolution spectra but found no change in either the Mg II chromospheric emission or the flux at 1800 Å/ between 1978 and 1993 when the pulsation amplitude dropped by 50 % (from 2.8 to 1.6 km sec-1). The energy distribution from 1700 Å/ through V, B, R(KC), and I(KC) is like that of a nonvariable supergiant of the same color rather than a full amplitude Cepheid in that it has nonradiative flux at 1800 Å/ which the full amplitude Cepheid δ Cep lacks. Period Change: Polaris also has a rapidly changing period (3.2 sec/year), in common with other overtone pulsators. We argue that this is a natural consequence of the different envelope locations which dominate in growth rates in fundamental and overtone pulsation. In fundamental mode pulsators, the deeper envelope is more important in determining growth rates than for overtone pulsators. For fundamental mode pulsators, evolutionary changes in the radius produce approximately linear changes in period. In overtone pulsators, pulsation reacts to small evolutionary changes in a more unstable way because the modes are more sensitive to high envelope features such as opacity bumps, and the growth rates for the many closely spaced overtone modes change easily. Companions: The upper limit to the X-ray flux from an Einstein observation implies that the companion in the astrometric orbit is probably earlier than F4 V. The combination of upper and lower limits on the companion from IUE and Einstein respectively catch the companion mass between 1.7 and 1.4 M⊙ . The X-ray limit is consistent with the more distant companion α UMi B being a physical companion in a hierarchal triple system. However the X-ray limits imply that

  2. The Impact of Stellar Multiplicity on Planetary Systems. I. The Ruinous Influence of Close Binary Companions

    NASA Astrophysics Data System (ADS)

    Kraus, Adam L.; Ireland, Michael J.; Huber, Daniel; Mann, Andrew W.; Dupuy, Trent J.

    2016-07-01

    The dynamical influence of binary companions is expected to profoundly influence planetary systems. However, the difficulty of identifying planets in binary systems has left the magnitude of this effect uncertain; despite numerous theoretical hurdles to their formation and survival, at least some binary systems clearly host planets. We present high-resolution imaging of 382 Kepler Objects of Interest (KOIs) obtained using adaptive-optics imaging and nonredundant aperture-mask interferometry on the Keck II telescope. Among the full sample of 506 candidate binary companions to KOIs, we super-resolve some binary systems to projected separations of <5 au, showing that planets might form in these dynamically active environments. However, the full distribution of projected separations for our planet-host sample more broadly reveals a deep paucity of binary companions at solar-system scales. For a field binary population, we should have found 58 binary companions with projected separation ρ < 50 au and mass ratio q > 0.4 we instead only found 23 companions (a 4.6σ deficit), many of which must be wider pairs that are only close in projection. When the binary population is parametrized with a semimajor axis cutoff a cut and a suppression factor inside that cutoff S bin, we find with correlated uncertainties that inside {a}{cut}={47}-23+59 au, the planet occurrence rate in binary systems is only {S}{bin}={0.34}-0.15+0.14 times that of wider binaries or single stars. Our results demonstrate that a fifth of all solar-type stars in the Milky Way are disallowed from hosting planetary systems due to the influence of a binary companion.

  3. A PAN-STARRS + UKIDSS SEARCH FOR YOUNG, WIDE PLANETARY-MASS COMPANIONS IN UPPER SCORPIUS

    SciTech Connect

    Aller, Kimberly M.; Kraus, Adam L.; Liu, Michael C.; Burgett, William S.; Chambers, Kenneth C.; Hodapp, Klaus W.; Kaiser, Nick; Magnier, Eugene A.; Price, Paul A.

    2013-08-10

    We have combined optical and NIR photometry from Pan-STARRS 1 and UKIDSS to search the young (5-10 Myr) star-forming region of Upper Scorpius for wide ( Almost-Equal-To 400-4000 AU) substellar companions down to {approx}5 M{sub Jup}. Our search is Almost-Equal-To 4 mag deeper than previous work based on the Two Micron All Sky Survey. We identified several candidates around known stellar members using a combination of color selection and spectral energy distribution fitting. Our follow-up spectroscopy has identified two new companions as well as confirmed two companions previously identified from photometry, with spectral types of M7.5-M9 and masses of {approx}15-60 M{sub Jup}, indicating a frequency for such wide substellar companions of {approx}0.6% {+-} 0.3%. Both USco 1610-1913B and USco 1612-1800B are more luminous than expected for their spectral type compared with known members of Upper Sco. HIP 77900B has an extreme mass ratio (M{sub 2}/M{sub 1} Almost-Equal-To 0.005) and an extreme separation of 3200 AU. USco 1602-2401B also has a very large separation of 1000 AU. We have also confirmed a low-mass stellar companion, USco 1610-2502B (730 AU, M5.5). Our substellar companions appear both non-coeval with their primary stars according to evolutionary models and, as a group, are systematically more luminous than the Upper Sco cluster sequence. One possible reason for these luminosity discrepancies could be different formation processes or accretion histories for these objects.

  4. VizieR Online Data Catalog: Search for UMa group companions (Ammler-von Eiff+, 2016)

    NASA Astrophysics Data System (ADS)

    Ammler-von Eiff, M.; Bedalov, A.; Kranhold, C.; Mugrauer, M.; Schmidt, T. O. B.; Neuhaeuser, R.; Errmann, R.

    2016-03-01

    The astrometric and photometric data of companion candidates of members of the Ursa Major (UMa) group are presented. They were identified by coronagraphic observations obtained with the S27 camera of NACO at the ESO VLT, Chile, in 2003-2006. Most of the candidates were observed a second time to assess whether they share the proper motion of the star. For this purpose, the change in position with respect to the star was compared to the stellar parallactic and proper motion known from Hipparcos. This way, all candidates with two epochs of observations were rejected being distant background objects. The layout of the included table deviates from the article version to facilitate automatic reading, i.e. the epoch date and the primary name are added to each row, and the candidate identifier is added to the corresponding data set for each epoch. (2 data files).

  5. Photometric follow-up observation of some SuperWASP transiting planet candidates

    NASA Astrophysics Data System (ADS)

    Gu, Sheng-hong; Collier Cameron, Andrew; Wang, Xiao-bin; Zhang, Li-yun; Fang, Xiang-song; Li, Xue-jing

    2008-05-01

    Three SuperWASP transiting planet candidates were observed through R or I filters using the 1-meter telescope and CCD camera of Yunnan Observatory from 2006 to 2007. The relative photometric data were corrected for the systematic errors by means of Tamuz et al. (2005) and Collier Cameron et al. (2006)'s algorithms. The resulting light curves demonstrate that one of three targets is a potential exoplanet candidate, which is worthy to perform further follow-up observation to clarify.

  6. INFERENCE OF INHOMOGENEOUS CLOUDS IN AN EXOPLANET ATMOSPHERE

    SciTech Connect

    Demory, Brice-Olivier; De Wit, Julien; Lewis, Nikole; Zsom, Andras; Seager, Sara; Fortney, Jonathan; Knutson, Heather; Desert, Jean-Michel; Heng, Kevin; Madhusudhan, Nikku; Gillon, Michael; Barclay, Thomas; Cowan, Nicolas B.

    2013-10-20

    We present new visible and infrared observations of the hot Jupiter Kepler-7b to determine its atmospheric properties. Our analysis allows us to (1) refine Kepler-7b's relatively large geometric albedo of Ag = 0.35 ± 0.02, (2) place upper limits on Kepler-7b thermal emission that remains undetected in both Spitzer bandpasses and (3) report a westward shift in the Kepler optical phase curve. We argue that Kepler-7b's visible flux cannot be due to thermal emission or Rayleigh scattering from H{sub 2} molecules. We therefore conclude that high altitude, optically reflective clouds located west from the substellar point are present in its atmosphere. We find that a silicate-based cloud composition is a possible candidate. Kepler-7b exhibits several properties that may make it particularly amenable to cloud formation in its upper atmosphere. These include a hot deep atmosphere that avoids a cloud cold trap, very low surface gravity to suppress cloud sedimentation, and a planetary equilibrium temperature in a range that allows for silicate clouds to potentially form in the visible atmosphere probed by Kepler. Our analysis does not only present evidence of optically thick clouds on Kepler-7b but also yields the first map of clouds in an exoplanet atmosphere.

  7. The Exoplanet Census: A General Method Applied to Kepler

    NASA Astrophysics Data System (ADS)

    Youdin, Andrew N.

    2011-11-01

    We develop a general method to fit the underlying planetary distribution function (PLDF) to exoplanet survey data. This maximum likelihood method accommodates more than one planet per star and any number of planet or target star properties. We apply the method to announced Kepler planet candidates that transit solar-type stars. The Kepler team's estimates of the detection efficiency are used and are shown to agree with theoretical predictions for an ideal transit survey. The PLDF is fit to a joint power law in planet radius, down to 0.5 R ⊕, and orbital period, up to 50 days. The estimated number of planets per star in this sample is ~0.7-1.4, where the range covers systematic uncertainties in the detection efficiency. To analyze trends in the PLDF we consider four planet samples, divided between shorter and longer periods at 7 days and between large and small radii at 3 R ⊕. The size distribution changes appreciably between these four samples, revealing a relative deficit of ~3 R ⊕ planets at the shortest periods. This deficit is suggestive of preferential evaporation and sublimation of Neptune- and Saturn-like planets. If the trend and explanation hold, it would be spectacular observational support of the core accretion and migration hypotheses, and would allow refinement of these theories.

  8. Hiding in the Shadows. II. Collisional Dust as Exoplanet Markers

    NASA Astrophysics Data System (ADS)

    Dobinson, Jack; Leinhardt, Zoë M.; Lines, Stefan; Carter, Philip J.; Dodson-Robinson, Sarah E.; Teanby, Nick A.

    2016-03-01

    Observations of the youngest planets (˜1-10 Myr for a transitional disk) will increase the accuracy of our planet formation models. Unfortunately, observations of such planets are challenging and time-consuming to undertake, even in ideal circumstances. Therefore, we propose the determination of a set of markers that can preselect promising exoplanet-hosting candidate disks. To this end, N-body simulations were conducted to investigate the effect of an embedded Jupiter-mass planet on the dynamics of the surrounding planetesimal disk and the resulting creation of second-generation collisional dust. We use a new collision model that allows fragmentation and erosion of planetesimals, and dust-sized fragments are simulated in a post-process step including non-gravitational forces due to stellar radiation and a gaseous protoplanetary disk. Synthetic images from our numerical simulations show a bright double ring at 850 μm for a low-eccentricity planet, whereas a high-eccentricity planet would produce a characteristic inner ring with asymmetries in the disk. In the presence of first-generation primordial dust these markers would be difficult to detect far from the orbit of the embedded planet, but would be detectable inside a gap of planetary origin in a transitional disk.

  9. THE EXOPLANET CENSUS: A GENERAL METHOD APPLIED TO KEPLER

    SciTech Connect

    Youdin, Andrew N.

    2011-11-20

    We develop a general method to fit the underlying planetary distribution function (PLDF) to exoplanet survey data. This maximum likelihood method accommodates more than one planet per star and any number of planet or target star properties. We apply the method to announced Kepler planet candidates that transit solar-type stars. The Kepler team's estimates of the detection efficiency are used and are shown to agree with theoretical predictions for an ideal transit survey. The PLDF is fit to a joint power law in planet radius, down to 0.5 R{sub Circled-Plus }, and orbital period, up to 50 days. The estimated number of planets per star in this sample is {approx}0.7-1.4, where the range covers systematic uncertainties in the detection efficiency. To analyze trends in the PLDF we consider four planet samples, divided between shorter and longer periods at 7 days and between large and small radii at 3 R{sub Circled-Plus }. The size distribution changes appreciably between these four samples, revealing a relative deficit of {approx}3 R{sub Circled-Plus} planets at the shortest periods. This deficit is suggestive of preferential evaporation and sublimation of Neptune- and Saturn-like planets. If the trend and explanation hold, it would be spectacular observational support of the core accretion and migration hypotheses, and would allow refinement of these theories.

  10. Characterization of Transiting Exoplanets by Way of Differential Photometry

    ERIC Educational Resources Information Center

    Cowley, Michael; Hughes, Stephen

    2014-01-01

    This paper describes a simple activity for plotting and characterizing the light curve from an exoplanet transit event by way of differential photometry analysis. Using free digital imaging software, participants analyse a series of telescope images with the goal of calculating various exoplanet parameters, including size, orbital radius and…

  11. Stellar-coronagraph observations of the phase curves of exoplanets

    NASA Astrophysics Data System (ADS)

    Frolov, P. N.; Anan'eva, V. I.; Ksanfomality, L. V.; Tavrov, A. V.

    2015-12-01

    Over the two decades that have passed since the discovery of the first extrasolar planet 51 Peg b, almost all of the newly discovered exoplanets have been found either by radial velocity observations or by the transit method. Here we discuss the possibilities for observation of exoplanets and their phase curves by stellar coronagraphy, which has proven effective in experiments.

  12. Earth-Like Exoplanets: The Science of NASA's Navigator Program

    NASA Technical Reports Server (NTRS)

    Lawson, Peter R. (Editor); Traub, Wesley A. (Editor)

    2006-01-01

    This book outlines the exoplanet science content of NASA's Navigator Program, and it identifies the exoplanet research priorities. The goal of Navigator Program missions is to detect and characterize Earth-like planets in the habitable zone of nearby stars and to search for signs of life on those planets.

  13. DISCOVERY OF A PROBABLE 4-5 JUPITER-MASS EXOPLANET TO HD 95086 BY DIRECT IMAGING

    SciTech Connect

    Rameau, J.; Chauvin, G.; Lagrange, A.-M.; Delorme, P.; Quanz, S. P.; Bonnefoy, M.; Klahr, H.; Mordasini, C.; Girard, J. H.; Dumas, C.; Desidera, S.; Bonavita, M.

    2013-08-01

    Direct imaging has only begun to inventory the population of gas giant planets on wide orbits around young stars in the solar neighborhood. Following this approach, we carried out a deep imaging survey in the near-infrared using VLT/NaCo to search for substellar companions. Here we report the discovery of a probable companion orbiting the young (10-17 Myr), dusty, early-type (A8) star HD 95086 at 56 AU in L' (3.8 {mu}m) images. This discovery is based on observations with more than a year time lapse. Our first epoch clearly revealed the source at {approx_equal} 10{sigma}, while our second epoch lacks good observing conditions, yielding a {approx_equal} 3{sigma} detection. Various tests were thus made to rule out possible artifacts. This recovery is consistent with the signal at the first epoch but requires cleaner confirmation. Nevertheless, our astrometric precision suggests that the companion is comoving with the star with a 3{sigma} confidence level. The planetary nature of the source is reinforced by a non-detection in the Ks-band (2.18 {mu}m) images according to its possible extremely red Ks-L' color. Conversely, background contamination is rejected with good confidence level. The luminosity yields a predicted mass of about 4-5 M{sub Jup} (at 10-17 Myr) using ''hot-start'' evolutionary models, making HD 95086 b the exoplanet with the lowest mass ever imaged around a star.

  14. A New Way to Confirm Planet Candidates

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    automated batch processing of a large number of candidates.In a recently published study the results of which were announced yesterday the teamapplied their code to the entire catalog of 7,470 Kepler objects of interest.New Planets and False PositivesThe teams code was able to successfully evaluate the total false-positive probability (FPP) for 7,056 of the objects of interest. Of these, 428 objects previously identified as candidates were found to have FPP of more than 90%, suggesting that they are most likely false positives.Periods and radii of candidate and confirmed planets in the Kepler Objects of Interest catalog. Blue circles have previously been identified as confirmed planets. Candidates (orange) are shaded by false positive probability; more transparent means more likely to be a false positive. [Morton et al. 2016]In contrast, 1,935 candidates were found to have FPP of less than 1%, and were therefore declared validated planets. Of these confirmations, 1,284 were previously unconfirmed, more than doubling Keplers previous catalog of 1,041 confirmed planets. Morton and collaborators believe that 9 of these newly confirmed planets may fall within the habitable zone of their host stars.While the announcement of 1,284 newly confirmed planets is huge, the analysis presented in this study is the real news. The code used is publicly available and can be applied to any transiting exoplanet candidate. This means that this analysis technique can be used to find batches of exoplanets in data from the extended Kepler mission (K2) or from the future TESS and PLATO transit missions.CitationTimothy D. Morton et al 2016 ApJ 822 86. doi:10.3847/0004-637X/822/2/86

  15. High-resolution transmission spectrum of the Earth's atmosphere-seeing Earth as an exoplanet using a lunar eclipse

    NASA Astrophysics Data System (ADS)

    Yan, F.; Fosbury, R. A. E.; Petr-Gotzens, M. G.; Zhao, G.; Wang, W.; Wang, L.; Liu, Y.; Pallé, E.

    2015-04-01

    With the rapid developments in the exoplanet field, more and more terrestrial exoplanets are being detected. Characterizing their atmospheres using transit observations will become a key datum in the quest for detecting an Earth-like exoplanet. The atmospheric transmission spectrum of our Earth will be an ideal template for comparison with future exo-Earth candidates. By observing a lunar eclipse, which offers a similar configuration to that of an exoplanet transit, we have obtained a high-resolution and high signal-to-noise ratio (SNR) transmission spectrum of the Earth's atmosphere. This observation was performed with the High Resolution Spectrograph at Xinglong Station, China during the total lunar eclipse in December 2011. We compare the observed transmission spectrum with our atmospheric model, and determine the characteristics of the various atmospheric species in detail. In the transmission spectrum, O2, O3, O2 . O2, NO2 and H2O are detected, and their column densities are measured and compared with the satellites data. The visible Chappuis band of ozone produces the most prominent absorption feature, which suggests that ozone is a promising molecule for the future exo-Earth characterization. Due to the high resolution and high SNR of our spectrum, several novel details of the Earth atmosphere's transmission spectrum are presented. The individual O2 lines are resolved and O2 isotopes are clearly detected. Our new observations do not confirm the absorption features of Ca II or Na I which have been reported in previous lunar eclipse observations. However, features in these and some other strong Fraunhofer line positions do occur in the observed spectrum. We propose that these are due to a Raman-scattered component in the forward-scattered sunlight appearing in the lunar umbral spectrum. Water vapour absorption is found to be rather weak in our spectrum because the atmosphere we probed is relatively dry, which prompts us to discuss the detectability of water

  16. Polaris: Amplitude, Period Change, and Companions

    NASA Astrophysics Data System (ADS)

    Evans, Nancy Remage; Sasselov, Dimitar D.; Short, C. Ian

    2002-03-01

    Polaris has presented us with the rare phenomenon of a Cepheid with a pulsation amplitude that has decreased over the last 50 yr. In this study we have used this property to see whether the amplitude decrease during the last 15 yr has had any effect on upper atmosphere heating. We obtained IUE high- and low-resolution spectra but found no change in either the Mg II chromospheric emission or the flux at 1800 Å between 1978 and 1993 when the pulsation amplitude dropped by 50% (from 2.8 to 1.6 km s-1). The energy distribution from 1700 Å through V, B, R(KC), and I(KC) is like that of a nonvariable supergiant of the same color rather than a full amplitude Cepheid in that it has more flux at 1800 Å than the full amplitude Cepheid δ Cep. Polaris also has a rapidly changing period (3.2 s yr-1), in common with other overtone pulsators. We argue that this is a natural consequence of the different envelope locations that dominate pulsation growth rates in fundamental and overtone pulsation. In fundamental mode pulsators, the deeper envelope is more important in determining growth rates than for overtone pulsators. For fundamental mode pulsators, evolutionary changes in the radius produce approximately linear changes in period. In overtone pulsators, pulsation reacts to small evolutionary changes in a more unstable way because the modes are more sensitive to high envelope features such as opacity bumps, and the growth rates for the many closely spaced overtone modes change easily. Finally, the upper limit to the X-ray flux from an Einstein observation implies that the companion in the astrometric orbit is earlier than F4 V. The combination of upper and lower limits on the companion from IUE and Einstein respectively catch the companion mass between 1.7 and 1.4 Msolar. The X-ray limit is consistent with the more distant companion α UMi B being a physical companion in a hierarchal triple system. However the X-ray limits require that the even more distant companions α UMi

  17. Weighing Rocky Exoplanets with Improved Radial Velocimetry

    NASA Astrophysics Data System (ADS)

    Xuesong Wang, Sharon; Wright, Jason; California Planet Survey Consortium

    2016-01-01

    The synergy between Kepler and the ground-based radial velocity (RV) surveys have made numerous discoveries of small and rocky exoplanets, opening the age of Earth analogs. However, most (29/33) of the RV-detected exoplanets that are smaller than 3 Earth radii do not have their masses constrained to better than 20% - limited by the current RV precision (1-2 m/s). Our work improves the RV precision of the Keck telescope, which is responsible for most of the mass measurements for small Kepler exoplanets. We have discovered and verified, for the first time, two of the dominant terms in Keck's RV systematic error budget: modeling errors (mostly in deconvolution) and telluric contamination. These two terms contribute 1 m/s and 0.6 m/s, respectively, to the RV error budget (RMS in quadrature), and they create spurious signals at periods of one sidereal year and its harmonics with amplitudes of 0.2-1 m/s. Left untreated, these errors can mimic the signals of Earth-like or Super-Earth planets in the Habitable Zone. Removing these errors will bring better precision to ten-year worth of Keck data and better constraints on the masses and compositions of small Kepler planets. As more precise RV instruments coming online, we need advanced data analysis tools to overcome issues like these in order to detect the Earth twin (RV amplitude 8 cm/s). We are developing a new, open-source RV data analysis tool in Python, which uses Bayesian MCMC and Gaussian processes, to fully exploit the hardware improvements brought by new instruments like MINERVA and NASA's WIYN/EPDS.

  18. Carbon cycles on super-Earth exoplanets

    NASA Astrophysics Data System (ADS)

    Wordsworth, Robin; Pierrehumbert, Raymond; Hébrard, Eric

    2013-04-01

    On Earth, the long-term global carbon cycle primarily consists of a balance between volcanic emissions of CO2 and the formation and burial of carbonate rocks (the carbonate-silicate weathering 'thermostat'), with important modifications due to the biosphere. On gas giant planets, the carbon cycle is driven by photolysis in the upper atmosphere: methane is converted to longer-chain hydrocarbons such as acetylene, ethane and soot particles, which are then dissociated by thermolysis lower in the atmosphere where the temperature and pressure are much higher. Hydrogen escape rates on terrestrial exoplanets are predicted to be a strong function of their orbital distances, ages and masses. In particular, larger exoplanets around stars with lower extreme ultraviolet (XUV) emissions may have significant difficulties in losing their hydrogen to space, and hence may retain H2 envelopes of varying mass. It is therefore interesting to investigate what happens in the transition between the terrestrial and hydrogen-dominated regimes. Here we present a first attempt to investigate the range of scenarios that occur for terrestrial mass (~1-10 ME) planets with varying hydrogen escape rates. We are developing climate evolution simulations for a range of cases that account for surface processes (primarily outgassing and weathering), hydrogen escape to space, and simple atmospheric chemistry. We discuss various feedbacks that may occur as a result of the influences of CO2, CH4 and H2 on atmospheric and surface temperatures. Finally, we discuss the implications of our results for future observations, with a particular emphasis on the search for biosignatures on exoplanets similar to the Earth.

  19. Density Estimation for Projected Exoplanet Quantities

    NASA Astrophysics Data System (ADS)

    Brown, Robert A.

    2011-05-01

    Exoplanet searches using radial velocity (RV) and microlensing (ML) produce samples of "projected" mass and orbital radius, respectively. We present a new method for estimating the probability density distribution (density) of the unprojected quantity from such samples. For a sample of n data values, the method involves solving n simultaneous linear equations to determine the weights of delta functions for the raw, unsmoothed density of the unprojected quantity that cause the associated cumulative distribution function (CDF) of the projected quantity to exactly reproduce the empirical CDF of the sample at the locations of the n data values. We smooth the raw density using nonparametric kernel density estimation with a normal kernel of bandwidth σ. We calibrate the dependence of σ on n by Monte Carlo experiments performed on samples drawn from a theoretical density, in which the integrated square error is minimized. We scale this calibration to the ranges of real RV samples using the Normal Reference Rule. The resolution and amplitude accuracy of the estimated density improve with n. For typical RV and ML samples, we expect the fractional noise at the PDF peak to be approximately 80 n -log 2. For illustrations, we apply the new method to 67 RV values given a similar treatment by Jorissen et al. in 2001, and to the 308 RV values listed at exoplanets.org on 2010 October 20. In addition to analyzing observational results, our methods can be used to develop measurement requirements—particularly on the minimum sample size n—for future programs, such as the microlensing survey of Earth-like exoplanets recommended by the Astro 2010 committee.

  20. Studies of exo-planets and solar systems with SPICA

    NASA Astrophysics Data System (ADS)

    Takami, Michihiro

    SPICA (SPace Infrared telescope for Cosmology and Astrophysics) is a mission for MIR/FIR astronomy, equipped with a single 3.5m-aperture cooled (<5 K) telescope. With the high spatial resolution and unprecedented sensitivity, the mission will be a powerful tool for revealing the origins of galaxies, stars and planets. In particular, the MIR capabilities of SPICA covering a greater wavelength range, providing higher spectral resolution (R˜30000) and a state-of-art coronagraph are providing unique observational chances for studies of planet formation and detection. In this presentation we will summarize the Galactic "key" science with SPICA stressing on this topic. We propose direct observations of exoplanets with the mid-infrared (MIR) coronagraph of SPICA. With a clean pupil of SPICA due to its non-segmented mirror, its coronagraph can achieve a contrast as large as 106 at a wide working area. The primary aim of these observations is not only the direct detection but also the spectroscopy of Jovian exoplanets. We also propose to conduct transiting planet spectroscopy at 5-200 microns with SPICA. The targets will be hundreds of stars with transiting planets which will be discovered by other space missions such as COROT and Kepler or ground-based large telescopes. SPICA will also provide meaningful constraints on the size and albedo of asteroids and Trans-Neptunian Objects (TNOs), as well as future 'dwarf planet' candidates, in our solar system. The MIR coronagraphic capabilities provide us with unprecedented opportunities to detect and probe into debris disks as dim as that exists in our own solar system. We propose to observe statistical numbers of such tenuous debris disks to the level as faint as our own in order to study current status of the planetary systems and their forming histories. SPICA's high resolution spectrograph will allow us to observe IR lines from a variety of molecules, atoms and ions. These arise from the regions at temperature of 100-1000 K

  1. How frequent are substellar companions in T Tauri binary systems?

    NASA Astrophysics Data System (ADS)

    Woitas, J.; Leinert, Ch.

    Using speckle interferometry we have determined the J-band magnitudes for the components of 27 close T Tauri multiples (separations <= 1 arcsec) in Taurus-Auriga detected by Leinert et al. (A&A 278, 129, 1993). The J-band is least affected by emission of circumstellar material, so it can be used as an estimator for a star's luminosity. Taking the spectral type of the system as that of the main component and assuming that both stars are coeval, we can place them into the HRD. A comparison with theoretical PMS evolution tracks by D'Antona & Mazzitelli (ApJS, 90, 467, 1994) yields the masses of the components. Since almost all T Tauri stars in Taurus-Auriga form in multiple systems (Leinert et al. ,1993, see above), the resultant mass function should be an estimation of the initial mass function (IMF) in this star forming region. The result is that the IMF has a turnover at M ~0.3M_{\\odot} and that there are not many brown dwarf candidates. Only three out of 57 stars, namely the companions of CZ Tau, FS Tau and Haro 6-28 seem to have masses close to or below the substellar limit. Multiplicity surveys of e. g. Koehler & Leinert (A&A 331, 977, 1998) have revealed that the binary frequency among T Tauri stars in Taurus-Auriga is about twice as high as that observed in the solar neighbourhood (Duquennoy & Mayor, A&A 248, 485, 1991). One proposed explanation for this overabundance is that there are many substellar companions that are relatively bright during their PMS evolution, but are not detectable on the main sequence stage. Our results suggest that this is in fact not the case.

  2. Collaboration and Competition in Exoplanet Research

    NASA Technical Reports Server (NTRS)

    Beichman, Charles

    2009-01-01

    Collaboration and competition are strong driving forces in the modern search for exoplanets, appears between individuals, agencies and nations as well as between observing techniques and theoretical interpretation. I will argue that these forces, taken in balance, are beneficial to the field and are partly responsible for the rapid progress in the search for planets and ultimately the search for life beyond the solar system. Specific examples will include indirect detection of Earth analogs from ground and space and the direct detection of gas giant and terrestrial planets.

  3. Transit of Exoplanet WASP 24-b

    NASA Astrophysics Data System (ADS)

    Thompson, Robert; Turner, J.; Hardegree-Ullman, K.; Raphael, B.; Smith, C.; Towner, A. P.; Walker-LaFollette, A.; Wallace, S.; Berkson, E.; Greenwood, N.

    2013-01-01

    We observed two primary transits of exoplanet WASP-24b with the Steward Observatory 1.55 meter Kuiper Telescope in the R photometric band. With our results, we have been able to produce a more complete light curve and refine previously published values for the planet’s mass, radius, density, surface gravity, Safronov number, equilibrium temperature, orbital distance, orbital inclination. One of the goals of this project is to give undergraduates opportunity to learn astronomical observing techniques, get practical experience using a research-class telescope, and perform data reduction using IRAF and Transit Analysis Package (TAP).

  4. A Multi-object Exoplanet Detecting Technique

    NASA Astrophysics Data System (ADS)

    Zhang, K.

    2011-05-01

    Exoplanet exploration is not only a meaningful astronomical action, but also has a close relation with the extra-terrestrial life. High resolution echelle spectrograph is the key instrument for measuring stellar radial velocity (RV). But with higher precision, better environmental stability and higher cost are required. An improved technique of RV means invented by David J. Erskine in 1997, External Dispersed Interferometry (EDI), can increase the RV measuring precision by combining the moderate resolution spectrograph with a fixed-delay Michelson interferometer. LAMOST with large aperture and large field of view is equipped with 16 multi-object low resolution fiber spectrographs. And these spectrographs are capable to work in medium resolution mode (R=5{K}˜10{K}). LAMOST will be one of the most powerful exoplanet detecting systems over the world by introducing EDI technique. The EDI technique is a new technique for developing astronomical instrumentation in China. The operating theory of EDI was generally verified by a feasibility experiment done in 2009. And then a multi-object exoplanet survey system based on LAMOST spectrograph was proposed. According to this project, three important tasks have been done as follows: Firstly, a simulation of EDI operating theory contains the stellar spectrum model, interferometer transmission model, spectrograph mediation model and RV solution model. In order to meet the practical situation, two detecting modes, temporal and spatial phase-stepping methods, are separately simulated. The interference spectrum is analyzed with Fourier transform algorithm and a higher resolution conventional spectrum is resolved. Secondly, an EDI prototype is composed of a multi-object interferometer prototype and the LAMOST spectrograph. Some ideas are used in the design to reduce the effect of central obscuration, for example, modular structure and external/internal adjusting frames. Another feasibility experiment was done at Xinglong Station in

  5. Brown Dwarfs at the Exoplanet Mass Boundary

    NASA Astrophysics Data System (ADS)

    Faherty, J. K.; Cruz, K. L.; Rice, E. L.; Riedel, A.

    2014-10-01

    Young brown dwarfs and directly-imaged exoplanets have enticingly similar photometric and spectroscopic characteristics, indicating that their cool, low gravity atmospheres should be studied in concert. Similarities between the peculiar shaped H band, near and mid-IR photometry as well as location on color magnitude diagrams provide important clues about how to extract physical properties of planets from current brown dwarf observations. Our team has assigned >30 brown dwarfs to 10-150 Myr nearby moving groups. In so doing, we have discovered important diversity among this extremely low-mass (10 - 30 M_{Jup}) age-calibrated sample indicating that cloud properties play a critical role in their observables.

  6. Advances in exoplanet science from Kepler.

    PubMed

    Lissauer, Jack J; Dawson, Rebekah I; Tremaine, Scott

    2014-09-18

    Numerous telescopes and techniques have been used to find and study extrasolar planets, but none has been more successful than NASA's Kepler space telescope. Kepler has discovered most of the known exoplanets, the smallest planets to orbit normal stars and the planets most likely to be similar to Earth. Most importantly, Kepler has provided us with our first look at the typical characteristics of planets and planetary systems for planets with sizes as small as, and orbits as large as, those of Earth. PMID:25230655

  7. A Desktop Transiting Exoplanet Shimer, Aurnou

    NASA Astrophysics Data System (ADS)

    Shimer, P.; Aurnou, J. M.

    2013-12-01

    We will present, on-site, a small-scale experiment that simulates the transit of an exoplanet across the face of a star. This experiment consists of i) a rotating table with a light source ('star') at the center; ii) a variable length arm affixed to the table; iii) a small cylinder or sphere ('planet') affixed to the end of the arm; iv) a light intensity sensor ('telescope') placed in the system's orbital plane. Using the characteristic dip in light intensity as the transiting body blocks part of the light source, it is possible to invert the data to infer the body's radius.

  8. Scintillation Noise in Exoplanet Transit Photometry

    NASA Astrophysics Data System (ADS)

    Föhring, Dóra; Wilson, Richard; Osborn, James; Dhillon, Vik

    2015-04-01

    Transit photometry is a powerful technique for studying exoplanets. Transit observations from the ground of targets of magnitude V= 10 or brighter, however, are limited by scintillation noise due to Earth's atmosphere. Through turbulence profiling using instruments such as the stereo-SCIDAR, we have shown to able to accurately model scintillation noise, which is essential in order to fully account for the error budget of the observation. Through numerical modelling we find that employing scintillation reducing techniques enables an improvement of a factor between 1.36 — 1.6 on the astrophysical parameters.

  9. Searches for Exoplanets with Gravitational Microlensing

    NASA Astrophysics Data System (ADS)

    Zakharov, Alexander

    2016-07-01

    There are different methods for finding exoplanets such as radial spectral shifts, astrometrical measurements, transits, timing etc. Gravitational microlensing (including pixel-lensing) is among the most promising techniques with the potentiality of detecting Earth-like planets at distances about a few astronomical units from their host star. We emphasize the importance of polarization measurements which can help to resolve degeneracies in theoretical models. In particular, the polarization angle could give additional information about the relative position of the lens with respect to the source.

  10. DiskDetective.org: Finding Homes for Exoplanets Through Citizen Science

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc J.

    2016-01-01

    The Disk Detective project is scouring the data archive from the WISE all-sky survey to find new debris disks and protoplanetary disks-the dusty dens where exoplanets form and dwell. Volunteers on this citizen science website have already performed 1.6 million classifications, searching a catalog 8x the size of any published WISE survey. We follow up candidates using ground based telescopes in California, Arizona, Chile, Hawaii, and Argentina. We ultimately expect to increase the pool of known debris disks by approx. 400 and triple the solid angle in clusters of young stars examined with WISE, providing a unique new catalog of isolated disk stars, key planet-search targets, and candidate advanced extraterrestrial civilizations. Come to this talk to hear the news about our latest dusty discoveries and the trials and the ecstasy of launching a new citizen science project. Please bring your laptop or smartphone if you like!

  11. Companion animals: Translational scientist's new best friends.

    PubMed

    Kol, Amir; Arzi, Boaz; Athanasiou, Kyriacos A; Farmer, Diana L; Nolta, Jan A; Rebhun, Robert B; Chen, Xinbin; Griffiths, Leigh G; Verstraete, Frank J M; Murphy, Christopher J; Borjesson, Dori L

    2015-10-01

    Knowledge and resources derived from veterinary medicine represent an underused resource that could serve as a bridge between data obtained from diseases models in laboratory animals and human clinical trials. Naturally occurring disease in companion animals that display the defining attributes of similar, if not identical, diseases in humans hold promise for providing predictive proof of concept in the evaluation of new therapeutics and devices. Here we outline comparative aspects of naturally occurring diseases in companion animals and discuss their current uses in translational medicine, benefits, and shortcomings. Last, we envision how these natural models of disease might ultimately decrease the failure rate in human clinical trials and accelerate the delivery of effective treatments to the human clinical market. PMID:26446953

  12. Observing Faint Companions Close to Bright Stars

    NASA Astrophysics Data System (ADS)

    Serabyn, Eugene

    2012-04-01

    Progress in a number of technical areas is enabling imaging and interferometric observations at both smaller angular separations from bright stars and at deeper relative contrast levels. Here we discuss recent progress in several ongoing projects at the Jet Propulsion Laboratory. First, extreme adaptive optics wavefront correction has recently enabled the use of very short (i.e., blue) wavelengths to resolve close binaries. Second, phase-based coronagraphy has recently allowed observations of faint companions to within nearly one diffraction beam width of bright stars. Finally, rotating interferometers that can observe inside the diffraction beam of single aperture telescopes are being developed to detect close-in companions and bright exozodiacal dust. This paper presents a very brief summary of the techniques involved, along with some illustrative results.

  13. The Oxford Companion to the Earth

    NASA Astrophysics Data System (ADS)

    Hancock, Paul L.

    2001-06-01

    Here is a wealth of information on planet Earth, ranging from the heights of the ionsphere down to the red-hot molten core. Written by some 200 expert contributors, and illustrated with over 600 pictures, including 16 pages of color plates, The Oxford Companion to the Earth offers 900 alphabetically arranged entries that cover everything from deserts and wetlands to mountains, caves, glaciers, and coral reefs. There are articles on natural phenomena such as tornadoes and tsunamis, volcanoes and earthquakes, jet streams and weather fronts; on the history of Earth, including the origin of life, Burgess Shale fauna, dinosaurs, and the Ice Ages; on key figures, such as Agassiz, Cuvier, Darwin, and Lamarck; and on such important ecological concerns as acid rain, the ozone layer, industrial waste disposal, and the greenhouse effect. The Companion also examines the great sources of wealth to be found in the Earth, from coal and oil to gold, silver, and diamonds, and many curious land formations, from sinkholes and fiords to yardangs and quicksand. There are brief entries on rock types, from amber to travertine, and extensive essays on cutting-edge aspects of the earth sciences, such as seismology and marine geology. The Companion includes extensive cross-references, suggested further reading, an index, and many useful appendices, with a geological timescale, facts and figures about the Earth, and a table of chemical elements. The Oxford Companion to the Earth is a unique reference work, offering unrivaled coverage of our home planet. Generously illustrated and vividly written, it is a treasure house of information for all lovers of natural history, geology, and ecology, whether professional or amateur.

  14. Transiting exoplanets and magnetic spots characterized with optical interferometry

    NASA Astrophysics Data System (ADS)

    Ligi, R.; Mourard, D.; Lagrange, A.-M.; Perraut, K.; Chiavassa, A.

    2015-02-01

    Context. Stellar activity causes difficulties in the characterization of transiting exoplanets. In particular, the magnetic spots present on most exoplanet host stars can lead to false detections with radial velocity, photometry, or astrometry techniques. Studies have been performed to quantify their impact on infrared interferometry, but no such studies have been performed in the visible domain. This wavelength domain, however, allows reaching better angular resolution than in the infrared and is also the wavelength most often used for spectroscopic and photometric measurements. Aims: We use a standard case to completely analyse the impact of an exoplanet and a spot on interferometric observables and relate it to current instrument capabilities, taking into account realistic achievable precisions. Methods: We built a numerical code called COMETS using analytical formulae to perform a simple comparison of exoplanet and spot signals. We explored instrumental specificities needed to detect them, such as the required baseline length, the accuracy, and signal-to-noise ratio. We also discuss the impact of exoplanet and spot parameters on squared visibility and phase: exoplanet diameter and size, exoplanet position, spot temperature, star diameter. Results: According to our study, the main improvement to achieve is the instrument sensitivity. The accuracy on squared visibilities has to be improved by a factor 10 to detect an exoplanet of 0.10 mas, leading to <0.5% precision, along with phase measurements of ~5° accuracy beyond the first null of visibility. For an exoplanet of 0.05 mas, accuracies of ~0.1% and ~1° from the first null are required on squared visibilities and phases. Magnetic spots can mimic these signals, leading to false exoplanet characterization. Phase measurements from the third lobe are needed to distinguish between the spot and the exoplanet if they have the same radius. Conclusions: By increasing interferometer sensitivity, more objects will

  15. Extension of Companion Modeling Using Classification Learning

    NASA Astrophysics Data System (ADS)

    Torii, Daisuke; Bousquet, François; Ishida, Toru

    Companion Modeling is a methodology of refining initial models for understanding reality through a role-playing game (RPG) and a multiagent simulation. In this research, we propose a novel agent model construction methodology in which classification learning is applied to the RPG log data in Companion Modeling. This methodology enables a systematic model construction that handles multi-parameters, independent of the modelers ability. There are three problems in applying classification learning to the RPG log data: 1) It is difficult to gather enough data for the number of features because the cost of gathering data is high. 2) Noise data can affect the learning results because the amount of data may be insufficient. 3) The learning results should be explained as a human decision making model and should be recognized by the expert as being the result that reflects reality. We realized an agent model construction system using the following two approaches: 1) Using a feature selction method, the feature subset that has the best prediction accuracy is identified. In this process, the important features chosen by the expert are always included. 2) The expert eliminates irrelevant features from the learning results after evaluating the learning model through a visualization of the results. Finally, using the RPG log data from the Companion Modeling of agricultural economics in northeastern Thailand, we confirm the capability of this methodology.

  16. Palomar Ultraviolet Laser for the Study of Exoplanets

    NASA Astrophysics Data System (ADS)

    Baranec, C.; Dekany, R.; van Dam, M.; Burruss, R.

    2013-09-01

    PULSE is a new concept to augment the currently operating 5.1-m Hale PALM-3000 exoplanet adaptive optics system with an ultraviolet Rayleigh laser and associated wavefront sensor. By using an ultraviolet laser to measure the high spatial and temporal order turbulence near the telescope aperture, where it dominates, one can extend the faintness limit of natural guide stars needed by PALM-3000. Initial simulations indicate that very-high infrared contrast ratios and good visible-light adaptive optics performance will be achieved by such an upgraded system on stars as faint as mV = 16-17 using an optimized low-order NGS sensor. This will enable direct imaging searches for, and subsequent characterization of, companions around cool, low-mass stars for the first time, as well as routine visible-light imaging twice as sharp as HST for fainter targets. PULSE will reuse the laser and wavefront sensor technology developed for the automated Robo-AO laser system currently operating at the Palomar 60-inch telescope, as well as take advantage of pending optimization of low-order NGS wavefront sensing and planned new interfaces to the PALM-3000 real-time reconstruction computer. A copy of the Robo-AO laser will be installed in the prime focus cage of the 5.1-m, and a new ultraviolet high-order wavefront sensor, fed by an ultraviolet dichroic, will be installed in the space above the PALM-3000 optical bench near the calibration sources. The laser measurements will drive the 3,388 active element high-order deformable mirror in open-loop, while an adaptive optics sharpened faint natural source will be measured by the current PALM-3000 wavefront sensor in its lowest spatial sampling mode, with commands sent in closed-loop to the 241 active element low-order deformable mirror. The natural guide star loop corrects for both the relatively weak low-order high-altitude turbulence as well as functioning as both the tip-tilt and low-bandwidth `truth' sensor loops in a traditional laser

  17. Characterization of Kepler Exoplanet Host Stars

    NASA Astrophysics Data System (ADS)

    Howell, Steve B.; Everett, M.; Ciardi, D. R.; Silva, D.; Szkody, P.

    2014-01-01

    Using a sample of 220 Exoplanet host stars in the Kepler field for which spectroscopic properties have been determined, we examine their spatial, physical, and time variable properties. Covering effective temperatures from 4670K to 6400K (K4 to F4) and masses from 0.7 to 1.4 M-sun, this sample represents host stars covering the entire Kepler field of view. The majority of the host stars contain one or more Earth-sized exoplanet and range in log g from 4.0 to 4.7 and [Fe/H] from -02.4 to +0.3. Using Yale-Yonsei isochrone fits and photometric information form the Howell-Everett UBV survey of the Kepler field, we examine a complete set of parameters for these stars including their likely residence in the thin or thick disk of the Galaxy. the variability of this sample, in terms of time sale and amplitude, is examined as well.

  18. Exoplanet Magnetic Fields and Their Detectability

    NASA Astrophysics Data System (ADS)

    Stanley, S.; Tian, B. Y.; Vilim, R.

    2014-12-01

    The investigation of planetary magnetic fields in our solar system provides a wealth of information on planetary interior structure and dynamics. Satellite magnetic data demonstrates that planetary dynamos can produce a range of magnetic field morphologies and intensities. Numerical dynamo simulations are working towards determining relationships between planetary properties and the resulting magnetic field characteristics. However, with only a handful of planetary dynamos in our solar system, it is challenging to determine specific dependence of magnetic field properties on planetary characteristics. Extrasolar planets therefore provide a unique opportunity by significantly increasing the number of planets for study as well as offering a much larger range of planetary properties to investigate. Although detection of exoplanet magnetic fields is challenging at present, the increasing sophistication of observational tools available to astronomers implies these extrasolar planetary magnetic fields may eventually be detectable. This presentation will discuss potential observational trends for magnetic field strength and morphology for exoplanets based on numerical simulations and interior structure modeling. We will focus on the influence of planetary age, environment, composition and structure.

  19. Light from Exoplanets: Present and Future

    NASA Technical Reports Server (NTRS)

    Deming, Leo

    2010-01-01

    Measurements using the Spitzer Space Telescope have revealed thermal emission from planets orbiting very close to solar-type stars, primarily transiting "hot Jupiter" exoplanets. The thermal emission spectrum of these worlds has been measured by exploiting their secondary eclipse. Also, during transit of the planet, absorption signatures from atoms and molecules in the planet's atmosphere are imprinted onto the spectrum of the star. Results to date from transit and eclipse studies show that the hot Jupiters often have significant haze and cloud components in their atmospheres, and the temperature structure can often be inverted, i.e. temperature is rising with height. New and very strongly irradiated examples of hot Jupiters have been found that are being stripped of their atmospheres by tidal forces from the star. In parallel, transiting superEarth exoplanets are being discovered, and their atmospheres should also be amenable to study using transit techniques. The 2014 launch of the James Webb Space Telescope will clarify the physical nature of hot Jupiters, and will extend transit and eclipse studies to superEarths orbiting in the habitable zones of lower main sequence stars.

  20. Exoplanet Curriculum at the International Space University

    NASA Astrophysics Data System (ADS)

    Burke, J. D.; Hill, H. G. M.

    2012-04-01

    Rapidly-expanding knowledge of exoplanets is providing a huge opportunity for education at all levels. In addition to the intrinsic scientific interest of finding other planetary systems and developing testable hypotheses about stellar evolution, based for the first time in history on more than one example, there is the prospect of finding habitats for other life. Even if actual life signatures cannot yet be unambiguously detected, just a credible possibility is enough to catalyze new discussions and stimulate new ideas emerging from the rich background of science fiction and the ancient concept of a plurality of inhabited worlds. At the International Space University, a graduate-level institution devoted to identifying, informing and encouraging young professionals from throughout the world, this exploding new field of science provides a grand opportunity for seminars and other activities engaging students in creative thinking about the vast human implications of a populated cosmos. Once a planet's existence and orbit are confirmed by long-continued observations, it may be a suitable object for spectrometry and other techniques to begin finding characteristics of its interior, atmosphere, magnetosphere, possibly even oceans. These observations require not only very advanced instrumentation and data methods but also patience and skill in operations both on Earth and in space. They can serve as an organizing principle for education across all of the specialties represented at ISU. In this paper we discuss the ISU curriculum, focusing on those parts of it that can benefit from the interdisciplinary expansion enabled by exoplanet discoveries.

  1. The science of exoplanets and their systems.

    PubMed

    Lammer, Helmut; Blanc, Michel; Benz, Willy; Fridlund, Malcolm; Foresto, Vincent Coudé du; Güdel, Manuel; Rauer, Heike; Udry, Stephane; Bonnet, Roger-Maurice; Falanga, Maurizio; Charbonneau, David; Helled, Ravit; Kley, Willy; Linsky, Jeffrey; Elkins-Tanton, Linda T; Alibert, Yann; Chassefière, Eric; Encrenaz, Therese; Hatzes, Artie P; Lin, Douglas; Liseau, Rene; Lorenzen, Winfried; Raymond, Sean N

    2013-09-01

    A scientific forum on "The Future Science of Exoplanets and Their Systems," sponsored by Europlanet and the International Space Science Institute (ISSI) and co-organized by the Center for Space and Habitability (CSH) of the University of Bern, was held during December 5 and 6, 2012, in Bern, Switzerland. It gathered 24 well-known specialists in exoplanetary, Solar System, and stellar science to discuss the future of the fast-expanding field of exoplanetary research, which now has nearly 1000 objects to analyze and compare and will develop even more quickly over the coming years. The forum discussions included a review of current observational knowledge, efforts for exoplanetary atmosphere characterization and their formation, water formation, atmospheric evolution, habitability aspects, and our understanding of how exoplanets interact with their stellar and galactic environment throughout their history. Several important and timely research areas of focus for further research efforts in the field were identified by the forum participants. These scientific topics are related to the origin and formation of water and its delivery to planetary bodies and the role of the disk in relation to planet formation, including constraints from observations as well as star-planet interaction processes and their consequences for atmosphere-magnetosphere environments, evolution, and habitability. The relevance of these research areas is outlined in this report, and possible themes for future ISSI workshops are identified that may be proposed by the international research community over the coming 2-3 years. PMID:24015759

  2. M Dwarf Flares: Exoplanet Detection Implications

    NASA Astrophysics Data System (ADS)

    Tofflemire, B. M.; Wisniewski, J. P.; Hilton, E. J.; Kowalski, A. F.; Kundurthy, P.; Schmidt, S. J.; Hawley, S. L.; Holtzman, J. A.

    2011-12-01

    Low mass stars such as M dwarfs have become prime targets for exoplanet transit searches as their low luminosities and small stellar radii could enable the detection of super-Earths residing in their habitable zones. While promising transit targets, M dwarfs are also inherently variable and can exhibit up to ˜6 magnitude flux enhancements in the optical U-band. This is significantly higher than the predicted transit depths of habitable zone super-Earths (0.005 magnitude flux decrease). The behavior of flares at infrared (IR) wavelengths, particularly those likely to be used to study and characterize M dwarf exoplanets using facilities such as the James Web Space Telescope (JWST), remains largely unknown. To address these uncertainties, we are executing a coordinated, contemporaneous monitoring program of the optical and IR flux of M dwarfs known to regularly flare. A suite of telescopes located at the Kitt Peak National Observatory and the Apache Point Observatory are used for the observations. We present the initial results of this program.

  3. Exoplanet Science in the National Science Olympiad

    NASA Astrophysics Data System (ADS)

    Komacek, Thaddeus D.; Young, Donna

    2015-11-01

    The National Science Olympiad is one of the United States' largest science competitions, reaching over 6,000 schools in 48 states. The Olympiad includes a wide variety of events, stretching a full range of potential future STEM careers, from biological sciences to engineering to earth and space sciences. The Astronomy event has been a mainstay at the high school level for well over a decade, and nominally focuses on aspects of stellar evolution. For the 2014-2015 competition season, the event focus was aligned to include exoplanet discovery and characterization along with star formation. Teams studied both the qualitative features of exoplanets and exoplanetary systems and the quantitative aspects behind their discovery and characterization, including basic calculations with the transit and radial velocity methods. Students were also expected to have a qualitative understanding of stellar evolution and understand the differences between classes of young stars including T Tauri and FU Orionis variables, and Herbig Ae/Be stars. Based on the successes of this event topic, we are continuing this event into the 2015-2016 academic year. The key modification is the selection of new exoplanetary systems for students to research. We welcome feedback from the community on how to improve the event and the related educational resources that are created for Science Olympiad students and coaches. We also encourage any interested community members to contact your regional or state Science Olympiad tournament directors and volunteer to organize competitions and supervise events locally.

  4. Technology Enabling the First 100 Exoplanets

    NASA Astrophysics Data System (ADS)

    Marcy, Geoffrey W.

    2014-01-01

    The discoveries of the first 100 exoplanets by precise radial velocities in the late 1990's at Lick Observatory and Observatoire de Haute-Provence were enabled by several technological advances and a cultural one. A key ingredient was a cross-dispersed echelle spectrometer at a stable, coude focus, with a CCD detector, offering high spectral resolution, large wavelength coverage, and a linear response to photons. A second ingredient was a computer capable of storing the megabyte images from such spectrometers and analyzing them for Doppler shifts. Both Lick and OHP depended on these advents. A third ingredient was a stable wavelength calibration. Here, two technologies emerged independently, with iodine gas employed by Marcy's group (used first by solar physicists doing helioseismology) and simultaneous thorium-argon spectra (enabled by fiber optics) used by Mayor's group. A final ingredient was a new culture emerging in the 1990's of forward-modeling of spectra on computers, enabled by the well-behaved photon noise of CCDs, giving Poisson errors amenable to rigorous statistical algorithms for measuring millipixel Doppler shifts. The prospect of detecting the 12 meter/sec reflex velocity (1/100 pixel) of a Jupiter-like planet was considered impossible, except to a few who asked, "What actually limits Doppler precision?". Inspired insights were provided by Robert Howard, Paul Schechter, Bruce Campbell, and Gordon Walker, leading to the first 100 exoplanets.

  5. Exploring exoplanet populations with NASA's Kepler Mission.

    PubMed

    Batalha, Natalie M

    2014-09-01

    The Kepler Mission is exploring the diversity of planets and planetary systems. Its legacy will be a catalog of discoveries sufficient for computing planet occurrence rates as a function of size, orbital period, star type, and insolation flux. The mission has made significant progress toward achieving that goal. Over 3,500 transiting exoplanets have been identified from the analysis of the first 3 y of data, 100 planets of which are in the habitable zone. The catalog has a high reliability rate (85-90% averaged over the period/radius plane), which is improving as follow-up observations continue. Dynamical (e.g., velocimetry and transit timing) and statistical methods have confirmed and characterized hundreds of planets over a large range of sizes and compositions for both single- and multiple-star systems. Population studies suggest that planets abound in our galaxy and that small planets are particularly frequent. Here, I report on the progress Kepler has made measuring the prevalence of exoplanets orbiting within one astronomical unit of their host stars in support of the National Aeronautics and Space Administration's long-term goal of finding habitable environments beyond the solar system. PMID:25049406

  6. Amateur and Professional Astronomer Collaboration Exoplanet Research Programs and Techniques

    NASA Astrophysics Data System (ADS)

    Bissinger, R.

    2007-05-01

    In 1995 the breakthrough announcement was made that a planet had been discovered orbiting a star in the constellation Pegasus. Prior to that time, for decades astronomers had searched in vain to confirm that planets existed around any other star besides our own Sun. Yet it was a mere five years after the first exoplanet discovery that the first amateur astronomers observed a transit of an exoplanet using a 16-inch (40 cm) telescope in Finland. The realization that amateur astronomers could in fact detect exoplanets lead to the formation of transitsearch. org, the first amateur/ professional collaboration to discover exoplanets. In the ensuing years numerous other such collaborations have been formed and dozens of amateur astronomers around the world now regularly observe stars identified by professional astronomers as possibly harboring exoplanets. This paper summarizes the more notable amateur and professional collaborations now ongoing to discover and characterize exoplanets. Tools and techniques used by amateur astronomers in such research are reviewed with an eye towards how amateur astronomers may soon help discover the first earth-sized exoplanet capable of supporting life as we know it.

  7. Colors of Alien Worlds from Direct Imaging Exoplanet Missions

    NASA Astrophysics Data System (ADS)

    Hu, Renyu

    2015-08-01

    Future direct-imaging exoplanet missions such as WFIRST/AFTA, Exo-C, and Exo-S will measure the reflectivity of exoplanets at visible wavelengths. Most of the exoplanets to be observed will be located further away from their parent stars than is Earth from the Sun. These “cold” exoplanets have atmospheric environments conducive for the formation of water and/or ammonia clouds, like Jupiter in the Solar System. I find the mixing ratio of methane and the pressure level of the uppermost cloud deck on these planets can be uniquely determined from their reflection spectra, with moderate spectral resolution, if the cloud deck is between 0.6 and 1.5 bars. The existence of this unique solution is useful for exoplanet direct imaging missions for several reasons. First, the weak bands and strong bands of methane enable the measurement of the methane mixing ratio and the cloud pressure, although an overlying haze layer can bias the estimate of the latter. Second, the cloud pressure, once derived, yields an important constraint on the internal heat flux from the planet, and thus indicating its thermal evolution. Third, water worlds having H2O-dominated atmospheres are likely to have water clouds located higher than the 10-3 bar pressure level, and muted spectral absorption features. These planets would occupy a confined phase space in the color-color diagrams, likely distinguishable from H2-rich giant exoplanets by broadband observations. Therefore, direct-imaging exoplanet missions may offer the capability to broadly distinguish H2-rich giant exoplanets versus H2O-rich super-Earth exoplanets, and to detect ammonia and/or water clouds and methane gas in their atmospheres.

  8. Colors of Alien Worlds from Direct Imaging Exoplanet Missions

    NASA Astrophysics Data System (ADS)

    Hu, Renyu

    2016-01-01

    Future direct-imaging exoplanet missions such as WFIRST will measure the reflectivity of exoplanets at visible wavelengths. Most of the exoplanets to be observed will be located further away from their parent stars than is Earth from the Sun. These "cold" exoplanets have atmospheric environments conducive for the formation of water and/or ammonia clouds, like Jupiter in the Solar System. I find the mixing ratio of methane and the pressure level of the uppermost cloud deck on these planets can be uniquely determined from their reflection spectra, with moderate spectral resolution, if the cloud deck is between 0.6 and 1.5 bars. The existence of this unique solution is useful for exoplanet direct imaging missions for several reasons. First, the weak bands and strong bands of methane enable the measurement of the methane mixing ratio and the cloud pressure, although an overlying haze layer can bias the estimate of the latter. Second, the cloud pressure, once derived, yields an important constraint on the internal heat flux from the planet, and thus indicating its thermal evolution. Third, water worlds having H2O-dominated atmospheres are likely to have water clouds located higher than the 10-3 bar pressure level, and muted spectral absorption features. These planets would occupy a confined phase space in the color-color diagrams, likely distinguishable from H2-rich giant exoplanets by broadband observations. Therefore, direct-imaging exoplanet missions may offer the capability to broadly distinguish H2-rich giant exoplanets versus H2O-rich super-Earth exoplanets, and to detect ammonia and/or water clouds and methane gas in their atmospheres.

  9. The clinical benefits, ethics, and economics of stratified medicine and companion diagnostics.

    PubMed

    Trusheim, Mark R; Berndt, Ernst R

    2015-12-01

    The stratified medicine companion diagnostic (CDx) cut-off decision integrates scientific, clinical, ethical, and commercial considerations, and determines its value to developers, providers, payers, and patients. Competition already sharpens these issues in oncology, and might soon do the same for emerging stratified medicines in autoimmune, cardiovascular, neurodegenerative, respiratory, and other conditions. Of 53 oncology targets with a launched therapeutic, 44 have competing therapeutics. Only 12 of 141 Phase III candidates addressing new targets face no competition. CDx choices might alter competitive positions and reimbursement. Under current diagnostic incentives, payers see novel stratified medicines that improve public health and increase costs, but do not observe companion diagnostics for legacy treatments that would reduce costs. It would be in the interests of payers to rediscover their heritage of direct investment in diagnostic development. PMID:26542060

  10. The Frequency of Wide Companions to Planet-Host Stars: A New Wide Brown Dwarf Companion

    NASA Astrophysics Data System (ADS)

    Lodieu, N.; Pérez-Garrido, A.; Béjar, V. J. S.; Gauza, B.; Ruiz, M. T.; Rebolo, R.

    2015-07-01

    The aim of the project is to improve our knowledge of the multiplicity of planet-host stars at wide physical separations. We cross-matched approximately 6,200 square degrees imaged by the Visible Infrared Survey Telescope for Astronomy (VISTA) Hemisphere Survey (VHS) with the Two Micron All Sky Survey (2MASS) to look for wide common proper motion companions to known planet-host stars. We report two new stellar M dwarf companions as well as a T4.5 dwarf companion, at 6.3 arcmin (˜9,000 au) from the K7V star HIP 70849, yielding stellar and substellar frequencies of 5.4±3.8% and 2.7±2.7% (1σ), respectively. We refer the reader to our refereed paper (Lodieu et al. 2014) for more detailed information on the results.

  11. Search for Life Beyond the Solar System. Exoplanets, Biosignatures & Instruments

    NASA Astrophysics Data System (ADS)

    Apai, Daniel; Gabor, Pavel

    2014-03-01

    Motivated by the rapidly increasing number of known Earth-sized planets, the increasing range of extreme conditions in which life on Earth can persist, and the progress toward a technology that will ultimately enable the search for life on exoplanets, the Vatican Observatory and the Steward Observatory announce a major conference entitled The Search for Life Beyond the Solar System: Exoplanets, Biosignatures & Instruments. The goal of the conference is to bring together the interdisciplinary community required to address this multi-faceted challenge: experts on exoplanet observations, early and extreme life on Earth, atmospheric biosignatures, and planet-finding telescopes.

  12. THESIS: the terrestrial habitable-zone exoplanet spectroscopy infrared spacecraft

    NASA Astrophysics Data System (ADS)

    Swain, Mark R.; Vasisht, Gautam; Henning, Thomas; Tinetti, Giovanna; Beaulieu, Jean-Phillippe

    2010-07-01

    THESIS, the Transiting Habitable-zone Exoplanet Spectroscopy Infrared Spacecraft, is a concept for a medium/Probe class exoplanet mission. Building on the recent Spitzer successes in exoplanet characterization, THESIS would extend these types of measurements to super-Earth-like planets. A strength of the THESIS concept is simplicity, low technical risk, and modest cost. The mission concept has the potential to dramatically advance our understanding of conditions on extrasolar worlds and could serve as a stepping stone to more ambitious future missions. We envision this mission as a joint US-European effort with science objectives that resonate with both the traditional astronomy and planetary science communities.

  13. Surveying Nearby M dwarfs with Gaia: A Treasure Trove for Exoplanet Astrophysics

    NASA Astrophysics Data System (ADS)

    Sozzetti, A.; Tinetti, G.; Lattanzi, M. G.; Micela, G.; Morbidelli, R.; Giacobbe, P.

    2011-10-01

    Cool, nearby M dwarfs within a few tens of parsecs from the Sun are today becoming the focus of dedicated experiments in the realm of exoplanets astrophysics. This is due to the shift in theoretical paradigms in light of new observations, and thanks to the improved understanding of the observational opportunities for planet detection and characterization provided by this sample. Gaia, in its all-sky survey, will deliver precision astrometry for a magnitude-limited (V=20) sample of M dwarfs in the vicinity of the Sun, providing an inventory of cool nearby stars with a much higher degree of completeness (particularly for late sub-types) with respect to currently available catalogs. We gauge the Gaia potential for precision astrometry of exoplanets orbiting a sample of actual M stars within 30 pc from the Sun. The stellar reservoir is carefully selected based on cross-correlation among catalogs in the literature (e.g., Lepine, PMSU).We express Gaia sensitivity thresholds as a function of system parameters and in view of the latest mission profile, including the most up-to-date astrometric error model. The simulations also provide insight on the capability of high-precision astrometry to reconstruct the underlying orbital elements and mass distributions of the generated companions. We investigate the synergy between the Gaia data on nearby M dwarfs and other ground-based and spaceborne programs for planet detection and characterization, with a particular focus on: a) the improvements in the determination of transiting planet parameters thanks to the exquisitely precise stellar distances determined by Gaia; b) the betterment in orbit modeling when Gaia astrometry and precision radial-velocities are available for the same targets; and c) the ability of Gaia to carefully predict the ephemerides of detected (transiting and non-transiting) planets aroundM stars, for the purpose of spectroscopic characterization of their atmospheres with dedicated observatories in space

  14. The Gaia Astrometric Survey of Nearby M Dwarfs: A Treasure Trove for Exoplanet Astrophysics

    NASA Astrophysics Data System (ADS)

    Sozzetti, Alessandro; Giacobbe, P.; Lattanzi, M. G.; Micela, G.; Tinetti, G.

    2011-09-01

    Cool, nearby M dwarfs within a few tens of parsecs from the Sun are becoming the focus of dedicated experiments in the realm of exoplanets astrophysics. This is due to the shift in theoretical paradigms in light of new observations, and to the improved understanding of the observational opportunities for planet detection and characterization provided by this sample. Gaia, in its all-sky survey, will deliver precision astrometry for a magnitude-limited (V=20) sample of M dwarfs, providing an inventory of cool nearby stars with a much higher degree of completeness (particularly for late sub-types) with respect to currently available catalogs. We gauge the Gaia potential for precision astrometry of exoplanets orbiting a sample of already known dM stars within 30 pc from the Sun, carefully selected based on cross-correlation among catalogs in the literature (e.g., Lepine, PMSU). We express Gaia sensitivity thresholds as a function of system parameters and in view of the latest mission profile, including the most up-to-date astrometric error model. The simulations also provide insight on the capability of high-precision astrometry to reconstruct the underlying orbital elements and mass distributions of the generated companions. These results will help in evaluating the complete expected Gaia planet population around late-type stars. We investigate the synergy between the Gaia data on nearby M dwarfs and other ground-based and space-borne programs for planet detection and characterization, with a particular focus on: a) the improvements in the determination of transiting planet parameters thanks to the exquisitely precise stellar distances determined by Gaia; b) the betterment in orbit modeling when Gaia astrometry and precision radial-velocities are available for the same targets; and c) the ability of Gaia to carefully predict the ephemerides of (transiting and non-transiting) planets around M stars, for spectroscopic characterization of their atmospheres with

  15. The SEEDS High-Contrast Imaging Survey: Exoplanet and Brown Dwarf Survey for Nearby Young Stars Dated with Gyrochronology and Activity Age Indicators

    NASA Astrophysics Data System (ADS)

    Kuzuhara, Masayuki; Tamura, Motohide; Helminiak, Kris; Mede, Kyle; Brandt, Timothy; Janson, Markus; Kandori, Ryo; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Hashimoto, Jun

    2015-12-01

    The SEEDS campaign has successfully discovered and characterized exoplanets, brown dwarfs, and circumstellar disks since it began in 2009, via the direct imaging technique. The survey has targeted nearby young stars, as well as stars associated to star-forming regions, the Pleiades open cluster, moving groups, and debris disks. We selected the nearby young stars that have been dated with age indicators based on stellar rotation periods (i.e., gyrochronology) and chromoshperic/coronal activities. Of these, nearly 40 were observed, with ages mainly between 100 and 1000 Myr and distances less than 40 pc. Our observations typically attain the contrast of ~6 x 10-6 at 1'' and better than ~1 x 10-6 beyond 2'', enabling us to detect a planetary-mass companion even around such old stars. Indeed, the SEEDS team reported the discovery that the nearby Sun-like star GJ 504 hosts a Jovian companion GJ 504b, which has a mass of 3-8.5 Jupiter masses that is inferred according to the hot-start cooling models and our estimated system age of 100-510 Myr. The remaining observations out of the selected ~40 stars have resulted in no detection of additional planets or brown dwarf companions. Meanwhile, we have newly imaged a low-mass stellar companion orbiting the G-type star HIP 10321, for which the presence of companion was previously announced via radial velocity technique. The astrometry and radial velocity measurements are simultaneously analyzed to determine the orbit, providing constraints on the dynamical mass of both objects and stellar evolution models. Here we summarize our direct imaging observations for the nearby young stars dated with gyrochrolorogy and activity age indicators. Furthermore, we report the analysis for the HIP 10321 system with the imaged low-mass companion.

  16. Exoplanet atmosphere. Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy.

    PubMed

    Stevenson, Kevin B; Désert, Jean-Michel; Line, Michael R; Bean, Jacob L; Fortney, Jonathan J; Showman, Adam P; Kataria, Tiffany; Kreidberg, Laura; McCullough, Peter R; Henry, Gregory W; Charbonneau, David; Burrows, Adam; Seager, Sara; Madhusudhan, Nikku; Williamson, Michael H; Homeier, Derek

    2014-11-14

    Exoplanets that orbit close to their host stars are much more highly irradiated than their solar system counterparts. Understanding the thermal structures and appearances of these planets requires investigating how their atmospheres respond to such extreme stellar forcing. We present spectroscopic thermal emission measurements as a function of orbital phase ("phase-curve observations") for the highly irradiated exoplanet WASP-43b spanning three full planet rotations using the Hubble Space Telescope. With these data, we construct a map of the planet's atmospheric thermal structure, from which we find large day-night temperature variations at all measured altitudes and a monotonically decreasing temperature with pressure at all longitudes. We also derive a Bond albedo of 0.18(-0.12)(+0.07) and an altitude dependence in the hot-spot offset relative to the substellar point. PMID:25301972

  17. ORBITAL ORIENTATIONS OF EXOPLANETS: HAT-P-4b IS PROGRADE AND HAT-P-14b IS RETROGRADE

    SciTech Connect

    Winn, Joshua N.; Albrecht, Simon; Howard, Andrew W.; Marcy, Geoffrey W.; Isaacson, Howard; Johnson, John Asher; Crepp, Justin R.; Morton, Timothy D.; Shporer, Avi; Bakos, Gaspar A.; Hartman, Joel D.; Holman, Matthew J.

    2011-02-15

    We present observations of the Rossiter-McLaughlin effect for two exoplanetary systems, revealing the orientations of their orbits relative to the rotation axes of their parent stars. HAT-P-4b is prograde, with a sky-projected spin-orbit angle of {lambda} = -4.9 {+-} 11.9 deg. In contrast, HAT-P-14b is retrograde, with {lambda} = 189.1 {+-} 5.1 deg. These results conform with a previously noted pattern among the stellar hosts of close-in giant planets: hotter stars have a wide range of obliquities and cooler stars have low obliquities. This, in turn, suggests that three-body dynamics and tidal dissipation are responsible for the short-period orbits of many exoplanets. In addition, our data revealed a third body in the HAT-P-4 system, which could be a second planet or a companion star.

  18. VLT Detects First Superstorm on Exoplanet

    NASA Astrophysics Data System (ADS)

    2010-06-01

    Astronomers have measured a superstorm for the first time in the atmosphere of an exoplanet, the well-studied "hot Jupiter" HD209458b. The very high-precision observations of carbon monoxide gas show that it is streaming at enormous speed from the extremely hot day side to the cooler night side of the planet. The observations also allow another exciting "first" - measuring the orbital speed of the exoplanet itself, providing a direct determination of its mass. The results appear this week in the journal Nature. "HD209458b is definitely not a place for the faint-hearted. By studying the poisonous carbon monoxide gas with great accuracy we found evidence for a super wind, blowing at a speed of 5000 to 10 000 km per hour" says Ignas Snellen, who led the team of astronomers. HD209458b is an exoplanet of about 60% the mass of Jupiter orbiting a solar-like star located 150 light-years from Earth towards the constellation of Pegasus (the Winged Horse). Circling at a distance of only one twentieth the Sun-Earth distance, the planet is heated intensely by its parent star, and has a surface temperature of about 1000 degrees Celsius on the hot side. But as the planet always has the same side to its star, one side is very hot, while the other is much cooler. "On Earth, big temperature differences inevitably lead to fierce winds, and as our new measurements reveal, the situation is no different on HD209458b," says team member Simon Albrecht. HD209458b was the first exoplanet to be found transiting: every 3.5 days the planet moves in front of its host star, blocking a small portion of the starlight during a three-hour period. During such an event a tiny fraction of the starlight filters through the planet's atmosphere, leaving an imprint. A team of astronomers from the Leiden University, the Netherlands Institute for Space Research (SRON), and MIT in the United States, have used ESO's Very Large Telescope and its powerful CRIRES spectrograph to detect and analyse these faint

  19. First Solid Evidence for a Rocky Exoplanet - Mass and density of smallest exoplanet finally measured

    NASA Astrophysics Data System (ADS)

    2009-09-01

    The longest set of HARPS measurements ever made has firmly established the nature of the smallest and fastest-orbiting exoplanet known, CoRoT-7b, revealing its mass as five times that of Earth's. Combined with CoRoT-7b's known radius, which is less than twice that of our terrestrial home, this tells us that the exoplanet's density is quite similar to the Earth's, suggesting a solid, rocky world. The extensive dataset also reveals the presence of another so-called super-Earth in this alien solar system. "This is science at its thrilling and amazing best," says Didier Queloz, leader of the team that made the observations. "We did everything we could to learn what the object discovered by the CoRoT satellite looks like and we found a unique system." In February 2009, the discovery by the CoRoT satellite [1] of a small exoplanet around a rather unremarkable star named TYC 4799-1733-1 was announced one year after its detection and after several months of painstaking measurements with many telescopes on the ground, including several from ESO. The star, now known as CoRoT-7, is located towards the constellation of Monoceros (the Unicorn) at a distance of about 500 light-years. Slightly smaller and cooler than our Sun, CoRoT-7 is also thought to be younger, with an age of about 1.5 billion years. Every 20.4 hours, the planet eclipses a small fraction of the light of the star for a little over one hour by one part in 3000 [2]. This planet, designated CoRoT-7b, is only 2.5 million kilometres away from its host star, or 23 times closer than Mercury is to the Sun. It has a radius that is about 80% greater than the Earth's. The initial set of measurements, however, could not provide the mass of the exoplanet. Such a result requires extremely precise measurements of the velocity of the star, which is pulled a tiny amount by the gravitational tug of the orbiting exoplanet. The problem with CoRoT-7b is that these tiny signals are blurred by stellar activity in the form of

  20. ExoplanetSat: detecting transiting exoplanets using a low-cost CubeSat platform

    NASA Astrophysics Data System (ADS)

    Smith, Matthew W.; Seager, Sara; Pong, Christopher M.; Villaseñor, Jesus S.; Ricker, George R.; Miller, David W.; Knapp, Mary E.; Farmer, Grant T.; Jensen-Clem, Rebecca

    2010-07-01

    Nanosatellites, i.e. spacecraft that weigh between 1 and 10 kg, are drawing increasing interest as platforms for conducting on-orbit science. This trend is primarily driven by the ability to piggyback nanosatellites on the launch of large spacecraft and hence achieve orbit at greatly reduced cost. The CubeSat platform is a standardized nanosatellite configuration, consisting of one, two, or three 10 cm x 10 cm x 10 cm units (1, 2, or 3 "U"s) arranged in a row. We present a CubeSat-based concept for the discovery of transiting exoplanets around the nearest and brightest Sun-like stars. The spacecraft prototype - termed ExoplanetSat - is a 3U space telescope capable of monitoring a single target star from low Earth orbit. Given the volume limitations of the CubeSat form factor, designing a capable spacecraft requires overcoming significant challenges. This work presents the initial satellite configuration along with several subsystem-specific solutions to the aforementioned constraints. An optical design based on a modified commercial off-the-shelf camera lens is given. We also describe a novel two-stage attitude control architecture that combines 3-axis reaction wheels for coarse pointing with a piezoelectric translation stage at the focal plane for fine pointing. Modeling and simulation results are used to demonstrate feasibility by quantifying ExoplanetSat pointing precision, signal-to-noise ratio, guide star magnitude, and additional design parameters which determine system performance.

  1. X-Exoplanets: An X-ray and EUV Database for Exoplanets

    NASA Astrophysics Data System (ADS)

    Sanz-Forcada, J.; García-Álvarez, D.; Velasco, A.; Solano, E.; Ribas, I.; Micela, G.; Pollock, A.

    2010-10-01

    Extreme ultraviolet (EUV) and X-ray emission is of great importance in several phenomena related to the formation of planetary systems and the atmospheres of planets. The atmospheric composition and the mass of an exoplanet are partly dependent on the X-ray and EUV radiation received during the first stages of formation and even during main sequence of the star. Biological life developing on exoplanets would depend severely on the high energy radiation arriving from its parent star. Here we present a database of the X-ray and EUV emission of all the stars currently known to host exoplanets. The archive is public and accessible through the Spanish Virtual Observatory (SVO). The database gives the user the option to download observed X-rays and EUV spectra. Synthetic spectra covering the spectral range 1-912 Å are also available (present day telescopes do not give access to the EUV range at λ > ;180 Å). These spectra are created using coronal models after fitting observed spectra.

  2. X-exoplanets: an X-ray and EUV database for exoplanets

    NASA Astrophysics Data System (ADS)

    Sanz-Forcada, J.; García-Álvarez, D.; Velasco, A.; Solano, E.; Ribas, I.; Micela, G.; Pollock, A.

    2010-02-01

    Extreme Ultraviolet (EUV) and X-ray emission is of great importance in several phenomena related to the formation of planetary systems and the atmospheres of planets. The atmospheric composition, and the mass of an exoplanet, are partly dependent on the X-ray and EUV radiation received during the first stages of formation and even during main sequence of the star. Biological life developing on exoplanets would depend severely on the high energy radiation arriving from its parent star. Here we present a database of the X-ray and EUV emission of all the stars currently known to host exoplanets. The archive is public and accessible through the Spanish Virtual Observatory (SVO). The database gives the user the option to download observed X-rays and EUV spectra. Synthetic spectra covering the spectral range 1-912 Å are also available (present day telescopes do not give access to the EUV range at λ > 180 Å). These spectra are created using coronal models after fitting observed spectra.

  3. Companion Cases in a Large Urban Medical Examiner's Office.

    PubMed

    Hlavaty, Leigh; Njiwaji, Chantel; Sung, LokMan

    2015-12-01

    Companion death cases, as defined in this study, include 2 or more deaths that occur at the same location or 1 death at a specific location combined with 1 or more individuals transported from that same location to a hospital where death was pronounced within 1 hour of arrival. These types of cases can have multiple causes and manners of death. The Wayne County Medical Examiner's Office conducted a retrospective study of companion death cases that came into the office from mid 2007 to the end of 2014. The purpose of the study was to identify and examine patterns of companion death cases in a large urban area that would assist future companion death case investigations. Three hundred fifty deaths were found to be companion cases, including 135 pairs (2 connected deaths in the same location), 20 trios, and 5 quartets. Approximately 49% of companion case deaths were homicides. Approximately 30% of companion case deaths were traumatic accidental deaths. Around 14% of companion case deaths that were from the same scene location had different manners of death, including suicide, homicide, natural, and indeterminate. The remainder of companion death cases were either drug related or natural. Through this study, we have identified a pattern to these companion death cases and have concluded that it is important to conduct a thorough medicolegal death investigation of such cases to establish and elucidate the true circumstances surrounding these deaths. PMID:26332646

  4. MASS-RADIUS RELATIONSHIPS FOR EXOPLANETS

    SciTech Connect

    Swift, D. C.; Eggert, J. H.; Hicks, D. G.; Hamel, S.; Caspersen, K.; Schwegler, E.; Collins, G. W.; Nettelmann, N.; Ackland, G. J.

    2012-01-01

    For planets other than Earth, particularly exoplanets, interpretation of the composition and structure depends largely on comparing the mass and radius with the composition expected given their distance from the parent star. The composition implies a mass-radius relation which relies heavily on equations of state calculated from electronic structure theory and measured experimentally on Earth. We lay out a method for deriving and testing equations of state, and deduce mass-radius and mass-pressure relations for key, relevant materials whose equation of state (EOS) is reasonably well established, and for differentiated Fe/rock. We find that variations in the EOS, such as may arise when extrapolating from low-pressure data, can have significant effects on predicted mass-radius relations and on planetary pressure profiles. The relations are compared with the observed masses and radii of planets and exoplanets, broadly supporting recent inferences about exoplanet structures. Kepler-10b is apparently 'Earth-like', likely with a proportionately larger core than Earth's, nominally 2/3 of the mass of the planet. CoRoT-7b is consistent with a rocky mantle over an Fe-based core which is likely to be proportionately smaller than Earth's. GJ 1214b lies between the mass-radius curves for H{sub 2}O and CH{sub 4}, suggesting an 'icy' composition with a relatively large core or a relatively large proportion of H{sub 2}O. CoRoT-2b is less dense than the hydrogen relation, which could be explained by an anomalously high degree of heating or by higher than assumed atmospheric opacity. HAT-P-2b is slightly denser than the mass-radius relation for hydrogen, suggesting the presence of a significant amount of matter of higher atomic number. CoRoT-3b lies close to the hydrogen relation. The pressure at the center of Kepler-10b is 1.5{sup +1.2}{sub -1.0} TPa. The central pressure in CoRoT-7b is probably close to 0.8 TPa, though may be up to 2 TPa. These pressures are accessible by planar

  5. Dynamos in Terrestrial Exoplanets as Magnetic Shields

    NASA Astrophysics Data System (ADS)

    Driscoll, Peter; Olson, Peter

    2010-05-01

    In order to retain large amounts of water and maintain a habitable surface over long time-scales a magnetic field may be required to shield the atmosphere from mass loss and the surface from harmful stellar radiation. Terrestrial exoplanets in the 1-10 Earth-mass regime orbiting inside of 3 AU with an Earth-like composition, referred to as Super-Earths, are expected to have large, mostly Iron cores that could sustain a convectively driven dynamo. We present a model to estimate the maximum self-sustained magnetic moment of a terrestrial dynamo given the total mass and core-mass fraction. Assuming the magnetic field is self-sustained by a convectively driven dynamo we estimate the magnetic moment using a dynamo scaling law, which relies on dynamical properties of the planetary interior, such as the convective heat flux at the core-mantle boundary and size of the dynamo region. To estimate these properties we model the internal structure of the planet using a sub-solidus, mobile lid convection profile for the mantle and a thermal convection profile for the core. We present models for 1-10 Earth-masses and a range of core-mass fractions. In order to maintain a strong magnetic field we maximize the energy available to drive the dynamo by allowing the core-mantle boundary temperature to be at the perovskite solidus, denoted as the "optimal" state for magnetic field generation. We estimate an optimal Earth-mass planet can maintain a core heat flow of 30 TW, which implies a surface field intensity and magnetic moment of about twice that of the Earth. For a 10 Earth-mass planet that is 65% core by mass (Super-Mercury) we find a core heat flow of 180 TW, and a surface field intensity and magnetic moment of about 6 and 25 times that of the Earth, respectively. We demonstrate that exoplanets with large cores that produce strong magnetic fields can act to shield the surface from stellar radiation, minimizing atmospheric volatile loss and maintaining a habitable surface over

  6. Direct exoplanet detection and characterization using the ANDROMEDA method: Performance on VLT/NaCo data

    NASA Astrophysics Data System (ADS)

    Cantalloube, F.; Mouillet, D.; Mugnier, L. M.; Milli, J.; Absil, O.; Gomez Gonzalez, C. A.; Chauvin, G.; Beuzit, J.-L.; Cornia, A.

    2015-10-01

    Context. The direct detection of exoplanets with high-contrast imaging requires advanced data processing methods to disentangle potential planetary signals from bright quasi-static speckles. Among them, angular differential imaging (ADI) permits potential planetary signals with a known rotation rate to be separated from instrumental speckles that are either statics or slowly variable. The method presented in this paper, called ANDROMEDA for ANgular Differential OptiMal Exoplanet Detection Algorithm, is based on a maximum likelihood approach to ADI and is used to estimate the position and the flux of any point source present in the field of view. Aims: In order to optimize and experimentally validate this previously proposed method, we applied ANDROMEDA to real VLT/NaCo data. In addition to its pure detection capability, we investigated the possibility of defining simple and efficient criteria for automatic point source extraction able to support the processing of large surveys. Methods: To assess the performance of the method, we applied ANDROMEDA on VLT/NaCo data of TYC-8979-1683-1 which is surrounded by numerous bright stars and on which we added synthetic planets of known position and flux in the field. In order to accommodate the real data properties, it was necessary to develop additional pre-processing and post-processing steps to the initially proposed algorithm. We then investigated its skill in the challenging case of a well-known target, β Pictoris, whose companion is close to the detection limit and we compared our results to those obtained by another method based on principal component analysis (PCA). Results: Application on VLT/NaCo data demonstrates the ability of ANDROMEDA to automatically detect and characterize point sources present in the image field. We end up with a robust method bringing consistent results with a sensitivity similar to the recently published algorithms, with only two parameters to be fine tuned. Moreover, the companion flux

  7. Combinatorics and companion galaxies: Paradox lost

    NASA Technical Reports Server (NTRS)

    Newman, William I.; Terzian, Yervant

    1995-01-01

    Arp (1994) has presented redshift data for the Local Group of galaxies and for the next major group, whose largest galaxies are M31 and M81, respectively. He observed that the relative redshifts of all 22 of their companions were positive and claimed that the likelihood that this would occur is 1 in 4 x 10(exp 6). We show using the classical combinatoric paradigm of ordered samples (without replacement) that the correct probability for the dominant member of each cluster to possess the lowest observed redshift is approximately 8%.

  8. The search for companions to Epsilon Eridani.

    PubMed

    Lawton, A T; Wright, P

    1990-12-01

    The authors review efforts to examine the star Epsilon Eridani and determine the possibility for the existence of an Earth-like planet. Early data indicated that there must be a habitable ecosphere about 82.5 million Km from the primary. Research into the existence of another planetary system determined that Epsilon Eridani was a binary star with an Oort cloud system, indicating the possibility of planet formation. A review of the evidence suggests that the presence of the small red Dwarf companion star precludes the existence of a planetary system surrounding Epsilon Eridani. It is suggested that observations continue to provide further data about the formation of binary systems. PMID:11540498

  9. A Statistical Study of Brown Dwarf Companions from the SDSS-III MARVELS Survey

    NASA Astrophysics Data System (ADS)

    Grieves, Nolan; Ge, Jian; Thomas, Neil; Ma, Bo; De Lee, Nathan M.; Lee, Brian L.; Fleming, Scott W.; Sithajan, Sirinrat; Varosi, Frank; Liu, Jian; Zhao, Bo; Li, Rui; Agol, Eric; MARVELS Team

    2016-01-01

    We present 23 new Brown Dwarf (BD) candidates from the Multi-object APO Radial-Velocity Exoplanet Large-Area Survey (MARVELS) of the Sloan Digital Sky Survey III (SDSS-III). The BD candidates were selected from the processed MARVELS data using the latest University of Florida 2D pipeline, which shows significant improvement and reduction of systematic errors over the 1D pipeline results included in the SDSS Data Release 12. This sample is the largest BD yield from a single radial velocity survey. Of the 23 candidates, 18 are around main sequence stars and 5 are around giant stars. Given a giant contamination rate of ~24% for the MARVELS survey, we find a BD occurrence rate around main sequence stars of ~0.7%, which agrees with previous studies and confirms the BD desert, while the BD occurrence rate around the MARVELS giant stars is ~0.6%. Preliminary results show that our new candidates around solar type stars support a two population hypothesis, where BDs are divided at a mass of ~42.5 MJup. BDs less massive than 42.5 MJup have eccentricity distributions consistent with planet-planet scattering models, where BDs more massive than 42.5 MJup have both period and eccentricity distributions similar to that of stellar binaries. Special Brown Dwarf systems such as multiple BD systems and highly eccentric BDs will also be presented.

  10. BANYAN. VI. Discovery of a Companion at the Brown Dwarf/Planet-Mass Limit to a Tucana–Horologium M Dwarf

    NASA Astrophysics Data System (ADS)

    Artigau, Étienne; Gagné, Jonathan; Faherty, Jacqueline; Malo, Lison; Naud, Marie-Eve; Doyon, René; Lafrenière, David; Beletsky, Yuri

    2015-06-01

    We report the discovery of a substellar companion to 2MASS J02192210–3925225, a young M6 γ candidate member of the Tucana–Horologium association (30–40 Myr). This L4 γ companion has been discovered with seeing-limited direct imaging observations; at a 4″ separation (160 AU) and a modest contrast ratio, it joins the very short list of young low-mass companions amenable to study without the aid of adaptive optics, enabling its characterization with a much wider suite of instruments than is possible for companions uncovered by high-contrast imaging surveys. With a model-dependent mass of 12–15 {M}{Jup}, it straddles the boundary between the planet and brown dwarf mass regimes. We present near-infrared spectroscopy of this companion and compare it to various similar objects uncovered in the last few years. The J0219–3925 system falls in a sparsely populated part of the host mass versus mass ratio diagram for binaries; the dearth of known similar companions may be due to observational biases in previous low-mass companion searches.

  11. Thesis: A Combined-light Mission For Exoplanet Molecular Spectroscopy

    NASA Astrophysics Data System (ADS)

    Deroo, Pieter; Swain, M. R.; Tinetti, G.; Griffith, C.; Vasisht, G.; Deming, D.; Henning, T.; Beaulieu, J.

    2010-01-01

    THESIS, the Transiting Habitable-zone Exoplanet Spectroscopy Infrared Spacecraft, is a concept for a MIDEX/Discovery class exoplanet mission. Building on the recent Spitzer and Hubble successes in exoplanet characterization and molecular spectroscopy, THESIS would extend these types of measurements to a large population of planets including non-transiting planets and super-Earths. The ability to acquire high-stability, spectroscopic data from the near-visible to the mid-infrared is a unique aspect of THESIS. A strength of the THESIS concept is simplicity low technical risk, and modest cost. By enabling molecular spectroscopy of exoplanet atmospheres, THESIS mission has the potential to dramatically advance our understanding of conditions on extrasolar worlds while serving as a stepping stone to more ambitious future missions.

  12. TERMS PHOTOMETRY OF KNOWN TRANSITING EXOPLANETS

    SciTech Connect

    Dragomir, Diana; Kane, Stephen R.; Ciardi, David R.; Gelino, Dawn M.; Payne, Alan; Ramirez, Solange V.; Von Braun, Kaspar; Wyatt, Pamela; Pilyavsky, Genady; Mahadevan, Suvrath; Wright, Jason T.; Zachary Gazak, J.; Rabus, Markus

    2011-10-15

    The Transit Ephemeris Refinement and Monitoring Survey conducts radial velocity and photometric monitoring of known exoplanets in order to refine planetary orbits and predictions of possible transit times. This effort is primarily directed toward planets not known to transit, but a small sample of our targets consists of known transiting systems. Here we present precision photometry for six WASP (Wide Angle Search for Planets) planets acquired during their transit windows. We perform a Markov Chain Monte Carlo analysis for each planet and combine these data with previous measurements to redetermine the period and ephemerides for these planets. These observations provide recent mid-transit times which are useful for scheduling future observations. Our results improve the ephemerides of WASP-4b, WASP-5b, and WASP-6b and reduce the uncertainties on the mid-transit time for WASP-29b. We also confirm the orbital, stellar, and planetary parameters of all six systems.

  13. A sub-Mercury-sized exoplanet.

    PubMed

    Barclay, Thomas; Rowe, Jason F; Lissauer, Jack J; Huber, Daniel; Fressin, François; Howell, Steve B; Bryson, Stephen T; Chaplin, William J; Désert, Jean-Michel; Lopez, Eric D; Marcy, Geoffrey W; Mullally, Fergal; Ragozzine, Darin; Torres, Guillermo; Adams, Elisabeth R; Agol, Eric; Barrado, David; Basu, Sarbani; Bedding, Timothy R; Buchhave, Lars A; Charbonneau, David; Christiansen, Jessie L; Christensen-Dalsgaard, Jørgen; Ciardi, David; Cochran, William D; Dupree, Andrea K; Elsworth, Yvonne; Everett, Mark; Fischer, Debra A; Ford, Eric B; Fortney, Jonathan J; Geary, John C; Haas, Michael R; Handberg, Rasmus; Hekker, Saskia; Henze, Christopher E; Horch, Elliott; Howard, Andrew W; Hunter, Roger C; Isaacson, Howard; Jenkins, Jon M; Karoff, Christoffer; Kawaler, Steven D; Kjeldsen, Hans; Klaus, Todd C; Latham, David W; Li, Jie; Lillo-Box, Jorge; Lund, Mikkel N; Lundkvist, Mia; Metcalfe, Travis S; Miglio, Andrea; Morris, Robert L; Quintana, Elisa V; Stello, Dennis; Smith, Jeffrey C; Still, Martin; Thompson, Susan E

    2013-02-28

    Since the discovery of the first exoplanets, it has been known that other planetary systems can look quite unlike our own. Until fairly recently, we have been able to probe only the upper range of the planet size distribution, and, since last year, to detect planets that are the size of Earth or somewhat smaller. Hitherto, no planets have been found that are smaller than those we see in the Solar System. Here we report a planet significantly smaller than Mercury. This tiny planet is the innermost of three that orbit the Sun-like host star, which we have designated Kepler-37. Owing to its extremely small size, similar to that of the Moon, and highly irradiated surface, the planet, Kepler-37b, is probably rocky with no atmosphere or water, similar to Mercury. PMID:23426260

  14. Exoplanet Population Estimate from Kepler Data

    NASA Astrophysics Data System (ADS)

    Traub, Wesley A.

    2015-11-01

    The intrinsic population of exoplanets around Kepler target stars is estimated by comparing the observed numbers of planets at each radius and period against a simulation that accounts for the probability of transit and the estimated instrument sensitivity. By assuming that the population can be modeled as a function of period times a function of radius, and further assuming that these functions are broken power laws, sufficient leverage is gained such that the well-measured short-period planet distribution can effectively be used as a template for the less-well sampled long-period terrestrial planets. The resulting population distribution provides a challenge to models of the origin and evolution of planetary systems.

  15. Diagnosing clouds and hazes in exoplanet atmospheres

    NASA Astrophysics Data System (ADS)

    Fraine, Jonathan David

    Exoplanet atmospheres provide a probe into the conditions on alien worlds, from hot Jupiters to Super-Earths. We can now glimpse the behaviour of extreme solar systems that defy our understanding of planet formation and capture our imaginations about the possibilities for understanding planets and life in our universe. I combined multi-epoch, multi-instrument observations from both space and ground based facilities. I developed observational techniques and tools to constrain exoplanetary atmospheric compositions, temperature profiles, and scale heights over a span of planetary masses and wavelengths, that provided a probe into the properties of these diverse planetary atmospheres. I led a team that used the Spitzer Space Telescope, with the IR Array Camera (IRAC), to observe the well known transiting Super-Earth, GJ 1214b (˜2.7 R⊕). My precisely constrained infrared transit depth, error ˜ O(40 ppm), significantly constrained the lack of any molecular detections out to a wavelength of 5mum. The significance of this null detection challenges self-consistent models for the atmosphere of this super-Earth. Models must invoke thick, grey opacity clouds that uniformly cause the atmosphere to be opaque at all wavelengths. My team and I used the Hubble Space Telescope Wide Field Camera 3 (HST-WFC3) to spectroscopically probe the atmosphere of the transiting warm Neptune, HAT-P-11b (˜4.5 R⊕), and detected the first molecular signature from a small exoplanet (Rp < RSaturn), inferring the presence of a hydrogen rich atmosphere. The average densities of many transiting exoplanets are known, but the degree to which atmospheric composition---abundance of Hydrogen relative to other atoms and molecules---correlates with the bulk composition has not yet been established. In an effort to characterize the atmospheric metallicity in greater detail, my team observed HAT-P-11 using warm Spitzer IRAC at 3.6 and 4.5mum. The non-detections of eclipses HAT-P-11b provided upper limits

  16. HOMES Holographic Optical Method for Exoplanet Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.; McGrew, Stephen P.

    2013-09-01

    A novel telescope architecture is proposed specifically for the purpose of taking spectra of exoplanets orbiting stars within 10 pc ("the neighborhood"). The primary objective and the secondary spectrograph are holographic optical elements (HOEs) formed on flat membrane substrates of low areal mass that can be transported on cylinder rolls that are compatible with the payload geometry of delivery vehicles. Ribbon-shaped HOEs of up to 100 x 10 meters are contemplated. Computer models are presented with these dimensions. The models predict resolving power better than 10 mas. Because the primary separates wavelengths, we consider coronagraphs that use the divide and conquer strategy of one wavelength at a time. After delivery at the second Lagrange point, the stowed membranes are unfurled into flat holographic optics positioned in a four part formation spanning 1 km of open space.

  17. French Pro/Am collaborations in exoplanet

    NASA Astrophysics Data System (ADS)

    Santerne, A.; Moutou, C.; Vanhuysse, M.; Bouchy, F.; Buil, C.; Cochard, F.; Thizy, O.; Martinez, P.; Desnoux, V.; Pujol, M.; Colas, F.

    2011-10-01

    Amateur astronomers have access to huge telescope time and can reach photometric precision up to a few mmag as well as radial velocity precision up to ˜ 50m.s-1 on brightest stars. We will first present some results of french amateur astronomers in transit photometry and radial velocity and then, we will present an over-view of all the collaborations which can be done between professional and amateur astronomers in the competitive exoplanet domain, and especially the current collaboration between french Pro & Am astronomers which was used in publication in A&A. Finally, we will present a new internet wiki page which goal is to develop such collaboration in different countries.

  18. COMPLETENESS OF IMAGING SURVEYS FOR ECCENTRIC EXOPLANETS

    SciTech Connect

    Kane, Stephen R.

    2013-03-20

    The detection of exoplanets through direct imaging has produced numerous new positive identifications in recent years. The technique is biased toward planets at wide separations due to the difficulty in removing the stellar signature at small angular separations. Planets in eccentric orbits will thus move in and out of the detectable region around a star as a function of time. Here we use the known diversity of orbital eccentricities to determine the range of orbits that may lie beneath the detection threshold of current surveys. We quantify the percentage of the orbit that yields a detectable signature as a function of semimajor axis, eccentricity, and orbital inclination and estimate the fraction of planets which likely remain hidden by the flux of the host star.

  19. Engaging Undergraduate Students in Transiting Exoplanet Research with Small Telescopes

    NASA Astrophysics Data System (ADS)

    Stephens, Denise C.; Stoker, E.; Gaillard, C.; Ranquist, E.; Lara, P.; Wright, K.

    2013-10-01

    Brigham Young University has a relatively large undergraduate physics program with 300 to 360 physics majors. Each of these students is required to be engaged in a research group and to produce a senior thesis before graduating. For the astronomy professors, this means that each of us is mentoring at least 4-6 undergraduate students at any given time. For the past few years I have been searching for meaningful research projects that make use of our telescope resources and are exciting for both myself and my students. We first started following up Kepler Objects of Interest with our 0.9 meter telescope, but quickly realized that most of the transits we could observe were better analyzed with Kepler data and were false positive objects. So now we have joined a team that is searching for transiting planets, and my students are using our 16" telescope to do ground based follow-up on the hundreds of possible transiting planet candidates produced by this survey. In this presentation I will describe our current telescopes, the observational setup, and how we use our telescopes to search for transiting planets. I'll describe some of the software the students have written. I'll also explain how to use the NASA Exoplanet Archive to gather data on known transiting planets and Kepler Objects of Interests. These databases are useful for determining the observational limits of your small telescopes and teaching your students how to reduce and report data on transiting planets. Once that is in place, you are potentially ready to join existing transiting planet missions by doing ground-based follow-up. I will explain how easy it can be to implement this type of research at any high school, college, or university with a small telescope and CCD camera.

  20. Search for surviving companions in type Ia supernova remnants

    SciTech Connect

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E. E-mail: pmricker@illinois.edu E-mail: taam@asiaa.sinica.edu.tw

    2014-09-01

    The nature of the progenitor systems of type Ia supernovae (SNe Ia) is still unclear. One way to distinguish between the single-degenerate scenario and double-degenerate scenario for their progenitors is to search for the surviving companions (SCs). Using a technique that couples the results from multi-dimensional hydrodynamics simulations with calculations of the structure and evolution of main-sequence- (MS-) and helium-rich SCs, the color and magnitude of MS- and helium-rich SCs are predicted as functions of time. The SC candidates in Galactic type Ia supernova remnants (Ia SNR) and nearby extragalactic Ia SNRs are discussed. We find that the maximum detectable distance of MS SCs (helium-rich SCs) is 0.6-4 Mpc (0.4-16 Mpc), if the apparent magnitude limit is 27 in the absence of extinction, suggesting that the Large and Small Magellanic Clouds and the Andromeda Galaxy are excellent environments in which to search for SCs. However, only five Ia SNRs have been searched for SCs, showing little support for the standard channels in the singe-degenerate scenario. To better understand the progenitors of SNe Ia, we encourage the search for SCs in other nearby Ia SNRs.

  1. Search for Surviving Companions in Type Ia Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E.

    2014-09-01

    The nature of the progenitor systems of type Ia supernovae (SNe Ia) is still unclear. One way to distinguish between the single-degenerate scenario and double-degenerate scenario for their progenitors is to search for the surviving companions (SCs). Using a technique that couples the results from multi-dimensional hydrodynamics simulations with calculations of the structure and evolution of main-sequence- (MS-) and helium-rich SCs, the color and magnitude of MS- and helium-rich SCs are predicted as functions of time. The SC candidates in Galactic type Ia supernova remnants (Ia SNR) and nearby extragalactic Ia SNRs are discussed. We find that the maximum detectable distance of MS SCs (helium-rich SCs) is 0.6-4 Mpc (0.4-16 Mpc), if the apparent magnitude limit is 27 in the absence of extinction, suggesting that the Large and Small Magellanic Clouds and the Andromeda Galaxy are excellent environments in which to search for SCs. However, only five Ia SNRs have been searched for SCs, showing little support for the standard channels in the singe-degenerate scenario. To better understand the progenitors of SNe Ia, we encourage the search for SCs in other nearby Ia SNRs.

  2. Doppler methods of search and monitoring of exoplanets

    NASA Astrophysics Data System (ADS)

    Panchuk, V. E.; Klochkova, V. G.; Sachkov, M. E.; Yushkin, M. V.

    2015-12-01

    The main stages of the development of Doppler methods of search and study of extrasolar planetary systems (exoplanets) are described. The main instrumental and methodological effects that influence the measurement accuracy of spectral line positions in the study of exoplanets are considered. The development of the domestic spectrograph for spectroscopic monitoring with high-precision determination of radial velocities is reported. Directions for further development of high-resolution spectroscopy are discussed.

  3. Exoplanet Photometry and Spectroscopy with HII/L2

    NASA Astrophysics Data System (ADS)

    Tamura, M.

    2000-12-01

    With the recent discovery of extrasolar planets (exoplanets) around nearby stars by indirect methods, one of the next goals of the exoplanet study is to directly detect the giant exoplanets and to make photometry and spectroscopy. The next decade will be the time to move from discovery to characterization of exoplanet systems. This, however, requires all of high sensitivity, high spatial resolution, and high dynamic range observations at infrared wavelengths, which will be difficult to achieve from the ground. In this paper, we describe a coronagraphic camera and spectrometer for the HII/L2 mission for mid- and far-infrared astronomy and show the photometry and spectroscopy of exoplanets to be one of the most important scientific aims for this mission. The proposed HII/L2 coronagraph will cover the wavelength between 4 and 27 micron, optimized at 5 micron. The plate scale is about 0.06 arcsec, covering a field-of-view of about 1 arcmin by 1 arcmin with a 1024x1024 array detector. Occulting masks of diameter greater than 0.72 arcsec will be available, which enables the observations of exoplanets beyond ~2 AU around nearby (d~5 pc) stars. The coronagraph greatly takes advantage of the single (non-segmented) mirror of the HII/L2 telescope design. A high-efficiency Ge or CdTe grism with a resolution of a few hundreds will be installed for the coronagraphic spectroscopy of the exoplanet atmosphere. Rich spectral features at mid-infrared wavelengths enable us to study various atmospheric components and to make a comparative study of the exoplanets and our solar system planets.

  4. The search for exoplanets in the ESA Science Programme

    NASA Astrophysics Data System (ADS)

    Volonte, S.; Fridlund, C. V. M.

    2003-10-01

    The Darwin mission is a mission aimed at the search for and study of Terrestrial Exoplanets. As such it may be one of the most ambitious objectives undertaken by the European Space Agency. We describe the place of it as an integral part in the COSMIC VISION science plans and the topic of exo-planets. We describe the context within which it will be carried out in the next decade.

  5. Tidal Decay and Disruption of Gaseous Exoplanets

    NASA Astrophysics Data System (ADS)

    Jackson, Brian K.; Arras, Phil; Jensen, Emily; Peacock, Sarah; Marchant, Pablo; Penev, Kaloyan

    2015-11-01

    Many gaseous exoplanets in short-period orbits are on the verge of Roche-lobe overflow, and observations, along with orbital stability analysis, show tides probably drive significant orbital decay. Thus, the coupled processes of orbital evolution and tidal disruption likely shape the observed distribution of close-in exoplanets and may even be responsible for producing the shortest-period solid planets. However, the exact outcome for an overflowing planet depends on its internal response to mass loss and variable stellar insolation, and the accompanying orbital evolution can act to enhance or inhibit the disruption process. The final orbits of the denuded remnants of gas giants may be predictable from their mass-radius relationship, and so a distinctive mass-period relationship for some short-period solid planets may provide evidence for their origins as gaseous planets. In this presentation, we will discuss our work on tidal decay and disruption of close-in gaseous planets using a new model that accounts for the fact that short-period planets have hot, distended atmospheres, which can result in overflow even for planets that are not officially in Roche lobe contact. We will also point out that the orbital expansion that can accompany mass transfer may be less effective than previously realized because the resulting accretion disk may not return all of its angular momentum to the donor, as is usually assumed. Both of these effects have bee incorporated into the fully-featured and robust Modules for Experiments in Stellar Astrophysics (MESA) suite.

  6. LIGHT SCATTERING FROM EXOPLANET OCEANS AND ATMOSPHERES

    SciTech Connect

    Zugger, M. E.; Kane, T. J.; Kasting, J. F.; Williams, D. M.; Philbrick, C. R.

    2010-11-10

    Orbital variation in reflected starlight from exoplanets could eventually be used to detect surface oceans. Exoplanets with rough surfaces, or dominated by atmospheric Rayleigh scattering, should reach peak brightness in full phase, orbital longitude (OL) = 180{sup 0}, whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30{sup 0}. Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 74{sup 0}; however, our model shows that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column dilute the polarization fraction and shift the peak to other OLs. Observing at longer wavelengths reduces the obfuscation of the water polarization signature by Rayleigh scattering but does not mitigate the other effects. Planets with thick Rayleigh scattering atmospheres reach peak polarization near OL = 90{sup 0}, but clouds and Lambertian surface scattering dilute and shift this peak to smaller OL. A shifted Rayleigh peak might be mistaken for a water signature unless data from multiple wavelength bands are available. Our calculations suggest that polarization alone may not positively identify the presence of an ocean under an Earth-like atmosphere; however, polarization adds another dimension which can be used, in combination with unpolarized orbital light curves and contrast ratios, to detect extrasolar oceans, atmospheric water aerosols, and water clouds. Additionally, the presence and direction of the polarization vector could be used to determine planet association with the star, and constrain orbit inclination.

  7. Direct Exoplanet Detection with Binary Differential Imaging

    NASA Astrophysics Data System (ADS)

    Rodigas, Timothy J.; Weinberger, Alycia; Mamajek, Eric E.; Males, Jared R.; Close, Laird M.; Morzinski, Katie; Hinz, Philip M.; Kaib, Nathan

    2015-10-01

    Binaries are typically excluded from direct imaging exoplanet surveys. However, the recent findings of Kepler and radial velocity programs show that planets can and do form in binary systems. Here, we suggest that visual binaries offer unique advantages for direct imaging. We show that Binary Differential Imaging (BDI), whereby two stars are imaged simultaneously at the same wavelength within the isoplanatic patch at a high Strehl ratio, offers improved point spread function (PSF) subtraction that can result in increased sensitivity to planets close to each star. We demonstrate this by observing a young visual binary separated by 4″ with MagAO/Clio-2 at 3.9 μm, where the Strehl ratio is high, the isoplanatic patch is large, and giant planets are bright. Comparing BDI to angular differential imaging (ADI), we find that BDI’s 5σ contrast is ˜0.5 mag better than ADI’s within ˜1″ for the particular binary we observed. Because planets typically reside close to their host stars, BDI is a promising technique for discovering exoplanets in stellar systems that are often ignored. BDI is also 2-4× more efficient than ADI and classical reference PSF subtraction, since planets can be detected around both the target and PSF reference simultaneously. We are currently exploiting this technique in a new MagAO survey for giant planets in 140 young nearby visual binaries. BDI on a space-based telescope would not be limited by isoplanatism effects and would therefore be an even more powerful tool for imaging and discovering planets. This paper includes data obtained at the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  8. EQUATORIAL SUPERROTATION ON TIDALLY LOCKED EXOPLANETS

    SciTech Connect

    Showman, Adam P.; Polvani, Lorenzo M.

    2011-09-01

    The increasing richness of exoplanet observations has motivated a variety of three-dimensional (3D) atmospheric circulation models of these planets. Under strongly irradiated conditions, models of tidally locked, short-period planets (both hot Jupiters and terrestrial planets) tend to exhibit a circulation dominated by a fast eastward, or 'superrotating', jet stream at the equator. When the radiative and advection timescales are comparable, this phenomenon can cause the hottest regions to be displaced eastward from the substellar point by tens of degrees longitude. Such an offset has been subsequently observed on HD 189733b, supporting the possibility of equatorial jets on short-period exoplanets. Despite its relevance, however, the dynamical mechanisms responsible for generating the equatorial superrotation in such models have not been identified. Here, we show that the equatorial jet results from the interaction of the mean flow with standing Rossby waves induced by the day-night thermal forcing. The strong longitudinal variations in radiative heating-namely intense dayside heating and nightside cooling-trigger the formation of standing, planetary-scale equatorial Rossby and Kelvin waves. The Rossby waves develop phase tilts that pump eastward momentum from high latitudes to the equator, thereby inducing equatorial superrotation. We present an analytic theory demonstrating this mechanism and explore its properties in a hierarchy of one-layer (shallow-water) calculations and fully 3D models. The wave-mean-flow interaction produces an equatorial jet whose latitudinal width is comparable to that of the Rossby waves, namely the equatorial Rossby deformation radius modified by radiative and frictional effects. For conditions typical of synchronously rotating hot Jupiters, this length is comparable to a planetary radius, explaining the broad scale of the equatorial jet obtained in most hot-Jupiter models. Our theory illuminates the dependence of the equatorial jet

  9. Companion animal parasitology: a clinical perspective.

    PubMed

    Irwin, Peter J

    2002-05-01

    In recent years there have been many changes to the ways that clinical veterinary science is conducted and nowhere is this more evident than in companion animal practice. Veterinarians working with pet dogs and cats are facing new challenges associated with the emergence and re-emergence of parasitic diseases. Some, such as Neospora caninum, have been recently recognised; others like Giardia and Cryptosporidium have been reported with increasing frequency, in part as a result of laboratory tests with improved sensitivity and specificity. In many regions, the emergence of parasitic diseases has been a consequence of pet travel and exotic diseases pose a unique diagnostic challenge for the veterinarian, as the index of suspicion for these conditions may be absent. The ranges of certain vector-borne diseases such as babesiosis, hepatozoonosis, ehrlichiosis, leishmaniasis and dirofilariasis are extending due to ecological and climatic changes and enhanced by animals with subclinical infection returning home from endemic areas. In companion animal practice, veterinarians have the additional responsibility of providing accurate information about the zoonotic transmission of parasite infections from pets, especially to those most vulnerable such as children, the elderly and the immunocompromised. Effective education is vital to allay public concerns and promote responsible pet ownership. PMID:11943231

  10. 20 Years of Exoplanets: From Surveys Towards Characterization

    NASA Astrophysics Data System (ADS)

    Rauscher, Emily

    2015-11-01

    Twenty years ago the discovery of the first planet outside of our solar system ushered in a new subfield of exoplanet study. In the years since, the number of known planets has skyrocketed into the thousands, due to an ever-expanding pool of detection methods, projects and missions, and substantial improvements in technique. These remarkable discoveries have revealed an exoplanet population that is highly diverse, in many cases breaking expectations set by the single example of our own solar system, and providing us with the opportunity to study planets under a wide range of physical conditions. Equally as exciting as the increasing number of known exoplanets, within the last dozen years we have seen the move from exoplanet discovery to characterization we are currently able to measure atmospheric properties of many of the brightest exoplanets. We are now in an era where we can study the diversity of atmospheric conditions for dozens of exoplanets, including measurements of their temperatures, albedos, compositions, and in some cases even more detailed information about their two- or three-dimensional atmospheric structures and circulation patterns. In this talk I will review the current state of theory and observations, the lessons we have learned, and the questions and techniques that direct future work.

  11. Spectroscopy of Exoplanet Atmospheres with the FINESSE Explorer

    NASA Technical Reports Server (NTRS)

    Deroo, Pieter; Swain, Mark R.; Green, Robert O.

    2012-01-01

    FINESSE (Fast INfrared Exoplanet Spectroscopic Survey Explorer) will provide uniquely detailed information on the growing number of newly discovered planets by characterizing their atmospheric composition and temperature structure. This NASA Explorer mission, selected for a competitive Phase A study, is unique in its breath and scope thanks to broad instantaneous spectroscopy from the optical to the mid-IR (0.7 - 5 micron), with a survey of exoplanets measured in a consistent, uniform way. For 200 transiting exoplanets ranging from Terrestrial to Jovians, FINESSE will measure the chemical composition and temperature structure of their atmospheres and trace changes over time with exoplanet longitude. The mission will do so by measuring the spectroscopic time series for a primary and secondary eclipse over the exoplanet orbital phase curve. With spectrophotometric precision being a key enabling aspect for combined light exoplanet characterization, FINESSE is designed to produce spectrophotometric precision of better than 100 parts-per-million per spectral channel without the need for decorrelation. The exceptional stability of FINESSE will even allow the mission to characterize non-transiting planets, potentially as part of FINESSE's Participating Scientist Program. In this paper, we discuss the flow down from the target availability to observations and scheduling to the analysis and calibration of the data and how it enables FINESSE to be the mission that will truly expand the new field of comparative exoplanetology.

  12. Warm Debris Disk Candidates from WISE

    NASA Technical Reports Server (NTRS)

    Padgett, Deborah; Stapelfeldt, Karl; Liu, Wilson; Leisawitz, David

    2011-01-01

    The Wide Field Infrared Survey Explorer (WISE) has just completed a sensitive all-sky survey in photometric bands at 3.4, 4.6, 12, and 22 microns. We report on a preliminary investigation of main sequence Hipparcos and Tycho catalog stars with 22 micron emission in excess of photospheric levels. This warm excess emission traces material in the circumstellar region likely to host terrestrial planets and is preferentially found in young systems with ages < 1 Gyr. Nearly a hundred new warm debris disk candidates are detected among FGK stars and 150 A stars within 120 pc. We are in the process of obtaining spectra to determine spectral types and activity level of these stars and are using HST, Herschel and Keck to characterize the dust, multiplicity, and substellar companions of these systems. In this contribution, we will discuss source selection methods and individual examples from among the WISE debris disk candidates.

  13. An abundance of small exoplanets around stars with a wide range of metallicities.

    PubMed

    Buchhave, Lars A; Latham, David W; Johansen, Anders; Bizzarro, Martin; Torres, Guillermo; Rowe, Jason F; Batalha, Natalie M; Borucki, William J; Brugamyer, Erik; Caldwell, Caroline; Bryson, Stephen T; Ciardi, David R; Cochran, William D; Endl, Michael; Esquerdo, Gilbert A; Ford, Eric B; Geary, John C; Gilliland, Ronald L; Hansen, Terese; Isaacson, Howard; Laird, John B; Lucas, Philip W; Marcy, Geoffrey W; Morse, Jon A; Robertson, Paul; Shporer, Avi; Stefanik, Robert P; Still, Martin; Quinn, Samuel N

    2012-06-21

    The abundance of heavy elements (metallicity) in the photospheres of stars similar to the Sun provides a 'fossil' record of the chemical composition of the initial protoplanetary disk. Metal-rich stars are much more likely to harbour gas giant planets, supporting the model that planets form by accumulation of dust and ice particles. Recent ground-based surveys suggest that this correlation is weakened for Neptunian-sized planets. However, how the relationship between size and metallicity extends into the regime of terrestrial-sized exoplanets is unknown. Here we report spectroscopic metallicities of the host stars of 226 small exoplanet candidates discovered by NASA's Kepler mission, including objects that are comparable in size to the terrestrial planets in the Solar System. We find that planets with radii less than four Earth radii form around host stars with a wide range of metallicities (but on average a metallicity close to that of the Sun), whereas large planets preferentially form around stars with higher metallicities. This observation suggests that terrestrial planets may be widespread in the disk of the Galaxy, with no special requirement of enhanced metallicity for their formation. PMID:22722196

  14. Constructing Mass-radius Relationships of Low Mass Gaseous Exoplanets with MESA

    NASA Astrophysics Data System (ADS)

    Chen, Howard; Rogers, Leslie

    2015-01-01

    To date, over 3500 exoplanets and planetary candidates have been discovered. This astonishing feat allows us to answer a cornerstone question in astronomy and planetary science: what are these 'other worlds' in the solar neighborhood like? Apart from characterization efforts based on observations, a good avenue to explore is to use computer simulations to model the planets' atmospheres and interiors under the influence of stellar irradiation. We present a prescription to extend the stellar evolution code MESA (Modules for Experimental Stellar Astrophysics) to model the thermal evolution of low mass exoplanets having hydrogen-helium envelopes. With the addition of routines treating the planet core luminosity, heavy element enrichment, and mass loss due to hydrodynamic winds, the evolutionary pathways of planets with diverse properties are accurately constrained. Using these dynamic models, we construct mass-radius relationships of planets from 1 to 300 MEarth with varying ages, energy flux received, envelope metallicity and opacity. These relations are benchmarked against previous theoretical studies and the current census of observed planets. In doing so, we demonstrate MESA's ability to incorporate these planetary phenomena in its 1D numerical computations. We anticipate that this versatile, user-friendly code will see widespread applications in complementing future exoplanetary surveys such as K-2, TESS, and PLATO.

  15. Spectrashift Exoplanet Transit Search Project: 40,000 Light Curves and Counting

    NASA Astrophysics Data System (ADS)

    Kaye, Thomas G.; Healy, David

    2009-05-01

    Spectrashift has recently branched out from its radial velocity work detecting exoplanets, and has now fully implemented an exoplanet transit search program. Junk Bond Observatory's 0.8 meter fully automated RC telescope has been engaged in this effort full-time since October of 2008. To date the search has examined more than 40,000 light curves. The Spectrashift strategy is to look at fewer but fainter stars putting this search into the magnitude range the majority of professional searches can not penetrate. Custom software was developed for the reduction pipeline to handle the volume of data. The software implements artificial intelligence algorithms to sort out the most likely candidates for human inspection at the end of the pipeline. To date the project has come up with several "triple hits" where a transit-like event has happened on three occasions. The Spectrashift team's ultimate goal is to include a network of non-professional telescopes around the world for 24 hour coverage of star fields. It is believed this is the first serious non-professional transit search effort.

  16. Transit Timing Variations as a Tool for the Bayesian Characterization of Exoplanets

    NASA Astrophysics Data System (ADS)

    Ford, Eric B.; Jontof-Hutter, Daniel; Dawson, Rebekah; Fabrycky, Daniel; Mills, Sean; Ragozzine, Darin; Rogers, Leslie Anne; Shabram, Megan

    2015-08-01

    NASA's Kepler mission has revolutionized time-domain photometry with its photometric precision, high duty cycle, and long observing baseline. In addition to discovering thousands of planet candidates that pass in front of their host star, Kepler's has enabled the precise measurement of transit timing variations (TTV), deviations of transit times from a Keplerian ephemeris due to gravitational interactions among planets (or more massive bodies in the same planetary system). For dozens of planets, TTVs enable the precise characterization of planet masses and orbits, including many planets for which characterization via Doppler observations is impractical.For example, TTVs have: 1) characterized of masses of planets in systems with 2-6 transiting exoplanets, 2) measured densities for low-mass, low-density mass planets that orbit stars with periods of ~50-200 days, and provided precise measurements of orbital eccentricities even in the challenging regime of e<0.1. In addition to characterizing properties of individual planets, analysing the transit times for populations of transiting planets (including those for which no deviations from Keplerian orbits are detected) enable the characterization of the exoplanet distribution function.In both cases, attention to details of the statistical model and computational methods are essential for drawing robust conclusions. I will present selected TTV success stories, describing how these studies dealt with various statistical and computational challenges. Finally, I will describe opportunities for further improvements in the statistical analyses of transit timing variations and the potential science return.

  17. THE WFC3 GALACTIC BULGE TREASURY PROGRAM: METALLICITY ESTIMATES FOR THE STELLAR POPULATION AND EXOPLANET HOSTS

    SciTech Connect

    Brown, Thomas M.; Sahu, Kailash; Anderson, Jay E-mail: ksahu@stsci.ed

    2010-12-10

    We present new UV-to-IR stellar photometry of four low-extinction windows in the Galactic bulge, obtained with the Wide Field Camera 3 on the Hubble Space Telescope (HST). Using our five bandpasses, we have defined reddening-free photometric indices sensitive to stellar effective temperature and metallicity. We find that the bulge populations resemble those formed via classical dissipative collapse: each field is dominated by an old ({approx}10 Gyr) population exhibiting a wide metallicity range (-1.5{approx}< [Fe/H] {approx}<0.5). We detect a metallicity gradient in the bulge population, with the fraction of stars at super-solar metallicities dropping from 41% to 35% over distances from the Galactic center ranging from 0.3 to 1.2 kpc. One field includes candidate exoplanet hosts discovered in the SWEEPS HST transit survey. Our measurements for 11 of these hosts demonstrate that exoplanets in the distinct bulge environment are preferentially found around high-metallicity stars, as in the solar neighborhood, supporting the view that planets form more readily in metal-rich environments.

  18. High-Contrast 3.8 Micron Imaging of the Brown Dwarf/Planet-Mass Companion to GJ 758

    NASA Technical Reports Server (NTRS)

    Currie, Thayne; Bailey, Vanessa; Fabrycky, Daniel; Murray-Clay, Ruth; Rodigas, Timothy; Hinz, Phil

    2010-01-01

    We present L' band (3.8 Micron) MMT/Clio high-contrast imaging data for the nearby star GJ 758, which was recently reported by Thalmann et al. (2009) to have one -- possibly two-- faint comoving companions (GJ 7588 and "C", respectively). GJ 758B is detected in two distinct datasets. Additionally, we report a \\textit(possible) detection of the object identified by Thalmann et al as "GJ 758C" in our more sensitive dataset, though it is likely a residual speckle. However, if it is the same object as that reported by Thalmann et al. it cannot be a companion in a bound orbit. GJ 758B has a H-L'color redder than nearly all known L--T8 dwarfs. Based on comparisons with the COND evolutionary models, GJ 758B has Te approx. 560 K (+150 K, -90 K) and a mass ranging from approx. 10-20 Mj if it is approx. 1 Gyr old to approx. 25-40 Mj if it is 8.7 Gyr old. GJ 758B is likely in a highly eccentric orbit, e approx. 0.73 (+0.12,-0.21), with a semimajor axis of approx. 44 AU (+32 AU, -14 AU). Though GJ 758B is sometimes discussed within the context of exoplanet direct imaging, its mass is likely greater than the deuterium-burning limit and its formation may resemble that of binary stars rather than that of jovian-mass planets.

  19. High-Contrast 3.8 Micron Imaging of the Brown Dwarf/Planet-Mass Companion to GJ 758

    NASA Technical Reports Server (NTRS)

    Currie, Thayne M.; Bailey, Vanessa; Fabrycky, Daniel; Murray-Clay, Ruth; Rodigas, Timothy; Hinz, Phil

    2011-01-01

    We present L' band (3.8 Micron) MMT/Clio high-contrast imaging data for the nearby star GJ 758, which was recently reported by Thalmann et al. (2009) to have one - possibly two - faint comoving companions (GJ 7588 and "C", respectively). GJ 758B is detected in two distinct datasets. Additionally, we report a \\textit{possible} detection of the object identified by Thalmann et al as "GJ 758C" in our more sensitive dataset, though it is likely a residual speckle. However, if it is the same object as that reported by Thalmann et al. it cannot be a companion in a bound orbit. GJ 7588 has a H-L' color redder than nearly all known L-T8 dwarfs. 8ased on comparisons with the COND evolutionary models, GJ 7588 has Te approx. 560 K (+150 K, -90 K) and a mass ranging from approx.10-20 Mj if it is approx.1 Gyr old to approx. 25-40 Mj if it is 8.7 Gyr old. GJ 7588 is likely in a highly eccentric orbit, e approx. 0.73 (+0.12,-0.21), with a semimajor axis of approx. 44 AU (+32 AU, -14 AU). Though GJ 7588 is sometimes discussed within the context of exoplanet direct imaging, its mass is likely greater than the deuterium-burning limit and its formation may resemble that of binary stars rather than that of jovian-mass planets.

  20. Methods for the detection and characterization of exoplanets and their population

    NASA Astrophysics Data System (ADS)

    Foreman-Mackey, Daniel

    The study of exoplanets has been revolutionized in recent years thanks, in large part, to new data collected by NASA's Kepler Mission. The Mission has enabled the discovery of thousands of planets orbiting stars throughout the Galaxy. These discoveries span orders of magnitude in physical parameter space but many of the most physically interesting questions remain open. The deepest of these questions is: how common are planetary systems like our own Solar System? In this dissertation, I approach this question from several different angles and make inferences about the frequency and distribution of planets based on the large, publicly-available datasets from the Kepler Mission. I develop two powerful and practical methods for mining for planetary transit signals in the hundreds of thousands of stellar light curves measured by Kepler. The first method is designed to find planets using the data from the K2 phase of the Mission where systematics introduced by the instrument dominate the measurements. Applying this method to the first publicly available dataset from K2, Campaign 1, I published more than thirty new exoplanet candidates. The second transit search technique is designed to find transits of planets with orbital periods longer than the four year baseline of the Kepler Mission. These are interesting planets because they are expected to have the largest dynamical influence on the formation and evolution of their planetary systems but, to date, no systematic search for these signals has been published. I demonstrate that this method is robust and tractable and make predictions for the planet yields in the Kepler dataset. I derive a general framework for making justified probabilistic inferences about the population of planets based on noisy and incomplete catalogs of exoplanet measurements. Applying this to a previously published catalog of exoplanets orbiting stars like our Sun, I measure the joint period-radius distribution of these planets taking into account

  1. First light of the VLT planet finder SPHERE. I. Detection and characterization of the substellar companion GJ 758 B

    NASA Astrophysics Data System (ADS)

    Vigan, A.; Bonnefoy, M.; Ginski, C.; Beust, H.; Galicher, R.; Janson, M.; Baudino, J.-L.; Buenzli, E.; Hagelberg, J.; D'Orazi, V.; Desidera, S.; Maire, A.-L.; Gratton, R.; Sauvage, J.-F.; Chauvin, G.; Thalmann, C.; Malo, L.; Salter, G.; Zurlo, A.; Antichi, J.; Baruffolo, A.; Baudoz, P.; Blanchard, P.; Boccaletti, A.; Beuzit, J.-L.; Carle, M.; Claudi, R.; Costille, A.; Delboulbé, A.; Dohlen, K.; Dominik, C.; Feldt, M.; Fusco, T.; Gluck, L.; Girard, J.; Giro, E.; Gry, C.; Henning, T.; Hubin, N.; Hugot, E.; Jaquet, M.; Kasper, M.; Lagrange, A.-M.; Langlois, M.; Le Mignant, D.; Llored, M.; Madec, F.; Martinez, P.; Mawet, D.; Mesa, D.; Milli, J.; Mouillet, D.; Moulin, T.; Moutou, C.; Origné, A.; Pavlov, A.; Perret, D.; Petit, C.; Pragt, J.; Puget, P.; Rabou, P.; Rochat, S.; Roelfsema, R.; Salasnich, B.; Schmid, H.-M.; Sevin, A.; Siebenmorgen, R.; Smette, A.; Stadler, E.; Suarez, M.; Turatto, M.; Udry, S.; Vakili, F.; Wahhaj, Z.; Weber, L.; Wildi, F.

    2016-03-01

    GJ 758 B is a brown dwarf companion to a nearby (15.76%) solar-type, metal-rich (M / H = + 0.2 dex) main-sequence star (G9V) that was discovered with Subaru/HiCIAO in 2009. From previous studies, it has drawn attention as being the coldest (~600 K) companion ever directly imaged around a neighboring star. We present new high-contrast data obtained during the commissioning of the SPHERE instrument at the Very Large Telescope (VLT). The data was obtained in Y-, J-, H-, and Ks-bands with the dual-band imaging (DBI) mode of IRDIS, thus providing a broad coverage of the full near-infrared (near-IR) range at higher contrast and better spectral sampling than previously reported. In this new set of high-quality data, we report the re-detection of the companion, as well as the first detection of a new candidate closer-in to the star. We use the new eight photometric points for an extended comparison of GJ 758 B with empirical objects and four families of atmospheric models. From comparison to empirical object, we estimate a T8 spectral type, but none of the comparison objects can accurately represent the observed near-IR fluxes of GJ 758 B. From comparison to atmospheric models, we attribute a Teff = 600 ± 100 K, but we find that no atmospheric model can adequately fit all the fluxes of GJ 758 B. The lack of exploration of metal enrichment in model grids appears as a major limitation that prevents an accurate estimation of the companion physical parameters. The photometry of the new candidate companion is broadly consistent with L-type objects, but a second epoch with improved photometry is necessary to clarify its status. The new astrometry of GJ 758 B shows a significant proper motion since the last epoch. We use this result to improve the determination of the orbital characteristics using two fitting approaches: Least-Squares Monte Carlo and Markov chain Monte Carlo. We confirm the high-eccentricity of the orbit (peak at 0.5), and find a most likely semi-major axis of

  2. Evidence for Nemesis: a solar companion star

    SciTech Connect

    Muller, R.A.

    1985-01-01

    The evidence that the sun has a companion star ''Nemesis'' responsible for periodic mass extinctions is reviewed. A gaussian ideogram of the rates of family extinctions in the oceans shows periods of 26 and 30 Myr. Analysis of impact cratering on the earth shows a period of either 28.4 or 30 Myr, depending on the crater selection. Models which attempt to explain these periods with either oscillations through the galactic plane, or through the effects of a tenth planet, are seriously flawed. If the periods seen in the data are real (and not a spurious result of a statistical fluctuation) then the ''Nemesis hypothesis'' is the only suggested explanation that has survived close scrutiny. The Nemesis model predicts that the impacts took place during brief storms of several million years duration, perhaps accounting for the ''extended'' nature of the mass extinctions. A search for Nemesis is under way at Berkeley. 18 refs., 4 figs.