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1

The Nine Planets: Jupiter  

NSDL National Science Digital Library

This page of Nine Planets contains details about the gas giant planet Jupiter. Information includes planet diameter, mass, distance from the Sun, orbit, and mythology. Also covered are planet composition, surface features, atmosphere and magnetic field data, results from exploration spacecraft, and temperature on the planet. Jupiters' moons are also covered in detail, including Io, Europa, Ganymede, Callisto, and others. The site provides links to more images and facts, and discusses unanswered questions about Jupiter and its moons.

Arnett, Bill

2

Accretion Rates Of Planetesimals On A Jupiter-mass Planet  

NASA Astrophysics Data System (ADS)

We performed 3D calculations of the motion of a swarm of planetesimals in a protoplanetary disk that is perturbed by a Jupiter-mass planet. The interactions between the planet and the gaseous disk and the accretion of gas on the planet were modeled through a 3D hydrodynamics code. The trajectory of each planetesimal, in the gravitational field of the planet and of a solar-mass star, was determined by means of a 4th order Runge-Kutta algorithm that takes into account gas drag forces. Thermodynamics conditions that may apply to a protoplanetary disk towards the end of the planet's gas accretion epoch were used. The planetesimals were initially deployed on random Keplerian orbits about the star, between 1.1 and 1.5 planet's orbital radii. The gas dynamics around the planet was resolved on a length-scale of 0.01 planet's Hill radii (Rh). Planetesimals within a few tenths of Rh from the planet and whose velocity relative to the planet was smaller than the escape velocity were taken as accreted. Experiments were executed with a size distribution of an equal number of 1, 10, and 100 km radius planetesimals. The dynamics of the smallest size planetesimals appears to be more strongly affected by gas drag forces than it is that of planetesimals of larger sizes. However, results suggest that the accretion rates on the planet are of the same order of magnitude, once the initial surface density of planetesimals is corrected so that all size bins contain equal masses of solids. These rates, estimated at about 5 AU, are on the order of 1e-6 sigma Earth masses per year, where sigma is the solids' surface density of a given size bin, in grams per square centimeters, exterior of the planet's orbit. Support from NASA Origins of Solar Systems Program grants NNX08AH82G and NNX07AI72G is gratefully acknowledged.

D'Angelo, Gennaro

2010-10-01

3

Accretion of Jupiter-mass Planets in the Limit of Vanishing Viscosity  

NASA Astrophysics Data System (ADS)

Motivation: the rate of gas accretion by the giant planets is crucial to understand their mass distribution. Too fast runaway accretion leads to too massive planets. Method: we investigated the characteristics of the circumplanetary disc (CPD) of a Jupiter-mass planet with a three-dimensional hydrodynamical nested grid code. We looked for the accretion mechanisms operating in inviscid (MRI inactive) CPD. Main results: 1) the main accretion mechanism from the CPD to the planet is the stellar tide 2) Jupiter's accretion rate could be >10x slower than previously thought 3) runaway growth could happen on a timescale comparable to the disc's lifetime

Szulagyi, Judit; Morbidelli, Alessandro; Crida, Aurelien; Masset, Frederic

2013-07-01

4

Exploring the Planets: Jupiter  

NSDL National Science Digital Library

This site contains most of the up-to-date information known about the planet Jupiter, including mean distance from the Sun, length of year, rotation period, mean orbital velocity, inclination of axis, spacecraft encounters, diameter, and number of observed satellites. The Galilean satellites Callisto, Ganymede, Europa, and Io are shown here in their correct positions relative to the planet and the odd moon Amalthea is discussed. There is tabular data on several of the other major moons. There are many thumbnail photographs that can be enlarged, including a grand view of the red spot. The radiation and radio noise of Jupiter is discussed, along with its atmosphere as compared to Saturn. The Galileo mission is discussed and links are provided for more information.

5

Predictions on the core mass of Jupiter and of giant planets in general  

NASA Astrophysics Data System (ADS)

More than 80 giant planets are known by mass and radius. Their interior structure in terms of core mass, number of layers, and composition however is still poorly known. An overview is presented about the core mass M core and envelope mass of metals M Z in Jupiter as predicted by various equations of state. It is argued that the uncertainty about the true H/He EOS in a pressure regime where the gravitational moments J 2 and J 4 are most sensitive, i.e. between 0.5 and 4 Mbar, is in part responsible for the broad range M_{core}=0{-}18M_{oplus }, MZ=0{-}38M_{oplus }, and M_{core}+MZ=14{-}38M_{oplus } currently offered for Jupiter. We then compare the Jupiter models obtained when we only match J 2 with the range of solutions for the exoplanet GJ436b, when we match an assumed tidal Love number k 2 value.

Nettelmann, Nadine

2011-11-01

6

The SOPHIE search for northern extrasolar planets. III. A Jupiter-mass companion around HD 109246  

NASA Astrophysics Data System (ADS)

We report the detection of a Jupiter-mass planet discovered with the SOPHIE spectrograph mounted on the 1.93-m telescope at the Haute-Provence Observatory. The new planet orbits HD 109246, a G0V star slightly more metallic than the Sun. HD 109246b has a minimum mass of 0.77 MJup, an orbital period of 68 days, and an eccentricity of 0.12. It is placed in a sparsely populated region of the period distribution of extrasolar planets. We also present a correction method for the so-called seeing effect that affects the SOPHIE radial velocities. We complement this discovery announcement with a description of some calibrations that are implemented in the SOPHIE automatic reduction pipeline. These calibrations allow the derivation of the photon-noise radial velocity uncertainty and some useful stellar properties (v sin i, [Fe/H], log R’HK) directly from the SOPHIE data. Based on observations made with the SOPHIE spectrograph on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS/OAMP), France (program 07A.PNP.CONS).RV tables (Tables C.1 and C.2) are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/523/A88

Boisse, I.; Eggenberger, A.; Santos, N. C.; Lovis, C.; Bouchy, F.; Hébrard, G.; Arnold, L.; Bonfils, X.; Delfosse, X.; Desort, M.; Díaz, R. F.; Ehrenreich, D.; Forveille, T.; Gallenne, A.; Lagrange, A. M.; Moutou, C.; Udry, S.; Pepe, F.; Perrier, C.; Perruchot, S.; Pont, F.; Queloz, D.; Santerne, A.; Ségransan, D.; Vidal-Madjar, A.

2010-11-01

7

Jupiter: Lord of the Planets.  

ERIC Educational Resources Information Center

|Presents a chapter from an introductory college-level astronomy textbook in which full-color photographs and numerous diagrams highlight an extensive description of the planet Jupiter. Topics include Jupiter's geology, rotation, magnetic field, atmosphere (including clouds and winds), and the Great Red Spot. (DH)|

Kaufmann, William

1984-01-01

8

Definitive orbit of minor planet (29) Amphitrite from 91 oppositions 1825-1985 and a new determination of the mass of Jupiter  

Microsoft Academic Search

A definitive orbit of minor planet (29) Amphitrite based on 1,577 observations from 91 apparitions covering the time span 1825 to 1985 is evaluated. (29) Amphitrite moves near to the 3:1 resonance to Jupiter and seems particularly suited for a new determination of the mass of the Jupiter system. A most probable mass value of 1\\/(1047.369±0.029) solar masses is obtained

L. D. Schmadel

1986-01-01

9

WASP26b: a 1-Jupiter-mass planet around an early-G-type star  

Microsoft Academic Search

We report the discovery of WASP-26b, a moderately over-sized Jupiter-mass exoplanet transiting its 11.3-mag early-G-type host star (1SWASP J001824.70-151602.3; TYC 5839-876-1) every 2.7566 days. A simultaneous fit to transit photometry and radial-velocity measurements yields a planetary mass of 1.02 ± 0.03 MJup and radius of 1.32 ± 0.08 RJup. The host star, WASP-26, has a mass of 1.12 ± 0.03

B. Smalley; D. R. Anderson; A. Collier Cameron; M. Gillon; C. Hellier; T. A. Lister; P. F. L. Maxted; D. Queloz; A. H. M. J. Triaud; R. G. West; S. J. Bentley; B. Enoch; F. Pepe; D. L. Pollacco; D. Segransan; A. M. S. Smith; J. Southworth; S. Udry; P. J. Wheatley; P. L. Wood; J. Bento

2010-01-01

10

Kepler Constraints on Planet near Hot Jupiters.  

National Technical Information Service (NTIS)

We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis...

A. P. Boss D. Ragozzine D. C. Fabrycky D. R. Ciardi E. B. Ford J. A. Carter J. F. Rowe J. H. Steffen M. J. Holman S. N. Quinn W. F. Welsh W. J. Borucki

2012-01-01

11

Hot Jupiters from secular planet-planet interactions.  

PubMed

About 25 per cent of 'hot Jupiters' (extrasolar Jovian-mass planets with close-in orbits) are actually orbiting counter to the spin direction of the star. Perturbations from a distant binary star companion can produce high inclinations, but cannot explain orbits that are retrograde with respect to the total angular momentum of the system. Such orbits in a stellar context can be produced through secular (that is, long term) perturbations in hierarchical triple-star systems. Here we report a similar analysis of planetary bodies, including both octupole-order effects and tidal friction, and find that we can produce hot Jupiters in orbits that are retrograde with respect to the total angular momentum. With distant stellar mass perturbers, such an outcome is not possible. With planetary perturbers, the inner orbit's angular momentum component parallel to the total angular momentum need not be constant. In fact, as we show here, it can even change sign, leading to a retrograde orbit. A brief excursion to very high eccentricity during the chaotic evolution of the inner orbit allows planet-star tidal interactions to rapidly circularize that orbit, decoupling the planets and forming a retrograde hot Jupiter. PMID:21562558

Naoz, Smadar; Farr, Will M; Lithwick, Yoram; Rasio, Frederic A; Teyssandier, Jean

2011-05-12

12

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

SciTech Connect

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.

Bower, Geoffrey C.; Bolatto, Alberto; Ford, Eric B.; Fries, Adam; Kalas, Paul; Sanchez, Karol; Viscomi, Vincent [Astronomy Department and Radio Astronomy Laboratory, University of California, Berkeley, CA 94720 (United States); Sanderbeck, Phoebe, E-mail: gbower@astro.berkeley.edu [Department of Physics, Brandeis University, Abelson-Bass-Yalem 107, MS 057, Waltham, MA 02453 (United States)

2011-10-10

13

Io-Jupiter system: a unique case of moon-planet interaction  

Microsoft Academic Search

Io and Jupiter constitute a moon-planet system that is unique in our solar system. Io is the most volcanically active planetary body, while Jupiter is the first among the planets in terms of size, mass, magnetic field strength, spin rate, and volume of the magnetosphere. That Io is electrodynamically linked to Jupiter is known for nearly four decades from the

Anil Bhardwaj; Marykutty Michael

2002-01-01

14

Kepler constraints on planets near hot Jupiters  

SciTech Connect

We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 2:1 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly two-thirds to five times the size of the Earth, depending upon the noise properties of the target star. A search for dynamically induced deviations from a constant period (transit timing variations) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history.

Steffen, Jason H.; /Fermilab; Ragozzine, Darin; /Harvard-Smithsonian Ctr. Astrophys.; Fabrycky, Daniel C.; /UC, Santa Cruz, Astron. Astrophys.; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Ford, Eric B.; /Florida U.; Holman, Matthew J.; /Harvard-Smithsonian Ctr. Astrophys.; Rowe, Jason F.; /NASA, Ames; Welsh, William F.; /San Diego State U., Astron. Dept.; Borucki, William J.; /NASA, Ames; Boss, Alan P.; /Carnegie Inst., Wash., D.C., DTM; Ciardi, David R.; /Caltech /Harvard-Smithsonian Ctr. Astrophys.

2012-05-01

15

Kepler constraints on planets near hot Jupiters.  

PubMed

We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 21 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly two-thirds to five times the size of the Earth, depending upon the noise properties of the target star. A search for dynamically induced deviations from a constant period (transit timing variations) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history. PMID:22566651

Steffen, Jason H; Ragozzine, Darin; Fabrycky, Daniel C; Carter, Joshua A; Ford, Eric B; Holman, Matthew J; Rowe, Jason F; Welsh, William F; Borucki, William J; Boss, Alan P; Ciardi, David R; Quinn, Samuel N

2012-05-07

16

On uncertainty of Jupiter's core mass due to observational errors  

Microsoft Academic Search

The origins of extrasolar gas giant planets have been discussed, based on our understanding of the gas giant planets in the solar system, Jupiter and Saturn. However, how Jupiter and Saturn formed is still uncertain because of the uncertainty in their interiors, especially the core mass (Mc). The uncertainty in Mc is partly due to those in observational data such

Yasunori Hori; Takayoshi Sano; Masahiro Ikoma; Shigeru Ida

2008-01-01

17

Stability of a terrestrial planet in a planetary system with a Hot Jupiter  

NASA Astrophysics Data System (ADS)

With the discovery of over 200 Extra-solar planetary systems recently, it appears that the existence of a "Hot Jupiter" in a planetary system is a fairly common event. Jupiter size planets and larger have been found at the location of orbits of terrestrial planets in our own solar system. This raises the question, under what conditions could an Earth type planet have a stable orbit in the Habitable Zone of a planetary system if a Hot Jupiter is also a part of the system? In this study I will consider a systems with three and four bodies. The star will be one solar mass. The terrestrial planet will have one earth mass, placed at one AU from the star. The other two bodies will have masses on the order that of Jupiter. One "Jupiter" will be a Hot Jupiter, with an orbit closer to the star than that of the terrestrial planet. The other "Jupiter" will be put at an orbit further out than that of the terrestrial planet. Of particular interest are orbits where the terrestrial planet is in resonance with one or both of the Jupiter size planets, to determine whether certain resonances have an effect on the stability of the Earth type planet's orbit. The stability of the Earth size planet will be explored using a Fourier Analysis of its orbital parameters based on a previously developed method called the Frequency Map Analysis (FMA). Using the FMA, the goal is to determine what are the conditions for a "stable" Earth orbit, stability being one of the keys to the development of life on an Earth type planet.

Gorman, Patrick

18

Jupiter-sized Planets in the Solar System and Elsewhere  

Microsoft Academic Search

The discovery of the first extrasolar planet, 51 Pegasi, in 1995 has opened up a new and exciting area of planetary astronomy.\\u000a Using a number of different techniques 170 extrasolar planets have now been discovered, and this number is rapidly increasing.\\u000a Due partly to observational biases, just over half of these newly discovered planets are ‘Hot Jupiters’ — Jupiter sized

Patrick G. J. Irwin

19

Microlensing Constraints on the Frequency of Jupiter-Mass Companions: Analysis of 5 Years of PLANET Photometry  

NASA Astrophysics Data System (ADS)

We analyze 5 years of PLANET photometry of microlensing events toward the Galactic bulge to search for the short-duration deviations from single-lens light curves that are indicative of the presence of planetary companions to the primary microlenses. Using strict event-selection criteria, we construct a well-defined sample of 43 intensively monitored events. We search for planetary perturbations in these events over a densely sampled region of parameter space spanning two decades in mass ratio and projected separation, but find no viable planetary candidates. By combining the detection efficiencies of the events, we find that, at 95% confidence, less than 25% of our primary lenses have companions with mass ratio q=10-2 and separations in the lensing zone, [0.6-1.6]?E, where ?E is the Einstein ring radius. Using a model of the mass, velocity, and spatial distribution of bulge lenses, we infer that the majority of our lenses are likely M dwarfs in the Galactic bulge. We conclude that less than 33% of M dwarfs in the Galactic bulge have companions with mass mp=MJ between 1.5 and 4 AU, and less than 45% have companions with mp=3MJ between 1 and 7 AU, the first significant limits on planetary companions to M dwarfs. We consider the effects of the finite size of the source stars and changing our detection criterion, but find that these do not alter our conclusions substantially.

Gaudi, B. S.; Albrow, M. D.; An, J.; Beaulieu, J.-P.; Caldwell, J. A. R.; DePoy, D. L.; Dominik, M.; Gould, A.; Greenhill, J.; Hill, K.; Kane, S.; Martin, R.; Menzies, J.; Naber, R. M.; Pel, J.-W.; Pogge, R. W.; Pollard, K. R.; Sackett, P. D.; Sahu, K. C.; Vermaak, P.; Vreeswijk, P. M.; Watson, R.; Williams, A.

2002-02-01

20

Luminosity of young Jupiters revisited. Massive cores make hot planets  

NASA Astrophysics Data System (ADS)

Context. The intrinsic luminosity of young Jupiters is of high interest for planet formation theory. It is an observable quantity that is determined by important physical mechanisms during formation, namely, the structure of the accretion shock and, even more fundamentally, the basic formation mechanism (core accretion or gravitational instability). Aims: Our aim is to study the impact of the core mass on the post-formation entropy and luminosity of young giant planets forming via core accretion with a supercritical accretion shock that radiates all accretion shock energy (cold accretion). Methods: For this, we conduct self-consistently coupled formation and evolution calculations of giant planets with masses between 1 and 12 Jovian masses and core masses between 20 and 120 Earth masses in the 1D spherically symmetric approximation. Results: As the main result, it is found that the post-formation luminosity of massive giant planets is very sensitive to the core mass. An increase in the core mass by a factor 6 results in an increase in the post-formation luminosity of a 10-Jovian mass planet by a factor 120, indicating a dependency as mcore2-3. Due to this dependency, there is no single well-defined post-formation luminosity for core accretion, but a wide range, even for completely cold accretion. For massive cores ( 100 Earth masses), the post-formation luminosities of core accretion planets become so high that they approach those in the hot start scenario that is often associated with gravitational instability. For the mechanism to work, it is necessary that the solids are accreted before or during gas runaway accretion and that they sink during this time deep into the planet. Conclusions: We make no claims about whether such massive cores can actually form in giant planets especially at large orbital distances. But if they can form, it becomes difficult to rule out core accretion as the formation mechanism based solely on luminosity for directly imaged planets that are more luminous than predicted for low core masses. Instead of invoking gravitational instability as the consequently necessary formation mode, the high luminosity can also be caused, at least in principle, simply by a more massive core.

Mordasini, C.

2013-10-01

21

WASP-54b, WASP-56b, and WASP-57b: Three new sub-Jupiter mass planets from SuperWASP  

NASA Astrophysics Data System (ADS)

We present three newly discovered sub-Jupiter mass planets from the SuperWASP survey: WASP-54b is a heavily bloated planet of mass 0.636+0.025-0.024RJ. It orbits a F9 star, evolving off the main sequence, every 3.69 days. Our MCMC fit of the system yields a slightly eccentric orbit (e = 0.067+0.033-0.025) for WASP-54b. We investigated further the veracity of our detection of the eccentric orbit for WASP-54b, and we find that it could be real. However, given the brightness of WASP-54 V = 10.42 mag, we encourage observations of a secondary eclipse to draw robust conclusions on both the orbital eccentricity and the thermal structure of the planet. WASP-56b and WASP-57b have masses of 0.571+0.034-0.035MJ and 0.672+0.049-0.046MJ, respectively; and radii of 1.092+0.035-0.033RJ for WASP-56b and 0.916+0.017-0.014RJ for WASP-57b. They orbit main sequence stars of spectral type G6 every 4.67 and 2.84 days, respectively. WASP-56b and WASP-57b show no radius anomaly and a high density possibly implying a large core of heavy elements; possibly as high as ~50 M? in the case of WASP-57b. However,the composition of the deep interior of exoplanets remains still undetermined. Thus, more exoplanet discoveries such as the ones presented in this paper, are needed to understand and constrain giant planets' physical properties. RV data (Tables 6-9) are available in electronic form at http://www.aanda.orgPhotometric data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A73

Faedi, F.; Pollacco, D.; Barros, S. C. C.; Brown, D.; Collier Cameron, A.; Doyle, A. P.; Enoch, R.; Gillon, M.; Gómez Maqueo Chew, Y.; Hébrard, G.; Lendl, M.; Liebig, C.; Smalley, B.; Triaud, A. H. M. J.; West, R. G.; Wheatley, P. J.; Alsubai, K. A.; Anderson, D. R.; Armstrong, D.; Bento, J.; Bochinski, J.; Bouchy, F.; Busuttil, R.; Fossati, L.; Fumel, A.; Haswell, C. A.; Hellier, C.; Holmes, S.; Jehin, E.; Kolb, U.; McCormac, J.; Miller, G. R. M.; Moutou, C.; Norton, A. J.; Parley, N.; Queloz, D.; Santerne, A.; Skillen, I.; Smith, A. M. S.; Udry, S.; Watson, C.

2013-03-01

22

Jupiter Observation Campaign: Citizen Science at the Outer Planets  

Microsoft Academic Search

How can NASA Outreach help the citizen scientist? NASA Solar System Education and Public Outreach (EPO) may coordinate and disseminate a consistent process for receiving Jupiter and other outer planet observation data from citizen scientists.

J. H. Jones; A. S. Wessen; R. Pappalardo; S. Vance; P. Dyches; K. Beisser; J. Perry

2011-01-01

23

Jupiter Observation Campaign: Citizen Science at the Outer Planets  

NASA Astrophysics Data System (ADS)

How can NASA Outreach help the citizen scientist? NASA Solar System Education and Public Outreach (EPO) may coordinate and disseminate a consistent process for receiving Jupiter and other outer planet observation data from citizen scientists.

Jones, J. H.; Wessen, A. S.; Pappalardo, R.; Vance, S.; Dyches, P.; Beisser, K.; Perry, J.

2011-03-01

24

Heavy-element Enrichment of a Jupiter-mass Protoplanet as a Function of Orbital Location  

Microsoft Academic Search

One possible mechanism for giant planet formation is disk instability in which the planet is formed as a result of gravitational instability in the protoplanetary disk surrounding the young star. The final composition and core mass of the planet will depend on the planet's mass, environment, and the planetesimal accretion efficiency. We calculate heavy-element enrichment in a Jupiter-mass protoplanet formed

R. Helled; G. Schubert

2009-01-01

25

Scientists Revise Thinking on Comets, Planet Jupiter  

ERIC Educational Resources Information Center

|Discusses scientific information obtained from Pioneer 10's Jupiter flyby and the comet Kohoutek's first trip around the sun, including the high hydrogen emission of Jupiter's principal moon, Io. (CC)|

Chemical and Engineering News, 1974

1974-01-01

26

MULTIPLE-PLANET SCATTERING AND THE ORIGIN OF HOT JUPITERS  

SciTech Connect

Doppler and transit observations of exoplanets show a pile-up of Jupiter-size planets in orbits with a 3 day period. A fraction of these hot Jupiters have retrograde orbits with respect to the parent star's rotation, as evidenced by the measurements of the Rossiter-McLaughlin effect. To explain these observations we performed a series of numerical integrations of planet scattering followed by the tidal circularization and migration of planets that evolved into highly eccentric orbits. We considered planetary systems having three and four planets initially placed in successive mean-motion resonances, although the angles were taken randomly to ensure orbital instability in short timescales. The simulations included the tidal and relativistic effects, and precession due to stellar oblateness. Our results show the formation of two distinct populations of hot Jupiters. The inner population (Population I) is characterized by semimajor axis a < 0.03 AU and mainly formed in the systems where no planetary ejections occurred. Our follow-up integrations showed that this population was transient, with most planets falling inside the Roche radius of the star in <1 Gyr. The outer population of hot Jupiters (Population II) formed in systems where at least one planet was ejected into interstellar space. This population survives the effects of tides over >1 Gyr and fits nicely the observed 3 day pile-up. A comparison between our three-planet and four-planet runs shows that the formation of hot Jupiters is more likely in systems with more initial planets. Due to the large-scale chaoticity that dominates the evolution, high eccentricities and/or high inclinations are generated mainly by close encounters between the planets and not by secular perturbations (Kozai or otherwise). The relative proportion of retrograde planets seems of be dependent on the stellar age. Both the distribution of almost aligned systems and the simulated 3 day pile-up also fit observations better in our four-planet simulations. This may suggest that the planetary systems with observed hot Jupiters were originally rich in the number of planets, some of which were ejected. In a broad perspective, our work therefore hints on an unexpected link between the hot Jupiters and recently discovered free floating planets.

Beauge, C. [Observatorio Astronomico, Universidad Nacional de Cordoba, Laprida 854, X5000BGR Cordoba (Argentina); Nesvorny, D. [Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

2012-06-01

27

Could Jupiter be a carbon-rich planet?  

NASA Astrophysics Data System (ADS)

Motivated by recent spectroscopic observations suggesting that atmospheres of some extrasolar giant-planets are carbon-rich, i.e. carbon/oxygen ratio (C/O) ? 1, we find that the whole set of compositional data for Jupiter is consistent with the hypothesis that it be a carbon-rich giant planet. We show that the formation of Jupiter in the cold outer part of an oxygen-depleted disk (C/O ˜1) reproduces the measured Jovian elemental abundances at least as well as the hitherto canonical model of Jupiter formed in a disk of solar composition (C/O = 0.54). The resulting O abundance in Jupiter's envelope is then moderately enriched by a factor of ˜2 × solar (instead of ˜7 × solar) and is found to be consistent with values predicted by thermochemical models of the atmosphere.

Mousis, O.; Lunine, J. I.; Madhusudhan, N.; Johnson, T. V.

2012-12-01

28

Could Jupiter be a carbon-rich planet?  

NASA Astrophysics Data System (ADS)

Motivated by recent spectroscopic observations suggesting that atmospheres of some extrasolar giantplanets are carbon-rich, i.e. carbon/oxygen ratio (C/O) ? 1, we find that the whole set of compositional data for Jupiter is consistent with the hypothesis that it be a carbon-rich giant planet. The Jovian oxygen abundance to be measured by NASA's Juno mission en route to Jupiter will provide a direct and strict test of our predictions.

Mousis, O.; Lunine, J. I.; Madhusudhan, N.; Johnson, T. V.

2012-09-01

29

Jupiter Observation Campaign: Citizen Science at the Outer Planets  

Microsoft Academic Search

NASA Solar System Education and Public Outreach (E\\/PO) will coordinate and disseminate a consistent process for receiving Jupiter observation data from citizen scientists. This may include a public repository or network matching scientists with citizen scientists who want to provide needed observations in a standard and consistent format. This will be a good Outer Planet mission contribution to the science

J. Houston. Jones; A. Wessen; Robert Pappalardo; Kerri Beisser; Preston Dyches

2010-01-01

30

Jupiter  

NSDL National Science Digital Library

This site discusses the planet Jupiter. Some of the topics discussed include: its interior, surface, and atmosphere, its magnetosphere, its moons and rings, missions, myths, and latest news. There is also numerous pictures and additional websites for more information.

2005-06-07

31

Jupiter  

NSDL National Science Digital Library

This NASA (National Aeronautics and Space Administration) planet profile provides data and images of the planet Jupiter. These data include planet size, orbit facts, distance from the Sun, rotation and revolution times, temperature, atmospheric composition, density and albedo. Images with descriptions include the Jovian system, the great red spot, clouds in Jupiters atmosphere, and the ring system. Moon images show Io and its volcanics, Callisto with its craters and the Valhalla Basin, Europa, and Ganymede with its tectonic features. All of the images on this page were taken by the Voyager Spacecraft.

32

An orbital period of 0.94 days for the hot-Jupiter planet WASP-18b.  

PubMed

The 'hot Jupiters' that abound in lists of known extrasolar planets are thought to have formed far from their host stars, but migrate inwards through interactions with the proto-planetary disk from which they were born, or by an alternative mechanism such as planet-planet scattering. The hot Jupiters closest to their parent stars, at orbital distances of only approximately 0.02 astronomical units, have strong tidal interactions, and systems such as OGLE-TR-56 have been suggested as tests of tidal dissipation theory. Here we report the discovery of planet WASP-18b with an orbital period of 0.94 days and a mass of ten Jupiter masses (10 M(Jup)), resulting in a tidal interaction an order of magnitude stronger than that of planet OGLE-TR-56b. Under the assumption that the tidal-dissipation parameter Q of the host star is of the order of 10(6), as measured for Solar System bodies and binary stars and as often applied to extrasolar planets, WASP-18b will be spiralling inwards on a timescale less than a thousandth that of the lifetime of its host star. Therefore either WASP-18 is in a rare, exceptionally short-lived state, or the tidal dissipation in this system (and possibly other hot-Jupiter systems) must be much weaker than in the Solar System. PMID:19713926

Hellier, Coel; Anderson, D R; Cameron, A Collier; Gillon, M; Hebb, L; Maxted, P F L; Queloz, D; Smalley, B; Triaud, A H M J; West, R G; Wilson, D M; Bentley, S J; Enoch, B; Horne, K; Irwin, J; Lister, T A; Mayor, M; Parley, N; Pepe, F; Pollacco, D L; Segransan, D; Udry, S; Wheatley, P J

2009-08-27

33

Mass Growth and Evolution of Giant Planets on Resonant Orbits  

NASA Astrophysics Data System (ADS)

A pair of giant planets that tidally interact with a gaseous disk may undergo convergent orbital migration and become locked into a mean motion resonance (MMR). If the planet masses are similar to those of Jupiter and Saturn, typical after-formation conditions in protoplanetary disks lead to capture in the 2:1 MMR. Larger gas densities may cause capture in the 3:2 MMR instead. Here we present the results of hydrodynamical models of the evolution of a pair of planets, initially locked in the 2:1 or 3:2 MMR, as they interact with each other and the disk. We focus on the issue of ongoing gas accretion, the importance of which depends on the local disk mass. The high density required for capture in the 3:2 MMR causes a rapid change of the masses and mass ratio. Ensuing planet-planet interactions raises both orbital eccentricities and leads to scattering episodes and to the ejection of one of the planets from the system. Conditions compatible with 2:1 MMR locking can also lead to a more or less substantial growth of the planet masses, depending on the disk density. However, for planets orbiting in the 1 AU region, the resonant configuration appears stable up to masses of about 5 Jupiter's masses. Support from NASA Outer Planets Research Program and NASA Origins of Solar Systems Program is gratefully acknowledged.

Marzari, Francesco; D'Angelo, G.

2013-10-01

34

An Interpretation of the Orbital Period Difference Between Hot Jupiters and Giant Planets on Long-period Orbits  

NASA Astrophysics Data System (ADS)

It is believed that a hot Jupiter (giant planet with a short period less than 10 days) forms in the outer region of a protoplanetary disk, then migrates inward to an orbit with a short period around 3 days, and stops there by a final stopping mechanism. The prominent problem is why hot Jupiters migrate inward to short-period orbits, while other extrasolar giant planets and Jovian planets in our solar system exist on long-period orbits. Here we show that this difference in orbital periods is caused by two populations of protoplanetary disks. One population experiences gravitational instability during some periods of their lifetime (GI disks), while the other does not (No-GI disks). In GI disks, planets can quickly migrate inward to short-period orbits to become hot Jupiters. In No-GI disks, the migration is so slow that planets can exist on long-period orbits. Protoplanetary disks are classified into the two populations because of the differences in properties of molecular cloud cores, from which disks from. We specifically compare our theory with observations. Our theory is supported by observations of extrasolar planets. We analyze the current status of our solar system and find that our solar nebula belongs to the population with a low migration rate. This is consistent with the observation that Jupiter and Saturn are indeed on long-period orbits. Our results further suggest that, in the future observations, a hot Jupiter cannot be found around a star with mass below a critical mass (0.14-0.28 M sun).

Jin, Liping

2010-09-01

35

The Search For Jupiter: Combing the Kepler Database for Long Period, Jovian Planets  

NASA Astrophysics Data System (ADS)

The number of known exoplanets is increasingly rapidly, with progress accelerated by dedicated missions such as the Kepler Space Telescope. As NASA's statistics of the planetary census improve, we gain a better understanding of our solar system's place in the galaxy. A satisfactory assessment, however, requires the answers to two questions still just beyond our grasp: (1) What is the frequency of rocky planets with orbits similar to Earth's, and (2) How common are Jupiter-mass planets in roughly circular, decade-long orbits? The Kepler team is actively addressing the first question, but the second still requires significant effort. My work focuses on developing an independent data analysis pipeline that statistically analyzes the public Kepler database for single event, long duration transit signatures. I will present an overview of the data reduction process along with preliminary results that include a number of previously unidentified transit events from Quarters 1-13 of the Kepler mission.

Burt, Jennifer; Laughlin, G.

2013-01-01

36

Masses and Orbital Constraints for the OGLE2006-BLG-109Lb,c Jupiter\\/Saturn Analog Planetary System  

Microsoft Academic Search

We present a new analysis of the Jupiter+Saturn analog system, OGLE-2006-BLG-109Lb,c, which was the first double planet system discovered with the gravitational microlensing method. This is the only multi-planet system discovered by any method with measured masses for the star and both planets. In addition to the signatures of two planets, this event also exhibits a microlensing parallax signature and

D. P. Bennett; S. H. Rhie; S. Nikolaev; B. S. Gaudi; A. Udalski; A. Gould; G. W. Christie; D. Maoz; S. Dong; J. McCormick; M. K. Szymanski; P. J. Tristram; B. Macintosh; K. H. Cook; M. Kubiak; G. Pietrzynski; I. Soszynski; O. Szewczyk; K. Ulaczyk; L. Wyrzykowski; D. L. DePoy; C. Han; S. Kaspi; C.-U. Lee; F. Mallia; T. Natusch; B.-G. Park; R. W. Pogge; D. Polishook; F. Abe; I. A. Bond; C. S. Botzler; A. Fukui; J. B. Hearnshaw; Y. Itow; K. Kamiya; A. V. Korpela; P. M. Kilmartin; W. Lin; J. Ling; K. Masuda; Y. Matsubara; M. Motomura; Y. Muraki; S. Nakamura; T. Okumura; K. Ohnishi; Y. C. Perrott; N. J. Rattenbury; T. Sako; To. Saito; S. Sato; L. Skuljan; D. J. Sullivan; T. Sumi; W. L. Sweatman; P. C. M. Yock; M. Albrow; A. Allan; J.-P. Beaulieu; D. M. Bramich; M. J. Burgdorf; C. Coutures; M. Dominik; S. Dieters; P. Fouqué; J. Greenhill; K. Horne; C. Snodgrass; I. Steele; Y. Tsapras; B. Chaboyer; A. Crocker; S. Frank

2010-01-01

37

The Now Frontier. Pioneer to Jupiter. Man Links Earth and Planets. Issue No. 1-5.  

ERIC Educational Resources Information Center

|This packet of space science instructional materials includes five issues related to the planet Jupiter. Each issue presents factual material about the planet, diagramatic representations of its movements and positions relative to bright stars or the earth, actual photographs and/or tables of data collected relevant to Pioneer 10, the spacecraft…

1973

38

Formation of terrestrial planets in a dissipating gas disk with Jupiter and Saturn  

Microsoft Academic Search

We have performed N-body simulations on final accretion stage of terrestrial planets, including the eccentricity and inclination damping effect due to tidal interaction with a gas disk. We investigated the dependence on a depletion time scale of the disk, and the effect of secular perturbations by Jupiter and Saturn. In the final stage, terrestrial planets are formed through coagulation of

Junko Kominami; Shigeru Ida

2004-01-01

39

Searching for Jupiter Analogues: Detection Limits of the McDonald Observatory Harlan J. Smith 2.7m Telescope Radial Velocity Planet Search  

NASA Astrophysics Data System (ADS)

The McDonald Observatory Planet Search has recorded twelve years of high precision radial velocity measurements. Now it is possible to test the frequency of Jupiter analogues in the database. 81 stars with a twelve-year timeline and no known companions were selected, and simulations were performed to test our sensitivity to the radial velocity signals of Jupiter analogues. Our criteria for a Jupiter analogue are a planetary companion of a sun-like star with a mass between .8 to 4 Jupiter masses, at a distance ranging from 4 to 5.5 AU. A true Jupiter signal is near the limit of our observations at a distance of 5AU with a period of 4330 days, or 11.9 years. The results of these simulations show the database's sensitivity to Jupiter analogues and the frequency of Jupiter analogues. The results demonstrate that the McDonald Observatory Planet Search is a valuable source of high precision radial velocity measurements, and that the continuation of the program is beneficial to the discovery and study of extra solar planets.

Caldwell, Caroline; Endl, M.; Cochran, W.; MacQueen, P. J.

2012-01-01

40

ON THE FUNDAMENTAL MASS-PERIOD FUNCTIONS OF EXTRASOLAR PLANETS  

SciTech Connect

Employing a catalog of 175 extrasolar planets (exoplanets) detected by the Doppler-shift method, we constructed the independent and coupled mass-period functions. It is the first time in this field that the selection effect is considered in the coupled mass-period functions. Our results are consistent with those of Tabachnik and Tremaine in 2002, with the major difference that we obtain a flatter mass function but a steeper period function. Moreover, our coupled mass-period functions show that about 2.5% of stars would have a planet with mass between Earth Mass and Neptune Mass, and about 3% of stars would have a planet with mass between Neptune Mass and Jupiter Mass.

Jiang, I.-G. [Department of Physics and Institute of Astronomy, National Tsing Hua University, Hsin-Chu, Taiwan (China); Yeh, L.-C.; Chang, Y.-C. [Department of Applied Mathematics, National Hsinchu University of Education, Hsin-Chu, Taiwan (China); Hung, W.-L. [Graduate Institute of Computer Science, National Hsinchu University of Education, Hsin-Chu, Taiwan (China)

2010-01-01

41

A common mass scaling for satellite systems of gaseous planets.  

PubMed

The Solar System's outer planets that contain hydrogen gas all host systems of multiple moons, which notably each contain a similar fraction of their respective planet's mass (approximately 10(-4)). This mass fraction is two to three orders of magnitude smaller than that of the largest satellites of the solid planets (such as the Earth's Moon), and its common value for gas planets has been puzzling. Here we model satellite growth and loss as a forming giant planet accumulates gas and rock-ice solids from solar orbit. We find that the mass fraction of its satellite system is regulated to approximately 10(-4) by a balance of two competing processes: the supply of inflowing material to the satellites, and satellite loss through orbital decay driven by the gas. We show that the overall properties of the satellite systems of Jupiter, Saturn and Uranus arise naturally, and suggest that similar processes could limit the largest moons of extrasolar Jupiter-mass planets to Moon-to-Mars size. PMID:16778883

Canup, Robin M; Ward, William R

2006-06-15

42

Enhancement of the Accretion of Jupiter’s Core by a Voluminous Low-Mass Envelope  

NASA Astrophysics Data System (ADS)

We present calculations of the early stages of the formation of Jupiter via core nucleated accretion and gas capture. The core begins as a seed body of about 350 kilometers in radius and orbits in a swarm of planetesimals whose initial radii range from 15 meters to 100 kilometers. We follow the evolution of the swarm by accounting for growth and fragmentation, viscous and gravitational stirring, and for drag-induced migration and velocity damping. Gas capture by the core substantially enhances the cross-section of the planet for accretion of small planetesimals. The dust opacity within the atmosphere surrounding the planetary core is computed self-consistently, accounting for coagulation and sedimentation of dust particles released in the envelope as passing planetesimals are ablated. The calculation is carried out at an orbital semi-major axis of 5.2 AU and an initial solids' surface density of 10 grams per square centimeter at that distance. The results give a core mass of 7 Earth masses and an envelope mass of ~ 0.3 Earth mass after 500,000 years, at which point the envelope growth rate surpasses that of the core. The same calculation without the envelope gives a core mass of only 4 Earth masses.

Lissauer, Jack J.; D’Angelo, G.; Weidenschilling, S. J.; Bodenheimer, P.; Hubickyj, O.

2013-10-01

43

On the formation of terrestrial planets in hot-Jupiter systems  

NASA Astrophysics Data System (ADS)

Context: There are numerous extrasolar giant planets which orbit close to their central stars. These "hot-Jupiters" probably formed in the outer, cooler regions of their protoplanetary disks, and migrated inward to ˜ 0.1 AU. Since these giant planets must have migrated through their inner systems at an early time, it is uncertain whether they could have formed or retained terrestrial planets. Aims: We present a series of calculations aimed at examining how an inner system of planetesimals/protoplanets, undergoing terrestrial planet formation, evolves under the influence of a giant planet undergoing inward type II migration through the region bounded between 5-0.1 AU. Methods: We have previously simulated the effect of gas giant planet migration on an inner system protoplanet/planetesimal disk using a N-body code which included gas drag and a prescribed migration rate. We update our calculations here with an improved model that incorporates a viscously evolving gas disk, annular gap and inner-cavity formation due to the gravitational field of the giant planet, and self-consistent evolution of the giant's orbit. Results: We find that ?60% of the solids disk survives by being scattered by the giant planet into external orbits. Planetesimals are scattered outward almost as efficiently as protoplanets, resulting in the regeneration of a solids disk where dynamical friction is strong and terrestrial planet formation is able to resume. A simulation that was extended for a few Myr after the migration of the giant planet halted at 0.1 AU, resulted in an apparently stable planet of ˜ 2 moplus forming in the habitable zone. Migration-induced mixing of volatile-rich material from beyond the "snowline" into the inner disk regions means that terrestrial planets that form there are likely to be water-rich. Conclusions: .We predict that hot-Jupiter systems are likely to harbor water-abundant terrestrial planets in their habitable zones. These planets may be detected by future planet search missions.

Fogg, M. J.; Nelson, R. P.

2007-01-01

44

A SHORT-PERIOD CENSOR OF SUB-JUPITER MASS EXOPLANETS WITH LOW DENSITY  

SciTech Connect

Despite the existence of many short-period hot Jupiters, there is not one hot Neptune with an orbital period less than 2.5 days. Here, we discuss a cluster analysis of the currently known 106 transiting exoplanets to investigate a possible explanation for this observation. We find two distinct clusters in the mass-density space, one with hot Jupiters with a wide range of orbital periods (0.8-114 days) and a narrow range of planet radii (1.2 {+-} 0.2 R{sub J} ) and another one with a mixture of super-Earths, hot Neptunes, and hot Jupiters, exhibiting a surprisingly narrow period distribution (3.7 {+-} 0.8 days). These two clusters follow strikingly different distributions in the period-radius parameter plane. The branch of sub-Jupiter mass exoplanets is censored by the orbital period at the large-radius end: no planets with mass between 0.02 and 0.8 M{sub J} or with radius between 0.25 and 1.0 R{sub J} are known with P{sub orb} < 2.5 days. This clustering is not predicted by current theories of planet formation and evolution, which we also review briefly.

Szabo, Gy. M.; Kiss, L. L. [Konkoly Observatory of the Hungarian Academy of Sciences, P.O. Box 67, H-1525 Budapest (Hungary)

2011-02-01

45

An Absence of Hot Jupiter Planets in 47 Tucanae: Results of a Wide-Field Transit Search  

NASA Astrophysics Data System (ADS)

This paper presents the results of a comprehensive wide-field search for transiting ``hot Jupiter'' planets (gas giant planets with an orbital period in the range 1day<=P<=16days) in the globular cluster 47 Tuc. Motivated by the detection of the transit in HD 209458 and the apparent lack of planetary detections in the core of 47 Tuc by Gilliland and coworkers, this work further addresses the question of giant planet frequency in 47 Tuc by observing from the ground a 52'×52' field centered on the cluster. Hence, this work is most sensitive to the uncrowded outer regions, where the stellar densities are significantly lower than in the core, and concentrates on 21,920 main-sequence stars within 2.5 mag of the cluster turnoff (hence approaching the solar value in mass). Our work comprises the largest ground-based transit search of a globular cluster to date, incorporating a 33 night time series that allows us excellent sensitivity to detect hot Jupiter planets. Detailed Monte Carlo simulations incorporating the actual temporal sampling and photometric precision of the data predict that seven planets with orbital periods in the range 1-16 days should be present in our data set if 47 Tuc has the same planetary frequency as that observed in the solar neighborhood. A detailed search utilizing a matched filter algorithm, developed specifically for this project, found no transit events. This 3.3 ? result is consistent with the Hubble Space Telescope cluster core null detection of Gilliland and coworkers. Our result indicates that system metallicity rather than crowding is the dominant effect inhibiting hot Jupiter formation in this environment. The 33 night data set used for this result also led to the detection of 100 variable stars, including 69 new discoveries, which are presented in a companion paper.

Weldrake, David T. F.; Sackett, Penny D.; Bridges, Terry J.; Freeman, Kenneth C.

2005-02-01

46

Optical Ground-Based Spectra of Jupiter and Saturn: An Exploration of Giant Planet Chromophores  

NASA Astrophysics Data System (ADS)

We present and interpret ground-based optical spectra of Jupiter and Saturn recently acquired in an effort to characterize candidate coloring agents, or chromophores, in the atmospheres of the gas giant planets of our solar system. Surprisingly, despite hundreds of years of observations, we still do not know the identity of the trace chemical compounds that color the atmospheres of the giant planets. Previous analyses have attempted to identify a specific chemical that is responsible for the colors, but none has yet been conclusively proven. We acquired spatially resolved optical spectra of various regions in the atmospheres of both Jupiter and Saturn in February 2013 using the Dual Imaging Spectrograph (DIS) on the Astrophysical Research Consortium's 3.5-meter telescope at Apache Point Observatory. The spectra cover the range of 300-1000 nm, with a spectral resolution of R ~ 1200. For the observations of both Jupiter and Saturn, we used DIS with the 6 arcminute long slit aligned with the planets' latitudinal bands and stepped the slit north-south to build up a spectral image cube with spectra at all locations on the planet. This enables the extraction of subapertures within the slit corresponding to specific locations, e.g. the Great Red Spot on Jupiter, during the data reduction process. We compare the optical spectra of various colored regions in the giant planet atmospheres to laboratory data of candidate chromophores. The characterization of chromophore materials will provide insight into the upper tropospheric dynamics and circulation patterns on Jupiter and Saturn that provide a stable environment for the creation and/or sustenance of chromophores. This will help further our understanding of the different evolutionary pathways of the gas giant planets of our solar system, providing a process-oriented view of their variations in cloud colors.

Chanover, Nancy J.; Simon-Miller, A. A.; Hudson, R. L.; Loeffler, M. J.

2013-10-01

47

What If There Were a Planet Between Mars and Jupiter?  

NSDL National Science Digital Library

This activity, a supplement to the Hall of Meteorites Educator's Guide, investigates the transition point between the rocky planets of the inner solar system and the gas planets of the outer solar system. After reviewing the characteristics of the nine planets of the inner and outer solar system, along with the asteroid belt that lies between them, students are asked to investigate this question: If these asteroids had come together at the same time and in the same way to form a 10th planet, what would it be like?

48

Little Stars Don't Like Big Planets: An Astrometric Search for Super-Jupiters Around Red Dwarfs  

NASA Astrophysics Data System (ADS)

The astrometric detection and characterization of extrasolar planets presents considerable technical challenges, but also promises to greatly enhance our understanding of these systems. Nearly all currently confirmed exoplanets have been discovered using transit or radial velocity techniques. The former is geometrically biased towards planets with small orbits, while the latter is biased towards massive planets with short periods that exert large gravitational accelerations on their host stars. Astrometric techniques are limited by the minimum detectable perturbation of a star's position due to a planet, but allow for the determination of orbit inclination and an accurate planetary mass. Here we present astrometric solutions for five nearby stars with known planets: four M dwarfs (GJ 317, GJ 581, GJ 849, and GJ 1214) and one K dwarf (BD -10 3166). Observations have baselines of three to thirteen years, and were made using the 0.9 m telescope at CTIO as part of the RECONS long-term astrometry program. We provide improved parallaxes for the stars and find that there are no planets of several Jupiter masses or brown dwarfs orbiting these stars with periods up to twice the length of the astrometric coverage. In the broader context, these results are consistent with the paucity of super-Jupiter and brown dwarf companions we find among the roughly 200 red dwarfs searched in our astrometric program. This effort has been supported by the National Science Foundation via grant AST 09-08402 and the long-term cooperative efforts of the National Optical Astronomy Observatories and the members of the SMARTS Consortium.

Lurie, John C.; Henry, T. J.; Jao, W.; Koerner, D. W.; Riedel, A. R.; Subasavage, J.; RECONS

2013-01-01

49

THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. I. MEASURING PHOTOMETRIC ECCENTRICITIES OF INDIVIDUAL TRANSITING PLANETS  

SciTech Connect

Exoplanet orbital eccentricities offer valuable clues about the history of planetary systems. Eccentric, Jupiter-sized planets are particularly interesting: they may link the 'cold' Jupiters beyond the ice line to close-in hot Jupiters, which are unlikely to have formed in situ. To date, eccentricities of individual transiting planets primarily come from radial-velocity measurements. Kepler has discovered hundreds of transiting Jupiters spanning a range of periods, but the faintness of the host stars precludes radial-velocity follow-up of most. Here, we demonstrate a Bayesian method of measuring an individual planet's eccentricity solely from its transit light curve using prior knowledge of its host star's density. We show that eccentric Jupiters are readily identified by their short ingress/egress/total transit durations-part of the 'photoeccentric' light curve signature of a planet's eccentricity-even with long-cadence Kepler photometry and loosely constrained stellar parameters. A Markov Chain Monte Carlo exploration of parameter posteriors naturally marginalizes over the periapse angle and automatically accounts for the transit probability. To demonstrate, we use three published transit light curves of HD 17156 b to measure an eccentricity of e = 0.71{sup +0.16}{sub -0.09}, in good agreement with the discovery value e = 0.67 {+-} 0.08 based on 33 radial-velocity measurements. We present two additional tests using Kepler data. In each case, the technique proves to be a viable method of measuring exoplanet eccentricities and their confidence intervals. Finally, we argue that this method is the most efficient, effective means of identifying the extremely eccentric, proto-hot Jupiters predicted by Socrates et al.

Dawson, Rebekah I. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-10, Cambridge, MA 02138 (United States); Johnson, John Asher, E-mail: rdawson@cfa.harvard.edu [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States)

2012-09-10

50

Planet Mass Dependence Of Rates And Source Region Of Temporary Capture Of Planetesimals By A Planet  

NASA Astrophysics Data System (ADS)

When planetesimals encounter with a planet, in some cases they can be captured by the planet's gravity and orbit about the planet for an extended period of time, before they escape from the vicinity of the planet. This phenomenon is called temporary capture, and may have played an important role in the origin and dynamical evolution of small bodies in the Solar System. Recently, we investigated temporary capture of planetesimals initially on eccentric orbits, and found that temporary capture orbits can be classified into four types (Suetsugu et al. 2011). Their orbital size and direction of revolution around the planet change depending on planetesimals' initial eccentricity and energy. We obtained rates of temporary capture of planetesimals and found that the rate of long capture increases with increasing eccentricity at low and high eccentricity but in intermediate values of eccentricity decreases with increasing eccentricity. In the above study, we performed three-body orbital integrations under Hill's approximations, where the masses of the planet and planetesimals are assumed to be much smaller than the solar mass. In this case, the effect of the curvature of their guiding-center orbits is neglected. This assumption is valid for the case of a low mass planet, but the effect of the curvature may be important for temporary capture by a high mass planet, like Jupiter. In the present work, we use a simple three-body system that consists of the Sun, a planet, and a test particle, and perform global orbital integration to examine temporary capture by a high mass planet. We will present the rates of temporary capture obtained by our global calculation, and also discuss the effect of the curvature on source region of temporary capture.

Suetsugu, Ryo; Ohtsuki, K.

2012-10-01

51

Orbital and Mass Evolution of Planets Undergoing Run-Away Gas Accretion  

NASA Astrophysics Data System (ADS)

We have analyzed the orbital and mass evolution of planets that undergo run-away gas accretion in a circumstellar disk by means of high-resolution, three-dimensional hydrodynamics simulations. The radial distribution of the disk torque per unit disk mass provides an important diagnostic for the nature of the disk-planet interactions. We first show that torque distributions for nonmigrating planets of fixed mass are in general agreement with the expectations of resonance theory. We then present results of calculations for migrating, mass-gaining planets. Our main findings are: (1) For planets with an initial mass Mp=5 Earth masses, which are embedded in disks with standard parameters (aspect ratio h~ 0.04--0.05 and alpha-viscosity ~ 0.001--0.1) and which undergo run-away gas accretion growth to one Jupiter mass, the torque distributions per unit disk mass are largely unaffected by migration and accretion for a given planet mass. The migration rates of these planets are in agreement with the predictions of the standard theory for planet migration (Type I and Type II migration). In the intermediate and Jupiter-mass regimes, migration rates can be accounted for by standard Type I theory, corrected for the gas depletion in the gap region. (2) The planet mass growth rate is dMp/dt? M3p/h7 (gas capture within the planet's Bondi sphere) at lower planet masses and dMp/dt? Mp/h (gas capture within the planet's Hill sphere) at intermediate planet masses. At higher planet masses, the accretion rate reduces due to gap formation. (3) During the run-away mass growth phase, a planet migrates inwards by only about 20% in radius before achieving a mass on the order of Jupiter's. (4) For standard planet and disk conditions, we find no evidence of fast migration driven by coorbital torques (Type III migration). We do find evidence of Type III migration for a planet of fixed Saturn's mass, which is immersed in a cold (h~ 0.03) and massive (~ 0.02 M?) disk, whose migration begins before gap formation completes. The migration can be explained with a model in which the torque is due to an asymmetry in density between trapped gas on the leading side of the planet and ambient gas on the trailing side of the planet.

Lubow, S. H.; D'Angelo, G.

2008-12-01

52

WASP-77 Ab: A Transiting Hot Jupiter Planet in a Wide Binary System  

NASA Astrophysics Data System (ADS)

We report the discovery of a transiting planet with an orbital period of 1.36 days orbiting the brighter component of the visual binary star BD 07 436. The host star, WASP-77 A, is a moderately bright G8 V star (V=10.3) with a metallicity close to solar ([Fe/H] = 0.0 ± 0.1). The companion star, WASP-77 B, is a K-dwarf approximately 2 mag fainter at a separation of approximately 3?. The spectrum of WASP-77 A shows emission in the cores of the Caii H and K lines, indicative of moderate chromospheric activity. The Wide Angle Search for Planets (WASP) light curves show photometric variability with a period of 15.3 days and an amplitude of about 0.3% that is probably due to the magnetic activity of the host star. We use an analysis of the combined photometric and spectroscopic data to derive the mass and radius of the planet (1.76 ± 0.06 MJup, 1.21 ± 0.02 RJup). The age of WASP-77 A estimated from its rotation rate (˜1 Gyr) agrees with the age estimated in a similar way for WASP-77 B (˜0.6 Gyr) but is in poor agreement with the age inferred by comparing its effective temperature and density to stellar models (˜8 Gyr). Follow-up observations of WASP-77 Ab will make a useful contribution to our understanding of the influence of binarity and host star activity on the properties of hot Jupiters.

Maxted, P. F. L.; Anderson, D. R.; Collier Cameron, A.; Doyle, A. P.; Fumel, A.; Gillon, M.; Hellier, C.; Jehin, E.; Lendl, M.; Pepe, F.; Pollacco, D. L.; Queloz, D.; Ségransan, D.; Smalley, B.; Southworth, K.; Smith, A. M. S.; Triaud, A. H. M. J.; Udry, S.; West, R. G.

2013-01-01

53

Sprite discharges on Venus and Jupiter-like planets: A laboratory investigation  

Microsoft Academic Search

Large sprite discharges at high atmospheric altitudes have been found to be physically similar to small streamer discharges in air at sea level density. Based on this understanding, we investigate possible sprite discharges on Venus or Jupiter-like planets through laboratory experiments on streamers in appropriate CO2-N2 and H2-He mixtures. First, the scaling laws are experimentally confirmed by varying the density

D. Dubrovin; S. Nijdam; E. M. van Veldhuizen; U. Ebert; Y. Yair; C. Price

2010-01-01

54

Planet Hunters. V. A Confirmed Jupiter-size Planet in the Habitable Zone and 42 Planet Candidates from the Kepler Archive Data  

NASA Astrophysics Data System (ADS)

We report the latest Planet Hunter results, including PH2 b, a Jupiter-size (R PL = 10.12 ± 0.56 R ?) planet orbiting in the habitable zone of a solar-type star. PH2 b was elevated from candidate status when a series of false-positive tests yielded a 99.9% confidence level that transit events detected around the star KIC 12735740 had a planetary origin. Planet Hunter volunteers have also discovered 42 new planet candidates in the Kepler public archive data, of which 33 have at least 3 transits recorded. Most of these transit candidates have orbital periods longer than 100 days and 20 are potentially located in the habitable zones of their host stars. Nine candidates were detected with only two transit events and the prospective periods are longer than 400 days. The photometric models suggest that these objects have radii that range between those of Neptune and Jupiter. These detections nearly double the number of gas-giant planet candidates orbiting at habitable-zone distances. We conducted spectroscopic observations for nine of the brighter targets to improve the stellar parameters and we obtained adaptive optics imaging for four of the stars to search for blended background or foreground stars that could confuse our photometric modeling. We present an iterative analysis method to derive the stellar and planet properties and uncertainties by combining the available spectroscopic parameters, stellar evolution models, and transiting light curve parameters, weighted by the measurement errors. Planet Hunters is a citizen science project that crowd sources the assessment of NASA Kepler light curves. The discovery of these 43 planet candidates demonstrates the success of citizen scientists at identifying planet candidates, even in longer period orbits with only two or three transit events. .

Wang, Ji; Fischer, Debra A.; Barclay, Thomas; Boyajian, Tabetha S.; Crepp, Justin R.; Schwamb, Megan E.; Lintott, Chris; Jek, Kian J.; Smith, Arfon M.; Parrish, Michael; Schawinski, Kevin; Schmitt, Joseph R.; Giguere, Matthew J.; Brewer, John M.; Lynn, Stuart; Simpson, Robert; Hoekstra, Abe J.; Jacobs, Thomas Lee; LaCourse, Daryll; Schwengeler, Hans Martin; Chopin, Mike; Herszkowicz, Rafal

2013-10-01

55

Two from Space: UC Berkeley Astronomers Find Jupiter-sized Planet Around Nearby Star in Big Dipper  

NSDL National Science Digital Library

In other space and planetary news, researchers have found signs of a Jupiter-sized planet near one of the Big Dipper's stars. To learn more, check out the University of California Planet Search program's press release that contains astronomical data, a sky chart, and links.

2001-01-01

56

Simulating Photoevaporative Mass Loss from Hot Jupiters in 3D  

NASA Astrophysics Data System (ADS)

Escaping planetary winds have been observed with UV transmission spectra from several transiting hot Jupiters. To find other observational signatures of these winds, we are developing a global model of atmospheric escape from hot Jupiters. Our goal is to model the full, asymmetric structure of the wind, which is driven by photoionizing stellar flux and shaped by stellar winds and orbital motion. This poster presents the current status of our model, which simultaneously includes photoionization heating and is done in three dimensions, unlike previous models. Using the Athena code for hydrodynamics, we model the planet as a static potential with a hydrostatic atmosphere, at the center of a three-dimensional Cartesian grid. We self-consistently treat the planetary wind's production by introducing a planar source of stellar UV flux and evolving it with ionizing radiative transfer coupled to the hydrodynamics. We have implemented our ionization algorithm to include Static Mesh Refinement (SMR) and parallelization with MPI, to resolve the planet's exosphere. Tests of the evolution of a planar ionization front in our code match analytic expectations for the propagation rate of a D-type ionization front. Further code development is in progress, and we plan to include the major contributions to the outflow's asymmetry - the stellar wind, which can confine the planetary wind structure, and the Coriolis force, which captures the planet's orbital motion. Since Athena and our radiative transfer code are compatible with MHD, extensions to the model can further include the planet's magnetic field.

Tripathi, Anjali; Kratter, Kaitlin; Krumholz, Mark; Murray-Clay, Ruth

2013-07-01

57

Trojan planets in HD108874?  

Microsoft Academic Search

Today there are about 190 extrasolar planets in 156 extrasolar systems confirmed. We have only observational evidence for planets from 7 (Gliese 876 d) earth masses up to several Jupiter masses; and up to now no planet with a mass comparable to the Earth was found. To ensure that an orbit of such a planet is stable in the so-called

R. Schwarz; R. Dvorak; E. Pilat-Lohinger; B. Erdi

2006-01-01

58

Spin-orbit angle measurements for six southern transiting planets. New insights into the dynamical origins of hot Jupiters  

NASA Astrophysics Data System (ADS)

Context. Several competing scenarios for planetary-system formation and evolution seek to explain how hot Jupiters came to be so close to their parent stars. Most planetary parameters evolve with time, making it hard to distinguish between models. The obliquity of an orbit with respect to the stellar rotation axis is thought to be more stable than other parameters such as eccentricity. Most planets, to date, appear aligned with the stellar rotation axis; the few misaligned planets so far detected are massive (> 2 MJ). Aims: Our goal is to measure the degree of alignment between planetary orbits and stellar spin axes, to search for potential correlations with eccentricity or other planetary parameters and to measure long term radial velocity variability indicating the presence of other bodies in the system. Methods: For transiting planets, the Rossiter-McLaughlin effect allows the measurement of the sky-projected angle ? between the stellar rotation axis and a planet's orbital axis. Using the HARPS spectrograph, we observed the Rossiter-McLaughlin effect for six transiting hot Jupiters found by the WASP consortium. We combine these with long term radial velocity measurements obtained with CORALIE. We used a combined analysis of photometry and radial velocities, fitting model parameters with the Markov Chain Monte Carlo method. After obtaining ? we attempt to statistically determine the distribution of the real spin-orbit angle ?. Results: We found that three of our targets have ? above 90°: WASP-2b: ? = 153°+11-15, WASP-15b: ? = 139.6°+5.2-4.3 and WASP-17b: ? = 148.5°+5.1-4.2; the other three (WASP-4b, WASP-5b and WASP-18b) have angles compatible with 0°. We find no dependence between the misaligned angle and planet mass nor with any other planetary parameter. All six orbits are close to circular, with only one firm detection of eccentricity e = 0.00848+0.00085-0.00095 in WASP-18b. No long-term radial acceleration was detected for any of the targets. Combining all previous 20 measurements of ? and our six and transforming them into a distribution of ? we find that between about 45 and 85% of hot Jupiters have ? > 30°. Conclusions: Most hot Jupiters are misaligned, with a large variety of spin-orbit angles. We find observations and predictions using the Kozai mechanism match well. If these observational facts are confirmed in the future, we may then conclude that most hot Jupiters are formed from a dynamical and tidal origin without the necessity to use type I or II migration. At present, standard disc migration cannot explain the observations without invoking at least another additional process. Using observations with the high resolution échelle spectrograph HARPS mounted on the ESO 3.6 m (under proposals 072.C-0488, 082.C-0040 & 283.C-5017), and with the high resolution échelle spectrograph CORALIE on the 1.2 m Euler Swiss Telescope, both installed at the ESO La Silla Observatory in Chile.RV data is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/524/A25

Triaud, A. H. M. J.; Collier Cameron, A.; Queloz, D.; Anderson, D. R.; Gillon, M.; Hebb, L.; Hellier, C.; Loeillet, B.; Maxted, P. F. L.; Mayor, M.; Pepe, F.; Pollacco, D.; Ségransan, D.; Smalley, B.; Udry, S.; West, R. G.; Wheatley, P. J.

2010-12-01

59

Embryo Impacts and Gas Giant Mergers. I. Dichotomy of Jupiter and Saturn's Core Mass  

NASA Astrophysics Data System (ADS)

Interior to the gaseous envelopes of Saturn, Uranus, and Neptune, there are high-density cores with masses larger than 10 Earth masses. According to the conventional sequential accretion hypothesis, such massive cores are needed for the onset of efficient accretion of their gaseous envelopes. However, Jupiter's gaseous envelope is more massive and its core may be less massive than those of Saturn. In order to account for this structural diversity and the super-solar metallicity in the envelope of Jupiter and Saturn, we investigate the possibility that they may have either merged with other gas giants or consumed several Earth-mass protoplanetary embryos during or after the rapid accretion of their envelope. In general, impinging sub-Earth-mass planetesimals disintegrate in gas giants' envelopes, deposit heavy elements well outside the cores, and locally suppress the convection. Consequently, their fragments sediment to promote the growth of cores. Through a series of numerical simulations, we show that it is possible for colliding super-Earth-mass embryos to reach the cores of gas giants. Direct parabolic collisions also lead to the coalescence of gas giants and merging of their cores. In these cases, the energy released from the impact leads to vigorous convective motion throughout the envelope and the erosion of the cores. This dichotomy contributes to the observed dispersion in the internal structure and atmospheric composition between Jupiter and Saturn and other gas giant planets and elsewhere.

Li, Shu Lin; Agnor, C. B.; Lin, D. N. C.

2010-09-01

60

Photochemistry and diffusion in Jupiter's stratosphere: Constraints from ISO observations and comparisons with other giant planets  

NASA Astrophysics Data System (ADS)

We have developed a one-dimensional, diurnally averaged, photochemical model for Jupiter's stratosphere that couples photodissociation, chemical kinetics, vertical diffusion, and radiative transport. The predictions regarding the abundances and vertical profiles of hydrocarbon compounds are compared with observations from the Infrared Space Observatory (ISO) to better constrain the atmospheric composition, to better define the eddy diffusion coefficient profile, and to better understand the chemical reaction schemes that produce and destroy the observed constituents. From model-data comparisons we determine that the C2H6 mole fraction on Jupiter is (4.0 +/- 1.0) × 10-6 at 3.5 mbar and (2.7 +/- 0.7) × 10-6 at 7 mbar, and the C2H2 mole fraction is (1.4 +/- 0.8) × 10-6 at 0.25 mbar and (1.5 +/- 0.4) × 10-7 at 2 mbar. The column densities of CH3C2H and C6H6 are (1.5 +/- 0.4) × 1015 cm-2 and (8.0 +/- 2) × 1014 cm-2, respectively, above 30 mbar. Using identical reaction lists, we also have developed photochemical models for Saturn, Uranus, and Neptune. Although the models provide good first-order predictions of hydrocarbon abundances on the giant planets, our current chemical reaction schemes do not reproduce the relative abundances of C2Hx hydrocarbons. Unsaturated hydrocarbons like C2H4 and C2H2 appear to be converted to saturated hydrocarbons like C2H6 more effectively on Jupiter than on the other giant planets, more effectively than is predicted by the models. Further progress in our understanding of photochemistry at low temperatures and low pressures in hydrogen-dominated atmospheres hinges on the acquisition of high-quality kinetics data.

Moses, J. I.; Fouchet, T.; Bézard, B.; Gladstone, G. R.; Lellouch, E.; Feuchtgruber, H.

2005-08-01

61

A search for Mars-mass extrasolar planets with Spitzer  

Microsoft Academic Search

We propose to make 6 observations of the transits of the hot Jupiter planet HD 189733b and six observations of its secondary eclipse in order to detect variations of the times of transit\\/eclipse due to secondary planets in the system, if present. Spitzer is the best telescope for transit timing of this system, allowing nearly an order of magnitude better

Eric Agol; David Charbonneau; Nicolas Cowan; Drake Deming; Heather Knutson; Jason Steffen

2007-01-01

62

Multiple planets or exomoons in Kepler hot Jupiter systems with transit timing variations?  

NASA Astrophysics Data System (ADS)

Aims: Hot Jupiters are thought to belong to single-planet systems. Somewhat surprisingly, some hot Jupiters have been reported to exhibit transit timing variations (TTVs). The aim of this paper is to identify the origin of these observations, identify possible periodic biases leading to false TTV detections, and refine the sample to a few candidates with likely dynamical TTVs. Methods: We present TTV frequencies and amplitudes of hot Jupiters in Kepler Q0-6 data with Fourier analysis and a frequency-dependent bootstrap calculation to assess the false alarm probability levels of the detections. Results: We identified 36 systems with TTV above four standard deviation confidence, about half of them exhibiting multiple TTV frequencies. Fifteen of these objects (HAT-P-7b, KOI-13, 127, 183, 188, 190, 196, 225, 254, 428, 607, 609, 684, 774, 1176) probably show TTVs due to a systematic observational effect: long cadence data sampling is regularly shifted transit-by-transit, interacting with the transit light curves, introducing a periodic bias, and leading to a stroboscopic period. For other systems, the activity and rotation of the host star can modulate light curves and explain the observed TTVs. By excluding the systems that were inadequately sampled, showed TTV periods related to the stellar rotation, or turned out to be false positives or suspects, we ended up with seven systems. Three of them (KOI-186, 897, 977) show the weakest stellar rotation features, and these are our best candidates for dynamically induced TTV variations. Conclusions: Those systems with periodic TTVs that we cannot explain with systematics from observation, stellar rotation, activity, or inadequate sampling, may be multiple systems or even exomoon hosts. Appendix A is available in electronic form at http://www.aanda.org

Szabó, R.; Szabó, Gy. M.; Dálya, G.; Simon, A. E.; Hodosán, G.; Kiss, L. L.

2013-05-01

63

Galilean Moons, Kepler's Third Law, and the Mass of Jupiter  

NASA Astrophysics Data System (ADS)

Simulations of physical systems are widely available online, with no cost, and are ready to be used in our classrooms.1,2 Such simulations offer an accessible tool that can be used for a range of interactive learning activities. The Jovian Moons Applet2 allows the user to track the position of Jupiter's four Galilean moons with a variety of viewing options. For this activity, data are obtained from the orbital period and orbital radii charts. Earlier experiments have used telescopes to capture the orbital motion of the Galilean moons,3 although observation of astronomical events and the measurement of quantities may be difficult to achieve due to a combination of cost, training, and observing conditions. The applet allows a suitable set of data to be generated and data analysis that verifies Kepler's third law of planetary motion, which leads to a calculated value for the mass of Jupiter.

Bates, Alan

2013-10-01

64

Trojan planets in HD108874?  

NASA Astrophysics Data System (ADS)

Today there are about 190 extrasolar planets in 156 extrasolar systems confirmed. We have only observational evidence for planets from 7 (Gliese 876 d) earth masses up to several Jupiter masses; and up to now no planet with a mass comparable to the Earth was found. To ensure that an orbit of such a planet is stable in the so-called habitable zone around a host star in planetary systems with Jupiter-like planets we can have different confugurations: either a hot Jupiter (very close to the central star) or (and) a planet far enough not to perturb the motions of a planetary body in the habitable zone (which depends on the astrophysical parameters of the star). Besides the two former mentioned possibilites there may exist also stable orbits around a 'Jupiter' in this habitable zone: a planet as satelliteor - we cannot exclude it - a Trojan planet. For the first time in a multiplanetary system, namely in HD108872 (a sunlike star), we found that Trojan planets may exist in the 1:1 resonance with the inner Jupiter-like planet (with a semimajor axis of approximately 1AU). We investigate the region around the Lagrange points for a wide range of the orbital parameters of the two planets. It turned out that with the actually determined orbital elements of both planets (for HD108874c a=2.7AU) a small region around the Lagrange points may host earth-like planets in the habitable zone of this star.

Schwarz, R.; Dvorak, R.; Pilat-Lohinger, E.; Erdi, B.

65

PARASITIC INTERFERENCE IN LONG BASELINE OPTICAL INTERFEROMETRY: REQUIREMENTS FOR HOT JUPITER-LIKE PLANET DETECTION  

SciTech Connect

The observable quantities in optical interferometry, which are the modulus and the phase of the complex visibility, may be corrupted by parasitic fringes superimposed on the genuine fringe pattern. These fringes are due to an interference phenomenon occurring from stray light effects inside an interferometric instrument. We developed an analytical approach to better understand this phenomenon when stray light causes cross talk between beams. We deduced that the parasitic interference significantly affects the interferometric phase and thus the associated observables including the differential phase and the closure phase. The amount of parasitic flux coupled to the piston between beams appears to be very influential in this degradation. For instance, considering a point-like source and a piston ranging from lambda/500 to lambda/5 in the L band (lambda = 3.5 mum), a parasitic flux of about 1% of the total flux produces a parasitic phase reaching at most one-third of the intrinsic phase. The piston, which can have different origins (instrumental stability, atmospheric perturbations, etc.), thus amplifies the effect of parasitic interference. According to the specifications of piston correction in space or at ground level (respectively lambda/500 approx 2 nm and lambda/30 approx 100 nm), the detection of hot Jupiter-like planets, one of the most challenging aims for current ground-based interferometers, limits parasitic radiation to about 5% of the incident intensity. This was evaluated by considering different types of hot Jupiter synthetic spectra. Otherwise, if no fringe tracking is used, the detection of a typical hot Jupiter-like system with a solar-like star would admit a maximum level of parasitic intensity of 0.01% for piston errors equal to lambda/15. If the fringe tracking specifications are not precisely observed, it thus appears that the allowed level of parasitic intensity dramatically decreases and may prevent the detection. In parallel, the calibration of the parasitic phase by a reference star, at this accuracy level, seems very difficult. Moreover, since parasitic phase is an object-dependent quantity, the use of a hypothetical phase abacus, directly giving the parasitic phase from a given parasitic flux level, is also impossible. Some instrumental solutions, implemented at the instrument design stage for limiting or preventing this parasitic interference, appear to be crucial and are presented in this paper.

Matter, A.; Lopez, B.; Lagarde, S. [Laboratoire Fizeau, UMR 6525, UNS-Observatoire de la cote d'azur, BP 4229, F-06304 Nice Cedex 4 (France); Danchi, W. C. [NASA/GSFC, Greenbelt, MD 20771 (United States); Robbe-Dubois, S.; Petrov, R. G. [Laboratoire Fizeau, UMR 6525, UNS-Observatoire de la cote d'azur, 06108 Nice Cedex 02 (France); Navarro, R., E-mail: matter@oca.e [NOVA-ASTRON, P.O. Box 2, 7990 AA Dwingeloo (Netherlands)

2009-12-01

66

Effects of mass loss for highly-irradiated giant planets  

NASA Astrophysics Data System (ADS)

We present calculations for the evolution and surviving mass of highly-irradiated extrasolar giant planets (EGPs) at orbital semimajor axes ranging from 0.023 to 0.057 AU using a generalized scaled theory for mass loss, together with new surface-condition grids for hot EGPs and a consistent treatment of tidal truncation. Theoretical estimates for the rate of energy-limited hydrogen escape from giant-planet atmospheres differ by two orders of magnitude, when one holds planetary mass, composition, and irradiation constant. Baraffe et al. [Baraffe, I., Selsis, F., Chabrier, G., Barman, T.S., Allard, F., Hauschildt, P.H., Lammer, H., 2004. Astron. Astrophys. 419, L13 L16] predict the highest rate, based on the theory of Lammer et al. [Lammer, H., Selsis, F., Ribas, I., Guinan, E.F., Bauer, S.J., Weiss, W.W., 2003. Astrophys. J. 598, L121 L124]. Scaling the theory of Watson et al. [Watson, A.J., Donahue, T.M., Walker, J.C.G., 1981. Icarus 48, 150 166] to parameters for a highly-irradiated exoplanet, we find an escape rate ˜10 lower than Baraffe's. With the scaled Watson theory we find modest mass loss, occurring early in the history of a hot EGP. In this theory, mass loss including the effect of Roche-lobe overflow becomes significant primarily for masses below a Saturn mass, for semimajor axes ?0.023 AU. This contrasts with the Baraffe model, where hot EGPs are claimed to be remnants of much more massive bodies, originally several times Jupiter and still losing substantial mass fractions at present.

Hubbard, W. B.; Hattori, M. F.; Burrows, A.; Hubeny, I.; Sudarsky, D.

2007-04-01

67

Mass Loss for Highly-Irradiated Giant Planets  

NASA Astrophysics Data System (ADS)

We present calculations for the surviving mass of highly-irradiated extrasolar giant planets (EGPs) at orbital semimajor axes ranging from 0.023 to 0.057 AU using a generalized scaled theory for mass loss, together with new surface-condition grids for hot EGPs and a consistent treatment of tidal truncation. Available theoretical estimates for the rate of energy-limited hydrogen escape from giant-planet atmospheres range over four orders of magnitude, when one holds planetary mass, composition, and irradiation constant. Yelle (Icarus 170, 167-179, 2004) predicts the lowest escape rate. Baraffe et al. (A&A 419, L13-L16, 2004) predict the highest rate, based on the theory of Lammer et al. (ApJ 598, L121-L124, 2003). Scaling the theory of Watson et al. (Icarus 48, 150-166, 1981) to parameters for a highly-irradiated exoplanet, we find an intermediate escape rate, ˜ 102 higher than Yelle's but ˜ 102 lower than Baraffe's. With the scaled Watson theory and the scaled Yelle theory we find modest mass loss, occurring early in the history of a hot EGP. Particularly for the Yelle theory, the effect of tidal truncation sets the minimum mass limit, well below a Saturn mass for the distances investigated. This contrasts with the Baraffe model, where hot EGPs are claimed to be remnants of much more massive bodies, originally several times Jupiter and still losing substantial mass fractions at present. Supported by NASA Grant NAG5-13775 (PGG) and NASA Grant NNG04GL22G (ATP).

Hubbard, W. B.; Burrows, A.; Hubeny, I.; Sudarsky, D.; Hattori, M. F.

2005-08-01

68

Mass-Radius Relationships for Very Low Mass Gaseous Planets  

NASA Astrophysics Data System (ADS)

Recently, the Kepler spacecraft has detected a sizable aggregate of objects, characterized by giant-planet-like radii and modest levels of stellar irradiation. With the exception of a handful of objects, the physical nature, and specifically the average densities, of these bodies remain unknown. Here, we propose that the detected giant planet radii may partially belong to planets somewhat less massive than Uranus and Neptune. Accordingly, in this work, we seek to identify a physically sound upper limit to planetary radii at low masses and moderate equilibrium temperatures. As a guiding example, we analyze the interior structure of the Neptune-mass planet Kepler-30d and show that it is acutely deficient in heavy elements, especially compared with its solar system counterparts. Subsequently, we perform numerical simulations of planetary thermal evolution and in agreement with previous studies, show that generally, 10-20 M ?, multi-billion year old planets, composed of high density cores and extended H/He envelopes can have radii that firmly reside in the giant planet range. We subject our results to stability criteria based on extreme ultraviolet radiation, as well as Roche-lobe overflow driven mass-loss and construct mass-radius relationships for the considered objects. We conclude by discussing observational avenues that may be used to confirm or repudiate the existence of putative low mass, gas-dominated planets.

Batygin, Konstantin; Stevenson, David J.

2013-05-01

69

WFIRST Planet Masses from Microlens Parallax  

NASA Astrophysics Data System (ADS)

I present a method using only a few ground-based observations of magnified microlensing events to routinely measure the parallaxes of WFIRST events if WFIRST is in an L2 orbit. This could be achieved for all events with A max > 30 using target-of-opportunity observations of select WFIRST events, or with a complementary, ground-based survey of the WFIRST field, which can push beyond this magnification limit. When combined with a measurement of the angular size of the Einstein ring, which is almost always measured in planetary events, these parallax measurements will routinely give measurements of the lens masses and hence the absolute masses of the planets. They can also lead to mass measurements for dark, isolated objects such as brown dwarfs, free-floating planets, and stellar remnants if the size of the Einstein ring is measured.

Yee, J. C.

2013-06-01

70

A COLD NEPTUNE-MASS PLANET OGLE-2007-BLG-368Lb: COLD NEPTUNES ARE COMMON  

SciTech Connect

We present the discovery of a Neptune-mass planet OGLE-2007-BLG-368Lb with a planet-star mass ratio of q = [9.5 +- 2.1] x 10{sup -5} via gravitational microlensing. The planetary deviation was detected in real-time thanks to the high cadence of the Microlensing Observations in Astrophysics survey, real-time light-curve monitoring and intensive follow-up observations. A Bayesian analysis returns the stellar mass and distance at M{sub l} = 0.64{sup +0.21}{sub -0.26} M{sub sun} and D{sub l} = 5.9{sup +0.9}{sub -1.4} kpc, respectively, so the mass and separation of the planet are M{sub p} = 20{sup +7}{sub -8} M{sub +} and a = 3.3{sup +1.4}{sub -0.8} AU, respectively. This discovery adds another cold Neptune-mass planet to the planetary sample discovered by microlensing, which now comprises four cold Neptune/super-Earths, five gas giant planets, and another sub-Saturn mass planet whose nature is unclear. The discovery of these 10 cold exoplanets by the microlensing method implies that the mass ratio function of cold exoplanets scales as dN{sub pl}/dlog q {proportional_to} q {sup -0.7+}-{sup 0.2} with a 95% confidence level upper limit of n < -0.35 (where dN{sub pl}/dlog q {proportional_to} q{sup n} ). As microlensing is most sensitive to planets beyond the snow-line, this implies that Neptune-mass planets are at least three times more common than Jupiters in this region at the 95% confidence level.

Sumi, T.; Abe, F.; Fukui, A., E-mail: sumi@stelab.nagoya-u.ac.j, E-mail: abe@stelab.nagoya-u.ac.j, E-mail: afukui@stelab.nagoya-u.ac.j [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan)

2010-02-20

71

Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing  

SciTech Connect

Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the first detection of a multiple-planet system with microlensing. We identify two planets with masses of {approx} 0.71 and {approx} 0.27 times the mass of Jupiter and orbital separations of {approx} 2.3 and {approx} 4.6 astronomical units orbiting a primary of mass {approx} 0.50 solar masses. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only 6 confirmed microlensing planet detections suggests that solar system analogs may be common.

Gaudi, B; Bennett, D; Udalski, A; Gould, A; Christie, G; Maoz, D; Dong, S; McCormick, J; Szymanski, M; Tristram, P; Nikolaev, S; Paczynski, B; Kubiak, M; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; DePoy, D; Han, C; Kaspi, S; Lee, C; Mallia, F; Natusch, T; Pogge, R; Park, B; Abe, F; Bond, I; Botzler, C; Fukui, A; Hearnshaw, J; Itow, Y; Kamiya, K; Korpela, A; Kilmartin, P; Lin, W; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okumura, T; Ohnishi, K; Rattenbury, N; Sako, T; Saito, T; Sato, S; Skuljan, L; Sullivan, D; Sumi, T; Sweatman, W; Yock, P; Albrow, M; Beaulieu, J; Burgdorf, M; Cook, K; Coutures, C; Dominik, M; Dieters, S; Fouque, P; Greenhill, J; Horne, K; Steele, I; Tsapras, Y; Chaboyer, B; Crocker, A; Frank, S; Macintosh, B

2007-11-08

72

Nebular gas drag and planetary accretion with eccentric high-mass planets  

NASA Astrophysics Data System (ADS)

Aims: We investigate the dynamics of pebbles immersed in a gas disk interacting with a planet on an eccentric orbit. The model has a prescribed gap in the disk around the location of the planetary orbit, as is expected for a giant planet with a mass in the range of 0.1-1 Jupiter masses. The pebbles with sizes in the range of 1 cm to 3 m are placed in a ring outside of the giant planet orbit at distances between 10 and 30 planetary Hill radii. The process of the accumulation of pebbles closer to the gap edge, its possible implication for the planetary accretion, and the importance of the mass and the eccentricity of the planet in this process are the motivations behind the present contribution. Methods: We used the Bulirsch-Stoer numerical algorithm, which is computationally consistent for close approaches, to integrate the Newtonian equations of the planar (2D), elliptical restricted three-body problem. The angular velocity of the gas disk was determined by the appropriate balance between the gravity, centrifugal, and pressure forces, such that it is sub-Keplerian in regions with a negative radial pressure gradient and super-Keplerian where the radial pressure gradient is positive. Results: The results show that there are no trappings in the 1:1 resonance around the L4 and L5 Lagrangian points for very low planetary eccentricities (e2 < 0.07). The trappings in exterior resonances, in the majority of cases, are because the angular velocity of the disk is super-Keplerian in the gap disk outside of the planetary orbit and because the inward drift is stopped. Furthermore, the semi-major axis location of such trappings depends on the gas pressure profile of the gap (depth) and is a = 1.2 for a planet of 1 MJ. A planet on an eccentric orbit interacts with the pebble layer formed by these resonances. Collisions occur and become important for planetary eccentricity near the present value of Jupiter (e2 = 0.05). The maximum rate of the collisions onto a planet of 0.1 MJ occurs when the pebble size is 37.5 cm ? s < 75 cm; for a planet with the mass of Jupiter, it is15 cm ? s < 30 cm. The accretion stops when the pebble size is less than 2 cm and the gas drag dominates the motion. Appendices are available in electronic form at http://www.aanda.org

Chanut, T. G. G.; Winter, O. C.; Tsuchida, M.

2013-04-01

73

The planet search programme at the ESO CES and HARPS. IV. The search for Jupiter analogues around solar-like stars  

NASA Astrophysics Data System (ADS)

Context. In 1992 we began a precision radial velocity survey for planets around solar-like stars with the Coudé Echelle Spectrograph and the Long Camera (CES LC) at the 1.4 m telescope in La Silla (Chile) resulting in the discovery of the planet ? Hor b. We have continued the survey with the upgraded CES Very Long Camera (VLC) and the HARPS spectrographs, both at the 3.6 m telescope, until 2007. Aims: In this paper we present additional radial velocities for 31 stars of the original sample with higher precision. The observations cover a time span of up to 15 years and permit a search for Jupiter analogues. Methods: The survey was carried out with three different instruments/instrument configurations using the iodine absorption cell and the ThAr methods for wavelength calibration. We combine the data sets and perform a joint analysis for variability, trends, and periodicities. We compute Keplerian orbits for companions and detection limits in case of non-detections. Moreover, the HARPS radial velocities are analysed for correlations with activity indicators (CaII H&K and cross-correlation function shape). Results: We achieve a long-term RV precision of 15 m/s (CES+LC, 1992-1998), 9 m/s (CES+VLC, 1999-2006), and 2.8 m/s (HARPS, 2003-2009, including archive data), respectively. This enables us to confirm the known planetary signals in ? Hor and HR 506 as well as the three known planets around HR 3259. A steady RV trend for ? Ind A can be explained by a planetary companion and calls for direct imaging campaigns. On the other hand, we find previously reported trends to be smaller for ? Hyi and not present for ? Men. The candidate planet ? Eri b was not detected despite our better precision. Also the planet announced for HR 4523 cannot be confirmed. Long-term trends in several of our stars are compatible with known stellar companions. We provide a spectroscopic orbital solution for the binary HR 2400 and refined solutions for the planets around HR 506 and ? Hor. For some other stars the variations could be attributed to stellar activity, as e.g. the magnetic cycle in the case of HR 8323. Conclusions: The occurrence of two Jupiter-mass planets in our sample is in line with the estimate of 10% for the frequency of giant planets with periods smaller than 10 yr around solar-like stars. We have not detected a Jupiter analogue, while the detections limits for circular orbits indicate at 5 AU a sensitivity for minimum mass of at least 1MJup (2MJup) for 13% (61%) of the stars. Based on observations collected at the European Southern Observatory, La Silla Chile, ESO programmes 50.7-0095, 51.7-0054, 52.7-0002, 53.7-0064, 54.E-0424, 55.E-0361, 56.E-0490, 57.E-0142, 58.E-0134, 59.E-0597, 60.E-0386, 61.E-0589, 62.L-0490, 64.L-0568, 66.C-0482, 67.C-0296, 69.C-0723, 70.C-0047, 71.C-0599, 072.C-0513, 073.C-0784, 074.C-0012, 076.C-0878, 077.C-0530, 078.C-0833, 079.C-0681. Also based on data obtained from the ESO Science Archive Facility.Appendices are available in electronic form at http://www.aanda.orgTables of the radial velocities, bisector spans, and log R'_HK are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/552/A78

Zechmeister, M.; Kürster, M.; Endl, M.; Lo Curto, G.; Hartman, H.; Nilsson, H.; Henning, T.; Hatzes, A. P.; Cochran, W. D.

2013-04-01

74

The Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters  

Microsoft Academic Search

The questions of how planets form and how common Earth-like planets are can be addressed by measuring the distribution of exoplanet masses and orbital periods. We report the occurrence rate of close-in planets (with orbital periods less than 50 days), based on precise Doppler measurements of 166 Sun-like stars. We measured increasing planet occurrence with decreasing planet mass (M). Extrapolation

Andrew W. Howard; Geoffrey W. Marcy; John Asher Johnson; Debra A. Fischer; Jason T. Wright; Howard Isaacson; Jeff A. Valenti; Jay Anderson; Doug N. C. Lin; Shigeru Ida

2010-01-01

75

Clouds in Low-mass, Low-density Planets  

NASA Astrophysics Data System (ADS)

The Kepler Space Telescope has revealed huge populations of low-mass, low-density planets, but their compositions remain elusive. For example, the density of GJ 1214b is consistent with either a water-world with a water atmosphere or a rock-iron core with a H/He envelope. Other super-Earths must contain hydrogen and helium to match their observed masses and radii. To understand this population of objects, we must be able to characterize their compositions through spectroscopy. The formation of clouds in exoplanet atmospheres significantly changes their observable spectra. For exoplanets, the opacity of hazes or clouds has been invoked as a possible explanation for the observed flat transmission spectrum of transiting super-Earth GJ 1214b as well as for the strong Rayleigh scattering feature in HD 189733b, the best-studied hot Jupiter. Here, we examine the effect of clouds on low-mass, low-density exoplanet spectra. We include the condensates that are present in chemical equilibrium for objects at these temperatures (500-900 K) which include minerals like sulfides and alkali salts. The most important of these clouds are sodium sulfide, potassium chloride, and zinc sulfide. These clouds should be most prominent at low surface gravity, strongly super-solar atmospheric abundances, and at the slant viewing geometry appropriate for transits. Hence they could be quite important for affecting the transmission spectra of cool low density super-Earth and Neptune-class planets. Another class of clouds may also dramatically alter the spectra of irradiated planets: photochemical hazes. We additionally include a hydrocarbon haze layer similar to the tholin haze in Titan’s atmosphere. We calculate the location and density of the haze layer using photochemical models from Kempton et al. 2012. We present new results that show that for enhanced metallicity atmospheres, either the clouds that form in equilibrium or a hydrocarbon haze layer could become sufficiently optically thick to reproduce the observations of GJ 1214b. We also present predictions for other low-mass, low-density exoplanets which will be targets of future observational campaigns: HD 97658b and GJ 3470b.

Morley, Caroline; Fortney, J.; Marley, M.; Kempton, E.; Visscher, C.; Zahnle, K.

2013-10-01

76

High-resolution imaging of young M-type stars of the solar neighbourhood: probing for companions down to the mass of Jupiter  

NASA Astrophysics Data System (ADS)

Context. High-contrast imaging is a powerful technique when searching for gas giant planets and brown dwarfs orbiting at separations greater than several AU. Around solar-type stars, giant planets are expected to form by core accretion or by gravitational instability, but since core accretion is increasingly difficult as the primary star becomes lighter, gravitational instability would be a probable formation scenario for still-to-find distant giant planets around a low-mass star. A systematic survey for such planets around M dwarfs would therefore provide a direct test of the efficiency of gravitational instability. Aims: We search for gas giant planets orbiting late-type stars and brown dwarfs of the solar neighbourhood. Methods: We obtained deep high-resolution images of 16 targets with the adaptive optic system of VLT-NACO in the L' band, using direct imaging and angular differential imaging. This is currently the largest and deepest survey for Jupiter-mass planets around M-dwarfs. We developed and used an integrated reduction and analysis pipeline to reduce the images and derive our 2D detection limits for each target. The typical contrast achieved is about 9 mag at 0.5? and 11 mag beyond 1?. For each target we also determine the probability of detecting a planet of a given mass at a given separation in our images. Results: We derived accurate detection probabilities for planetary companions, taking orbital projection effects into account, with in average more than 50% probability to detect a 3 MJup companion at 10 AU and a 1.5 MJup companion at 20 AU, bringing strong constraints on the existence of Jupiter-mass planets around this sample of young M-dwarfs. Based on observations made with the NACO at VLT UT-4 at the Paranal Observatory under programme IDs 084.C-0739, 085.C-0675(A), 087.C-0413(A) and 087.C-0450(B).

Delorme, P.; Lagrange, A. M.; Chauvin, G.; Bonavita, M.; Lacour, S.; Bonnefoy, M.; Ehrenreich, D.; Beust, H.

2012-03-01

77

The occurrence and mass distribution of close-in super-Earths, Neptunes, and Jupiters.  

PubMed

The questions of how planets form and how common Earth-like planets are can be addressed by measuring the distribution of exoplanet masses and orbital periods. We report the occurrence rate of close-in planets (with orbital periods less than 50 days), based on precise Doppler measurements of 166 Sun-like stars. We measured increasing planet occurrence with decreasing planet mass (M). Extrapolation of a power-law mass distribution fitted to our measurements, df/dlogM = 0.39 M(-0.48), predicts that 23% of stars harbor a close-in Earth-mass planet (ranging from 0.5 to 2.0 Earth masses). Theoretical models of planet formation predict a deficit of planets in the domain from 5 to 30 Earth masses and with orbital periods less than 50 days. This region of parameter space is in fact well populated, implying that such models need substantial revision. PMID:21030652

Howard, Andrew W; Marcy, Geoffrey W; Johnson, John Asher; Fischer, Debra A; Wright, Jason T; Isaacson, Howard; Valenti, Jeff A; Anderson, Jay; Lin, Doug N C; Ida, Shigeru

2010-10-29

78

Giant Planet Occurrence Rate as a Function of Stellar Mass  

NASA Astrophysics Data System (ADS)

For over 12 years we have carried out a Doppler survey at Lick Observatory, identifying 15 planets and 20 candidate planets in a sample of 373 G and K giant stars. We investigate giant planet occurrence rate as a function of stellar mass and metallicity in this sample, which covers the mass range from about 1 to 3.5-5.0 solar masses. We confirm the presence of a strong planet-metallicity correlation in our giant star sample, which is fully consistent with the well-known planet-metallicity correlation for main-sequence stars. Furthermore, we find a very strong dependence of the giant planet occurrence rate on stellar mass, which we fit with a gaussian distribution. Stars with masses of about 1.9 solar masses have the highest probability of hosting a giant planet, whereas the planet occurrence rate drops rapidly for masses larger than 2.5 to 3.0 solar masses. We do not find any planets around stars more massive than 2.7 solar masses, although we have 113 stars with masses between 2.7 and 5.0 solar masses in our sample (planet occurrence rate in that mass range: 0% +1.6% at 68.3% confidence). This result is not due to a bias related to planet detectability as a function of stellar mass. We conclude that larger mass stars do not form giant planets which are observable at orbital distances of a few AU today. Possible reasons include slower growth rate due to the snow-line being located further out, longer migration timescale and faster disk depletion.

Reffert, Sabine; Bergmann, Christoph; Quirrenbach, Andreas; Trifonov, Trifon; Künstler, Andreas

2013-07-01

79

Detectability Of Low-Mass Trojan Planets In Transiting Systems Using Transit Timing Variation Method  

NASA Astrophysics Data System (ADS)

We present the results of a study of the feasibility of detecting small, terrestrial-sized planets in a transiting system consisting of a Jupiter-like planet and an M-dwarf using the variations in the transit timing of the larger body. Specifically, we studied the case where the two planets are in 1:1 mean-motion resonance. To determine the detectability of such Trojan planets, a number of systems with different masses, eccentricities, and periods were numerically integrated and the amplitudes of their TTV signals were calculated. Results indicate that Trojan planets in 3 to 10 day orbits and with eccentricities ranging from 0 to 0.15 have a high probability for detection. We present the results of our study and discuss the applicability of our analysis to the probability of the detection of such planets with the recently launched Kepler space telescope. Support for S.C. through the NSF funded REU program at the Institute for Astronomy, University of Hawaii is acknowledged.

Capen, Stephanie; Haghighipour, N.; Kirste, S.

2009-12-01

80

Origin of the Regular Satellites of Jupiter and Saturn: Mass and Composition Constraints  

NASA Astrophysics Data System (ADS)

It has often been noted that the compositional gradient of the Galilean satellites may provide a link to the environment in which they formed (e.g., Estrada et al. 2008). The similarities in the bulk properties of the regular satellites of Jupiter and Saturn favor a unified framework for their origin; yet, the inner, icy satellites of Saturn exhibit no such trend. We set-aside for now the inner satellites, and focus instead on the large, outer regular satellites of each satellite system. We seek to account for the masses and compositions of Ganymede and Callisto in the case of Jupiter, and Titan and Iapetus, for Saturn. For objects the size of Iapetus or larger, the porosity is likely to be small not only because the internal pressure is large enough to close pore spaces, but also because the presence of short-lived radioactive nuclides heats the interior causing ice to flow. For such satellites, densities can be interpreted in terms of rock/ice fractions. Iapetus' low density, and correspondingly low rock/ice fraction, presents a puzzle when compared to the other three satellites, each of which is roughly 50% ice and rock. In turn, the rock/ice fractions for Ganymede, Titan and Callisto are comparable to that of (captured) Saturnian irregular satellite Phoebe. Progress in understanding these observations requires tying the properties of solar nebula planetesimals to subnebula satellitesimals. We argue that planetesimal break-up following giant planet formation, in tandem with delivery via ablation of planetesimal fragments crossing the subdisk can provide a framework for understanding the mass budget and compositions of regular satellites. In particular, ablation can result in fractionation, and account for the observed density of Iapetus provided this satellite formed in situ (Mosqueira and Estrada, 2005). For this to work (solar nebula) planetesimals of size 10 km or larger may need to be at least partially differentiated, which argues that the first generation of planetesimals in the Jupiter-Saturn region (and possibly beyond) incorporated significant quantities of 26Al. Acknowledgements: This work is supported by PG&G and OPR NASA grants.

Mosqueira, I.; Estrada, P.

2008-12-01

81

The Masses and Metallicities of Kepler's Planet-hosting M Dwarfs  

NASA Astrophysics Data System (ADS)

While much attention is focused on Kepler's Sun-like target stars, there are many target stars that reside at the bottom of the main sequence. Thus, Kepler provides valuable information about planet formation around the Galaxy's most numerous denizens, the M dwarfs. We will present recent advances in understanding the fundamental physical properties of M dwarfs using both broadband photometry and optical spectroscopy. These techniques provide revised estimates of stellar masses and radii, thereby elucidating the radius distribution of planets orbiting low-mass stars. We will present the specific case studies LHS6343C and KOI-254.01, a transiting brown dwarf and hot Jupiter, respectively, orbiting two of Kepler's least massive and most proximate target stars.

Johnson, John A.; Pineda, S.; Bottom, M.

2012-01-01

82

Halogens in the Giant Planets: Upper Limits to HBr in Saturn and Jupiter  

NASA Astrophysics Data System (ADS)

I have searched for absorptions from the molecule HBr in the 4 ?m spectra of Jupiter and Saturn and find upper limits to the mole fraction of HBr to be q(HBr) ? 1.6 ppb in Saturn and q(HBr) ? 3 ppb in Jupiter, or two and four times the solar abundance of bromine in Saturn and Jupiter, respectively. The upper limit for Saturn is lower than the global abundance of bromine, if, as expected, bromine is enriched in Saturn relative to C1 carbonaceous chondrites. This deficiency is most likely the result of local sinks for HBr. Less likely is a global depletion of bromine, conceivably related to the low condensation temperature of bromine-containing solids in the presolar nebula. Searches for HCl in the 4 ?m window are also possible, but require large enrichments of Cl for detection with existing data.

Noll, Keith S.

1996-12-01

83

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)

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.

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

84

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

SciTech Connect

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.

Dawson, Rebekah I.; Murray-Clay, Ruth A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, MS-10, Cambridge, MA 02138 (United States); Johnson, John Asher; Morton, Timothy D. [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, California 95064 (United States); Howard, Andrew W., E-mail: rdawson@cfa.harvard.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822-1839 (United States)

2012-12-20

85

Protoplanetary disks and planet formation around brown dwarfs and very low-mass stars  

NASA Astrophysics Data System (ADS)

Brown dwarfs and very low-mass stars are very common in the Galaxy, yet we know little about the planetary systems they may host. Here we review observational evidence emerging from comparative studies of disks around brown dwarfs and sun-like stars. These studies show that very young brown dwarfs and very low mass stars have disks as frequently as sun-like stars do, arguing for the same formation processes. There are indications, but no conclusive evidence yet, for a longer disk lifetime around the lowest-mass stars and brown dwarfs. At the same time, evidence for faster dust processing and more strongly reduced disk scale heights is found, demonstrating that the first steps of planet formation also take place around brown dwarfs. With increasingly sensitive infrared instruments a new window is opening on gas-phase chemistry in these disks and the first surveys indicate a different gas-phase chemistry and, perhaps, a suppressed nitrogen chemistry. Sub-millimeter surveys reveal disk masses of a few Jupiter mass, which core accretion models show is enough to form few Earth-mass and smaller planets, but not gas giant planets.

Apai, D.

2013-02-01

86

A Dynamical Method for Measuring the Masses of Stars with Transiting Planets  

NASA Astrophysics Data System (ADS)

As a planet transits the face of a star, it accelerates along the line of sight. The changing delay in the propagation of photons produces an apparent deceleration of the planet across the sky throughout the transit. This persistent transverse deceleration breaks the time-reversal symmetry in the transit light curve of a spherical planet in a circular orbit around a perfectly symmetric star. For ``hot Jupiter'' systems, ingress advances at a higher rate than egress by a fraction of ~10-4-10-3. Forthcoming space telescopes such as Kepler or COROT will reach the sensitivity required to detect this asymmetry. The scaling of the fractional asymmetry with stellar mass M* and planetary orbital radius a, as M*/a2, is different from that of the orbital period, which scales as (M*/a3)-1/2. Therefore, this effect constitutes a new method for a purely dynamical determination of the mass of the star. Radial velocity data for the reflex motion of the star can then be used to determine the planet's mass. Although orbital eccentricity could introduce a larger asymmetry than the light-propagation delay, the eccentricity is expected to decay by tidal dissipation to negligible values for a close-in planet with no perturbing third body. Future detection of the eclipse of a planet's emission by its star could be used to measure the light-propagation delay across the orbital diameter, 46.7(a/7×1011 cm) s, and also determine the stellar mass from the orbital period.

Loeb, Abraham

2005-04-01

87

Lone Planet Under a Cosmic Magnifying Glass  

NASA Video Gallery

This artist's animation illustrates the technique used for finding free-floating, Jupiter-mass planets in space. Astronomers found evidence for 10 of these worlds, thought to have been ejected early on from their developing solar systems.

Anthony Greicius

2011-05-18

88

A survey of the outer planets Jupiter, Saturn, Uranus, Neptune, Pluto, and their satellites  

Microsoft Academic Search

A survey of current knowledge about Jupiter, Saturn, Uranus, Neptune, Pluto, and their satellites is presented. The best available\\u000a numerical values are given for physical parameters, including orbital and body properties, atmospheric composition and structure,\\u000a and photometric parameters. The more acceptable current theories of these bodies are outlined with thorough referencing offering\\u000a access to the details. The survey attempts to

R. L. Newburn; S. Gulkis

1973-01-01

89

Transiting exoplanets from the CoRoT space mission. IX. CoRoT-6b: a transiting ``hot Jupiter'' planet in an 8.9d orbit around a low-metallicity star  

NASA Astrophysics Data System (ADS)

The CoRoT satellite exoplanetary team announces its sixth transiting planet in this paper. We describe and discuss the satellite observations as well as the complementary ground-based observations - photometric and spectroscopic - carried out to assess the planetary nature of the object and determine its specific physical parameters. The discovery reported here is a “hot Jupiterplanet in an 8.9d orbit, 18 stellar radii, or 0.08 AU, away from its primary star, which is a solar-type star (F9V) with an estimated age of 3.0 Gyr. The planet mass is close to 3 times that of Jupiter. The star has a metallicity of 0.2 dex lower than the Sun, and a relatively high 7Li abundance. While the light curve indicates a much higher level of activity than, e.g., the Sun, there is no sign of activity spectroscopically in e.g., the [Ca ii] H&K lines. The CoRoT space mission, launched on December 27, 2006, has been developed and is being operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA, The Research and Scientific Support Department of ESA, Germany and Spain.

Fridlund, M.; Hébrard, G.; Alonso, R.; Deleuil, M.; Gandolfi, D.; Gillon, M.; Bruntt, H.; Alapini, A.; Csizmadia, Sz.; Guillot, T.; Lammer, H.; Aigrain, S.; Almenara, J. M.; Auvergne, M.; Baglin, A.; Barge, P.; Bordé, P.; Bouchy, F.; Cabrera, J.; Carone, L.; Carpano, S.; Deeg, H. J.; de La Reza, R.; Dvorak, R.; Erikson, A.; Ferraz-Mello, S.; Guenther, E.; Gondoin, P.; den Hartog, R.; Hatzes, A.; Jorda, L.; Léger, A.; Llebaria, A.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier, M.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Samuel, B.; Schneider, J.; Shporer, A.; Stecklum, B.; Tingley, B.; Weingrill, J.; Wuchterl, G.

2010-03-01

90

Detecting earth-mass planets with gravitational microlensing  

Microsoft Academic Search

We show that Earth-mass planets orbiting stars in the Galactic disk and bulge can be detected by monitoring microlensed stars in the Galactic bulge. The star and its planet act as a binary lens which generates a light curve that can differ substantially from the light curve due only to the star itself. We show that the planetary signal remains

David P. Bennett; Sun Hong Rhie

1996-01-01

91

Embryo Impacts and Gas Giant Mergers. I. Dichotomy of Jupiter and Saturn's Core Mass  

Microsoft Academic Search

Interior to the gaseous envelopes of Saturn, Uranus, and Neptune, there are high-density cores with masses larger than 10 Earth masses. According to the conventional sequential accretion hypothesis, such massive cores are needed for the onset of efficient accretion of their gaseous envelopes. However, Jupiter's gaseous envelope is more massive and its core may be less massive than those of

Shu Lin Li; C. B. Agnor; D. N. C. Lin

2010-01-01

92

EMBRYO IMPACTS AND GAS GIANT MERGERS. I. DICHOTOMY OF JUPITER AND SATURN's CORE MASS  

Microsoft Academic Search

Interior to the gaseous envelopes of Saturn, Uranus, and Neptune, there are high-density cores with masses larger than 10 Earth masses. According to the conventional sequential accretion hypothesis, such massive cores are needed for the onset of efficient accretion of their gaseous envelopes. However, Jupiter's gaseous envelope is more massive and its core may be less massive than those of

Li Shulin; C. B. Agnor; D. N. C. Lin

2010-01-01

93

Probing Clouds in Planets with a Simple Radiative Transfer Model: The Jupiter Case  

ERIC Educational Resources Information Center

|Remote sensing of planets evokes using expensive on-orbit satellites and gathering complex data from space. However, the basic properties of clouds in planetary atmospheres can be successfully estimated with small telescopes even from an urban environment using currently available and affordable technology. This makes the process accessible for…

Mendikoa, Inigo; Perez-Hoyos, Santiago; Sanchez-Lavega, Agustin

2012-01-01

94

Probing Clouds in Planets with a Simple Radiative Transfer Model: The Jupiter Case  

ERIC Educational Resources Information Center

Remote sensing of planets evokes using expensive on-orbit satellites and gathering complex data from space. However, the basic properties of clouds in planetary atmospheres can be successfully estimated with small telescopes even from an urban environment using currently available and affordable technology. This makes the process accessible for…

Mendikoa, Inigo; Perez-Hoyos, Santiago; Sanchez-Lavega, Agustin

2012-01-01

95

Different times of formation of the planet pairs earth-Mars and Jupiter-Saturn  

Microsoft Academic Search

Using the argument that the angular velocity of a more dense body increases faster than that of a less dense body, an attempt is made to explain the difference in angular velocities of earth and Mars. It is suggested that these planets formed at roughly the same time and had the same initial angular velocity, but that the difference in

P. P. Loginov

1977-01-01

96

PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS  

SciTech Connect

We study the final architecture of planetary systems that evolve under the combined effects of planet-planet and planetesimal scattering. Using N-body simulations we investigate the dynamics of marginally unstable systems of gas and ice giants both in isolation and when the planets form interior to a planetesimal belt. The unstable isolated systems evolve under planet-planet scattering to yield an eccentricity distribution that matches that observed for extrasolar planets. When planetesimals are included the outcome depends upon the total mass of the planets. For M {sub tot} {approx}> 1 M{sub J} the final eccentricity distribution remains broad, whereas for M {sub tot} {approx}< 1 M{sub J} a combination of divergent orbital evolution and recircularization of scattered planets results in a preponderance of nearly circular final orbits. We also study the fate of marginally stable multiple planet systems in the presence of planetesimal disks, and find that for high planet masses the majority of such systems evolve into resonance. A significant fraction leads to resonant chains that are planetary analogs of Jupiter's Galilean satellites. We predict that a transition from eccentric to near-circular orbits will be observed once extrasolar planet surveys detect sub-Jovian mass planets at orbital radii of a {approx_equal} 5-10 AU.

Raymond, Sean N. [Center for Astrophysics and Space Astronomy, 389 UCB, University of Colorado, Boulder, CO 80309 (United States); Armitage, Philip J. [Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Gorelick, Noel [Google, Inc., 1600 Amphitheatre Parkway, Mountain View, CA 94043 (United States)], E-mail: sean.raymond@colorado.edu

2009-07-10

97

Changes in One Planet's Mass or Semi-Major Axis Affects All Planets' Eccentricities  

NASA Astrophysics Data System (ADS)

If one or more of the planets in a system ungoes gradual change in either semi-major axis (e.g. by tides) or mass (e.g. by evaporation of a close-in planet) the underlying secular dynamics of the system change, such that the orbital eccentricities of all the planets are affected. In a non-resonant multi-planet system each planet's eccentricity is a sum of eigenmodes, described by classical secular theory. The planets' masses m and semi-major axes a set the underlying structure of the eigenmodes, while the eccentricities e and longitudes of pericenter set the modes' amplitudes and phases. If a physical process (whatever it may physically be) changes only an m or a value, but not e, the underlying eigenmode structure will change, and also the eigenmode amplitudes (and phases) will respond. Thus, this process will change the range of values that each planet's eccentricity will take over a secular cycle, and how quickly secular eccentricity variation happens. Wu and Goldreich (ApJ 564, 1024, 2002) developed a theory that incorporates changing semi-major axis into secular theory, but an implicit assumption of their analysis was that only a single eigenmode has non-zero amplitude. Therefore, that result can only be applied to a system that has already damped to a “quasi-fixed-point”, not to its interesting previous evolution; moreover, Van Laerhoven and Greenberg (C.M.&Dyn.Astr., 113, 215, 2012) showed that in the context of tidal evolution there are often modes that damp on similar timescales so there may be several long-lived eigenmodes. To address this issue, we have developed formulae to describe the more general solution for a system of any number of planets with multiple active eigenmodes incorporating externally driven change in any semi-major axis or mass. Such effects may have significant implications for some multi-planet systems.

Van Laerhoven, Christa L.; Greenberg, R.

2012-10-01

98

EXTRACTING PLANET MASS AND ECCENTRICITY FROM TTV DATA  

SciTech Connect

Most planet pairs in the Kepler data that have measured transit time variations (TTVs) are near first-order mean-motion resonances. We derive analytical formulae for their TTV signals. We separate planet eccentricity into free and forced parts, where the forced part is purely due to the planets' proximity to resonance. This separation yields simple analytical formulae. The phase of the TTV depends sensitively on the presence of free eccentricity: if the free eccentricity vanishes, the TTV will be in phase with the longitude of conjunctions. This effect is easily detectable in current TTV data. The amplitude of the TTV depends on planet mass and free eccentricity, and it determines planet mass uniquely only when the free eccentricity is sufficiently small. We analyze the TTV signals of six short-period Kepler pairs. We find that three of these pairs (Kepler 18, 24, 25) have a TTV phase consistent with zero. The other three (Kepler 23, 28, 32) have small TTV phases, but ones that are distinctly non-zero. We deduce that the free eccentricities of the planets are small, {approx}< 0.01, but not always vanishing. Furthermore, as a consequence of this, we deduce that the true masses of the planets are fairly accurately determined by the TTV amplitudes, within a factor of {approx}< 2. The smallness of the free eccentricities suggests that the planets have experienced substantial dissipation. This is consistent with the hypothesis that the observed pile-up of Kepler pairs near mean-motion resonances is caused by resonant repulsion. But the fact that some of the planets have non-vanishing free eccentricity suggests that after resonant repulsion occurred there was a subsequent phase in the planets' evolution when their eccentricities were modestly excited, perhaps by interplanetary interactions.

Lithwick, Yoram [Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA and Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) (United States); Xie Jiwei; Wu Yanqin [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada)

2012-12-20

99

Extracting Planet Mass and Eccentricity from TTV Data  

NASA Astrophysics Data System (ADS)

Most planet pairs in the Kepler data that have measured transit time variations (TTVs) are near first-order mean-motion resonances. We derive analytical formulae for their TTV signals. We separate planet eccentricity into free and forced parts, where the forced part is purely due to the planets' proximity to resonance. This separation yields simple analytical formulae. The phase of the TTV depends sensitively on the presence of free eccentricity: if the free eccentricity vanishes, the TTV will be in phase with the longitude of conjunctions. This effect is easily detectable in current TTV data. The amplitude of the TTV depends on planet mass and free eccentricity, and it determines planet mass uniquely only when the free eccentricity is sufficiently small. We analyze the TTV signals of six short-period Kepler pairs. We find that three of these pairs (Kepler 18, 24, 25) have a TTV phase consistent with zero. The other three (Kepler 23, 28, 32) have small TTV phases, but ones that are distinctly non-zero. We deduce that the free eccentricities of the planets are small, <~ 0.01, but not always vanishing. Furthermore, as a consequence of this, we deduce that the true masses of the planets are fairly accurately determined by the TTV amplitudes, within a factor of <~ 2. The smallness of the free eccentricities suggests that the planets have experienced substantial dissipation. This is consistent with the hypothesis that the observed pile-up of Kepler pairs near mean-motion resonances is caused by resonant repulsion. But the fact that some of the planets have non-vanishing free eccentricity suggests that after resonant repulsion occurred there was a subsequent phase in the planets' evolution when their eccentricities were modestly excited, perhaps by interplanetary interactions.

Lithwick, Yoram; Xie, Jiwei; Wu, Yanqin

2012-12-01

100

Inflated Planets and Their Low-Mass Companions  

NASA Astrophysics Data System (ADS)

Various mechanisms have been proposed to explain the inflated size of HD 209458b after it became clear that it has no companions capable of producing a stellar reflex velocity greater than around 5 m s-1. Had there been such a companion, the hypothesis that it forces the eccentricity of the inflated planet thereby tidally heating it may have been readily accepted. Here we summarize a paper by the author which shows that companion planets with masses as low as a fraction of an Earth mass are capable of sustaining a non-zero eccentricity in the observed planet for at least the age of the system. While such companions produce stellar reflex velocities which are fractions of a meter per second and hence are below the stellar jitter limit, they are consistent with recent theoretical work which suggests that the planet migration process often produces low-mass companions to short-period giants.

Mardling, R. A.

101

The Influence of Giant Planet Mass on Long-Period Comet Flux  

NASA Astrophysics Data System (ADS)

We study the effect of the outer solar system architecture on the flux of Earth-crossing comets. In particular, we seek to quantify the role of the giant planets as ``planetary protectors''. Because the outer planets modify the structure of the Oort Cloud throughout its formation, we must follow its evolution over the full age of the solar system. We have run simulations in each of 4 different planetary mass configurations to analyze the structure and formation of each Oort Cloud and to better constrain the flux of comets into the inner solar system. Particles are integrated over 4.5 Gyrs under the influence of the giant planets, the Galactic tide, and passing stars. We find that the structure of the Oort Cloud, including the location of boundaries and the relative number of comets in the inner and outer Oort Cloud, does not change significantly between configurations. As overall planetary mass decreases, the flux of comets increases. Trapping efficiency of the Oort Cloud also increases, as expected. We find that Saturn is as effective as Jupiter at deflecting possible Earth-crossing comets, as reflected by the fact that a comparable numbers of particles enter the inner solar system when we independently reduce their masses. In each configuration, we confirm the conclusion from Kaib & Quinn (2009) that the majority of observable comets originate in the inner Oort Cloud. Although the final effect may be small, accounting for the formation and growth of the giant planets in simulations may help us better understand the trapping efficiency of the Oort Cloud and the mass of the protoplanetary disk.

Lewis, Alexia; Quinn, T.

2012-01-01

102

The Structural and Thermal Evolution of Transiting Exoplanets: From Hot Jupiters to Kepler's Super Earths  

ScienceCinema

Large numbers of exoplanets can now be seen to transit their parent stars, which allows for measurements of their radii, masses, and densities. We can now begin to examine the Jupiter-class gas giant planets as a class of astrophysical objects. At the same time, thanks to NASA’s Kepler telescope, the number of transiting planets below 10 Earth masses is now moving beyond just a handful. For the Jupiter-like planets, we model their interior structure and find several interesting properties regarding the amount of ice and rock within these planets, which gives us clues to their formation. For the lowest-mass planets, such as the 6-planet Kepler-11 system, signs point to a large populations of mini-Neptunes---low-mass, low-density planets with hydrogen-dominated atmospheres. The Kepler-11 system may tell us much about the evaporation of the atmospheres of these kinds of planets.

103

The Structural and Thermal Evolution of Transiting Exoplanets: From Hot Jupiters to Kepler's Super Earths  

SciTech Connect

Large numbers of exoplanets can now be seen to transit their parent stars, which allows for measurements of their radii, masses, and densities. We can now begin to examine the Jupiter-class gas giant planets as a class of astrophysical objects. At the same time, thanks to NASA’s Kepler telescope, the number of transiting planets below 10 Earth masses is now moving beyond just a handful. For the Jupiter-like planets, we model their interior structure and find several interesting properties regarding the amount of ice and rock within these planets, which gives us clues to their formation. For the lowest-mass planets, such as the 6-planet Kepler-11 system, signs point to a large populations of mini-Neptunes---low-mass, low-density planets with hydrogen-dominated atmospheres. The Kepler-11 system may tell us much about the evaporation of the atmospheres of these kinds of planets.

Fortney, Jonathan (University of California Santa Cruz)

2011-06-11

104

Terrestrial Planet Formation in a protoplanetary disk with a local mass depletion: A successful scenario for the formation of Mars  

NASA Astrophysics Data System (ADS)

Models of terrestrial planet formation have been successful in producing terrestrial-class planets with sizes in the range of Venus and Earth. However, these models have generally failed to produce Mars-sized objects around 1.5 AU. The body that is usually formed around Mars' semimajor axis is, in general, much more massive than Mars. Only when Jupiter and Saturn are assumed to have very eccentric orbits, or alternately, if they have experienced a wide inward-then-outward migration in a gas-rich phase, simulations have been able to produce Mars-like bodies. In this work, we have examined a different scenario for the formation of Mars in which a local depletion in the density of the protosolar nebula results in a non-uniform formation of planetary embryos. We have carried out extensive numerical simulations of the formation of terrestrial planets in such a disk for different scales of the local density depletion, and for different orbital configurations of giant planets. Our simulations point to the possibility of the formation of Mars-sized bodies around 1.5 AU, specifically when the scale of the disk local mass-depletion is moderately high (50-75%) and Jupiter and Saturn are initially in their current orbits. In these systems, Mars analogs are formed from the protoplanetary materials that originate in the region of disk where there is no local mass-depletion. Results also indicate that in the same systems Earth-sized planets can form around 1 AU with a substantial amount of water due to accretion of water-rich material originated from past 2 AU. We present the results of our study and discuss their implications for the formation of terrestrial planets in our solar system.

Izidoro, André; Haghighipour, N.; Cabo Winter, O.; Tsuchida, M.

2013-10-01

105

Qatar-2: A K Dwarf Orbited by a Transiting Hot Jupiter and a Longer-Period Massive Planet  

NASA Astrophysics Data System (ADS)

We report the discovery and initial characterization of Qatar-2b, a hot Jupiter transiting a K dwarf in a circular orbit with a short period, Pb = 1.34 days. Differential photometry and model fitting of transit data from both KeplerCam and LCOGT yielded light curve parameters Rp/Rs, a/Rs, u1, u2, and i that were optimized using the Markov Chain Monte Carlo technique. Radial velocity measurements from the Tillinghast Reflector Echelle Spectrograph of Qatar-2 over a span of 153 days provided a mass estimate for Qatar-2b, with velocity residuals from the orbital solution that pointed to the presence of a third body in the system. The light curve parameter a/Rs and spectroscopic values for effective temperature and metallicity were used in conjunction with stellar models to estimate the mass and radius of Qatar-2, leading to a mass and radius for Qatar-2b of MP = 2.54 MJ and RP = 1.14 RJ, respectively. Next we used the Systemic Console to explore possible orbital solutions for the outer companion, Qatar-2c. Plausible solutions have periods slightly less than a year and a mass of several MJ. However, further observations are needed to determine a reliable orbit for Qatar-2c. Qatar-2 is only the fourth example in the short but growing list of systems with a transiting hot Jupiter and an outer companion. This system architecture is in sharp contrast to that found by Kepler for multi-transiting systems, which are dominated by objects smaller than Neptune, usually with tightly spaced orbits that must be nearly coplanar.

Bryan, Marta; Alsubai, K. A.; Latham, D. W.; Quinn, S. N.; Collier Cameron, A.; Carter, J. A.; Buchave, L. A.

2012-01-01

106

MASSES, RADII, AND CLOUD PROPERTIES OF THE HR 8799 PLANETS  

SciTech Connect

The near-infrared colors of the planets directly imaged around the A star HR 8799 are much redder than most field brown dwarfs of the same effective temperature. Previous theoretical studies of these objects have concluded that the atmospheres of planets b, c, and d are unusually cloudy or have unusual cloud properties. Some studies have also found that the inferred radii of some or all of the planets disagree with expectations of standard giant planet evolution models. Here, we compare the available data to the predictions of our own set of atmospheric and evolution models that have been extensively tested against observations of field L and T dwarfs, including the reddest L dwarfs. Unlike some previous studies, we require mutually consistent choices for effective temperature, gravity, cloud properties, and planetary radius. This procedure thus yields plausible values for the masses, effective temperatures, and cloud properties of all three planets. We find that the cloud properties of the HR 8799 planets are not unusual but rather follow previously recognized trends, including a gravity dependence on the temperature of the L to T spectral transition-some reasons for which we discuss. We find that the inferred mass of planet b is highly sensitive to whether or not we include the H- and the K-band spectrum in our analysis. Solutions for planets c and d are consistent with the generally accepted constraints on the age of the primary star and orbital dynamics. We also confirm that, like in L and T dwarfs and solar system giant planets, non-equilibrium chemistry driven by atmospheric mixing is also important for these objects. Given the preponderance of data suggesting that the L to T spectral type transition is gravity dependent, we present an exploratory evolution calculation that accounts for this effect. Finally we recompute the bolometric luminosity of all three planets.

Marley, Mark S. [NASA Ames Research Center, MS-245-3, Moffett Field, CA 94035 (United States); Saumon, Didier [Los Alamos National Laboratory, Mail Stop F663, Los Alamos, NM 87545 (United States); Cushing, Michael [Department of Physics and Astronomy, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Ackerman, Andrew S. [NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Freedman, Richard, E-mail: Mark.S.Marley@NASA.gov, E-mail: dsaumon@lanl.gov, E-mail: michael.cushing@utoledo.edu, E-mail: andrew.ackerman@nasa.gov, E-mail: jfortney@ucolick.org, E-mail: freedman@darkstar.arc.nasa.gov [SETI Institute and NASA Ames Research Center, MS-245-3, Moffett Field, CA 94035 (United States)

2012-08-01

107

Search for earth mass planets and dark matter too  

SciTech Connect

Gravitational microlensing is known for baryonic dark matter searches. Here we show that microlensing also provides a unique tool for the detection of low mass planets (such as earths and neptunes) from the ground. A planetary system forms a binary lens (or, a multi-point lens), and we can determine the mass ratio of the planet with respect to the star and relative distance (= separation/Einstein ring radius) between the star and planet. Such a microlensing planet search project requires a {approx} 2 m survey telescope, and a network of 1.5 - 2 m follow-up telescopes capable of monitoring stars in the Bulge on a 24-hour basis. During the off-season of the Galactic bulge, this network can be used for dark matter search by monitoring the stars in the LMC and SMC.

Rhie, S.H.; Bennett, D.P. [Lawrence Livermore National Lab., CA (United States)][California Univ., Berkeley, CA (United States)][California Univ., Davis, CA (United States)][Notre Dame Univ., IN (United States)

1996-02-01

108

An Earth-mass planet orbiting ? Centauri B.  

PubMed

Exoplanets down to the size of Earth have been found, but not in the habitable zone--that is, at a distance from the parent star at which water, if present, would be liquid. There are planets in the habitable zone of stars cooler than our Sun, but for reasons such as tidal locking and strong stellar activity, they are unlikely to harbour water-carbon life as we know it. The detection of a habitable Earth-mass planet orbiting a star similar to our Sun is extremely difficult, because such a signal is overwhelmed by stellar perturbations. Here we report the detection of an Earth-mass planet orbiting our neighbour star ? Centauri B, a member of the closest stellar system to the Sun. The planet has an orbital period of 3.236 days and is about 0.04 astronomical units from the star (one astronomical unit is the Earth-Sun distance). PMID:23075844

Dumusque, Xavier; Pepe, Francesco; Lovis, Christophe; Ségransan, Damien; Sahlmann, Johannes; Benz, Willy; Bouchy, François; Mayor, Michel; Queloz, Didier; Santos, Nuno; Udry, Stéphane

2012-10-17

109

An extrasolar planetary system with three Neptune-mass planets.  

PubMed

Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 au (the Sun-Earth distance). Simulations show that the system is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star. PMID:16710412

Lovis, Christophe; Mayor, Michel; Pepe, Francesco; Alibert, Yann; Benz, Willy; Bouchy, François; Correia, Alexandre C M; Laskar, Jacques; Mordasini, Christoph; Queloz, Didier; Santos, Nuno C; Udry, Stéphane; Bertaux, Jean-Loup; Sivan, Jean-Pierre

2006-05-18

110

Considerations on the Outward Migration of Jupiter and Saturn  

NASA Astrophysics Data System (ADS)

It has been proposed that the outward orbital migration of Jupiter and Saturn, driven by a gas-dominated protosolar disk, may help explain why they did not move much closer to the Sun. It has also been suggested that some properties of the inner Solar System may be interpreted by invoking an inward migration of Jupiter and Saturn followed by outward migration, once they get caught in the 2:3 mean motion resonance. Hydrodynamical calculations indicate that outward migration of a compact Jupiter-Saturn system may arise from an imbalance between positive and negative Lindblad torques exerted on Jupiter by the disk. The torque density distribution acting on Jupiter extends over ~3 Hill radii on either side of the planet's orbit. The negative part of the distribution samples outer disk portions, partially depleted by the tidal perturbations of both planets. The positive part of the distribution samples inner disk portions, depleted only by the action of Jupiter. The net result may be a positive torque exerted on Jupiter. Saturn, trapped in resonance with Jupiter, migrates outward as well. This mechanism requires the exterior planet's mass not to exceed the interior planet's mass. Thus, it is assumed that neither planet accretes gas from the disk. Yet, models of giant planet formation indicate that these planets would accrete gas at whatever rate the disk provides (Lissauer et al., 2009, Icarus, 199, 338). We performed 2D and 3D hydrodynamical calculations of a Jupiter-Saturn system tidally interacting with a protoplanetary disk and investigated how gas accretion affects their migration history. We assumed initial conditions shown to result in the outward migration of non-accreting planets and recovered such scenario. We then allowed the planets to accrete gas at a disk-limited rate. In agreement with estimates derived for single planets, the assumed disk conditions lead to a mass-doubling time scale of the exterior planet that is 6-9 times as short as that of interior planet. Under these circumstances, the exterior planet's mass would quickly approach the interior planet's mass, halting outward migration. Planetary accretion is responsible for another effect that conspires against outward migration. A stationary disk, in which the accretion rate is nearly constant over its radius, would have a reduced surface density S within the orbit of an accreting planet. The reduction factor depends on the planet's accretion efficiency E, i.e., the ratio of the accretion rate onto the planet to the accretion rate through the disk interpolated at the planet's position. One can show that dMe/dt~(1+E)dMi/dt, where dMe/dt and dMi/dt are the disk accretion rates exterior and interior of the planet's orbit (Lubow & D'Angelo, 2006, Astrophys. J., 641, 526). In a stationary disk, S is proportional to the accretion rate and therefore Si~Se/(1+E), reducing the positive Lindblad torques acting on the planet. We estimated the accretion efficiency allowing for accretion onto Jupiter, but not onto Saturn, and found that E~5-6. Including accretion onto Saturn would likely yield a smaller Si/Se ratio. We simulated the migration of the two planets in such a stationary disk and found that it is directed toward the star and occurs on a time scale of order the viscous diffusion time scale.

D'Angelo, G.; Marzari, F.

2011-12-01

111

Newton's determination of the masses and densities of the Sun, Jupiter, Saturn and the Earth  

Microsoft Academic Search

This article analyzes the methods Newton applied in his Principia for calculating the masses and densities of the Sun and planets, and in particular, investigates the origins of the numerical parameter values used by Newton in these calculations.

I. B. Cohen

1998-01-01

112

Terrestrial Planet Formation During the Migration and Resonance Crossings of the Giant Planets  

NASA Astrophysics Data System (ADS)

The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets in the planetesimal disk. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a ~1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter’s and Saturn’s more eccentric orbits (relative to present-day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars’ mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars’ small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths).

Lykawka, Patryk S.; Ito, T.

2013-10-01

113

Mars and Jupiter  

NSDL National Science Digital Library

Students explore Mars and Jupiter, the fourth and fifth planets from the Sun. They learn some of the unique characteristics of these planets. They also learn how engineers help us learn about these planets with the design and development of telescopes, deep space antennas, spacecraft and planetary rovers.

Integrated Teaching And Learning Program

114

On the Minimum Core Mass for Giant Planet Formation  

NASA Astrophysics Data System (ADS)

The core accretion model proposes that giant planets form by the accretion of gas onto a solid protoplanetary core. Previous studies have found that there exists a "critical core mass" past which hydrostatic solutions can no longer be found and unstable atmosphere collapse occurs. This core mass is typically quoted to be around 10Me. In standard calculations of the critical core mass, planetesimal accretion deposits enough heat to alter the luminosity of the atmosphere, increasing the core mass required for the atmosphere to collapse. In this study we consider the limiting case in which planetesimal accretion is negligible and Kelvin-Helmholtz contraction dominates the luminosity evolution of the planet. We develop a two-layer atmosphere model with an inner convective region and an outer radiative zone that matches onto the protoplanetary disk, and we determine the minimum core mass for a giant planet to form within the typical disk lifetime for a variety of disk conditions. We denote this mass as critical core mass. The absolute minimum core mass required to nucleate atmosphere collapse is ˜ 8Me at 5 AU and steadily decreases to ˜ 3.5Me at 100 AU, for an ideal diatomic gas with a solar composition and a standard ISM opacity law. Lower opacity and disk temperature significantly reduce the critical core mass, while a decrease in the mean molecular weight of the nebular gas results in a larger critical core mass. Our results yield lower mass cores than corresponding studies for large planetesimal accretion rates.

Piso, Ana-Maria; Youdin, Andrew; Murray-Clay, Ruth

2013-07-01

115

Jupiter and the other Giants: A Comparative Study  

NASA Astrophysics Data System (ADS)

The four giant planets - Jupiter, Saturn, Uranus and Neptune - have common properties which make them very different from the terrestrial planets: located at large distances from the Sun, they have big sizes and masses but low densities; they all have a ring system and a large number of satellites. These common properties can be understood in the light of their formation scenario, based upon the accretion of protosolar gas on an initial icy core. Giant planets have been explored by space missions (Pioneer 10 and 11, Voyager 1 and 2, Galileo and Cassini) but also by Earth-orbiting satellites and ground-based telescopes. There are still open questions related to the origin and evolution of the giant planets, in particular their moderate migration, the origin of the cold planetesimals which formed Jupiter, the origin of the atmospheric dynamics in Jupiter and Saturn, and the differences in the internal structures of Uranus and Neptune.

Encrenaz, Thérèse

2010-01-01

116

THE DEUTERIUM-BURNING MASS LIMIT FOR BROWN DWARFS AND GIANT PLANETS  

SciTech Connect

There is no universally acknowledged criterion to distinguish brown dwarfs from planets. Numerous studies have used or suggested a definition based on an object's mass, taking the {approx}13 Jupiter mass (M{sub J} ) limit for the ignition of deuterium. Here, we investigate various deuterium-burning masses for a range of models. We find that, while 13 M{sub J} is generally a reasonable rule of thumb, the deuterium fusion mass depends on the helium abundance, the initial deuterium abundance, the metallicity of the model, and on what fraction of an object's initial deuterium abundance must combust in order for the object to qualify as having burned deuterium. Even though, for most proto-brown dwarf conditions, 50% of the initial deuterium will burn if the object's mass is {approx}(13.0 {+-} 0.8) M{sub J} , the full range of possibilities is significantly broader. For models ranging from zero-metallicity to more than three times solar metallicity, the deuterium-burning mass ranges from {approx}11.0 M{sub J} (for three times solar metallicity, 10% of initial deuterium burned) to {approx}16.3 M{sub J} ( for zero metallicity, 90% of initial deuterium burned).

Spiegel, David S.; Burrows, Adam [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Milsom, John A., E-mail: dsp@astro.princeton.edu, E-mail: burrows@astro.princeton.edu, E-mail: milsom@physics.arizona.edu [Department of Physics, University of Arizona, Tucson, AZ 85721 (United States)

2011-01-20

117

Discovery and Mass Measurements of a Cold, 10 Earth Mass Planet and Its Host Star  

Microsoft Academic Search

We present the discovery and mass measurement of the cold, low-mass planet MOA-2009-BLG-266Lb, performed with the gravitational microlensing method. This planet has a mass of mp = 10.4 ± 1.7 M? and orbits a star of mass M sstarf = 0.56 ± 0.09 Msun at a semimajor axis of a = 3.2{+1.9\\\\atop -0.5} AU and an orbital period of P

Y. Muraki; C. Han; D. P. Bennett; D. Suzuki; L. A. G. Monard; U. G. Jorgensen; P. Kundurthy; J. Skowron; A. C. Becker; M. D. Albrow; P. Fouqué; D. Heyrovský; R. K. Barry; J.-P. Beaulieu; D. D. Wellnitz; I. A. Bond; T. Sumi; S. Dong; B. S. Gaudi; D. M. Bramich; M. Dominik; F. Abe; C. S. Botzler; M. Freeman; A. Fukui; K. Furusawa; F. Hayashi; J. B. Hearnshaw; S. Hosaka; Y. Itow; K. Kamiya; A. V. Korpela; P. M. Kilmartin; W. Lin; C. H. Ling; S. Makita; K. Masuda; Y. Matsubara; N. Miyake; K. Nishimoto; K. Ohnishi; Y. C. Perrott; N. J. Rattenbury; To. Saito; L. Skuljan; D. J. Sullivan; W. L. Sweatman; P. J. Tristram; K. Wada; P. C. M. Yock; G. W. Christie; D. L. DePoy; E. Gorbikov; A. Gould; S. Kaspi; C.-U. Lee; F. Mallia; D. Maoz; J. McCormick; D. Moorhouse; T. Natusch; B.-G. Park; R. W. Pogge; D. Polishook; A. Shporer; G. Thornley; J. C. Yee; A. Allan; P. Browne; K. Horne; N. Kains; C. Snodgrass; I. Steele; Y. Tsapras; V. Batista; C. S. Bennett; S. Brillant; J. A. R. Caldwell; A. Cassan; A. Cole; R. Corrales; Ch. Coutures; S. Dieters; D. Dominis Prester; J. Donatowicz; J. Greenhill; D. Kubas; J.-B. Marquette; R. Martin; J. Menzies; K. C. Sahu; I. Waldman; A. Williams; M. Zub; H. Bourhrous; Y. Matsuoka; T. Nagayama; N. Oi; Z. Randriamanakoto; IRSF Observers; V. Bozza; M. J. Burgdorf; S. Calchi Novati; S. Dreizler; F. Finet; M. Glitrup; K. Harpsøe; T. C. Hinse; M. Hundertmark; C. Liebig; G. Maier; L. Mancini; M. Mathiasen; S. Rahvar; D. Ricci; G. Scarpetta; J. Skottfelt; J. Surdej; J. Southworth; J. Wambsganss; F. Zimmer; A. Udalski; R. Poleski; L. Wyrzykowski; K. Ulaczyk; M. K. Szymanski; M. Kubiak; G. Pietrzynski; I. Soszynski

2011-01-01

118

Secular Chaos and the Production of Hot Jupiters  

NASA Astrophysics Data System (ADS)

In a planetary system with two or more well-spaced, eccentric, inclined planets, secular interactions may lead to chaos. The innermost planet may gradually become very eccentric and/or inclined as a result of the secular degrees of freedom drifting toward equipartition of angular momentum deficit. Secular chaos is known to be responsible for the eventual destabilization of Mercury in our own solar system. Here we focus on systems with three giant planets. We characterize the secular chaos and demonstrate the criterion for it to occur, but leave a detailed understanding of secular chaos to a companion paper. After an extended period of eccentricity diffusion, the inner planet's pericenter can approach the star to within a few stellar radii. Strong tidal interactions and ensuing tidal dissipation extract orbital energy from the planet and pull it inward, creating a hot Jupiter. In contrast to other proposed channels for the production of hot Jupiters, such a scenario (which we term "secular migration") explains a range of observations: the pile-up of hot Jupiters at 3 day orbital periods, the fact that hot Jupiters are in general less massive than other radial velocity planets, that they may have misaligned inclinations with respect to stellar spin, and that they have few easily detectable companions (but may have giant companions in distant orbits). Secular migration can also explain close-in planets as low in mass as Neptune; and an aborted secular migration can explain the "warm Jupiters" at intermediate distances. In addition, the frequency of hot Jupiters formed via secular migration increases with stellar age. We further suggest that secular chaos may be responsible for the observed eccentricities of giant planets at larger distances and that these planets could exhibit significant spin-orbit misalignment.

Wu, Yanqin; Lithwick, Yoram

2011-07-01

119

CLEA: The Revolution of the Moons of Jupiter  

NSDL National Science Digital Library

The purpose of this lab is to illustrate the measurement of the mass of a planet using Kepler's third law. The software provides a view of Jupiter at four magnifications, along with a highly accurate ephemeris program that draws the four Galilean satellites in their proper positions relative to the planet at any time. Students make observations of Jupiter and its satellites at regular intervals over a period of several weeks and, by graphing the separation of each moon from Jupiter versus time, they measure the period and radius of each satellite's orbit. This is sufficient information to derive the mass of Jupiter. Students use the mouse cursor to identify the moons and to measure distances. This is part of a larger collection of simulations, Project CLEA, hosted at Gettysburg College.

Marschall, Laurence; Snyder, Glenn; Cooper, P. R.; Hayden, Michael; Good, Rhonda

2009-05-20

120

Atmospheric Chemistry in Giant Planets, Brown Dwarfs, and Low-mass Dwarf Stars. III. Iron, Magnesium, and Silicon  

NASA Astrophysics Data System (ADS)

We use thermochemical equilibrium calculations to model iron, magnesium, and silicon chemistry in the atmospheres of giant planets, brown dwarfs, extrasolar giant planets (EGPs), and low-mass stars. The behavior of individual Fe-, Mg-, and Si-bearing gases and condensates is determined as a function of temperature, pressure, and metallicity. Our equilibrium results are thus independent of any particular model atmosphere. The condensation of Fe metal strongly affects iron chemistry by efficiently removing Fe-bearing species from the gas phase. Monatomic Fe is the most abundant Fe-bearing gas throughout the atmospheres of EGPs and L dwarfs, and in the deep atmospheres of giant planets and T dwarfs. Mg- and Si-bearing gases are effectively removed from the atmosphere by forsterite (Mg2SiO4) and enstatite (MgSiO3) cloud formation. Monatomic Mg is the dominant magnesium gas throughout the atmospheres of EGPs and L dwarfs and in the deep atmospheres of giant planets and T dwarfs. Silicon monoxide (SiO) is the most abundant Si-bearing gas in the deep atmospheres of brown dwarfs and EGPs, whereas SiH4 is dominant in the deep atmosphere of Jupiter and other gas giant planets. Several other Fe-, Mg-, and Si-bearing gases become increasingly important with decreasing effective temperature. In principle, a number of Fe, Mg, and Si gases are potential tracers of weather or diagnostic of temperature in substellar atmospheres.

Visscher, Channon; Lodders, Katharina; Fegley, Bruce, Jr.

2010-06-01

121

ATMOSPHERIC CHEMISTRY IN GIANT PLANETS, BROWN DWARFS, AND LOW-MASS DWARF STARS. III. IRON, MAGNESIUM, AND SILICON  

SciTech Connect

We use thermochemical equilibrium calculations to model iron, magnesium, and silicon chemistry in the atmospheres of giant planets, brown dwarfs, extrasolar giant planets (EGPs), and low-mass stars. The behavior of individual Fe-, Mg-, and Si-bearing gases and condensates is determined as a function of temperature, pressure, and metallicity. Our equilibrium results are thus independent of any particular model atmosphere. The condensation of Fe metal strongly affects iron chemistry by efficiently removing Fe-bearing species from the gas phase. Monatomic Fe is the most abundant Fe-bearing gas throughout the atmospheres of EGPs and L dwarfs, and in the deep atmospheres of giant planets and T dwarfs. Mg- and Si-bearing gases are effectively removed from the atmosphere by forsterite (Mg{sub 2}SiO{sub 4}) and enstatite (MgSiO{sub 3}) cloud formation. Monatomic Mg is the dominant magnesium gas throughout the atmospheres of EGPs and L dwarfs and in the deep atmospheres of giant planets and T dwarfs. Silicon monoxide (SiO) is the most abundant Si-bearing gas in the deep atmospheres of brown dwarfs and EGPs, whereas SiH{sub 4} is dominant in the deep atmosphere of Jupiter and other gas giant planets. Several other Fe-, Mg-, and Si-bearing gases become increasingly important with decreasing effective temperature. In principle, a number of Fe, Mg, and Si gases are potential tracers of weather or diagnostic of temperature in substellar atmospheres.

Visscher, Channon [Current address: Lunar and Planetary Institute, USRA, Houston, TX 77058-1113 (United States); Lodders, Katharina; Fegley, Bruce, E-mail: visscher@lpi.usra.ed, E-mail: lodders@wustl.ed, E-mail: bfegley@wustl.ed [Planetary Chemistry Laboratory, Department of Earth and Planetary Sciences, McDonnell Center for the Space Sciences, Washington University, St. Louis, MO 63130-4899 (United States)

2010-06-20

122

Estimating Masses and Orbits of Planets in Multiple-planet Systems with Joint Astrometry and RV Data Sets  

NASA Astrophysics Data System (ADS)

We describe a new algorithm for combining RV and astrometric observations of multiple-planet systems to obtain orbits and masses of individual planets. Because the algorithm uses only three nonlinear parameters per planet (instead of the usual five), its fast execution speed facilitates the application of MCMC methods to this problem. Multiple planet systems are relatively common; nearly 30 of about 200 known planetary systems discovered by RV have two or more planets, and many `single-planet’ systems show trends suggesting long period planets. RV observers routinely resolve multiple-planet systems, providing orbital solutions (but not masses or inclinations) for each planet. Though astrometry provides full orbital and mass solutions, the problem is more challenging; long-period orbits become confused with proper motion, and parallax can significantly attenuate the signal of a one-year planet. Combining longer-timespan RV data with astrometric data helps resolve multiple-planet systems by providing more information, as well as the capabilities to (1) access planets with periods between the timespans of the astrometric and RV observations, (2) determine orbit orientations in 3D, and (3) potentially eliminate `false alarm’ detections. In a recent double-blind test, we showed that combining simulated astrometric observations over 5 years (i.e., from the SIM-Lite mission) with ground-based RV observations covering 15 years provides the capability of detecting and characterizing Earthlike planets in multiple planet systems orbiting a solar-mass star at 10 pc. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.

Catanzarite, Joseph; Zhai, C.; Shao, M.

2009-01-01

123

Discovery and Mass Measurements of a Cold, 10 Earth Mass Planet and Its Host Star  

NASA Astrophysics Data System (ADS)

We present the discovery and mass measurement of the cold, low-mass planet MOA-2009-BLG-266Lb, performed with the gravitational microlensing method. This planet has a mass of mp = 10.4 ± 1.7 M? and orbits a star of mass M sstarf = 0.56 ± 0.09 Msun at a semimajor axis of a = 3.2{+1.9\\atop -0.5} AU and an orbital period of P = 7.6{+7.7\\atop -1.5} yrs. The planet and host star mass measurements are enabled by the measurement of the microlensing parallax effect, which is seen primarily in the light curve distortion due to the orbital motion of the Earth. But the analysis also demonstrates the capability to measure the microlensing parallax with the Deep Impact (or EPOXI) spacecraft in a heliocentric orbit. The planet mass and orbital distance are similar to predictions for the critical core mass needed to accrete a substantial gaseous envelope, and thus may indicate that this planet is a "failed" gas giant. This and future microlensing detections will test planet formation theory predictions regarding the prevalence and masses of such planets.

Muraki, Y.; Han, C.; Bennett, D. P.; Suzuki, D.; Monard, L. A. G.; Street, R.; Jorgensen, U. G.; Kundurthy, P.; Skowron, J.; Becker, A. C.; Albrow, M. D.; Fouqué, P.; Heyrovský, D.; Barry, R. K.; Beaulieu, J.-P.; Wellnitz, D. D.; Bond, I. A.; Sumi, T.; Dong, S.; Gaudi, B. S.; Bramich, D. M.; Dominik, M.; Abe, F.; Botzler, C. S.; Freeman, M.; Fukui, A.; Furusawa, K.; Hayashi, F.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Korpela, A. V.; Kilmartin, P. M.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Miyake, N.; Nishimoto, K.; Ohnishi, K.; Perrott, Y. C.; Rattenbury, N. J.; Saito, To.; Skuljan, L.; Sullivan, D. J.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Christie, G. W.; DePoy, D. L.; Gorbikov, E.; Gould, A.; Kaspi, S.; Lee, C.-U.; Mallia, F.; Maoz, D.; McCormick, J.; Moorhouse, D.; Natusch, T.; Park, B.-G.; Pogge, R. W.; Polishook, D.; Shporer, A.; Thornley, G.; Yee, J. C.; ?FUN Collaboration; Allan, A.; Browne, P.; Horne, K.; Kains, N.; Snodgrass, C.; Steele, I.; Tsapras, Y.; RoboNet Collaboration; Batista, V.; Bennett, C. S.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A.; Corrales, R.; Coutures, Ch.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Greenhill, J.; Kubas, D.; Marquette, J.-B.; Martin, R.; Menzies, J.; Sahu, K. C.; Waldman, I.; Williams, A.; Zub, M.; PLANET Collaboration; Bourhrous, H.; Matsuoka, Y.; Nagayama, T.; Oi, N.; Randriamanakoto, Z.; IRSF Observers; Bozza, V.; Burgdorf, M. J.; Calchi Novati, S.; Dreizler, S.; Finet, F.; Glitrup, M.; Harpsøe, K.; Hinse, T. C.; Hundertmark, M.; Liebig, C.; Maier, G.; Mancini, L.; Mathiasen, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Surdej, J.; Southworth, J.; Wambsganss, J.; Zimmer, F.; MiNDSTEp Consortium; Udalski, A.; Poleski, R.; Wyrzykowski, ?.; Ulaczyk, K.; Szyma?ski, M. K.; Kubiak, M.; Pietrzy?ski, G.; Soszy?ski, I.; OGLE Collaboration

2011-11-01

124

On the corotation torque for low-mass eccentric planets  

NASA Astrophysics Data System (ADS)

We present the results of high-resolution 2D simulations of low-mass planets on fixed eccentric orbits embedded in protoplanetary discs. The aim of this study is to determine how the strength of the sustained, non-linear corotation torque experienced by embedded planets varies as a function of orbital eccentricity, disc parameters and planetary mass. In agreement with previous work we find that the corotation torque diminishes as orbital eccentricity, e, increases. Analysis of the time-averaged streamlines in the disc demonstrates that the width of the horseshoe region narrows as the eccentricity increases, and we suggest that this narrowing largely explains the observed decrease in the corotation torque. We employ three distinct methods for estimating the strength of the unsaturated corotation torque from our simulations, and provide an empirical fit to these results. We find that a simple model where the corotation torque, ?C, decreases exponentially with increasing eccentricity [i.e. ?C ? exp (-e/ef)] provides a good global fit to the data with an e-folding eccentricity, ef, that scales linearly with the disc scale height at the planet location. We confirm that this model provides a good fit for planet masses of 5 and 10 M? in our simulations. The formation of planetary systems is likely to involve significant planet-planet interactions that will excite eccentric orbits, and this is likely to influence disc-driven planetary migration through modification of the corotation torque. Our results suggest that high fidelity models of planetary formation should account for these effects.

Fendyke, Stephen M.; Nelson, Richard P.

2013-10-01

125

THE ANGLO-AUSTRALIAN PLANET SEARCH. XXII. TWO NEW MULTI-PLANET SYSTEMS  

SciTech Connect

We report the detection of two new planets from the Anglo-Australian Planet Search. These planets orbit two stars each previously known to host one planet. The new planet orbiting HD 142 has a period of 6005 {+-} 427 days, and a minimum mass of 5.3 M{sub Jup}. HD 142c is thus a new Jupiter analog: a gas-giant planet with a long period and low eccentricity (e = 0.21 {+-} 0.07). The second planet in the HD 159868 system has a period of 352.3 {+-} 1.3 days and m sin i = 0.73 {+-} 0.05 M{sub Jup}. In both of these systems, including the additional planets in the fitting process significantly reduced the eccentricity of the original planet. These systems are thus examples of how multiple-planet systems can masquerade as moderately eccentric single-planet systems.

Wittenmyer, Robert A.; Horner, J.; Salter, G. S.; Tinney, C. G.; Bailey, J. [Department of Astrophysics, School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Tuomi, Mikko; Zhang, Z. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Butler, R. P. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States); Jones, H. R. A. [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom); O'Toole, S. J. [Australian Astronomical Observatory, P.O. Box 296, Epping, NSW 1710 (Australia); Carter, B. D. [Faculty of Sciences, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia); Jenkins, J. S. [Departamento de Astronomia, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago (Chile); Vogt, S. S.; Rivera, Eugenio J., E-mail: rob@phys.unsw.edu.au [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)

2012-07-10

126

A lower radius and mass for the transiting extrasolar planet HAT-P-8 b  

NASA Astrophysics Data System (ADS)

Context. The extrasolar planet HAT-P-8 b was thought to be one of the more inflated transiting hot Jupiters. Aims: By using new and existing photometric data, we computed precise estimates of the physical properties of the system. Methods: We present photometric observations comprising eleven light curves covering six transit events, obtained using five medium-class telescopes and telescope-defocussing technique. One transit was simultaneously obtained through four optical filters, and two transits were followed contemporaneously from two observatories. We modelled these and seven published datasets using the jktebop code. The physical parameters of the system were obtained from these results and from published spectroscopic measurements. In addition, we investigated the theoretically-predicted variation of the apparent planetary radius as a function of wavelength, covering the range 330-960 nm. Results: We find that HAT-P-8 b has a significantly lower radius (1.321 ± 0.037 RJup) and mass (1.275 ± 0.053 MJup) compared to previous estimates (1.50-0.06+0.08 R_{Jup} and 1.52-0.16+0.18 M_{Jup} respectively). We also detect a radius variation in the optical bands that, when compared with synthetic spectra of the planet, may indicate the presence of a strong optical absorber, perhaps TiO and VO gases, near the terminator of HAT-P-8 b. Conclusions: These new results imply that HAT-P-8 b is not significantly inflated, and that its position in the planetary mass-radius diagram is congruent with those of many other transiting extrasolar planets. Full Table 2 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A11

Mancini, L.; Southworth, J.; Ciceri, S.; Fortney, J. J.; Morley, C. V.; Dittmann, J. A.; Tregloan-Reed, J.; Bruni, I.; Barbieri, M.; Evans, D. F.; D'Ago, G.; Nikolov, N.; Henning, Th.

2013-03-01

127

Volatile-Rich Earth-Mass Planets in the Habitable Zone  

Microsoft Academic Search

A small planet is not necessarily a terrestrial planet. Planets that form\\u000abeyond the snow line with too little mass to seed rapid gas accretion (<~ 10\\u000aEarth masses) should be rich in volatile ices like water and ammonia. Some of\\u000athese planets should migrate inward by interacting with a circumstellar disk or\\u000awith other planets. Such objects can retain

Marc J. Kuchner

2003-01-01

128

Future Direct Spectroscopic Detection of Hot Jupiters with IGRINS  

NASA Astrophysics Data System (ADS)

With about 700 confirmed extrasolar planets, it is time to move beyond discovery and towards characterization. Perhaps the most basic parameter of an extrasolar planet is its mass; however, this is very difficult to determine if the planet does not transit the star. The radial velocity technique, still the most fruitful method of discovering planets in the solar neighborhood, can only determine a minimum planet mass. We investigate a method using the near-future IGRINS near infrared spectrograph to detect the orbital motion of the planet itself. We simulate several observations of a star with an orbiting planet, and search for the spectral signature of the planet by cross-correlating against planet model spectra. A detection appears as a strong peak in the cross-correlation function, and gives the radial velocity of the planet at the time of observation. This, combined with the motion of the star from traditional radial velocity planet search programs, can determine the actual planet mass. We find that the IGRINS instrument can detect the spectral signature from large planets on very close orbits (so-called Hot Jupiters), and that the detections can provide tight constraints on the true planet mass.

Gullikson, Kevin; Endl, Mike

2013-08-01

129

Accurate Stellar Parameters of Low-Mass Kepler Planet Hosts  

NASA Astrophysics Data System (ADS)

We report stellar parameters for low-mass planet-candidate host stars recently announced by the Kepler Mission. We obtained medium-resolution, K-band spectra of 84 low-mass Kepler Objects of Interest (KOIs). We identified one KOI as a giant; for the remaining dwarfs, we estimated effective temperatures by comparing measurements of K-band regions dominated by H2O opacity with predictions of synthetic spectra for low-mass stars. We measured overall metallicities ([M/H]) using the equivalent widths of Na I and Ca I absorption features and an empirical metallicity relation calibrated with nearby stars. With effective temperatures and metallicities, we estimate the masses and radii of the low-mass KOIs by interpolation onto two sets of evolutionary isochrones. The resultant stellar radii are significantly less than the values reported in the Kepler Input Catalogue and, by construction, correlate better with effective temperature. Using either set of isochrones, our results significantly reduce the sizes of the corresponding planet candidates, with many less than 1 Earth radius. We report recalculated equilibrium temperatures for the planet-candidates and the implications for Kepler's yield of terrestrial exoplanets in the habitable zones of their host stars.

Muirhead, Philip; Hamren, K.; Schlawin, E.; Rojas-Ayala, B.; Covey, K.; Lloyd, J.

2012-01-01

130

A closely packed system of low-mass, low-density planets transiting Kepler11  

Microsoft Academic Search

When an extrasolar planet passes in front of (transits) its star, its radius can be measured from the decrease in starlight and its orbital period from the time between transits. Multiple planets transiting the same star reveal much more: period ratios determine stability and dynamics, mutual gravitational interactions reflect planet masses and orbital shapes, and the fraction of transiting planets

Jack J. Lissauer; Daniel C. Fabrycky; Eric B. Ford; William J. Borucki; Francois Fressin; Geoffrey W. Marcy; Jerome A. Orosz; Jason F. Rowe; Guillermo Torres; William F. Welsh; Natalie M. Batalha; Stephen T. Bryson; Lars A. Buchhave; Douglas A. Caldwell; Joshua A. Carter; David Charbonneau; Jessie L. Christiansen; William D. Cochran; Jean-Michel Desert; Edward W. Dunham; Michael N. Fanelli; Jonathan J. Fortney; Thomas N. Gautier III; John C. Geary; Ronald L. Gilliland; Michael R. Haas; Jennifer R. Hall; Matthew J. Holman; David G. Koch; David W. Latham; Eric Lopez; Sean McCauliff; Neil Miller; Robert C. Morehead; Elisa V. Quintana; Darin Ragozzine; Dimitar Sasselov; Donald R. Short; Jason H. Steffen

2011-01-01

131

Formation of the Giant Planets  

Microsoft Academic Search

The structure of a gaseous envelope surrounding a protoplanet has been investigated in connection with the formation of the giant planets. Under the assumptions of spherical symmetry and hydrostatic equilibrium, the structure has been calculated for the regions of Jupiter, Saturn, Uranus and Neptune. Energy transfer in the envelope has been taken into account precisely. When the core mass increases

Hiroshi Mizuno

1980-01-01

132

Searching sequences of resonant orbits between a spacecraft and Jupiter  

NASA Astrophysics Data System (ADS)

This research shows a study of the dynamical behavior of a spacecraft that performs a series of close approaches with the planet Jupiter. The main idea is to find a sequence of resonant orbits that allows the spacecraft to stay in the region of the space near the orbit of Jupiter around the Sun gaining energy from each passage by the planet. The dynamical model considers the existence of only two massive bodies in the systems, which are the Sun and Jupiter. They are assumed to be in circular orbits around their center of mass. Analytical equations are used to obtain the values of the parameters required to get this sequence of close approaches. Those equations are useful, because they show which orbits are physically possible when taking into account that the periapsis distances have to be above the surface of the Sun and that the closest approach distances during the passage by Jupiter have to be above its surface.

Formiga, J. K. S.; Prado, A. F. B. A.

2013-10-01

133

Special Feature: The occurrence of Jovian planets and the habitability of planetary systems  

Microsoft Academic Search

Planets of mass comparable to or larger than Jupiter's have been detected around over 50 stars, and for one such object a definitive test of its nature as a gas giant has been accomplished with data from an observed planetary transit. By virtue of their strong gravitational pull, giant planets define the dynamical and collisional environment within which terrestrial planets

Jonathan I. Lunine

2001-01-01

134

Measuring the mass of solar system planets using pulsar timing  

NASA Astrophysics Data System (ADS)

High-precision pulsar timing relies on a solar system ephemeris in order to convert times of arrival (TOAs) of pulses measured at an observatory to the solar system barycenter. Any error in the conversion to the barycentric TOAs leads to a systematic variation in the observed timing residuals; specifically, an incorrect planetary mass leads to a predominantly sinusoidal variation having a period and phase associated with the planet's orbital motion about the Sun. By using an array of pulsars (PSRs J0437-4715, J1744-1134, J1857+0943, J1909-3744), the masses of the planetary systems from Mercury to Saturn have been determined. These masses are consistent with the best-known masses determined by spacecraft observations, with the mass of the Jovian system, 9.547921(2)×10-4Msolar, being significantly more accurate than the mass determined from the Pioneer and Voyager spacecraft, and consistent with but less accurate than the value from the Galileo spacecraft. While spacecraft are likely to produce the most accurate measurements for individual solar system bodies, the pulsar technique is sensitive to planetary system masses and has the potential to provide the most accurate values of these masses for some planets.

Champion, D. J.; Hobbs, G. B.; Manchester, R. N.; Edwards, R. T.; Backer, D. C.; Bailes, M.; Bhat, N. D. R.; Burke-Spolaor, S.; Coles, W.; Demorest, P. B.; Ferdman, R. D.; Folkner, W. M.; Hotan, A. W.; Kramer, M.; Lommen, A. N.; Nice, D. J.; Purver, M. B.; Sarkissian, J. M.; Stairs, I. H.; van Straten, W.; Verbiest, J. P. W.; Yardley, D. R. B.

2011-08-01

135

Jupiter: Earth's Shield  

NSDL National Science Digital Library

More than 155 planets have been found outside of our solar system since the first extra-solar planet was identified in 1995. The search has long been heavily biased towards finding massive planets with short orbits. Now, to find an Earth-like planet, scientists are looking for a planetary setup that is similar to our own, in which a Jupiter-like planet lies a good distance away from its sun. This video segment adapted from NOVA explores how the arrangement of planets in our solar system may have affected the development of life on Earth.

Foundation, Wgbh E.

2009-07-13

136

Planets  

NSDL National Science Digital Library

What planets are in our solar system? Today, we are going to learn about the eight planets in our solar system. While learning, we're going to try to answer the question: What planets are in our solar system? Use this Planet Organizer to fill in information about the solar system that you learn on your journey! First, we're going to find ...

Anderson, Ms.

2011-04-07

137

Planets  

NSDL National Science Digital Library

This radio broadcast discusses developments in the search for extraterrestrial planets. Topics include what causes a planet to form, and how they are detected. There is also speculation on the liklihood of an Earth-like planet being found and the basic requirements for extraterrestrial life. The broadcast is 42 minutes in length.

138

The Interior Structure, Composition, and Evolution of Giant Planets  

NASA Astrophysics Data System (ADS)

We discuss our current understanding of the interior structure and thermal evolution of giant planets. This includes the gas giants, such as Jupiter and Saturn, that are primarily composed of hydrogen and helium, as well as the “ice giants,” such as Uranus and Neptune, which are primarily composed of elements heavier than H/He. The effect of different hydrogen equations of state (including new first-principles computations) on Jupiter’s core mass and heavy element distribution is detailed. This variety of the hydrogen equations of state translate into an uncertainty in Jupiter’s core mass of 18 M ? . For Uranus and Neptune we find deep envelope metallicities up to 0.95, perhaps indicating the existence of an eroded core, as also supported by their low luminosity. We discuss the results of simple cooling models of our solar system’s planets, and show that more complex thermal evolution models may be necessary to understand their cooling history. We review how measurements of the masses and radii of the nearly 50 transiting extrasolar giant planets are changing our understanding of giant planets. In particular a fraction of these planets appear to be larger than can be accommodated by standard models of planetary contraction. We review the proposed explanations for the radii of these planets. We also discuss very young giant planets, which are being directly imaged with ground- and space-based telescopes.

Fortney, Jonathan J.; Nettelmann, Nadine

2010-05-01

139

A CORRELATION BETWEEN HOST STAR ACTIVITY AND PLANET MASS FOR CLOSE-IN EXTRASOLAR PLANETS?  

SciTech Connect

The activity levels of stars are influenced by several stellar properties, such as stellar rotation, spectral type, and the presence of stellar companions. Analogous to binaries, planetary companions are also thought to be able to cause higher activity levels in their host stars, although at lower levels. Especially in X-rays, such influences are hard to detect because coronae of cool stars exhibit a considerable amount of intrinsic variability. Recently, a correlation between the mass of close-in exoplanets and their host star's X-ray luminosity has been detected, based on archival X-ray data from the ROSAT All-Sky Survey. This finding has been interpreted as evidence for star-planet interactions. We show in our analysis that this correlation is caused by selection effects due to the flux limit of the X-ray data used and due to the intrinsic planet detectability of the radial velocity method, and thus does not trace possible planet-induced effects. We also show that the correlation is not present in a corresponding complete sample derived from combined XMM-Newton and ROSAT data.

Poppenhaeger, K.; Schmitt, J. H. M. M., E-mail: katja.poppenhaeger@hs.uni-hamburg.de [Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg (Germany)

2011-07-01

140

Spin-orbit angle measurements for six southern transiting planets. New insights into the dynamical origins of hot Jupiters  

Microsoft Academic Search

Context. Several competing scenarios for planetary-system formation and evolution seek to explain how hot Jupiters came to be so close to their parent stars. Most planetary parameters evolve with time, making it hard to distinguish between models. The obliquity of an orbit with respect to the stellar rotation axis is thought to be more stable than other parameters such as

A. H. M. J. Triaud; A. Collier Cameron; Didier Queloz; D. R. Anderson; Michaël Gillon; Leslie Hebb; Coel Hellier; Benoît Loeillet; P. F. L. Maxted; Michel Mayor; Francesco Pepe; Don Pollacco; Damien Ségransan; Barry Smalley; Stéphane Udry; R. G. West; P. J. Wheatley

2010-01-01

141

Planets  

NSDL National Science Digital Library

The purpose of this project is to gather information and learn interesting facts about the planets in our solar sytem to complete a research project for Mrs. Hutchinson\\'s class. Begin by taking a quiz to measure your knowledge. Click this link for information and quiz. Quiz Next, you will choose two of the following sites and search for information on the planets in our solar system. Fill in the questions on your work sheet as you go to each site. Factmonster Planets Kids Astronomy 9 planets for kids Windows to the Universe Just for ...

Bhanks

2006-11-02

142

On the origin and initial temperature of Jupiter and Saturn  

Microsoft Academic Search

A two-stage growth of the giant planets, Jupiter and Saturn, is considered, which is different from the model of contraction of large gaseous protoplanets. In the first stage, a nucleus forms from condensed material having the mass, about 10 to the 28th g, necessary for the beginning of accretion. In the second stage, a hydrodynamic instability in the gas develops

V. S. Safronov; E. L. Ruskol

1982-01-01

143

CAPTURE OF TROJANS BY JUMPING JUPITER  

NASA Astrophysics Data System (ADS)

Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here, we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to ~5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the observed asymmetry in the number of leading and trailing Trojans. We find that the capture probability is (6-8) × 10^-7 for each particle in the original transplanetary disk, implying that the disk contained (3-4) × 10^7 planetesimals with absolute magnitude H < 9 (corresponding to diameter D = 80 km for a 7% albedo). The disk mass inferred from this work, M_disk ~ 14-28 M_Earth, is consistent with the mass deduced from recent dynamical simulations of the planetary instability.

Nesvorny, David; Vokrouhlicky, D.; Morbidelli, A.

2013-10-01

144

Capture of Trojans by Jumping Jupiter  

NASA Astrophysics Data System (ADS)

Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here, we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to ~5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the observed asymmetry in the number of leading and trailing Trojans. We find that the capture probability is (6-8) × 10-7 for each particle in the original transplanetary disk, implying that the disk contained (3-4) × 107 planetesimals with absolute magnitude H < 9 (corresponding to diameter D = 80 km for a 7% albedo). The disk mass inferred from this work, M disk ~ 14-28 M Earth, is consistent with the mass deduced from recent dynamical simulations of the planetary instability.

Nesvorný, David; Vokrouhlický, David; Morbidelli, Alessandro

2013-05-01

145

Connecting the Dots: Low-Mass Stars, Brown Dwarfs, and Planets  

NASA Astrophysics Data System (ADS)

The lowest mass object that Mother Nature makes through the process of ``star formation'' is currently unknown. While numerous very low-mass stars, brown dwarfs, and planets have been found, their relation to each other remains unclear. Here I describe how the study of brown dwarfs has the potential to help us understand both star and planet formation mechanisms. I describe the physical traits attributed to stars, brown dwarfs, and planets; compare the mass functions of brown dwarfs and planets; and discuss how studies of brown dwarfs in both young clusters and in the field can be used to challenge and constrain star and planet formation theories.

Cruz, K.

2008-08-01

146

Results About Major Planets. Part I.  

National Technical Information Service (NTIS)

Contents: New optical measurements of the diameters of Jupiter, Saturn, Uranus and Neptune; The atmospheric activity of the planet Jupiter; and The activity of Jupiter's atmospheric belts between 1905 and 1963.

A. Dollfus J. H. Focas K. A. Hameen-Anttila R. Prinz

1969-01-01

147

The McDonald Observatory Planet Search: New Long-period Giant Planets and Two Interacting Jupiters in the HD 155358 System  

NASA Astrophysics Data System (ADS)

We present high-precision radial velocity (RV) observations of four solar-type (F7-G5) stars—HD 79498, HD 155358, HD 197037, and HD 220773—taken as part of the McDonald Observatory Planet Search Program. For each of these stars, we see evidence of Keplerian motion caused by the presence of one or more gas giant planets in long-period orbits. We derive orbital parameters for each system and note the properties (composition, activity, etc.) of the host stars. While we have previously announced the two-gas-giant HD 155358 system, we now report a shorter period for planet c. This new period is consistent with the planets being trapped in mutual 2:1 mean-motion resonance. We therefore perform an in-depth stability analysis, placing additional constraints on the orbital parameters of the planets. These results demonstrate the excellent long-term RV stability of the spectrometers on both the Harlan J. Smith 2.7 m telescope and the Hobby-Eberly telescope.

Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Wittenmyer, Robert A.; Horner, J.; Brugamyer, Erik J.; Simon, Attila E.; Barnes, Stuart I.; Caldwell, Caroline

2012-04-01

148

The McDonald Observatory Planet Search: New Long-Periodic Giant Planets, and Two Interacting Jupiters in the HD 155358 System  

NASA Astrophysics Data System (ADS)

We present high-precision radial velocity (RV) observations of four solar-type (F7-G5) stars -- HD 79498, HD 155358, HD 197037, and HD 220773 -- taken as part of the McDonald Observatory Planet Search Program. For each of these stars, we see evidence of Keplerian motion caused by the presence of one or more gas giant planets in long-period orbits. We derive orbital parameters for each system, and note the properties (composition, activity, etc.) of the host stars. While we have previously announced the two-gas-giant HD 155358 system, we now report a shorter period for planet c. This new period is consistent with the planets being trapped in mutual 2:1 mean-motion resonance. We therefore perform an in-depth stability analysis, placing additional constraints on the orbital parameters of the planets. These results demonstrate the excellent long-term RV stability of the spectrometers on both the Harlan J. Smith 2.7 m telescope and the Hobby-Eberly telescope.

Robertson, Paul; Endl, M.; Cochran, W. D.; MacQueen, P. J.; Wittenmyer, R. A.; Horner, J.; Brugamyer, E. J.; Simon, A. E.; Barnes, S. I.; Caldwell, C.

2012-01-01

149

THE McDONALD OBSERVATORY PLANET SEARCH: NEW LONG-PERIOD GIANT PLANETS AND TWO INTERACTING JUPITERS IN THE HD 155358 SYSTEM  

SciTech Connect

We present high-precision radial velocity (RV) observations of four solar-type (F7-G5) stars-HD 79498, HD 155358, HD 197037, and HD 220773-taken as part of the McDonald Observatory Planet Search Program. For each of these stars, we see evidence of Keplerian motion caused by the presence of one or more gas giant planets in long-period orbits. We derive orbital parameters for each system and note the properties (composition, activity, etc.) of the host stars. While we have previously announced the two-gas-giant HD 155358 system, we now report a shorter period for planet c. This new period is consistent with the planets being trapped in mutual 2:1 mean-motion resonance. We therefore perform an in-depth stability analysis, placing additional constraints on the orbital parameters of the planets. These results demonstrate the excellent long-term RV stability of the spectrometers on both the Harlan J. Smith 2.7 m telescope and the Hobby-Eberly telescope.

Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Brugamyer, Erik J.; Barnes, Stuart I.; Caldwell, Caroline [Department of Astronomy and McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States); Wittenmyer, Robert A.; Horner, J. [Department of Astrophysics and Optics, School of Physics, University of New South Wales, Sydney NSW 2052 (Australia); Simon, Attila E., E-mail: paul@astro.as.utexas.edu [Konkoly Observatory of the Hungarian Academy of Sciences, P.O. Box 67, H-1525 Budapest (Hungary)

2012-04-10

150

The ELODIE and SOPHIE search for northern extrasolar planets: Jupiter-analogs around Sun-like stars  

NASA Astrophysics Data System (ADS)

We present radial-velocity measurements (RV) obtained in one of a number of programs underway to search for extrasolar planets with the spectrograph SOPHIE at the 1.93-m telescope of the Observatoire de Haute-Provence. Targets were selected from catalogs observed with ELODIE, which had been mounted previously at the telescope, in order to detect long-period planets with an extended database close to 15 years.

Boisse, I.; Pepe, F.; Perrier, C.; Queloz, D.; Bouchy, F.; Santos, N. C.

2012-12-01

151

The PLANET Microlensing Campaign: Implications for Planets around Galactic Disk and Bulge Stars  

NASA Astrophysics Data System (ADS)

With round-the-clock monitoring of galactic bulge microlensing events, the PLANET experiment constrains the abundance and can yield the discovery of planets down to the mass of earth around galactic disk and bulge stars. Data taken until 1999 imply that less than 1/3 of bulge M-dwarfs are surrounded by jupiter-mass companions at orbital radii between 1 and 4 AU. The current rate of microlensing alerts allows 15--25 jupiters and 1--3 earths to be probed per year.

Dominik, M.; Albrow, M. D.; Beaulieu, J.-P.; Caldwell, J. A. R.; Cassan, A.; Coutures, C.; Greenhill, J.; Hill, K.; Fouqué, P.; Horne, K.; Jorgensen, U. G.; Kane, S.; Kubas, D.; Martin, R.; Menzies, J.; Pollard, K. R.; Sahu, K.; Wambsganss, J.; Watson, R.; Williams, A.

2004-12-01

152

PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS. II. PREDICTIONS FOR OUTER EXTRASOLAR PLANETARY SYSTEMS  

SciTech Connect

We develop an idealized dynamical model to predict the typical properties of outer extrasolar planetary systems, at radii comparable to the Jupiter-to-Neptune region of the solar system. The model is based upon the hypothesis that dynamical evolution in outer planetary systems is controlled by a combination of planet-planet scattering and planetary interactions with an exterior disk of small bodies ('planetesimals'). Our results are based on 5000 long duration N-body simulations that follow the evolution of three planets from a few to 10 AU, together with a planetesimal disk containing 50 M{sub +} from 10 to 20 AU. For large planet masses (M {approx}> M{sub Sat}), the model recovers the observed eccentricity distribution of extrasolar planets. For lower-mass planets, the range of outcomes in models with disks is far greater than that which is seen in isolated planet-planet scattering. Common outcomes include strong scattering among massive planets, sudden jumps in eccentricity due to resonance crossings driven by divergent migration, and re-circularization of scattered low-mass planets in the outer disk. We present the distributions of the eccentricity and inclination that result, and discuss how they vary with planet mass and initial system architecture. In agreement with other studies, we find that the currently observed eccentricity distribution (derived primarily from planets at a {approx}< 3 AU) is consistent with isolated planet-planet scattering. We explain the observed mass dependence-which is in the opposite sense from that predicted by the simplest scattering models-as a consequence of strong correlations between planet masses in the same system. At somewhat larger radii, initial planetary mass correlations and disk effects can yield similar modest changes to the eccentricity distribution. Nonetheless, strong damping of eccentricity for low-mass planets at large radii appears to be a secure signature of the dynamical influence of disks. Radial velocity measurements capable of detecting planets with K {approx} 5 m s{sup -1} and periods in excess of 10 years will provide constraints on this regime. Finally, we present an analysis of the predicted separation of planets in two-planet systems, and of the population of planets in mean-motion resonances (MMRs). We show that, if there are systems with {approx} Jupiter-mass planets that avoid close encounters, the planetesimal disk acts as a damping mechanism and populates MMRs at a very high rate (50%-80%). In many cases, resonant chains (in particular the 4:2:1 Laplace resonance) are set up among all three planets. We expect such resonant chains to be common among massive planets in outer planetary systems.

Raymond, Sean N. [Universite de Bordeaux, Observatoire Aquitain des Sciences de l'Univers, 2 rue de l'Observatoire, BP 89, F-33271 Floirac Cedex (France); Armitage, Philip J. [JILA, University of Colorado, Boulder, CO 80309 (United States); Gorelick, Noel, E-mail: pja@jilau1.colorado.ed [Google, Inc., 1600 Amphitheatre Parkway, Mountain View, CA 94043 (United States)

2010-03-10

153

Detecting Terrestrial Mass Planets Around M-dwarfs: Is SIM's performance competitive?  

Microsoft Academic Search

The exoplanet task force report emphasized M dwarfs as high priority targets for future planet finding efforts due to their large RV and astrometric signature and dominance in the local stellar population. Indeed, some of the least massive planets have been detected around M dwarfs and its only a matter of time before a bona fide terrestrial mass planet is

Angelle M. Tanner; N. Law; P. Plavchan; J. Catanzarite

2009-01-01

154

Jupiter: Earth's Shield  

NSDL National Science Digital Library

More than 155 planets have been found outside of our solar system since the first discovery in 1995, mostly massive Jupiter-like planets in orbits close to their suns. Now, to find an Earth-like planet, scientists are looking for a planetary setup that is similar to our own, in which a Jupiter-like planet lies a good distance away from its sun. This video segment explores how the arrangement of planets in our solar system may have affected the development of life on Earth and describes how researchers are searching for the right planetary setup. The segment is two minutes one second in length. A background essay and list of discussion questions are also provided.

155

On the Minimum Core Mass for Giant Planet Formation  

NASA Astrophysics Data System (ADS)

In the core accretion hypothesis, giant planets form by accreting gas from the protoplanetary disk onto a solid core. Ten Earth masses (10 M_E) is often quoted as the minimum or critical core mass required to form a gas giant. However, the critical core mass can vary greatly depending on various quantities, including: the location in and conditions of the disk, the atmospheric composition and opacity (which may differ from the disk) and the accretion rate of planetesimals or smaller solids. To investigate these issues, we consider the growth of atmospheres in the limiting case of a fixed core mass with no ongoing accretion of solids. We thus obtain absolute lower limits on the critical core mass because additional heat sources limit the ability of the atmosphere to cool and undergo Kelvin-Helmholtz contraction. To study this contraction over a wide range of parameter space, we develop a simplified two-layer cooling model. The model's main approximation is that atmospheric luminosity is primarily generated in the convective interior, so that the luminosity generated in the radiative exterior can be neglected. We focus our attention on the outer region of protoplanetary disks, where our approximations are more valid, and where direct imaging searches are finding giant planets that constrain formation models. To form a gas giant, we require that runaway gas growth occurs within 3 Myr, a characteristic disk lifetime, though the time to grow the core (in situ or otherwise) is not included. Our main finding is that the critical core mass declines with distance in the disk. For our standard model, the critical core mass drops from 8.5 M_E at 5 AU to 3.5 M_E at 100 AU. This result arises primarily from lower disk temperatures. A lower disk density or pressure (at fixed temperature) only modestly increases critical core masses. Lowering the opacity also gives lower critical core masses. We also develop a simplified analytic cooling model, which explains the basic trends and shows that atmospheric self-gravity plays a crucial role in atmospheric growth -- even when the atmosphere is less massive than the core.

Youdin, Andrew; Piso, A.

2013-10-01

156

Kepler-15b: A Hot Jupiter Enriched in Heavy Elements and the First Kepler Mission Planet Confirmed with the Hobby-Eberly Telescope  

NASA Astrophysics Data System (ADS)

We report the discovery of Kepler-15b (KOI-128), a new transiting exoplanet detected by NASA's Kepler mission. The transit signal with a period of 4.94 days was detected in the quarter 1 (Q1) Kepler photometry. For the first time, we have used the High Resolution Spectrograph (HRS) at the Hobby-Eberly Telescope (HET) to determine the mass of a Kepler planet via precise radial velocity (RV) measurements. The 24 HET/HRS RVs and 6 additional measurements from the Fibre-fed Échelle Spectrograph spectrograph at the Nordic Optical Telescope reveal a Doppler signal with the same period and phase as the transit ephemeris. We used one HET/HRS spectrum of Kepler-15 taken without the iodine cell to determine accurate stellar parameters. The host star is a metal-rich ([Fe/H] = 0.36 ± 0.07) G-type main-sequence star with T eff = 5515 ± 124 K. The semi-amplitude K of the RV orbit is 78.7+8.5 -9.5 m s-1, which yields a planet mass of 0.66 ± 0.1 M Jup. The planet has a radius of 0.96 ± 0.06 R Jup and a mean bulk density of 0.9 ± 0.2 g cm-3. The radius of Kepler-15b is smaller than the majority of transiting planets with similar mass and irradiation level. This suggests that the planet is more enriched in heavy elements than most other transiting giant planets. For Kepler-15b we estimate a heavy element mass of 30-40 M ?. 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.

Endl, Michael; MacQueen, Phillip J.; Cochran, William D.; Brugamyer, Erik J.; Buchhave, Lars A.; Rowe, Jason; Lucas, Phillip; Isaacson, Howard; Bryson, Steve; Howell, Steve B.; Fortney, Jonathan J.; Hansen, Terese; Borucki, William J.; Caldwell, Douglas; Christiansen, Jessie L.; Ciardi, David R.; Demory, Brice-Olivier; Everett, Mark; Ford, Eric B.; Haas, Michael R.; Holman, Matthew J.; Horch, Elliott; Jenkins, Jon M.; Koch, David J.; Lissauer, Jack J.; Machalek, Pavel; Still, Martin; Welsh, William F.; Sanderfer, Dwight T.; Seader, Shawn E.; Smith, Jeffrey C.; Thompson, Susan E.; Twicken, Joseph D.

2011-11-01

157

The Trojan minor planets  

NASA Astrophysics Data System (ADS)

There are (March, 1988) 3774 minor planets which have received a permanent number. Of these, there are some whose mean distance to the sun is very nearly equal to that of Jupiter, and whose heliocentric longitudes from that planet are about 60°, so that the three bodies concerned (sun, Jupiter, minor planet) make an approximate equilateral triangle. These minor planets, which occur in two distinct groups, one preceding Jupiter and one following, have received the names of the heroes of the Trojan war. This paper concerns the 49 numbered minor planets of this group.

Spratt, Christopher E.

1988-08-01

158

Case studies of habitable Trojan planets in the system of HD 23079  

Microsoft Academic Search

We investigate the possibility of habitable Trojan planets in the HD 23079 star-planet system. This system consists of a solar-type star and a Jupiter-type planet, which orbits the star near the outer edge of the stellar habitable zone in an orbit of low eccentricity. We find that in agreement with previous studies Earth-mass habitable Trojan planets are possible in this

J. Eberle; M. Cuntz; B. Quarles; Z. E. Musielak

2011-01-01

159

THE EFFECT OF MASS LOSS ON THE TIDAL EVOLUTION OF EXTRASOLAR PLANET  

SciTech Connect

By combining mass loss and tidal evolution of close-in planets, we present a qualitative study on their tidal migrations. We incorporate mass loss in tidal evolution for planets with different masses and find that mass loss could interfere with tidal evolution. In an upper limit case (beta = 3), a significant portion of mass may be evaporated in a long evolution timescale. Evidence of greater modification of the planets with an initial separation of about 0.1 AU than those with a = 0.15 AU can be found in this model. With the assumption of a large initial eccentricity, the planets with initial mass <=1 M{sub J} and initial distance of about 0.1 AU could not survive. With the supposition of beta = 1.1, we find that the loss process has an effect on the planets with low mass at a {approx} 0.05 AU. In both cases, the effect of evaporation on massive planets can be neglected. Also, heating efficiency and initial eccentricity have significant influence on tidal evolution. We find that even low heating efficiency and initial eccentricity have a significant effect on tidal evolution. Our analysis shows that evaporation on planets with different initial masses can accelerate (decelerate) the tidal evolution due to the increase (decrease) in tide of the planet (star). Consequently, the effect of evaporation cannot be neglected in evolutionary calculations of close-in planets. The physical parameters of HD 209458b can be fitted by our model.

Guo, J. H. [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China)

2010-04-01

160

The Europa Jupiter system mission  

NASA Astrophysics Data System (ADS)

Europa Jupiter System Mission (EJSM)— would be an international mission that would achieve Decadal Survey and Cosmic Vision goals. NASA and ESA have concluded a joint study of a mission to Europa, Ganymede and the Jupiter system with orbiters developed by NASA and ESA; contributions by JAXA are also possible. The baseline EJSM architecture consists of two primary elements operating in the Jovian system: the NASA-led Jupiter Europa Orbiter (JEO), and the ESA-led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute an intricately choreographed exploration of the Jupiter System be-fore settling into orbit around Europa and Ganymede, respectively. JEO and JGO would carry eleven and ten complementary instruments, respectively, to monitor dynamic phenomena (such as Io's volcanoes and Jupi-ter's atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and charac-terize water oceans beneath the ice shells of Europa and Ganymede. EJSM would fully addresses high priority science objectives identified by the National Research Coun-cil's (NRC's) Decadal Survey and ESA's Cosmic Vi-sion for exploration of the outer solar system. The De-cadal Survey recommended a Europa Orbiter as the highest priority outer planet flagship mission and also identified Ganymede as a highly desirable mission tar-get. EJSM would uniquely addresse several of the cen-tral themes of ESA's Cosmic Vision Programme, through its in-depth exploration of the Jupiter system and its evolution from origin to habitability. EJSM would investigate the potential habitability of the active ocean-bearing moons Europa and Gany-mede, detailing the geophysical, compositional, geo-logical, and external processes that affect these icy worlds. EJSM would also explore Io and Callisto, Jupi-ter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the formation and evolution of gas giant plan-ets and their satellites would be better known. Most important, EJSM would shed new light on the potential for the emergence of life in the celestial neighborhood and beyond. The EJSM mission architecture provides opportu-nities for coordinated synergistic observations by JEO and JGO of the Jupiter and Ganymede magnetospheres, the volcanoes and torus of Io, the atmosphere of Jupi-ter, and comparative planetology of icy satellites. Each spacecraft could and would conduct "stand-alone" measurements, including the detailed investigation of Europa and Ganymede, providing significant pro-grammatic flexibility. Although engineering advances are needed for JEO (radiation designs) and JGO, no new technologies would be required to execute either EJSM mission element. The development schedule for the mission is such that a technology developed by 2012 - 2013 could easily be incorporated if it enhances the mission capability. Risk mitigation activities are under way to ensure that the radiation designs are implemented in the lowest-risk approach. The baseline mission con-cepts include robust mass and power margins. The EJSM mission architecture provides the opti-mal balance between science, risk, and cost using three guiding principles: achieve Decadal science; builds on lessons learned; and leverages international collabora-tions.

Clark, K.; Stankov, A.; Pappalardo, R. T.; Greeley, R.; Blanc, M.; Lebreton, J.-P.; van Houten, T.

2009-04-01

161

The Planets  

NSDL National Science Digital Library

This tool allows users to find when planets are visible in a given year. The years covered by this site are 1900 to 2100. The positions given are for the 1st of the month, at 9 pm, and generally hold true for the entire month. Positions are noted by which constellation the planet is located in. The planets given are Venus, Mars, Jupiter, Saturn, Neptune, Uranus, and Pluto. Additional comments for Venus and Mars note their location and viewing times.

162

Is Jupiter getting brighter?  

NASA Astrophysics Data System (ADS)

Data on the angular distance from the sun at which a planet first becomes visible or becomes no longer visible are compiled from 33 astronomical calenders included in Chinese dynastic histories from 103 BC to 1368 AD and analyzed as indicators of observed planetary brightness. Venus is found to be the brightest planet, followed by Jupiter and Saturn, Mars and Mercury, and gradual decrease in the brightness of Venus, Saturn, Mars, and Mercury is attributed to changes in the brightness of the sun or in the transparency of the atmosphere. Jupiter, however, is observed to increase in brightness at a rate calculated as about 0.003 mag per 1000 yrs.

Liu, J.-Y.

163

STELLAR PARAMETERS AND METALLICITIES OF STARS HOSTING JOVIAN AND NEPTUNIAN MASS PLANETS: A POSSIBLE DEPENDENCE OF PLANETARY MASS ON METALLICITY  

SciTech Connect

The metal content of planet-hosting stars is an important ingredient that may affect the formation and evolution of planetary systems. Accurate stellar abundances require the determinations of reliable physical parameters, namely, the effective temperature, surface gravity, microturbulent velocity, and metallicity. This work presents the homogeneous derivation of such parameters for a large sample of stars hosting planets (N = 117), as well as a control sample of disk stars not known to harbor giant, closely orbiting planets (N = 145). Stellar parameters and iron abundances are derived from an automated analysis technique developed for this work. As previously found in the literature, the results in this study indicate that the metallicity distribution of planet-hosting stars is more metal rich by {approx}0.15 dex when compared to the control sample stars. A segregation of the sample according to planet mass indicates that the metallicity distribution of stars hosting only Neptunian-mass planets (with no Jovian-mass planets) tends to be more metal poor in comparison with that obtained for stars hosting a closely orbiting Jovian planet. The significance of this difference in metallicity arises from a homogeneous analysis of samples of FGK dwarfs which do not include the cooler and more problematic M dwarfs. This result would indicate that there is a possible link between planet mass and metallicity such that metallicity plays a role in setting the mass of the most massive planet. Further confirmation, however, must await larger samples.

Ghezzi, L.; Cunha, K.; De Araujo, F. X.; De la Reza, R. [Observatorio Nacional, Rua General Jose Cristino, 77, 20921-400, Sao Cristovao, Rio de Janeiro, RJ (Brazil); Smith, V. V.; Schuler, S. C., E-mail: luan@on.b [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)

2010-09-10

164

THE LICK-CARNEGIE EXOPLANET SURVEY: A URANUS-MASS FOURTH PLANET FOR GJ 876 IN AN EXTRASOLAR LAPLACE CONFIGURATION  

SciTech Connect

Continued radial velocity (RV) monitoring of the nearby M4V red dwarf star GJ 876 with Keck/High Resolution Echelle Spectrograph has revealed the presence of a Uranus-mass fourth planetary companion in the system. The new planet has a mean period of P{sub e} = 126.6 days (over the 12.6-year baseline of the RV observations), and a minimum mass of m{sub e} sin i{sub e} = 12.9 {+-} 1.7 M {sub +}. The detection of the new planet has been enabled by significant improvements to our RV data set for GJ 876. The data have been augmented by 36 new high-precision measurements taken over the past five years. In addition, the precision of all of the Doppler measurements have been significantly improved by the incorporation of a high signal-to-noise template spectrum for GJ 876 into the analysis pipeline. Implementation of the new template spectrum improves the internal rms errors for the velocity measurements taken during 1998-2005 from 4.1 m s{sup -1} to 2.5 m s{sup -1}. Self-consistent, N-body fits to the RV data set show that the four-planet system has an invariable plane with an inclination relative to the plane of the sky of i = 59.{sup 0}5. The fit is not significantly improved by the introduction of a mutual inclination between the planets 'b' and 'c', but the new data do confirm a non-zero eccentricity, e{sub d} = 0.207 {+-} 0.055 for the innermost planet, 'd'. In our best-fit coplanar model, the mass of the new component is m{sub e} = 14.6 {+-} 1.7 M {sub +}. Our best-fitting model places the new planet in a three-body resonance with the previously known giant planets (which have mean periods of P{sub c} = 30.4 and P{sub b} = 61.1 days). The critical argument, {psi}{sub Laplace} = {lambda} {sub c} - 3{lambda} {sub b} + 2{lambda} {sub e}, for the Laplace resonance librates with an amplitude of {Delta}{psi}{sub Laplace} = 40{sup 0} {+-} 13{sup 0} about {psi}{sub Laplace} = 0{sup 0}. Numerical integration indicates that the four-planet system is stable for at least a billion years (at least for the coplanar cases). This resonant configuration of three giant planets orbiting an M dwarf primary differs from the well-known Laplace configuration of the three inner Galilean satellites of Jupiter, which are executing very small librations about {psi}{sub Laplace} = 180{sup 0} and which never experience triple conjunctions. The GJ 876 system, by contrast, comes close to a triple conjunction between the outer three planets once per every orbit of the outer planet, 'e'.

Rivera, Eugenio J.; Laughlin, Gregory; Vogt, Steven S.; Meschiari, Stefano [UCO/Lick Observatory, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Butler, R. Paul [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington DC, 20015-1305 (United States); Haghighipour, Nader, E-mail: rivera@ucolick.or [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Monoa, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

2010-08-10

165

The Lick-Carnegie Exoplanet Survey: a Uranus-Mass Fourth Planet for GJ 876 in an Extrasolar Laplace Configuration  

NASA Astrophysics Data System (ADS)

Continued radial velocity (RV) monitoring of the nearby M4V red dwarf star GJ 876 with Keck/High Resolution Echelle Spectrograph has revealed the presence of a Uranus-mass fourth planetary companion in the system. The new planet has a mean period of Pe = 126.6 days (over the 12.6-year baseline of the RV observations), and a minimum mass of me sin ie = 12.9 ± 1.7 M ?. The detection of the new planet has been enabled by significant improvements to our RV data set for GJ 876. The data have been augmented by 36 new high-precision measurements taken over the past five years. In addition, the precision of all of the Doppler measurements have been significantly improved by the incorporation of a high signal-to-noise template spectrum for GJ 876 into the analysis pipeline. Implementation of the new template spectrum improves the internal rms errors for the velocity measurements taken during 1998-2005 from 4.1 m s-1 to 2.5 m s-1. Self-consistent, N-body fits to the RV data set show that the four-planet system has an invariable plane with an inclination relative to the plane of the sky of i = 59fdg5. The fit is not significantly improved by the introduction of a mutual inclination between the planets "b" and "c," but the new data do confirm a non-zero eccentricity, ed = 0.207 ± 0.055 for the innermost planet, "d." In our best-fit coplanar model, the mass of the new component is me = 14.6 ± 1.7 M ?. Our best-fitting model places the new planet in a three-body resonance with the previously known giant planets (which have mean periods of Pc = 30.4 and Pb = 61.1 days). The critical argument, phivLaplace = ? c - 3? b + 2? e , for the Laplace resonance librates with an amplitude of ?phivLaplace = 40° ± 13° about phivLaplace = 0°. Numerical integration indicates that the four-planet system is stable for at least a billion years (at least for the coplanar cases). This resonant configuration of three giant planets orbiting an M dwarf primary differs from the well-known Laplace configuration of the three inner Galilean satellites of Jupiter, which are executing very small librations about phivLaplace = 180° and which never experience triple conjunctions. The GJ 876 system, by contrast, comes close to a triple conjunction between the outer three planets once per every orbit of the outer planet, "e." Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology.

Rivera, Eugenio J.; Laughlin, Gregory; Butler, R. Paul; Vogt, Steven S.; Haghighipour, Nader; Meschiari, Stefano

2010-08-01

166

Microlensing Sensitivity to Earth-Mass Planets in the Habitable Zone  

Microsoft Academic Search

Microlensing is one of the most powerful methods that can detect extrasolar planets, and a future space-based survey with a high monitoring frequency is proposed to detect a large sample of Earth-mass planets. In this paper, we examine the sensitivity of the future microlensing survey to Earth-mass planets located in the habitable zone. For this, we estimate the fraction of

Byeong-Gon Park; Young-Beom Jeon; Chung-Uk Lee; Cheongho Han

2006-01-01

167

A Hot Gap around Jupiter's Orbit in the Solar Nebula  

NASA Astrophysics Data System (ADS)

The Sun was an order of magnitude more luminous during the first few hundred thousand years of its existence, due in part to the gravitational energy released by material accreting from the solar nebula. If Jupiter was already near its present mass, the planet's tides opened an optically thin gap in the nebula. Using Monte Carlo radiative transfer calculations, we show that sunlight absorbed by the nebula and re-radiated into the gap raised temperatures well above the sublimation threshold for water ice, with potentially drastic consequences for the icy bodies in Jupiter's feeding zone. Bodies up to a meter in size were vaporized within a single orbit if the planet was near its present location during this early epoch. Dust particles lost their ice mantles, and planetesimals were partially to fully devolatilized, depending on their size. Scenarios in which Jupiter formed promptly, such as those involving a gravitational instability of the massive early nebula, must cope with the high temperatures. Enriching Jupiter in the noble gases through delivery trapped in clathrate hydrates will be more difficult, but might be achieved by either forming the planet much farther from the star or capturing planetesimals at later epochs. The hot gap resulting from an early origin for Jupiter also would affect the surface compositions of any primordial Trojan asteroids.

Turner, N. J.; Choukroun, M.; Castillo-Rogez, J.; Bryden, G.

2012-04-01

168

A HOT GAP AROUND JUPITER'S ORBIT IN THE SOLAR NEBULA  

SciTech Connect

The Sun was an order of magnitude more luminous during the first few hundred thousand years of its existence, due in part to the gravitational energy released by material accreting from the solar nebula. If Jupiter was already near its present mass, the planet's tides opened an optically thin gap in the nebula. Using Monte Carlo radiative transfer calculations, we show that sunlight absorbed by the nebula and re-radiated into the gap raised temperatures well above the sublimation threshold for water ice, with potentially drastic consequences for the icy bodies in Jupiter's feeding zone. Bodies up to a meter in size were vaporized within a single orbit if the planet was near its present location during this early epoch. Dust particles lost their ice mantles, and planetesimals were partially to fully devolatilized, depending on their size. Scenarios in which Jupiter formed promptly, such as those involving a gravitational instability of the massive early nebula, must cope with the high temperatures. Enriching Jupiter in the noble gases through delivery trapped in clathrate hydrates will be more difficult, but might be achieved by either forming the planet much farther from the star or capturing planetesimals at later epochs. The hot gap resulting from an early origin for Jupiter also would affect the surface compositions of any primordial Trojan asteroids.

Turner, N. J.; Choukroun, M.; Castillo-Rogez, J.; Bryden, G., E-mail: neal.turner@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2012-04-01

169

Consequences of the Ejection and Disruption of Giant Planets  

NASA Astrophysics Data System (ADS)

The discovery of Jupiter-mass planets in close orbits about their parent stars has challenged models of planet formation. Recent observations have shown that a number of these planets have highly inclined, sometimes retrograde orbits about their parent stars, prompting much speculation as to their origin. It is known that migration alone cannot account for the observed population of these misaligned hot Jupiters, which suggests that dynamical processes after the gas disk dissipates play a substantial role in yielding the observed inclination and eccentricity distributions. One particularly promising candidate is planet-planet scattering, which is not very well understood in the nonlinear regime of tides. Through three-dimensional hydrodynamical simulations of multi-orbit encounters, we show that planets that are scattered into an orbit about their parent stars with closest approach distance being less than approximately three times the tidal radius are either destroyed or completely ejected from the system. We find that as few as 9 and as many as 12 of the currently known hot Jupiters have a maximum initial apastron for scattering that lies well within the ice line, implying that these planets must have migrated either before or after the scattering event that brought them to their current positions. If stellar tides are unimportant (Q * >~ 107), disk migration is required to explain the existence of the hot Jupiters present in these systems. Additionally, we find that the disruption and/or ejection of Jupiter-mass planets deposits a Sun's worth of angular momentum onto the host star. For systems in which planet-planet scattering is common, we predict that planetary hosts have up to a 35% chance of possessing an obliquity relative to the invariable plane of greater than 90°.

Guillochon, James; Ramirez-Ruiz, Enrico; Lin, Douglas

2011-05-01

170

Evidence from the Asteroid Belt for a Violent Past Evolution of Jupiter's Orbit  

NASA Astrophysics Data System (ADS)

We use the current orbital structure of large (>50 km) asteroids in the main asteroid belt to constrain the evolution of the giant planets when they migrated from their primordial orbits to their current ones. Minton & Malhotra showed that the orbital distribution of large asteroids in the main belt can be reproduced by an exponentially decaying migration of the giant planets on a timescale of ? ~ 0.5 Myr. However, self-consistent numerical simulations show that the planetesimal-driven migration of the giant planets is inconsistent with an exponential change in their semi-major axes on such a short timescale. In fact, the typical timescale is ? >= 5 Myr. When giant planet migration on this timescale is applied to the asteroid belt, the resulting orbital distribution is incompatible with the observed one. However, the planet migration can be significantly sped up by planet-planet encounters. Consider an evolution where both Jupiter and Saturn have close encounters with a Neptune-mass planet (presumably Uranus or Neptune itself) and where this third planet, after being scattered inward by Saturn, is scattered outward by Jupiter. This scenario leads to a very rapid increase in the orbital separation between Jupiter and Saturn which we show here to have only mild effects on the structure of the asteroid belt. This type of evolution is called a "jumping-Jupiter" case. Our results suggest that the total mass and dynamical excitation of the asteroid belt before migration were comparable to those currently observed. Moreover, they imply that, before migration, the orbits of Jupiter and Saturn were much less eccentric than their current ones.

Morbidelli, Alessandro; Brasser, Ramon; Gomes, Rodney; Levison, Harold F.; Tsiganis, Kleomenis

2010-11-01

171

Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System  

NASA Astrophysics Data System (ADS)

We report the discovery and confirmation of a transiting circumbinary planet (PH1b) around KIC 4862625, an eclipsing binary in the Kepler field. The planet was discovered by volunteers searching the first six Quarters of publicly available Kepler data as part of the Planet Hunters citizen science project. Transits of the planet across the larger and brighter of the eclipsing stars are detectable by visual inspection every ~137 days, with seven transits identified in Quarters 1-11. The physical and orbital parameters of both the host stars and planet were obtained via a photometric-dynamical model, simultaneously fitting both the measured radial velocities and the Kepler light curve of KIC 4862625. The 6.18 ± 0.17 R ? planet orbits outside the 20 day orbit of an eclipsing binary consisting of an F dwarf (1.734 ± 0.044 R ?, 1.528 ± 0.087 M ?) and M dwarf (0.378 ± 0.023 R ?, 0.408 ± 0.024 M ?). For the planet, we find an upper mass limit of 169 M ? (0.531 Jupiter masses) at the 99.7% confidence level. With a radius and mass less than that of Jupiter, PH1b is well within the planetary regime. Outside the planet's orbit, at ~1000 AU, a previously unknown visual binary has been identified that is likely bound to the planetary system, making this the first known case of a quadruple star system with a transiting planet.

Schwamb, Megan E.; Orosz, Jerome A.; Carter, Joshua A.; Welsh, William F.; Fischer, Debra A.; Torres, Guillermo; Howard, Andrew W.; Crepp, Justin R.; Keel, William C.; Lintott, Chris J.; Kaib, Nathan A.; Terrell, Dirk; Gagliano, Robert; Jek, Kian J.; Parrish, Michael; Smith, Arfon M.; Lynn, Stuart; Simpson, Robert J.; Giguere, Matthew J.; Schawinski, Kevin

2013-05-01

172

Prized results from HARPS. Low-mass/habitable/transiting planets orbiting M dwarfs  

NASA Astrophysics Data System (ADS)

Searching for planets around stars with different masses probes the outcome of planetary formation for different initial conditions. The low-mass M dwarfs are also the most frequent stars in our Galaxy and potentially therefore, the most frequent planet hosts. This has motivated our search for planets around M dwarfs with HARPS. That observing program has now run for almost a decade and detected most of the known low-mass planets orbiting M dwarfs (m sin i < 20 M?), including the least massive (GJ581e, msini = 1.9 M?) and the first potentially habitable planets (GJ581c&d GJ667Cc, GJ163c). This proceeding shortly reviews the detections made with HARPS, reports on the occurrence of planets around M dwarfs and how they mesh up with planet formation theory. It also highlights our sensitivity to low-mass habitable planets, the first direct measure of ??, and the recent detection of a transiting planet the size of Uranus.

Bonfils, Xavier; Bouchy, François; Delfosse, X.; Forveille, T.; Gillon, M.; Lovis, C.; Mayor, M.; Neves, V.; Pepe, F.; Perrier, C.; Queloz, D.; Santos, N.; Ségransan, D.; Udry, S.

2013-04-01

173

Sharpening Up Jupiter  

NASA Astrophysics Data System (ADS)

New image-correction technique delivers sharpest whole-planet ground-based picture ever A record two-hour observation of Jupiter using a superior technique to remove atmospheric blur has produced the sharpest whole-planet picture ever taken from the ground. The series of 265 snapshots obtained with the Multi-Conjugate Adaptive Optics Demonstrator (MAD) prototype instrument mounted on ESO's Very Large Telescope (VLT) reveal changes in Jupiter's smog-like haze, probably in response to a planet-wide upheaval more than a year ago. Sharpening Up Jupiter ESO PR Photo 33/08 Sharpening Up Jupiter Being able to correct wide field images for atmospheric distortions has been the dream of scientists and engineers for decades. The new images of Jupiter prove the value of the advanced technology used by MAD, which uses two or more guide stars instead of one as references to remove the blur caused by atmospheric turbulence over a field of view thirty times larger than existing techniques [1]. "This type of adaptive optics has a big advantage for looking at large objects, such as planets, star clusters or nebulae," says lead researcher Franck Marchis, from UC Berkeley and the SETI Institute in Mountain View, California, USA. "While regular adaptive optics provides excellent correction in a small field of view, MAD provides good correction over a larger area of sky. And in fact, were it not for MAD, we would not have been able to perform these amazing observations." MAD allowed the researchers to observe Jupiter for almost two hours on 16 and 17 August 2008, a record duration, according to the observing team. Conventional adaptive optics systems using a single Jupiter moon as reference cannot monitor Jupiter for so long because the moon moves too far from the planet. The Hubble Space Telescope cannot observe Jupiter continuously for more than about 50 minutes, because its view is regularly blocked by the Earth during Hubble's 96-minute orbit. Using MAD, ESO astronomer Paola Amico, MAD project manager Enrico Marchetti and Sébastien Tordo from the MAD team tracked two of Jupiter's largest moons, Europa and Io - one on each side of the planet - to provide a good correction across the full disc of the planet. "It was the most challenging observation we performed with MAD, because we had to track with high accuracy two moons moving at different speeds, while simultaneously chasing Jupiter," says Marchetti. With this unique series of images, the team found a major alteration in the brightness of the equatorial haze, which lies in a 16 000-kilometre wide belt over Jupiter's equator [2]. More sunlight reflecting off upper atmospheric haze means that the amount of haze has increased, or that it has moved up to higher altitudes. "The brightest portion had shifted south by more than 6000 kilometres," explains team member Mike Wong. This conclusion came after comparison with images taken in 2005 by Wong and colleague Imke de Pater using the Hubble Space Telescope. The Hubble images, taken at infrared wavelengths very close to those used for the VLT study, show more haze in the northern half of the bright Equatorial Zone, while the 2008 VLT images show a clear shift to the south. "The change we see in the haze could be related to big changes in cloud patterns associated with last year's planet-wide upheaval, but we need to look at more data to narrow down precisely when the changes occurred," declares Wong.

2008-10-01

174

Juno: Launching to Jupiter  

NASA Video Gallery

The Juno spacecraft will look deep beneath Jupiter's swirling curtains of clouds to decipher the planet's structure and history during a mission that will begin with a 5-year flight through deep space. The journey will begin aboard an Atlas V rocket equipped with five booster rockets and a large Centaur upper stage.

KSC Web Team

2011-08-03

175

Jupiter: Multidimensional Astrophysical Hydrocode  

NASA Astrophysics Data System (ADS)

Jupiter is a multidimensional astrophysical hydrocode. It is based on a Godunov method, and it is parallelized with MPI. The mesh geometry can either be cartesian, cylindrical or spherical. It allows mesh refinement and includes special features adapted to the description of planets embedded in disks and nearly steady states.

Masset, Frederic

2011-09-01

176

Kepler15b: A Hot Jupiter Enriched in Heavy Elements and the First Kepler Mission Planet Confirmed with the Hobby-Eberly Telescope  

Microsoft Academic Search

We report the discovery of Kepler-15b (KOI-128), a new transiting exoplanet detected by NASA's Kepler mission. The transit signal with a period of 4.94 days was detected in the quarter 1 (Q1) Kepler photometry. For the first time, we have used the High Resolution Spectrograph (HRS) at the Hobby-Eberly Telescope (HET) to determine the mass of a Kepler planet via

Michael Endl; Phillip J. MacQueen; William D. Cochran; Erik J. Brugamyer; Lars A. Buchhave; Jason Rowe; Phillip Lucas; Howard Isaacson; Steve Bryson; Steve B. Howell; Jonathan J. Fortney; Terese Hansen; William J. Borucki; Douglas Caldwell; Jessie L. Christiansen; David R. Ciardi; Brice-Olivier Demory; Mark Everett; Eric B. Ford; Michael R. Haas; Matthew J. Holman; Elliott Horch; Jon M. Jenkins; David J. Koch; Jack J. Lissauer; Pavel Machalek; Martin Still; William F. Welsh; Dwight T. Sanderfer; Shawn E. Seader; Jeffrey C. Smith; Susan E. Thompson; Joseph D. Twicken

2011-01-01

177

The First Kepler Mission Planet Confirmed With The Hobby-Eberly Telescope: Kepler15b, a Hot Jupiter Enriched In Heavy Elements  

Microsoft Academic Search

We report the discovery of Kepler-15b, a new transiting exoplanet detected by NASA's Kepler mission. The transit signal with a period of 4.94 days was detected in the quarter 1 (Q1) Kepler photometry. For the first time, we have used the High-Resolution-Spectrograph (HRS) at the Hobby-Eberly Telescope (HET) to determine the mass of a Kepler planet via precise radial velocity

Michael Endl; Phillip J. MacQueen; William D. Cochran; Erik Brugamyer; Lars A. Buchhave; Jason Rowe; Phillip Lucas; Howard Issacson; Steve Bryson; Steve B. Howell; Jonathan J. Fortney; Terese Hansen; William J. Borucki; Douglas Caldwell; Jessie L. Christiansen; David R. Ciardi; Brice-Olivier Demory; Mark Everett; Eric B. Ford; Michael R. Haas; Matthew J. Holman; Elliot Horch; Jon M. Jenkins; David J. Koch; Jack J. Lissauer; Pavel Machalek; Martin Still; William F. Welsh; Dwight T. Sanderfer; Shawn E. Seader; Jeffrey C. Smith; Susan E. Thompson; Joseph D. Twicken

2011-01-01

178

Resolving Jupiter's Aurora with the Juno Suite of Magnetospheric Instruments  

Microsoft Academic Search

The Juno mission, a Jupiter polar orbiting program that begins its 1-year mission at Jupiter in 2016, resolves critical questions regarding the processes that drive Jupiter's dramatic aurora and tests the universality of the processes that generate aurora and couple magnetized planets to their space environments. Jupiter's magnetosphere is known to be powered very differently than is Earth's, specifically by

B. H. Mauk; F. Bagenal

2008-01-01

179

Visualizations of the Properties of a Growing Giant Planet  

NASA Astrophysics Data System (ADS)

We present new visualizations that show the growth rate and properties of Jupiter. Starting with a Mars-sized core and modeling through the planet's final contraction and cooling phase, we demonstrate how pressure, opacity, temperature, and entropy change with time at varying altitudes. Our movie visualizations show the migration of the convective and radiative zones in the atmosphere throughout the planet's formation. We also show the time evolution of the overall luminosity, mass, radius, and gas and planetesimal accretion rates. Using our most recent numerical simulations based on the core accretion-gas capture model, we show how Jupiter could have formed within the generally quoted core mass and time constraints (< 11 M? and < 10 Myr, respectively). Moreover, the implications of our models extend beyond Jupiter to the evolution of Saturn and of giant extrasolar planets. MSR was supported by a grant from the Massachusetts Space Grant Consortium.

Rice, M. S.; Hubickyj, O.

2005-08-01

180

Strange Isotope Ratios in Jupiter  

NASA Astrophysics Data System (ADS)

At the January AAS meeting, Dr. Daniel Goldin ordered the release of isotopic data from the 1995 Galileo probe into Jupiter. This probe took mass readings for mass numbers 2-150, which includes all of the noble gas isotopes. A certain few noble gas isotopes, specifically those at mass/charge = 21, 40, 78, 124, and 126, are difficult to distinguish from background, while interference causes some variation in signals for noble gas isotopes at mass/charge = 20, 22, 36, 38, 40, 80, 82, 83, 84 and 86. Some contamination was caused by incomplete adsorption of low mass hydrocarbons by Carbosieve, the material used in the concentration cells [Space Sci. Rev. 60, 120 (1992)]. Thus, preliminary results are most reliable in the high mass region that includes xenon. The Galileo Probe provided the first direct measurements from a planet with a chemical composition drastically different from Earth. Our preliminary analyses indicate that Jupiter contains Xe-X [Nature 240, 99 (1972)], which differs significantly from Earth's xenon. Xe-X and primordial He are tightly coupled on the microscopic scale of meteorite minerals [Science 195, 208 (1977); Meteoritics 15, 117 (1980)]. The presence today of Xe-X in the He-rich atmosphere of Jupiter suggests that the primordial linkage of Xe-X with He extended across the protosolar nebula, on a planetary scale [Comments Astrophys. 18, 335 (1997)]. Contamination by hydrocarbons and other gases does not necessarily remove light noble gases from further consideration. Currently, isolation of signals of these elements from interference continues and may result in the presentation of many other interesting observations at the conference.

Manuel, O.; Ragland, D.; Windler, K.; Zirbel, J.; Johannes, L.; Nolte, A.

1998-05-01

181

The Effect of Planet-Planet Scattering on the Survival of Exomoons  

NASA Astrophysics Data System (ADS)

Compared to the giant planets in the solar system, exoplanets have many remarkable properties, such as the prevalence of giant planets on eccentric orbits and the presence of hot Jupiters. Planet-planet scattering (PPS) between giant planets is a possible mechanism to interpret the above and other observed properties. If the observed giant planet architectures are indeed outcomes of PPS, such a drastic dynamical process must affect their primordial moon systems. In this Letter, we discuss the effect of PPS on the survival of exoplanets' regular moons. From an observational viewpoint, some preliminary conclusions are drawn from the simulations. (1) PPS is a destructive process to the moon systems; single planets on eccentric orbits are not ideal moon-search targets. (2) If hot Jupiters formed through PPS, their original moons have little chance of survival. (3) Planets in multiple systems with small eccentricities are more likely to hold their primordial moons. (4) Compared with lower-mass planets, massive planets in multiple systems may not be the preferred moon-search targets if the system underwent a PPS history.

Gong, Yan-Xiang; Zhou, Ji-Lin; Xie, Ji-Wei; Wu, Xiao-Mei

2013-05-01

182

The Occurrence And Mass Distribution Of Close-in Super-earths, Neptunes, And Jupiters  

Microsoft Academic Search

We report the occurrence rate of close-in planets (orbital periods less than 50 days) based on precise Doppler measurements of 166 G and K-type dwarf stars. We statistically study the planet detections and non-detections on a star-by-star basis using 3.5 years of Keck RV measurements made specifically for the NASA-UC Eta-Earth Survey. We measure increasing planet occurrence with decreasing planet

Andrew Howard; G. Marcy; J. A. Johnson; D. Fischer; J. Wright; J. Valenti; J. Anderson; D. N. C. Lin; S. Ida

2011-01-01

183

A Cold Neptune-Mass Planet OGLE2007-BLG-368Lb: Cold Neptunes Are Common  

Microsoft Academic Search

We present the discovery of a Neptune-mass planet OGLE-2007-BLG-368Lb with a planet-star mass ratio of q = [9.5 ± 2.1] × 10-5 via gravitational microlensing. The planetary deviation was detected in real-time thanks to the high cadence of the Microlensing Observations in Astrophysics survey, real-time light-curve monitoring and intensive follow-up observations. A Bayesian analysis returns the stellar mass and distance

T. Sumi; D. P. Bennett; I. A. Bond; A. Udalski; V. Batista; M. Dominik; P. Fouqué; D. Kubas; A. Gould; B. Macintosh; K. Cook; S. Dong; L. Skuljan; A. Cassan; F. Abe; C. S. Botzler; A. Fukui; K. Furusawa; J. B. Hearnshaw; Y. Itow; K. Kamiya; P. M. Kilmartin; A. Korpela; W. Lin; C. H. Ling; K. Masuda; Y. Matsubara; N. Miyake; Y. Muraki; M. Nagaya; T. Nagayama; K. Ohnishi; T. Okumura; Y. C. Perrott; N. Rattenbury; To. Saito; T. Sako; D. J. Sullivan; W. L. Sweatman; P. J. Tristram; P. C. M. Yock; J. P. Beaulieu; A. Cole; Ch. Coutures; M. F. Duran; J. Greenhill; F. Jablonski; U. Marboeuf; E. Martioli; E. Pedretti; O. Pejcha; P. Rojo; M. D. Albrow; S. Brillant; M. Bode; D. M. Bramich; M. J. Burgdorf; J. A. R. Caldwell; H. Calitz; E. Corrales; S. Dieters; D. Dominis Prester; J. Donatowicz; K. Hill; M. Hoffman; K. Horne; U. G. Jørgensen; N. Kains; S. Kane; J. B. Marquette; R. Martin; P. Meintjes; J. Menzies; K. R. Pollard; C. Snodgrass; I. Steele; Y. Tsapras; J. Wambsganss; A. Williams; M. Zub; M. K. Szymanski; M. Kubiak; G. Pietrzynski; I. Soszynski; O. Szewczyk; L. Wyrzykowski; K. Ulaczyk; W. Allen; G. W. Christie; D. L. DePoy; B. S. Gaudi; C. Han; J. Janczak; C.-U. Lee; J. McCormick; F. Mallia; B. Monard; T. Natusch; B.-G. Park; R. W. Pogge; R. Santallo

2010-01-01

184

Constraints on the Mass of a Habitable Planet with Water of Nebular Origin  

Microsoft Academic Search

From an astrobiological point of view, special attention has been paid to the probability of habitable planets in extrasolar systems. The purpose of this study is to constrain a possible range of the mass of a terrestrial planet that can get water. We focus on the process of water production through oxidation of atmospheric hydrogen-the nebular gas having been attracted

Masahiro Ikoma; Hidenori Genda

2006-01-01

185

The stability of the orbits of Earth-mass planets in the habitable zone of 47 Ursae Majoris  

Microsoft Academic Search

We have investigated whether Earth-mass planets could survive in the habitable zone (HZ) of the 47 Ursae Majoris system. Mixed-variable symplectic numerical integration has been used to investigate the orbits of putative Earth-mass planets. Whereas the 47 UMa system as previously known, with just one giant planet, could have Earth-mass planets that remain confined to the HZ for a fairly

B. W. Jones; P. N. Sleep

2002-01-01

186

Direct imaging of multiple planets orbiting the star HR 8799  

SciTech Connect

Direct imaging of exoplanetary systems is a powerful technique that can reveal Jupiter-like planets in wide orbits, can enable detailed characterization of planetary atmospheres, and is a key step towards imaging Earth-like planets. Imaging detections are challenging due to the combined effect of small angular separation and large luminosity contrast between a planet and its host star. High-contrast observations with the Keck and Gemini telescopes have revealed three planets orbiting the star HR 8799, with projected separations of 24, 38, and 68 astronomical units. Multi-epoch data show counter-clockwise orbital motion for all three imaged planets. The low luminosity of the companions and the estimated age of the system imply planetary masses between 5 and 13 times that of Jupiter. This system resembles a scaled-up version of the outer portion of our Solar System.

Marois, C; Macintosh, B; Barman, T; Zuckerman, B; Song, I; Patience, J; Lafreniere, D; Doyon, R

2008-10-14

187

Short-duration Lensing Events. I. Wide-orbit Planets? Free-floating Low-mass Objects? Or High-velocity Stars?  

NASA Astrophysics Data System (ADS)

Short-duration lensing events tend to be generated by low-mass lenses or by lenses with high transverse velocities. Furthermore, for any given lens mass and speed, events of short duration are preferentially caused by nearby lenses (mesolenses) that can be studied in detail, or else by lenses so close to the source star that finite-source-size effects may be detected, yielding information about both the Einstein ring radius and the surface of the lensed star. Planets causing short-duration events may be in orbits with any orientation, and may have semimajor axes smaller than 1 AU, or they may reach the outer limits of their planetary systems, in the region corresponding to the solar system's Oort Cloud. They can have masses larger than Jupiter's or smaller than Pluto's. Lensing therefore has a unique potential to expand our understanding of planetary systems. A particular advantage of lensing is that it can provide precision measurements of system parameters, including the masses of and projected separation between star and planet. We demonstrate how the parameters can be extracted and show that a great deal can be learned. For example, it is remarkable that the gravitational mass of nearby free-floating planet-mass lenses can be measured by complementing observations of a photometric event with deep images that detect the planet itself. A fraction of short events may be caused by high-velocity stars located within a kiloparsec. Many high-velocity lenses are likely to be neutron stars that received large natal kicks. Other high-speed stars may be members of the halo population. Still others may be hypervelocity stars that have been ejected from the Galactic center, or runaway stars escaped from close binaries, possibly including the progenitor binaries of Type Ia supernovae.

Di Stefano, Rosanne

2012-08-01

188

SHORT-DURATION LENSING EVENTS. I. WIDE-ORBIT PLANETS? FREE-FLOATING LOW-MASS OBJECTS? OR HIGH-VELOCITY STARS?  

SciTech Connect

Short-duration lensing events tend to be generated by low-mass lenses or by lenses with high transverse velocities. Furthermore, for any given lens mass and speed, events of short duration are preferentially caused by nearby lenses (mesolenses) that can be studied in detail, or else by lenses so close to the source star that finite-source-size effects may be detected, yielding information about both the Einstein ring radius and the surface of the lensed star. Planets causing short-duration events may be in orbits with any orientation, and may have semimajor axes smaller than 1 AU, or they may reach the outer limits of their planetary systems, in the region corresponding to the solar system's Oort Cloud. They can have masses larger than Jupiter's or smaller than Pluto's. Lensing therefore has a unique potential to expand our understanding of planetary systems. A particular advantage of lensing is that it can provide precision measurements of system parameters, including the masses of and projected separation between star and planet. We demonstrate how the parameters can be extracted and show that a great deal can be learned. For example, it is remarkable that the gravitational mass of nearby free-floating planet-mass lenses can be measured by complementing observations of a photometric event with deep images that detect the planet itself. A fraction of short events may be caused by high-velocity stars located within a kiloparsec. Many high-velocity lenses are likely to be neutron stars that received large natal kicks. Other high-speed stars may be members of the halo population. Still others may be hypervelocity stars that have been ejected from the Galactic center, or runaway stars escaped from close binaries, possibly including the progenitor binaries of Type Ia supernovae.

Di Stefano, Rosanne [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-08-01

189

The Nitrogen Constraint on Habitability of Planets around Low Mass M-stars  

NASA Astrophysics Data System (ADS)

The traditional habitable zones around stars are defined based on the stability of liquid water over geological timescales. Being too far away from the stars, the planet would be incapable of maintaining a warm surface and thus no liquid water. Being too close to the star, the planet would experience a 'runaway' greenhouse phase, during which its oceans could be lost quickly, and end up similar to our sister planet, Venus. The definition of tranditional habitable zones does not consider the availability of other elements important for life. All life as we know it needs nitrogen. Our calculations of upper planetary atmospheres show that nitrogen could be lost rapidly from planetary atmospheres with CO2 concentrations lower than certain threshold. This suggests that life on planets around low mass M-stars may be selflimiting, and planets of low mass M-stars are less favorable places to search for life than G- or K-type stars.

Tian, F.

2011-10-01

190

The Nitrogen Constraint on Habitability of Planets of Low Mass M-stars  

NASA Astrophysics Data System (ADS)

The traditional habitable zones around stars are defined based on the stability of liquid water over geological timescales. Being too far away from the stars, the planet would be incapable of maintaining a warm surface and thus no liquid water. Being too close to the star, the planet would experience a 'runaway' greenhouse phase, during which its oceans could be lost quickly, and end up similar to our sister planet, Venus. The definition of tranditional habitable zones does not consider the availability of other elements important for life. All life as we know it needs nitrogen. Our calculations of upper planetary atmospheres show that nitrogen could be lost rapidly from planetary atmospheres with CO2 concentrations lower than certain threshold. This suggests that life on planets around low mass M-stars may be selflimiting, and planets of low mass M-stars are less favorable places to search for life than G- or K-type stars.

Tian, F.

2011-12-01

191

A decreased probability of habitable planet formation around low-mass stars  

Microsoft Academic Search

Smaller terrestrial planets (< 0.3 Earth masses) are less likely to retain\\u000athe substantial atmospheres and ongoing tectonic activity probably required to\\u000asupport life. A key element in determining if sufficiently massive \\

Sean N. Raymond; John Scalo; Victoria S. Meadows

2007-01-01

192

Detecting Planets in the Galactic Bulge  

NASA Astrophysics Data System (ADS)

Determination of the frequency of planets in environments different from the local neighborhood, such as the Galactic bulge, may provide clues to the origin of planets. There are three currently feasible methods of detecting planetary companions to stars in the bulge: gravitational microlensing, transit, and "direct" detection. Microlensing searches for planets have been ongoing for six years, and have yielded interesting constraints on the frequency of Jupiter-mass planets around typical stars in the bulge (M-dwarfs) with separations 1 AU ? a ? 5 AU. If continued, such searches should eventually result in detections. Detecting bulge planets via transits requires a campaign of least 10 nights on a 10m-class telescope at an excellent site. Such a campaign would detect 5-50 Jupiter-size planets with a? 0.1 AU, if the frequency of planets in the bulge is similar to that locally. As a consistency check, close-in giant planetary companions can also be "directly" detected in caustic crossing binary-lens events, where the reflected light of the planet can be magnified by two orders of magnitude. Direct detection requires a few hours of intensive monitoring per binary-lens microlensing light curve using a 10m-class telescope. Combining these methods may eventually yield a complete census of Jovian companions to stars in the bulge with separations 0.01-10 AU. With a larger investment in observing resources, this range could plausibly be extended to ? 20 AU.

Gaudi, B. S.

2000-12-01

193

Evaporation of extrasolar planets  

Microsoft Academic Search

This article presents a review on the observations and theoretical modeling of the evaporation of extrasolar planets. The observations and the resulting constraints on the upper atmosphere (thermosphere and exosphere) of the ``hot-Jupiters'' are described. The early observations of the first discovered transiting extrasolar planet, HD209458b, allowed the discovery that this planet has an extended atmosphere of escaping hydrogen. Subsequent

A. Lecavelier Des Etangs

2010-01-01

194

A Search for Companions in Kepler's Hot Jupiter Systems  

NASA Astrophysics Data System (ADS)

The presence or absence of additional, short-period planets in hot Jupiter systems is an important observational constraint on models of planet formation and dynamical evolution. Among the over 1000 Kepler exoplanet candidates is a large number of hot Jupiter candidates. We present results from a search for additional planets in these systems through a combination of photometric, geometric, and dynamical (TTV) probes. The results of this search may provide useful insight into the histories and orbital architectures of hot Jupiter systems.

Steffen, Jason H.; Holman, M.; Borucki, W. J.; Koch, D. G.; Kepler Science Team

2011-05-01

195

Extrasolar planets  

PubMed Central

The first known extrasolar planet in orbit around a Sun-like star was discovered in 1995. This object, as well as over two dozen subsequently detected extrasolar planets, were all identified by observing periodic variations of the Doppler shift of light emitted by the stars to which they are bound. All of these extrasolar planets are more massive than Saturn is, and most are more massive than Jupiter. All orbit closer to their stars than do the giant planets in our Solar System, and most of those that do not orbit closer to their star than Mercury is to the Sun travel on highly elliptical paths. Prevailing theories of star and planet formation, which are based on observations of the Solar System and of young stars and their environments, predict that planets should form in orbit about most single stars. However, these models require some modifications to explain the properties of the observed extrasolar planetary systems.

Lissauer, Jack J.; Marcy, Geoffrey W.; Ida, Shigeru

2000-01-01

196

Extrasolar planets.  

PubMed

The first known extrasolar planet in orbit around a Sun-like star was discovered in 1995. This object, as well as over two dozen subsequently detected extrasolar planets, were all identified by observing periodic variations of the Doppler shift of light emitted by the stars to which they are bound. All of these extrasolar planets are more massive than Saturn is, and most are more massive than Jupiter. All orbit closer to their stars than do the giant planets in our Solar System, and most of those that do not orbit closer to their star than Mercury is to the Sun travel on highly elliptical paths. Prevailing theories of star and planet formation, which are based on observations of the Solar System and of young stars and their environments, predict that planets should form in orbit about most single stars. However, these models require some modifications to explain the properties of the observed extrasolar planetary systems. PMID:11035782

Lissauer, J J; Marcy, G W; Ida, S

2000-11-01

197

Accretion of the gaseous envelope of Jupiter around a 5–10 Earth-mass core  

Microsoft Academic Search

New numerical simulations of the formation and evolution of Jupiter are presented. The formation model assumes that first a solid core of several M? accretes from the planetesimals in the protoplanetary disk, and then the core captures a massive gaseous envelope from the protoplanetary disk. Earlier studies of the core accretion–gas capture model [Pollack, J.B., Hubickyj, O., Bodenheimer, P., Lissauer,

Olenka Hubickyj; Peter Bodenheimer; Jack J. Lissauer

2005-01-01

198

ORBITAL MIGRATION OF INTERACTING LOW-MASS PLANETS IN EVOLUTIONARY RADIATIVE TURBULENT MODELS  

SciTech Connect

The torques exerted by a locally isothermal disk on an embedded planet lead to rapid inward migration. Recent work has shown that modeling the thermodynamics without the assumption of local isothermality reveals regions where the net torque on an embedded planet is positive, leading to outward migration of the planet. When a region with negative torque lies directly exterior to this, planets in the inner region migrate outward and planets in the outer region migrate inward, converging where the torque is zero. We incorporate the torques from an evolving non-isothermal disk into an N-body simulation to examine the behavior of planets or planetary embryos interacting in the convergence zone. We find that mutual interactions do not eject objects from the convergence zone. Small numbers of objects in a laminar disk settle into near resonant orbits that remain stable over the 10 Myr periods that we examine. However, either or both increasing the number of planets or including a correlated, stochastic force to represent turbulence drives orbit crossings and mergers in the convergence zone. These processes can build gas giant cores with masses of order 10 Earth masses from sub-Earth mass embryos in 2-3 Myr.

Horn, Brandon; Mac Low, Mordecai-Mark [Department of Astronomy, Columbia University, 550 West 120th St, New York, NY 10027 (United States); Lyra, Wladimir [Department of Astrophysics, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024 (United States); Sandor, Zsolt, E-mail: bhorn@astro.columbia.edu, E-mail: wlyra@amnh.org, E-mail: mordecai@amnh.org, E-mail: zsolt.sandor@uibk.ac.at [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117, Heidelberg (Germany)

2012-05-01

199

RESOLVING THE sin(I) DEGENERACY IN LOW-MASS MULTI-PLANET SYSTEMS  

SciTech Connect

Long-term orbital evolution of multi-planet systems under tidal dissipation often converges to a stationary state, known as the tidal fixed point. The fixed point is characterized by a lack of oscillations in the eccentricities and apsidal alignment among the orbits. Quantitatively, the nature of the fixed point is dictated by mutual interactions among the planets as well as non-Keplerian effects. We show that if a roughly coplanar system hosts a hot, sub-Saturn mass planet, and is tidally relaxed, separation of planet-planet interactions and non-Keplerian effects in the equations of motion leads to a direct determination of the true masses of the planets. Consequently, a 'snap-shot' observational determination of the orbital state resolves the sin(I) degeneracy and opens up a direct avenue toward identification of the true lowest-mass exoplanets detected. We present an approximate, as well as a general, mathematical framework for computation of the line-of-sight inclination of secular systems, and apply our models illustratively to the 61 Vir system. We conclude by discussing the observability of planetary systems to which our method is applicable and we set our analysis into a broader context by presenting a current summary of the various possibilities for determining the physical properties of planets from observations of their orbital states.

Batygin, Konstantin [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Laughlin, Gregory, E-mail: kbatygin@gps.caltech.edu [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)

2011-04-01

200

Interiors of giant planets inside and outside the solar system.  

PubMed

An understanding of the structure and composition of the giant planets is rapidly evolving because of (i) high-pressure experiments with the ability to study metallic hydrogen and define the properties of its equation of state and (ii) spectroscopic and in situ measurements made by telescopes and satellites that allow an accurate determination of the chemical composition of the deep atmospheres of the giant planets. However, the total amount of heavy elements that Jupiter, Saturn, Uranus, and Neptune contain remains poorly constrained. The discovery of extrasolar giant planets with masses ranging from that of Saturn to a few times the mass of Jupiter opens up new possibilities for understanding planet composition and formation. Evolutionary models predict that gaseous extrasolar giant planets should have a variety of atmospheric temperatures and chemical compositions, but the radii are estimated to be close to that of Jupiter (between 0.9 and 1.7 Jupiter radii), provided that they contain mostly hydrogen and helium. PMID:10506563

Guillot, T

1999-10-01

201

In search of planets and life around other stars  

PubMed Central

The discovery of over a dozen low-mass companions to nearby stars has intensified scientific and public interest in a longer term search for habitable planets like our own. However, the nature of the detected companions, and in particular whether they resemble Jupiter in properties and origin, remains undetermined.

Lunine, Jonathan I.

1999-01-01

202

TOO LITTLE, TOO LATE: HOW THE TIDAL EVOLUTION OF HOT JUPITERS AFFECTS TRANSIT SURVEYS OF CLUSTERS  

SciTech Connect

The tidal evolution of hot Jupiters may change the efficiency of transit surveys of stellar clusters. The orbital decay that hot Jupiters suffer may result in their destruction, leaving fewer transiting planets in older clusters. We calculate the impact tidal evolution has for different assumed stellar populations, including that of 47 Tuc, a globular cluster that was the focus of an intense Hubble Space Telescope search for transits. We find that in older clusters, one expects to detect fewer transiting planets by a factor of 2 for surveys sensitive to Jupiter-like planets in orbits out to 0.5 AU, and up to a factor of 25 for surveys sensitive to Jupiter-like planets in orbits out to 0.08 AU. Additionally, tidal evolution affects the distribution of transiting planets as a function of the semimajor axis, producing larger orbital period gaps for transiting planets as the age of the cluster increases. Tidal evolution can explain the lack of detected exoplanets in 47 Tuc without invoking other mechanisms. Four open clusters residing within the Kepler fields of view have ages that span 0.4-8 Gyr-if Kepler can observe a significant number of planets in these clusters, it will provide key tests for our tidal evolution hypothesis. Finally, our results suggest that observers wishing to discover transiting planets in clusters must have sufficient accuracy to detect lower mass planets, search larger numbers of cluster members, or have longer observation windows to be confident that a significant number of transits will occur for a population of stars.

Debes, John H.; Jackson, Brian [NASA Postdoctoral Program Fellow. (United States)

2010-11-10

203

Prospects of the Detection of Trojan Planets in Transiting Systems using Transit Timing Variation Method  

NASA Astrophysics Data System (ADS)

We present the results of a study of the feasibility of detecting small, terrestrial-sized planets in a transiting system consisting of a Jupiter-like planet and an M-dwarf using the variations in the transit timing of the Jupiter-sized body. Specifically, we studied the case where the two planets are in 1:1 mean-motion resonance. To determine the detectability of such Trojan planets, a number of systems with different masses, eccentricities, and periods were numerically integrated and the amplitudes of their TTV signals were calculated. Results indicate that Trojan planets in 3 to 10 day orbits and with eccentricities ranging from 0 to 0.15 have a high probability for detection. We present the results of our study and discuss the applicability of our analysis to the probability of the detection of such planets with the recently launched Kepler space telescope.

Capen, Stephanie; Haghighipour, N.

2010-05-01

204

Planet formation around low mass stars: the moving snow line and super-Earths  

Microsoft Academic Search

We develop a semi-analytic model for planet formation during the pre-main\\u000asequence contraction phase of a low mass star. During this evolution, the\\u000astellar magnetosphere maintains a fixed ratio between the inner disk radius and\\u000athe stellar radius. As the star contracts at constant effective temperature,\\u000athe `snow line', which separates regions of rocky planet formation from regions\\u000aof icy

Grant M. Kennedy; Scott J. Kenyon; Benjamin C. Bromley

2006-01-01

205

Orbits and Interiors of Planets  

NASA Astrophysics Data System (ADS)

The focus of this thesis is a collection of problems of timely interest in orbital dynamics and interior structure of planetary bodies. The first three chapters are dedicated to understanding the interior structure of close-in, gaseous extrasolar planets (hot Jupiters). In order to resolve a long-standing problem of anomalously large hot Jupiter radii, we proposed a novel magnetohydrodynamic mechanism responsible for inflation. The mechanism relies on the electro-magnetic interactions between fast atmospheric flows and the planetary magnetic field in a thermally ionized atmosphere, to induce electrical currents that flow throughout the planet. The resulting Ohmic dissipation acts to maintain the interior entropies, and by extension the radii of hot Jupiters at an enhanced level. Using self-consistent calculations of thermal evolution of hot Jupiters under Ohmic dissipation, we demonstrated a clear tendency towards inflated radii for effective temperatures that give rise to significant ionization of K and Na in the atmosphere, a trend fully consistent with the observational data. Furthermore, we found that in absence of massive cores, low-mass hot Jupiters can over-flow their Roche-lobes and evaporate on Gyr time-scales, possibly leaving behind small rocky cores. Chapters four through six focus on the improvement and implications of a model for orbital evolution of the solar system, driven by dynamical instability (termed the "Nice" model). Hydrodynamical studies of the orbital evolution of planets embedded in protoplanetary disks suggest that giant planets have a tendency to assemble into multi-resonant configurations. Following this argument, we used analytical methods as well as self-consistent numerical N-body simulations to identify fully-resonant primordial states of the outer solar system, whose dynamical evolutions give rise to orbital architectures that resemble the current solar system. We found a total of only eight such initial conditions, providing independent constraints for the solar system's birth environment. Next, we addressed a significant drawback of the original Nice model, namely its inability to create the physically unique, cold classical population of the Kuiper Belt. Specifically, we showed that a locally-formed cold belt can survive the transient instability, and its relatively calm dynamical structure can be reproduced. The last four chapters of this thesis address various aspects and consequences of dynamical relaxation of planetary orbits through dissipative effects as well as the formation of planets in binary stellar systems. Using octopole-order secular perturbation theory, we demonstrated that in multi-planet systems, tidal dissipation often drives orbits onto dynamical "fixed points," characterized by apsidal alignment and lack of periodic variations in eccentricities. We applied this formalism towards investigating the possibility that the large orbital eccentricity of the transiting Neptune-mass planet Gliese 436b is maintained in the face of tidal dissipation by a second planet in the system and computed a locus of possible orbits for the putative perturber. Following up along similar lines, we used various permutations of secular theory to show that when applied specifically to close-in low-mass planetary systems, various terms in the perturbation equations become separable, and the true masses of the planets can be solved for algebraically. In practice, this means that precise knowledge of the system's orbital state can resolve the sin( i) degeneracy inherent to non-transiting planets. Subsequently, we investigated the onset of chaotic motion in dissipative planetary systems. We worked in the context of classical secular perturbation theory, and showed that planetary systems approach chaos via the so-called period-doubling route. Furthermore, we demonstrated that chaotic strange attractors can exist in mildly damped systems, such as photo-evaporating nebulae that host multiple planets. Finally, we considered planetary formation in highly inclined binary systems,

Batygin, Konstantin

2012-05-01

206

Elliptical instability in hot Jupiter systems  

NASA Astrophysics Data System (ADS)

Several studies have already considered the influence of tides on the evolution of systems composed of a star and a close-in companion to tentatively explain different observations such as the spin-up of some stars with hot Jupiters, the radius anomaly of short orbital period planets and the synchronization or quasi-synchronization of the stellar spin in some extreme cases. However, the nature of the mechanism responsible for the tidal dissipation in such systems remains uncertain. In this paper, we claim that the so-called elliptical instability may play a major role in these systems, explaining some systematic features present in the observations. This hydrodynamic instability, arising in rotating flows with elliptical streamlines, is suspected to be present in both planet and star of such systems, which are elliptically deformed by tides. The presence and the influence of the elliptical instability in gaseous bodies, such as stars or hot Jupiters, are most of the time neglected. In this paper, using numerical simulations and theoretical arguments, we consider several features associated to the elliptical instability in hot-Jupiter systems. In particular, the use of ad hoc boundary conditions makes it possible to estimate the amplitude of the elliptical instability in gaseous bodies. We also consider the influence of compressibility on the elliptical instability, and compare the results to the incompressible case. We demonstrate the ability for the elliptical instability to grow in the presence of differential rotation, with a possible synchronized latitude, provided that the tidal deformation and/or the rotation rate of the fluid are large enough. Moreover, the amplitude of the instability for a centrally-condensed mass of fluid is of the same order of magnitude as for an incompressible fluid for a given distance to the threshold of the instability. Finally, we show that the assumption of the elliptical instability being the main tidal dissipation process in eccentric inflated hot Jupiters and misaligned stars is consistent with current data.

Cébron, David; Bars, Michael Le; Gal, Patrice Le; Moutou, Claire; Leconte, Jeremy; Sauret, Alban

2013-11-01

207

KEPLER-6b: A TRANSITING HOT JUPITER ORBITING A METAL-RICH STAR  

SciTech Connect

We announce the discovery of Kepler-6b, a transiting hot Jupiter orbiting a star with unusually high metallicity, [Fe/H]= +0.34{+-}0.04. The planet's mass is about 2/3 that of Jupiter, M {sub P} = 0.67 M {sub J}, and the radius is 30% larger than that of Jupiter, R {sub P} = 1.32 R {sub J}, resulting in a density of {rho}{sub P} = 0.35 g cm{sup -3}, a fairly typical value for such a planet. The orbital period is P = 3.235 days. The host star is both more massive than the Sun, M {sub *} = 1.21 M {sub sun}, and larger than the Sun, R {sub *} = 1.39 R {sub sun}.

Dunham, Edward W. [Lowell Observatory, Flagstaff, AZ 86001 (United States); Borucki, William J.; Koch, David G.; Lissauer, Jack J. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Batalha, Natalie M. [San Jose State University, San Jose, CA 95192 (United States); Buchhave, Lars A.; Furesz, Gabor; Geary, John C.; Latham, David W. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Brown, Timothy M. [Las Cumbres Observatory Global Telescope, Goleta, CA 93117 (United States); Caldwell, Douglas A.; Jenkins, Jon M. [SETI Institute, Mountain View, CA 94043 (United States); Cochran, William D.; Endl, Michael [University of Texas, Austin, TX 78712 (United States); Fischer, Debra [Yale University, New Haven, CT 06510 (United States); Gautier, Thomas N. [Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA 91109 (United States); Gilliland, Ronald L. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Gould, Alan [Lawrence Hall of Science, Berkeley, CA 94720 (United States); Howell, Steve B. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Kjeldsen, Hans [University of Aarhus, Aarhus (Denmark)] (and others)

2010-04-20

208

Gyro Evaluation for the Mission to Jupiter  

Microsoft Academic Search

As an important component in NASA's new frontiers program, the Jupiter polar orbiter (Juno) mission is designed to investigate in-depth physical properties of Jupiter. It will include the giant planet's ice-rock core and atmospheric studies as well as exploration of its polar magnetosphere. It will also provide the opportunity to understand the origin of the Jovian magnetic field. Due to

Sergei A. Jerebets

2007-01-01

209

Jupiter's aurora  

NASA Astrophysics Data System (ADS)

Observations of Jupiter's auroral emissions and magnetospheric processes, radio emissions and generation mechanisms, early auroral observations, near-IR aurora, comparison of UV and IR aurora, X-ray and thermal aurora, HST UV images, Galileo visible images, interpreting observations of Jupiter's aurora, the Earth's aurora: present understanding, Jupiter's aurora: post-Voyager picture, correlations of Jupiter's aurora with the solar wind; The Io interaction and satellite magnetic footprint aurora: radio emissions, conditions near Io, Io's magnetic footprint, other satellites; Jupiter's main auroral oval: theoretical ideas of the origin of the main oval, estimates of field-aligned current densities from spacecraft magnetometer data, theoretical models; Jupiter's polar aurora: overview of polar emissions, distorted structure in the northern aurora, theory of the polar aurora.

Clarke, John T.; Grodent, Denis; Cowley, Stan W. H.; Bunce, Emma J.; Zarka, Philippe; Connerney, John E. P.; Satoh, Takehiko

210

New Horizons At Jupiter: Overview Of Results  

NASA Astrophysics Data System (ADS)

NASA's New Horizons spacecraft has provided new data on the Jupiter system, acquiring new perspectives of the giant planet's atmosphere, rings, moons and magnetosphere. These new views include the closest look yet at the Earth-sized "Little Red Spot" storm churning materials through Jupiter's cloud tops; detailed images of small satellites herding dust and boulders through Jupiter's faint rings; and of volcanic eruptions and circular mega- troughs on the planet's largest moons. New Horizons came to within 2.3 million kilometers of Jupiter on February 28 of this year, using the planet's gravity to trim three years from its travel time to Pluto. For several weeks before and after this closest approach, the spacecraft trained its seven instruments on Jupiter and its four largest moons, storing data from nearly 700 observations and gradually sending that information back to Earth. New Horizons completed its visit to the Jupiter system with its unprecedented flight down Jupiter's enormous magnetotail. The presentation will cover a number of Jupiter system studies - observations such as Jovian meteorology, studies of the great and little red spots, auroral studies, and magnetospheric sampling. Surface mapping, compositional mapping and atmospheric studies of Jupiter's largest moons are to be covered as well. A detailed report of the findings for the volcanic moon Io will be given in a companion presentation.

Moore, J. M.

2007-12-01

211

The effect of composition on the evolution of giant and intermediate-mass planets  

NASA Astrophysics Data System (ADS)

We model the evolution of planets with various masses and compositions. We investigate the effects of the composition and its depth dependence on the long-term evolution of the planets. The effects of opacity and stellar irradiation are also considered. It is shown that the change in radius due to various compositions can be significantly smaller than the change in radius caused by the opacity. Irradiation also affects the planetary contraction but is found to be less important than the opacity effects. We suggest that the mass-radius relationship used for characterization of observed extrasolar planets should be taken with great caution since different physical conditions can result in very different mass-radius relationships.

Vazan, A.; Kovetz, A.; Podolak, M.; Helled, R.

2013-10-01

212

Chaotic capture of Jupiter's Trojan asteroids in the early Solar System.  

PubMed

Jupiter's Trojans are asteroids that follow essentially the same orbit as Jupiter, but lead or trail the planet by an angular distance of approximately 60 degrees (co-orbital motion). They are hypothesized to be planetesimals that formed near Jupiter and were captured onto their current orbits while Jupiter was growing, possibly with the help of gas drag and/or collisions. This idea, however, cannot explain some basic properties of the Trojan population, in particular its broad orbital inclination distribution, which ranges up to approximately 40 degrees (ref. 8). Here we show that the Trojans could have formed in more distant regions and been subsequently captured into co-orbital motion with Jupiter during the time when the giant planets migrated by removing neighbouring planetesimals. The capture was possible during a short period of time, just after Jupiter and Saturn crossed their mutual 1:2 resonance, when the dynamics of the Trojan region were completely chaotic. Our simulations of this process satisfactorily reproduce the orbital distribution of the Trojans and their total mass. PMID:15917801

Morbidelli, A; Levison, H F; Tsiganis, K; Gomes, R

2005-05-26

213

Secondary Eclipse Observations of the Low-Mass Hot-Jupiter WASP-11b/HAT-P-10b  

NASA Astrophysics Data System (ADS)

WASP-11b/HAT-P-10b is a hot-Jupiter planet that orbits a K3 dwarf every 3.722 days at a distance of 0.0439 AU. Using the Spitzer Space Telescope in 2009 (Harrington, P.I.) and 2010 (Knutson, P.I), we observed five secondary eclipses of WASP-11b/HAT-P-10b: two in the 3.6-micron channel, two in the 4.5-micron channel, and one in the 8-micron channel. We present eclipse-depth measurements, estimates of infrared brightness temperatures, and the first constraints on the atmospheric pressure and temperature profile and chemical compositions. We also refine its orbit using our own secondary-eclipse measurements in combination with external radial-velocity and transit observations from both professional and amateur observers. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported in part by NASA Planetary Atmospheres grant NNX13AF38G.

Bowman, M. Oliver; Harrington, J.; Blecic, J.; Foster, A.; Stevenson, K. B.; Cubillos, P.; Collier Cameron, A.; UCF Exoplanets Group

2013-10-01

214

A nebula of gases from Io surrounding Jupiter.  

PubMed

Several planetary missions have reported the presence of substantial numbers of energetic ions and electrons surrounding Jupiter; relativistic electrons are observable up to several astronomical units (au) from the planet. A population of energetic (>30[?]keV) neutral particles also has been reported, but the instrumentation was not able to determine the mass or charge state of the particles, which were subsequently labelled energetic neutral atoms. Although images showing the presence of the trace element sodium were obtained, the source and identity of the neutral atoms---and their overall significance relative to the loss of charged particles from Jupiter's magnetosphere---were unknown. Here we report the discovery by the Cassini spacecraft of a fast (>103[?]km[?]s-1) and hot magnetospheric neutral wind extending more than 0.5[?]au from Jupiter, and the presence of energetic neutral atoms (both hot and cold) that have been accelerated by the electric field in the solar wind. We suggest that these atoms originate in volcanic gases from Io, undergo significant evolution through various electromagnetic interactions, escape Jupiter's magnetosphere and then populate the environment around the planet. Thus a 'nebula' is created that extends outwards over hundreds of jovian radii. PMID:11875559

Krimigis, Stamatios M; Mitchell, Donald G; Hamilton, Douglas C; Dandouras, Jannis; Armstrong, Thomas P; Bolton, Scott J; Cheng, Andrew F; Gloeckler, George; Hsieh, K C; Keath, Edwin P; Krupp, Norbert; Lagg, Andreas; Lanzerotti, Louis J; Livi, Stefano; Mauk, Barry H; McEntire, Richard W; Roelof, Edmond C; Wilken, Berend; Williams, Donald J

2002-02-28

215

The Influence of Giant Planets Near a Mean Motion Resonance on Earth-like Planets in the Habitable Zone of Sun-like Stars  

NASA Astrophysics Data System (ADS)

We present a numerical study of several two-planet systems based on the motions of Jupiter and Saturn, in which the two giant planets move in low eccentric orbits close to a mean motion resonance. It is more likely to find two planets with similar characteristics in a system than a clone of the Jupiter-Saturn pair of our solar system. Therefore, we vary the distance between the two planets and their mass ratio by changing Saturn's semimajor axis from 8 to 11 AU and increasing its mass by factors of 2-40. The different two-planets were analyzed for the interacting perturbations due to the mean motion resonances of the giant planets. We select several mass ratios for the gas giants, for which we study their influence on test bodies (with negligible mass) moving in the habitable zone (HZ) of a Sun-like star. The orbits are calculated for 2×107 yr. In all cases the HZ is dominated by a significant curved band, indicating higher eccentricity, which corresponds to a secular resonance with Jupiter. Interesting results of this study are finding (1) an increase of Venus's eccentricity for the real Jupiter and Saturn masses and the actual semimajor axis of Saturn; (2) an increase of the eccentricity of a test planet at Earth's position when Saturn's mass was increased by a factor of 3 or more; and (3) if the two giant planets are in 2:1 resonance, we observe a strong influence on the outer region of the HZ.

Pilat-Lohinger, E.; Süli, Á.; Robutel, P.; Freistetter, F.

2008-07-01

216

Horseshoe periodic orbits in the restricted problem of three bodies for a sun-Jupiter mass ratio  

NASA Astrophysics Data System (ADS)

Segments of seven families of symmetric horseshoe periodic orbits of the restricted three body problem for a sun-Jupiter mass ratio have been numerically determined. Each family is found to have a region consisting of smooth horseshoe shaped orbits with the family evolving to orbits acquiring loops on both sides of the smooth horseshoes. The general evolution of these families is discussed and one in particular (Rabe's horseshoe is a member of this family) is described in more detail with the aid of computer plots of orbits in this family. The smooth horseshoes do not continuously evolve along one family but are members of many distinct families. The change in shape of the smooth horseshoe orbits is examined as they have closer approaches to Jupiter. Each family has a bifurcation with an asymmetric family of periodic orbits. The initial conditions and other quantities describing these bifurcation orbits are given. Starting from these orbits the initial segments of the asymmetric families has been determined.

Taylor, D. B.

1981-11-01

217

Volatiles in Terrestrial Planets Orbiting Within Habitable Zones of Low-Mass Stars  

NASA Astrophysics Data System (ADS)

Dynamical considerations derived from analytic calculations and numerical experiments imply that Earth-mass planets that accrete in regions that become habitable zones of M dwarf stars form within several million years. Temperatures in these regions during planetary accretion are higher than those encountered by the material that formed the Earth. Collision velocities during and after the prime planetary accretionary epoch are larger than for Earth. These factors suggest that planets orbiting low mass main sequence stars are likely to be either too distant (and thus too cold) for carbon/water based life on their surfaces or have abundances of the volatiles required life that are substantially less than those of Earth.

Lissauer, J. J.

2009-12-01

218

Periodicities in Jupiter's magnetotail  

NASA Astrophysics Data System (ADS)

The New Horizons spacecraft had a close flyby of Jupiter in 2007. The Pluto energetic particle spectrometer science investigation (PEPSSI) made measurements beginning early in the same year. It obtained data as the spacecraft flew inward through closest approach and out down Jupiter's magnetotail. Measurements of ions and electrons were obtained to tail distances of over 1 AU. General surveys of electron data from PEPSSI revealed increases in intensity at approximately the spin period of the planet. These periodic variations were obtained well down the tail. It is not completely understood whether there is a periodic source of particles that remain coherent to large distances or whether the planet's period is somehow communicated down the tail. In this work, we will discuss the PEPSSI data by species to study the periodicities in the data and to constrain the source of these phenomena. In the past, other spacecraft data have revealed multiple periodicities much closer to the planet. These have been associated with both the planet's rotation and the periodic release of plasma down the tail.

Paranicas, C.; Haggerty, D. K.; Khurana, K. K.; Bagenal, F.

2011-12-01

219

Revisiting the eccentricities of hot Jupiters  

NASA Astrophysics Data System (ADS)

Most short period transiting exoplanets have circular orbits, as expected from an estimation of the circularisation timescale using classical tidal theory. Interestingly, a small number of short period transiting exoplanets seem to have orbits with a small eccentricity. Such systems are valuable as they may indicate that some key physics is missing from formation and evolution models. We have analysed the results of a campaign of radial velocity measurements of known transiting planets with the SOPHIE and HARPS spectrographs using Bayesian methods and obtained new constraints on the orbital elements of 12 known transiting exoplanets. We also reanalysed the radial velocity data for another 42 transiting systems and show that some of the eccentric orbits reported in the Literature are compatible with a circular orbit. As a result, we show that the systems with circular and eccentric orbits are clearly separated on a plot of the planetary mass versus orbital period. We also show that planets following the trend where heavier hot Jupiters have shorter orbital periods (the ``mass-period relation'' of hot Jupiters), also tend to have circular orbits, with no confirmed exception to this rule so far.

Husnoo, Nawal; Pont, Frédéric; Mazeh, Tsevi; Fabrycky, Daniel; Hébrard, Guillaume; Moutou, Claire

2011-11-01

220

Magnetosphere-Ionosphere Current Systems at Jupiter and Saturn  

NASA Astrophysics Data System (ADS)

Jupiter and Saturn are both rapidly rotating planets with plasma sources inside their magnetospheres. However, Jupiter's main auroral emission is magnetically conjugate with equatorial radii from ~20 - 30 RJ, well inside the magnetopause, whilst Saturn's main auroral emission is magnetically conjugate with the outer magnetosphere. We compare limitations to magnetosphere-ionosphere coupling at both planets.

Ray, L. C.

2012-09-01

221

Young Solar System's Fifth Giant Planet?  

NASA Astrophysics Data System (ADS)

Studies of solar system formation suggest that the solar system's giant planets formed and migrated in the protoplanetary disk to reach the resonant orbits with all planets inside ~15 AU from the Sun. After the gas disk's dispersal, Uranus and Neptune were likely scattered by the gas giants, and approached their current orbits while dispersing the transplanetary disk of planetesimals, whose remains survived to this time in the region known as the Kuiper Belt. Here we performed N-body integrations of the scattering phase between giant planets in an attempt to determine which initial states are plausible. We found that the dynamical simulations starting with a resonant system of four giant planets have a low success rate in matching the present orbits of giant planets and various other constraints (e.g., survival of the terrestrial planets). The dynamical evolution is typically too violent, if Jupiter and Saturn start in the 3:2 resonance, and leads to final systems with fewer than four planets. Several initial states stand out in that they show a relatively large likelihood of success in matching the constraints. Some of the statistically best results were obtained when assuming that the solar system initially had five giant planets and one ice giant, with the mass comparable to that of Uranus and Neptune, and which was ejected to interstellar space by Jupiter. This possibility appears to be conceivable in view of the recent discovery of a large number of free-floating planets in interstellar space, which indicates that planet ejection should be common.

Nesvorný, David

2011-12-01

222

Thermosphere and exosphere of hot Jupiters  

NASA Astrophysics Data System (ADS)

Here we describe the observations and the resulting constraints on the upper atmosphere (thermosphere and exosphere) of hot Jupiters. In particular, observations and theoretical modeling of hot-Jupiter evaporation are described. The observations allowed the discovery that the planet orbiting HD209458 has an extended atmosphere of escaping hydrogen and showed the presence of oxygen and carbon at very high altitude. These observations give unique constraints on the escape rate and mechanism in the atmosphere of these planets. The most recent Lyman-alpha HST observations of HD189733b allow for the first time to compare the evaporation from two different planets in different environments. We present models to quantify the escape rate from the measured occultation depths, and an energy diagram to describe the evaporation state of hot Jupiters. Using this diagram, it is shown that few already known planets could be remnants of former giant planets.

Lecavelier des Etangs, Alain

2009-02-01

223

Magnetic activity of planet-hosting stars  

NASA Astrophysics Data System (ADS)

Magnetic activity in cool stars is a widely observed phenomenon, however it is still far from being understood. How fundamental stellar parameters like mass and rotational period quantitatively cause a stellar magnetic field which manifests itself in features such as spots, flares and high-energy coronal emission is a lively area of research in solar and stellar astrophysics. Especially for planet-hosting stars, stellar activity profiles are very interesting as exoplanets are affected by high-energy radiation, both at the time of planet formation as well as during the further lifetime of a star-planet system. In extreme cases, the atmosphere of a planet very close to its host star can be strongly heated by the stellar X-ray and EUV emission and finally escape the planet's gravitational attraction, so that the atmosphere of the planet evaporates over time. Theoretically, planets can also affect their host star's magnetic activity. In analogy to processes in binary stars which lead to enhanced - both overall and periodically varying - activity levels, also giant planets might influence the stellar activity by tidal or magnetic interaction processes, however on a weaker level than in binaries. Some indications for such interactions exist from chromospheric measurements in stars with Hot Jupiters. In this thesis I investigate the magnetic activity of planet-hosting stars and especially possible effects from star-planet interactions with an emphasis on stellar coronae in X-rays. I tested a complete sample of all known planet-hosting stars within 30 pc distance from the Sun for correlations of stellar X-ray properties with planetary parameters. A significant correlation exists between the stellar X-ray luminosity and the product of planetary mass and inverse semimajor axis. However, this could be traced back to a selection effect introduced by planetary detection methods. For stars in the solar neighborhood, planets are mainly detected by radial velocity shifts in the stellar spectra. This detection method introduces several trends in samples of planet-hosting stars which are investigated in detail in this thesis. On top of these selection effects, no significant other correlations which could be interpreted as manifestations of star-planet interactions were present in the sample. I also monitored the chromospheric and coronal activity of a promising individual star-planet system over several months. This system consists of upsilon Andromedae, a cool main-sequence star, a Hot Jupiter and three more planets in wider orbits. Contrary to earlier findings by other authors, the star did not show planet-induced activity variations, but displayed variability with the stellar rotation period instead. The star 51 Pegasi also hosts a Hot Jupiter; actually, it is the first exoplanet which was ever detected. In a detailed analysis of this star's coronal emission, I show that the star is in a Maunder minimum state, characterized by a very low coronal temperature of less than one million degrees and a persistent low activity level in coronal and chromospheric emission over sixteen years. The Hot Jupiter apparently does not enhance stellar activity in this system. I also present an analysis of the planet-hosting star tau Bootis, for which indications for a very short activity cycle of only one year duration have been published recently. The star rotates quickly compared to other stars of the same age, which might be due to a "spin-up" caused by its giant planet. My X-ray data that is available up to now suggests that a possible activity cycle is longer than thought so far; however, more data will be collected in 2011 and 2012 to allow a more detailed insight into this star's ac! tivity.

Poppenhaeger, Katja

2011-05-01

224

Kepler Planets: A Tale of Evaporation  

NASA Astrophysics Data System (ADS)

Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ~0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R ?. Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ~0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above 20 M ? and the majority of them should have core masses of a few Earth masses.

Owen, James E.; Wu, Yanqin

2013-10-01

225

The occurrence of Jovian planets and the habitability of planetary systems.  

PubMed

Planets of mass comparable to or larger than Jupiter's have been detected around over 50 stars, and for one such object a definitive test of its nature as a gas giant has been accomplished with data from an observed planetary transit. By virtue of their strong gravitational pull, giant planets define the dynamical and collisional environment within which terrestrial planets form. In our solar system, the position and timing of the formation of Jupiter determined the amount and source of the volatiles from which Earth's oceans and the source elements for life were derived. This paper reviews and brings together diverse observational and modeling results to infer the frequency and distribution of giant planets around solar-type stars and to assess implications for the habitability of terrestrial planets. PMID:11158551

Lunine, J

2001-01-30

226

Chaotic capture of Jupiter's Trojan asteroids in the early SolarSystem  

Microsoft Academic Search

Jupiter's Trojans are asteroids that follow essentially the same orbit as Jupiter, but lead or trail the planet by an angular distance of ~60 degrees (co-orbital motion). They are hypothesized to be planetesimals that formed near Jupiter and were captured onto their current orbits while Jupiter was growing, possibly with the help of gas drag and\\/or collisions. This idea, however,

A. Morbidelli; H. F. Levison; K. Tsiganis; R. Gomes

2005-01-01

227

Formation of planets around stars of various masses. I - Formulation and a star of one solar mass  

NASA Astrophysics Data System (ADS)

The processes of planet formation are investigated both in a gaseous nebula and after the gaseous nebula has been blown away. It is shown that a protoplanet of mass more than about 100 times the representative mass of the planetesimal rapidly captures the planetesimals whose orbital semimajor axes are near its own. Therefore the growth of the protoplanet is determined by the migration rate of planetesimals to the region where they can be captured. The growth and capture of planetesimals is investigated and the time of planet formation is determined as a function of distance from the central star. As an example, planet formation around a star of 1 solar mass is investigated. The earth is found to form at t of about 2 x 10 to the 6th yr in the gaseous nebula. The protoplanets at Jovian and Saturnian orbits grow to 10 times the earth mass at 2 x 10 to the 7th yr and 5 x 10 to the 7th yr, respectively, in the gaseous nebula. Therefore they can capture large amounts of gas and grow to giant planets as long as the gaseous nebula survives for 5 x 10 to the 7th yr in these regions. The formation time of Neptune in a gas-free state is found to be 3 x 10 to the 9th yr, which is shorter than the age of the solar system.

Nakano, T.

1987-01-01

228

Outer Planet Flagship Mission  

Microsoft Academic Search

Studies for Outer Planet Missions have been ongoing for many years, but in 2007 NASA commissioned four specific studies to be considered for further examination; the Europa Explorer, Titan Explorer, Enceladus Mission and Jupiter Science Orbiter. During the same time frame ESA invited Outer Planet proposals under the Cosmic Vision call. Two were submitted, TandEm and LaPlace, which focused on

James Cutts; C. Niebur; L. Dudzinski; M. Coradini; J. Lebreton

2008-01-01

229

Outer Planet Flagship Missions  

Microsoft Academic Search

Studies for Outer Planet Missions have been ongoing for many years, but in 2007 NASA commissioned four specific studies to be considered for further examination; the Europa Explorer, Titan Explorer, Enceladus Mission and Jupiter Science Orbiter. During the same time frame ESA invited Outer Planet proposals under the Cosmic Vision call. Two were submitted, TandEM and LaPlace, which focused on

C. Niebur; L. Dudzinski; M. Coradini; J. Lebreton; J. A. Cutts

2008-01-01

230

Classifying Planets: Nature vs. Nurture  

NASA Astrophysics Data System (ADS)

The idea of a planet was so simple when we learned about the solar system in elementary school. Now students and professional s alike are faced with confusing array of definitions --- from "Brown Dwarfs” to "Super Jupiters", from "Super Earths” to "Terrestrial Planets", and from "Planets” to "Small, Sort-of Round Things That Aren't Really Planets". I will discuss how planets might be defined by how they formed, where they are found, or by the life they might support.

Beichman, Charles A.

2009-05-01

231

Planetary Systems: Crossing the Jupiter Threshold  

NASA Astrophysics Data System (ADS)

We describe stellar Doppler measurements with a precision of 3 m s() -1, cabable of detecting extra-solar planets having masses less than one Jupiter-mass. No planetary systems around main sequence stars have yet been detected, nor does there exist a compelling detection of a brown dwarf, as a stellar companion or otherwise. Several groups are engaged in detecting planetary systems by using precise radial velocities to detect the wobble of the host star (cf. Campbell and Walker, 1988, ApJ,331,902 ; Cochran and Hatzes (1994, in ``Planetary Systems: Formation, Evolution, and Detection'', Kluwer Acad.). Among current search efforts, the Lick Observatory Planetary Search is extensive in both sample size and span of spectra types (Marcy and Butler, 1992, PASP,104,270). The project consists of a Doppler survey of 100 main sequence stars of spectral type, F, G, K, and M. The Lick Obs. full--format echelle gathers all Doppler information from 5000 to 5800 Ang. The wavelength calibration is accomplished with a gaseous iodine absorption cell placed at the slit of the Hamilton spectrometer which superimposes sharp I_2 lines on the stellar spectrum. The I_2 lines also provide the PSF of the spectrometer. A great breakthrough has occurred in the Doppler precision as a result of the improved Schmidt camera on the Hamilton. The Lick echelle now boasts a PSF with FWHM = 1.25 pixels for a narrow (0.3 arcsec) slit. The Doppler precision achieved is 3 m s() -1, based on velocity scatter during the past 5 months in our standard star, tau Ceti (G8V) . The velocities exhibit a standard deviation of 4 m s() -1 per exposure. However, we routinely obtain 4 quick exposures of the brightest target stars on our survey and average the 4 velocities. Such averaging for tau Ceti velocities yields a scatter of 3 m s() -1 due to errors in our Doppler measurements. For comparison, our Jupiter perturbs the Sun by 12.5 m s() -1 rendering Jupiter--like planets detectable at the 4--sigma level, even for typical orbital inclinations. We also report no detections of Jupiter-like planets for 30 main sequence stars, based on 7 years of past Doppler measurements at lower precision of 10 m s() -1. We expect to achieve precision of ~ 2 m s() -1 by improving the Doppler Analysis.

Marcy, G. W.; Butler, R. P.

1995-05-01

232

Influence of trans-neptunian objects on motion of major planets and limitation on the total TNO mass from planet and spacecraft ranging  

NASA Astrophysics Data System (ADS)

Perturbations from asteroids and Trans-Neptunian Objects affect significantly on the orbits of planets and should be taken into account when high-accuracy planetary ephemerides are constructed. On the other hand, from an analysis of motion of the major planets by processing of precise measurements of spacecraft a limitation on the total TNO mass may be obtained. To estimate influence of TNO on motion of planets the largest 21 TNO have been included into the process of simultaneous numerical integration, and positions of planets obtained with taking for TNO have been compared with positions of planets of numerical EPM ephemeris of IAA RAS constructed without these objects. The perturbations of other TNO have been modeled by the perturbation from a circular ring having a radius 43 AU and different masses. It has been shown that all the test masses of the TNO ring except the minimum mass (5.26?10-8M?) are too large and make the data residuals worse. Thus, the upper limit of the total mass of all TNO including Pluto, the 21 largest TNO and the TNO ring (with the 43 AU radius) should not exceed 8.04?10-8M?.

Pitjeva, E. V.

233

The Jupiter Ganymede Orbiter : An ESA Contribution to the Europa-Jupiter System Mission  

Microsoft Academic Search

In the framework of an outer planets mission, under study after the NASA-Juno mission, the Europa-Jupiter System Mission (EJSM) would combine a fleet of up to three satellites in order to investigate in depth many questions related to the Jupiter System. These investigations are essential for our understanding of the emergence and evolution of habitable worlds, not only within the

Pierre Drossart; M. Blanc; J. P. Lebreton; R. T. Pappalardo; R. Greeley; M. Fujimoto

2008-01-01

234

An Infrared Precision Radial Velocity Search for Earth-Mass Planets  

NASA Astrophysics Data System (ADS)

We discuss the scientific motivation and design of the Precision Radial Velocity Spectrograph (PRVS), a potential next generation near-infrared instrument for the Gemini Observatory. PRVS is a fiber-fed, white-pupil, cooled echelle (R=70,000) spectrograph working in the Y, J and H bands. Using a simultaneous arc-line calibration method, long-term instrumental radial velocity precisions of less than 1 m/s can be achieved. Through modelling and simulation of the fundamental Doppler information in the spectra of stars, considerations of intrinsic stellar stability, and the effects of telluric contamination, we conclude that the best place to search for earth-mass planets in the habitable zone using their radial velocity signatures is around mid- to late-M dwarf stars at wavelengths of 1-2 microns. Mock surveys show that PRVS can survey several hundred stars for planets in the range 1-10 earth-mass over a period of five years and provide an important test of planet formation models. We also compare the observing niche of PRVS with other techniques proposed to search for earth-mass planets.

Rayner, John; PRVS Team

2007-05-01

235

The phase-dependent infrared brightness of the extrasolar planet upsilon Andromedae b.  

PubMed

The star upsilon Andromedae is orbited by three known planets, the innermost of which has an orbital period of 4.617 days and a mass at least 0.69 that of Jupiter. This planet is close enough to its host star that the radiation it absorbs overwhelms its internal heat losses. Here, we present the 24-micrometer light curve of this system, obtained with the Spitzer Space Telescope. It shows a variation in phase with the orbital motion of the innermost planet, demonstrating that such planets possess distinct hot substellar (day) and cold antistellar (night) faces. PMID:17038587

Harrington, Joseph; Hansen, Brad M; Luszcz, Statia H; Seager, Sara; Deming, Drake; Menou, Kristen; Cho, James Y-K; Richardson, L Jeremy

2006-10-12

236

Chemistry of planet formation  

NASA Astrophysics Data System (ADS)

This thesis explores how the chemical environment in which planets develop influences planet formation. The total solid mass, gas/solid ratio, and specific ice inventory of protoplanetary disks can dramatically alter the planet's formation timescale, core/atmosphere mass ratio, and atmosphere composition. We present the results of three projects that probe the links between solar nebula composition and giant planet formation. The first project offers evidence that stars with planets exhibit statistically significant silicon and nickel enrichment over the general metal-rich population. To test whether this prediction is compatible with the core accretion theory of planet formation, we construct new numerical simulations of planet formation by core accretion that establish the timescale on which a planet forming at 5 AU reaches rapid gas accretion, t rga , as a function of solid surface density s solid : ( t rga /1 Myr) = (s solid /25.0 g cm -2 ) - 1.44 . This relation enables us to construct Monte Carlo simulations that predict the fraction of star-disk systems that form planets as a function of [Fe/H], [Si/Fe], disk mass, outer disk radius and disk lifetime. Our simulations reproduce both the known planet-metallicity correlation and the planet-silicon correlation reported in this paper. The simulations predict that 15% of Solar-type stars form Jupiter-mass planets, in agreement with 12% predicted from extrapolation of the observed planet frequency-semimajor axis distribution. Despite the success of our Monte Carlo simulation of the planet-silicon correlation at predicting the properties of extrasolar Jovian planets, there is still no in situ core accretion simulation that can successfully account for the formation of Saturn, Uranus or Neptune within the observed 2-3 Myr lifetimes of protoplanetary disks. Since solid accretion rate is directly proportional to the available planetesimal surface density, one way to speed up planet formation is to take a full inventory of all the solids present in the solar nebula. In Project 2 (Chapter 3) we combine a viscously evolving protostellar disk with a kinetic model of ice formation, which includes not just water but methane, ammonia, CO and 54 minor ices. We use this combined dynamical+chemical simulation to calculate the planetesimal composition and solid surface density in the solar nebula as a function of heliocentric distance and time. We find three effects that strongly favor giant planet formation: (1) a decretion flow that brings mass from the inner solar nebula to the giant planet-forming region, (2) recent lab results (Collings et al. 2004) showing that the ammonia and water ice lines should coincide, and (3) the presence of a substantial amount of methane ice in the trans-Saturnian region. Our results show higher solid surface densities than assumed in the core accretion models of Pollack et al. (1996) by a factor of 3-4 throughout the trans-Saturnian region. We also discuss the location of ice lines and their movement through the solar nebula, and provide new constraints on the possible initial disk configurations from gravitational stability arguments. Finally, we present a core accretion simulation of Saturn with a planet formation timescale of 3.37 Myr, consistent with observed protostellar disk lifetimes. The protostellar disk model underlying this simulation is also capable of forming Jupiter within 2.5 Myr. We observe a new manifestation of the core accretion theory, in which Saturn's solid core does not reach isolation mass, and argue that this paradigm should apply to Uranus and Neptune as well. The planet formation timescale is then governed primarily by the solid accretion rate instead of the gas contraction efficiency. Our model predicts a core mass of 44 M (+) for Saturn, heavier than inferred from observations by a factor of at least 2. We discuss possible mechanisms for reducing the core size without slowing down formation and comment on the similarity between our core- heavy Saturn model and the exoplanet HD 149026 b .

Robinson, Sarah Elaine

2008-02-01

237

A Search for Water and Methane on a Neptune-Mass Transiting Planet  

NASA Astrophysics Data System (ADS)

GJ 436b is the only known Neptune-mass transiting exoplanet. Like Neptune, more than 80% of the mass is ice and rock, surrounded by a thin H/He envelope of only 1-3 earth masses. The similarities end there, however, as GJ 436b orbits a mere 0.03 A.U. from its M dwarf primary and has a toasty 700 K atmosphere. Although it is much warmer than the gas giant planets in the solar system, GJ 436b is the coolest transiting planet discovered to date. As a result, we expect most of the carbon in GJ 436b's atmosphere to exist in the form of methane instead of the carbon monoxide found in the atmospheres of the hotter, more massive transiting planets. We propose to test this prediction by searching for the signature of water and methane absorption in this unusual planet's atmosphere as seen in the wavelength dependence of the transit depth from 1.4-2.5 micron. This wavelength range includes strong absorption bands from both water and methane, and will also allow us to place limits on the presence of clouds and atmospheric hazes if present. Using the technique of transit timing, these observations {which span four transits} will also allow us to search for additional planetary companions with masses as small as that of Mars. A second planet would provide a natural explanation for GJ 436b's ability to maintain a significant orbital eccentricity, despite the fact that the circularization time scale for this system is significantly shorter than its current age.;

Knutson, Heather

2008-07-01

238

Practical SPH models for major planets  

NASA Astrophysics Data System (ADS)

Modelling planets is done for two main reasons - the first to further understanding of their internal structure and the second to provide models to explore astrophysical situations in which planets play a role. For the latter reason, the requirements on accuracy are less severe, although the planet must be realistic in its major features. A numerical model of a layered giant planet is developed with an iron core, a silicate mantle, an ice region and a hydrogen-helium atmosphere. The Tillotson equation of state is used and examples of two model planets are given, one reproducing the mass and radius of Jupiter quite closely and the other with two Jupiter masses. Transferring these results into a smoothed particle hydrodynamics (SPH) model presents two main difficulties. A uniform distribution of SPH points leads to too few points representing the non-atmospheric component. It is shown that using a distorted lattice enables the core + silicate + ice to be represented by several hundred points so that the evolution of these regions can be followed in detail. Another difficulty concerns the density discontinuities attendant on a layered structure. Density estimates of SPH points are either too large or too small near material interfaces leading to unrealistic pressure gradients and, consequently, to large and unphysical local forces. Algorithms are described for avoiding this difficulty both at material interfaces and near the surface of the planet. In some astrophysical situations involving SPH-modelled planets, the main bulk of the planet is so opaque that internal heat transfer can be neglected. However, surface regions should radiate and a convenient way for including radiation from a planetary surface is described.

Woolfson, M. M.

2007-04-01

239

AN ULTRACOOL STAR'S CANDIDATE PLANET  

SciTech Connect

We report here the discovery of the first planet around an ultracool dwarf star. It is also the first extrasolar giant planet astrometrically discovered around a main-sequence star. The statistical significance of the detection is shown in two ways. First, there is a 2 x 10{sup -8} probability that the astrometric motion fits a parallax-and-proper-motion-only model. Second, periodogram analysis shows a false alarm probability of 3 x 10{sup -5} that the discovered period is randomly generated. The planetary mass is M {sub 2} = 6.4 (+2.6,-3.1) Jupiter-masses (M {sub J}), and the orbital period is P = 0.744 (+0.013,-0.008) yr in the most likely model. In less likely models, companion masses that are higher than the 13 M {sub J} planetary mass limit are ruled out by past radial velocity (RV) measurements unless the system RV is more than twice the current upper limits and the near-periastron orbital phase was never observed. This new planetary system is remarkable, in part, because its star, VB 10, is near the lower mass limit for a star. Our astrometric observations provide a dynamical mass measurement and will in time allow us to confront the theoretical models of formation and evolution of such systems and their members. We thus add to the diversity of planetary systems and to the small number of known M-dwarf planets. Planets such as VB 10b could be the most numerous type of planets because M stars comprise >70% of all stars. To date they have remained hidden since the dominant RV planet-discovery technique is relatively insensitive to these dim, red systems.

Pravdo, Steven H. [Jet Propulsion Laboratory, California Institute of Technology, 306-431, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Shaklan, Stuart B. [Jet Propulsion Laboratory, California Institute of Technology, 301-451, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)], E-mail: spravdo@jpl.nasa.gov, E-mail: stuart.shaklan@jpl.nasa.gov

2009-07-20

240

The Extrasolar Planet ? Eridani b Orbit and Mass  

Microsoft Academic Search

Hubble Space Telescope (HST) Fine Guidance Sensor astrometric observations of the nearby (3.22 pc), K2 V star epsilon Eridani have been combined with ground-based astrometric and radial velocity data to determine the mass of its known companion. We model astrometric and radial velocity measurements simultaneously to obtain the parallax, proper motion, perturbation period, perturbation inclination, and perturbation size. Due to

George F. Benedict; Barbara E. McArthur; George Gatewood; Edmund Nelan; William D. Cochran; Artie Hatzes; Michael Endl; Robert Wittenmyer; Sallie L. Baliunas; Gordon A. H. Walker; Stephenson Yang; Martin Kürster; Sebastian Els; Diane B. Paulson

2006-01-01

241

DID FOMALHAUT, HR 8799, AND HL TAURI FORM PLANETS VIA THE GRAVITATIONAL INSTABILITY? PLACING LIMITS ON THE REQUIRED DISK MASSES  

SciTech Connect

Disk fragmentation resulting from the gravitational instability has been proposed as an efficient mechanism for forming giant planets. We use the planet Fomalhaut b, the triple-planetary system HR 8799, and the potential protoplanet associated with HL Tau to test the viability of this mechanism. We choose the above systems since they harbor planets with masses and orbital characteristics favored by the fragmentation mechanism. We do not claim that these planets must have formed as the result of fragmentation, rather the reverse: if planets can form from disk fragmentation, then these systems are consistent with what we should expect to see. We use the orbital characteristics of these recently discovered planets, along with a new technique to more accurately determine the disk cooling times, to place both lower and upper limits on the disk surface density-and thus mass-required to form these objects by disk fragmentation. Our cooling times are over an order of magnitude shorter than those of Rafikov, which makes disk fragmentation more feasible for these objects. We find that the required mass interior to the planet's orbital radius is {approx}0.1 M{sub sun} for Fomalhaut b, the protoplanet orbiting HL Tau, and the outermost planet of HR 8799. The two inner planets of HR 8799 probably could not have formed in situ by disk fragmentation.

Nero, D.; Bjorkman, J. E. [Ritter Observatory, MS 113, Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606-3390 (United States)], E-mail: dnero@physics.utoledo.edu

2009-09-10

242

Photometric Follow-Up Observations of the Transiting Neptune-Mass Planet GJ 436b  

NASA Astrophysics Data System (ADS)

This paper presents multiband photometric follow-up observations of the Neptune-mass transiting planet GJ 436b, consisting of five new ground-based transit light curves obtained in 2007 May. Together with one already published light curve, we have at hand a total of six light curves, spanning 29 days. The analysis of the data yields an orbital period P = 2.64386 ± 0.00003 days, midtransit time Tc [HJD] = 2454235.8355 ± 0.0001, planet mass Mp = 23.1 ± 0.9 M ? = 0.073 ± 0.003 M Jup, planet radius Rp = 4.2 ± 0.2 R ? = 0.37 ± 0.01 R Jup, and stellar radius Rs = 0.45 ± 0.02 R sun. Our typical precision for the midtransit timing for each transit is about 30 s. We searched the data for a possible signature of a second planet in the system through transit timing variations (TTV) and variation of the impact parameter. The analysis could not rule out a small, of the order of a minute, TTV and a long-term modulation of the impact parameter, of the order of +0.2 yr-1.

Shporer, Avi; Mazeh, Tsevi; Pont, Frederic; Winn, Joshua N.; Holman, Matthew J.; Latham, David W.; Esquerdo, Gilbert A.

2009-04-01

243

A Framework for Characterizing the Atmospheres of Low-mass Low-density Transiting Planets  

NASA Astrophysics Data System (ADS)

We perform modeling investigations to aid in understanding the atmospheres and composition of small planets of ~2-4 Earth radii, which are now known to be common in our Galaxy. GJ 1214b is a well-studied example whose atmospheric transmission spectrum has been observed by many investigators. Here we take a step back from GJ 1214b to investigate the role that planetary mass, composition, and temperature play in impacting the transmission spectra of these low-mass low-density (LMLD) planets. Under the assumption that these planets accrete modest hydrogen-dominated atmospheres and planetesimals, we use population synthesis models to show that predicted metal enrichments of the H/He envelope are high, with metal mass fraction Z env values commonly 0.6-0.9, or ~100-400+ times solar. The high mean molecular weight of such atmospheres (? ? 5-12) would naturally help to flatten the transmission spectrum of most LMLD planets. The high metal abundance would also provide significant condensible material for cloud formation. It is known that the H/He abundance in Uranus and Neptune decreases with depth, and we show that atmospheric evaporation of LMLD planets could expose atmospheric layers with gradually higher Z env. However, values of Z env close to solar composition can also arise, so diversity should be expected. Photochemically produced hazes, potentially due to methane photolysis, are another possibility for obscuring transmission spectra. Such hazes may not form above T eq of ~800-1100 K, which is testable if such warm, otherwise low mean molecular weight atmospheres are stable against atmospheric evaporation. We find that available transmission data are consistent with relatively high mean molecular weight atmospheres for GJ 1214b and "warm Neptune" GJ 436b. We examine future prospects for characterizing GJ 1214b with Hubble and the James Webb Space Telescope.

Fortney, Jonathan J.; Mordasini, Christoph; Nettelmann, Nadine; Kempton, Eliza M.-R.; Greene, Thomas P.; Zahnle, Kevin

2013-09-01

244

A Strange New Planet  

NSDL National Science Digital Library

Scientists have been looking for extra-solar planets for decades, but only recently, with better equipment and improved techniques, have they finally unveiled new and unusual planets. Since 1995, over 155 planets have been discovered orbiting stars other than our Sun. This video segment, adapted from a NOVA television broadcast, gives an account of the discovery of the first confirmed extra-solar planet, a Jupiter-sized giant orbiting the star 51 Pegasi, and discusses the search for other extra-solar planets. The segment is three minutes nine seconds in length.

2011-05-05

245

A Strange New Planet  

NSDL National Science Digital Library

Scientists have been looking for extra-solar planets for decades, but only recently, with better equipment and improved techniques, have they finally unveiled new and unusual planets. Since 1995, over 155 planets have been discovered orbiting stars other than our Sun. This video segment, adapted from a NOVA television broadcast, gives an account of the discovery of the first confirmed extra-solar planet, a Jupiter-sized giant orbiting the star 51 Pegasi, and discusses the search for other extra-solar planets. The segment is three minutes nine seconds in length.

246

Jupiter: Internal Dynamics and Shape  

NASA Astrophysics Data System (ADS)

The physical shape of a giant planet reveals important information about its rotation and internal structure. We investigate how differential rotation on cylinders affects Jupiter's shape. We project Jupiter's measured zonal wind velocities along cylinders to describe its centrifugal potential which is then used to derive Jupiter's shape using an equipotential surface theory. The derived shape for different cylindrical radii is then compared with Jupiter's shape from radio occultation measurements. It is found that both solid-body rotation (System III rotation rate) and differential rotation up to a latitude of ~ 20-30 degrees are consistent with Jupiter's measured shape. We next use a first-order theory that relates the second gravitational coefficient J_2 to the flattening to calculate the corrections to J_2 for the different rotational configurations. We find that the contribution of the flattening to J_2 is significant. We therefore suggest that interior models of the giant planets must account for J_2n corrections caused by both shape (flattening) and internal dynamics.

Helled, R.; Schubert, G.; Anderson, J. D.

2011-12-01

247

Extrasolar Carbon Planets  

Microsoft Academic Search

We suggest that some extrasolar planets <~ 60 Earth masses will form substantially from silicon carbide and other carbon compounds. Pulsar planets and low-mass white dwarf planets are especially good candidate members of this new class of planets, but these objects could also conceivably form around stars like the Sun. This planet-formation pathway requires only a factor of two local

Marc J. Kuchner; S. Seager

2005-01-01

248

Formation of Large Regular Satellites of Giant Planets in an Extended Gaseous Nebula: Subnebula Model and Accretion of Satellites  

NASA Astrophysics Data System (ADS)

We model the subnebulae of Jupiter and Saturn wherein satellite accretion took place. We expect a giant planet subnebula to be composed of an optically thick (given gaseous opacity) inner region inside of the planet's centrifugal radius (located at r(sub c, sup J) = l5RJ for Jupiter and r(sub c, sup S) = 22RS for Saturn), and an optically thin, extended outer disk out to a fraction of the planet's Roche lobe, which we choose to be Rroche/5 (located at approximately 150RJ near the inner irregular satellites for Jupiter, and approximately 200RS near Phoebe for Saturn). This places Titan and Ganymede in the inner disk, Callisto and Iapetus in the outer disk, and Hyperion in the transition region. The inner disk is the leftover of the gas accreted by the protoplanet. The outer disk results from the solar torque on nebula gas flowing into the protoplanet during the time of giant planet gap opening. For the sake of specificity, we use a cosmic mixture 'minimum mass' model to constrain the gas densities of the inner disks of Jupiter and Saturn (and also Uranus). For the total mass of the outer disk we use the simple scaling Mdisk = MPtaugap/tauacc, where MP is the mass of the giant planet, taugap is the gap opening timescale, and tauacc is the giant planet accretion time. This gives a total outer disk mass of approximately 100MCallisto for Jupiter and possibly approximately 200MIapetus for Saturn (which contain enough condensables to form Callisto and Iapetus respectively). Our model has Ganymede at a subnebula temperature of approximately 250 K and Titan at approximately 100 K. The outer disks of Jupiter and Saturn have constant temperatures of 130 K and 90 K respectively.

Mosqueira, I.; Estrada, P. R.

2000-01-01

249

Auroral ultraviolet darkening on the outer planets  

SciTech Connect

The Voyager 2 Photopolarimeter Subsystem (PPS) has made photometric observations of Jupiter at 2400 A and photometric and polarimetric observations of Saturn and Uranus at 2650 A. At these wavelengths the instrument is observing each planet's stratosphere and upper troposphere. The most striking features are that both poles of Jupiter and the observed northern pole of Saturn are very dark, while Uranus has a uniformly bright appearance. All three planets show evidence for a stratospheric haze. Simple vertically homogeneous multiple scattering models are used to characterize these stratospheric hazes. Aurores occur at high latitudes on Jupiter and Saturn and at low latitudes on Uranus. The asymmetric polar darkening on Jupiter seen by PPS is roughly matched by the asymmetry in the auroral zones. Historical data suggest that the haze asymmetry is persistent. The dark north polar cap seen by PPS at Saturn is small and close to the pole, which corresponds to the small auroral zone close to the pole. A model is examined which attributes the darkening to auroral bombardment initiating methane chemistry that makes dark hydrocarbon particles. Possible chemical pathways are discussed, and mass balance calculations are presented for Jupiter, Saturn, and Uranus. The model is quantitatively plausible for Jupiter and Saturn. The lack of localized darkening on Uranus can be explained in this model by noting that weak vertical mixing and methane condensation near the 1-bar level lead to negligible methane abundances at auroral altitudes. The auroras must reach the methane for dark material to form. The thin haze that is seen on Uranus is ascribed to photochemical processes. Voyager 2 will reach Neptune this year. Ground-based observers have reported vigorous vertical mixing and large amounts of stratospheric methane there.

Pryor, W.R.

1989-01-01

250

A HOT JUPITER ORBITING THE 1.7 M {sub sun} SUBGIANT HD 102956  

SciTech Connect

We report the detection of a giant planet in a 6.4950 day orbit around the 1.68 M {sub sun} subgiant HD 102956. The planet has a semimajor axis a = 0.081 AU and a minimum mass M{sub P} sin i =0.96 M {sub Jup}. HD 102956 is the most massive star known to harbor a hot Jupiter, and its planet is only the third known to orbit within 0.6 AU of a star more massive than 1.5 M {sub sun}. Based on our sample of 137 subgiants with M {sub *}>1.45 M {sub sun}, we find that 0.5%-2.3% of A-type stars harbor a close-in planet (a < 0.1 AU) with M{sub P} sin i > 1 M {sub Jup}, consistent with hot-Jupiter occurrence for Sun-like stars. Thus, the paucity of planets with 0.1 AU < a < 1.0 AU around intermediate-mass stars may be an exaggerated version of the 'period valley' that is characteristic of planets around Sun-like stars.

Johnson, John Asher; Morton, Timothy D.; Crepp, Justin R. [Department of Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Bowler, Brendan P. [Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Howard, Andrew W.; Marcy, Geoffrey W.; Isaacson, Howard [Department of Astronomy, University of California, Mail Code 3411, Berkeley, CA 94720 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Brewer, John Michael; Fischer, Debra A., E-mail: johnjohn@astro.caltech.ed [Department of Astronomy, Yale University, New Haven, CT 06511 (United States)

2010-10-01

251

Making other earths: dynamical simulations of terrestrial planet formation and water delivery  

Microsoft Academic Search

We present results from 44 simulations of late stage planetary accretion, focusing on the delivery of volatiles (primarily water) to the terrestrial planets. Our simulations include both planetary “embryos” (defined as Moon to Mars sized protoplanets) and planetesimals, assuming that the embryos formed via oligarchic growth. We investigate volatile delivery as a function of Jupiter's mass, position and eccentricity, the

Sean N. Raymond; Thomas R. Quinn; Jonathan I. Lunine

2004-01-01

252

Jupiter after the Galileo Probe  

NASA Astrophysics Data System (ADS)

The atmospheric probe from the Galileo Spacecraft entered the atmosphere of Jupiter on 7 December 1995. This was the first in situ investigation of an outer planet atmosphere. The probe sent back a rich harvest of data down to a depth of 22 bars. The results include searches for cloud layers and lightning a detailed study of atmospheric structure and local winds and a comprehensive investigation of the atmospheric composition including a determination of isotope ratios. In addition to new information about the giant planet itself the probe results have implications for the composition of the solar nebula and for models of giant planet formation. They lead to new predictions for giant planet characteristics some of which will be tested by the Cassini-Huygens Mission currently underway to the Saturn system. This collection of investigations also provides an illuminating prototype for future probe missions to the other giant planets clearly a highly desirable enterprise.

Owen, Tobias C.; Young, Richard E.

253

The Relation Between Radius, Mass, and Incident Flux of Exoplanets  

NASA Astrophysics Data System (ADS)

We measure the mass of a modestly irradiated giant or "warm Jupiter," KOI-94d, in order to calculate its density. We wish to determine whether this planet, which is in a 22 day orbit and receives 107 times as much incident flux as the Earth, is bloated like "hot Jupiters" or as dense as our own Jupiter. In addition to its warm Jupiter, KOI-94 hosts at least 3 smaller planets, all of which were detected through transits by the Kepler Mission. This presents the opportunity to characterize a multi-planet system and to test dynamic stability and formation theory through observations of the masses and orbital elements of these planets. With 26 radial velocity measurements of KOI-94 from the W. M. Keck Observatory/HIRES, we measure the mass of the giant planet and upper limits to the masses of the three smaller planets. Transit timing variations will allow us to hone the mass measurements of the three smaller planets. Using the KOI-94 system and all other planets with published values for both mass and radius, we establish two fundamental planes for exoplanets that relate their mass, incident flux, and radius from a few Earth masses up to ten Jupiter masses: log(Rp/RE) = 0.007 + 0.53 log(M/ME) - 0.001 log(F/[erg/s/cm^2]) for Mp < 150ME; log(Rp/RE) = 0.67 - 0.036 log(M/ME) + 0.06 log(F/[erg/s/cm^2]) for Mp > 150ME. We also solve these planes in density-mass-flux space: log(?p/[g/cm^3]) = 0.69 - 0.57 log(M/ME) + 0.02 log(F/[erg/s/cm^2]) for Mp < 150ME; log(?p/[g/cm^3]) = -1.23 + 1.10 log(M/ME) - 0.18 log(F/[erg/s/cm^2]) for Mp > 150ME.

Weiss, Lauren M.; Marcy, G. W.; Rowe, J.; Isaacson, H. T.; Howard, A.; Fortney, J. J.; Miller, N.; Demory, B.; Fischer, D.; Adams, E. A.; Dupree, A. K.; Howell, S. B.; Horch, E.; Everett, M. E.; Seager, S.; Fabrycky, D. C.

2013-01-01

254

HAT-P-38b: A Saturn-Mass Planet Transiting a Late G Star  

NASA Astrophysics Data System (ADS)

We report on the discovery of HAT-P-38b, a Saturn-mass exoplanet, transiting the V = 12.56 dwarf star GSC 2314-00559 on a P = 4.6404 d circular orbit. The host star is a 0.89 M? late G dwarf, with solar metallicity and a radius of 0.92 R?. The planetary companion has a mass of 0.27 MJ and a radius of 0.82 RJ. HAT-P-38b is one of the planets the mass and radius of which have ever been discovered to be the closest to those of Saturn.

Sato, Bun'ei; Hartman, Joel D.; Bakos, Gáspár Á.; Béky, Bence; Torres, Guillermo; Latham, David W.; Kovács, Géza; Csubry, Zoltán; Penev, Kaloyan; Noyes, Robert W.; Buchhave, Lars A.; Quinn, Samuel N.; Everett, Mark; Esquerdo, Gilbert A.; Fischer, Debra A.; Howard, Andrew W.; Johnson, John A.; Marcy, Geoff W.; Sasselov, Dimitar D.; Szklenár, Tamás; Lázár, József; Papp, István; Sári, Pál

2012-10-01

255

Simultaneous Solution for the Masses of the Principal Planets from Analysis of Optical, Radar, and Radio Tracking Data  

Microsoft Academic Search

The Jet Propulsion Laboratory has developed a set of computer programs known as the Solar System Data Processing System (SSDPS) which is employed in improving the ephemerides of the major planets and for improving the values of several associated astronomical constants. A group of solutions for the masses of the major planets, together with the AU and radii of Mercury,

J. H. Lieske; W. G. Melbourne; D. A. O'Handley; D. B. Holdridge; D. E. Johnson; W. S. Sinclair

1971-01-01

256

Simultaneous solution for the masses of the principal planets from analysis of optical, radar, and radio tracking data  

Microsoft Academic Search

The Jet Propulsion Laboratory has developed a set of computer programs known as the Solar System Data Processing System (SSDPS) which is employed in improving the ephemerides of the major planets and for improving the values of several associated astronomical constants. A group of solutions for the masses of the major planets, together with the AU and radii of Mercury,

J. H. Lieske; W. G. Melbourne; D. A. O'Handley; D. B. Holdridge; D. E. Johnson; W. S. Sinclair

1971-01-01

257

Extrasolar planets and Their Parent Stars  

NASA Astrophysics Data System (ADS)

Extrasolar planetas (exoplanets), or planets orbiting stars other than our own Sun, are a relatively new field of the astronomical and planetary sciences. After the discovery of Pluto in 1930, planet-finding activities appeared to have reached an end for the foreseeable future. Several brown dwarfs have been discovered between 1930 and 1993 orbiting other solar-type star. Brown dwarfs (or "failed stars") are low-mass celestial objects (M?10MJUP) that formed by stellar processes but did not obtain the critical mass required to sustain hydrogen burning within their core. Other claims for planetary detections were also made during the period 1944 - 1970 but were never verified or were later shown to be false, produced by timing artifacts or instrumentation errors. The first confirmed detection of an extrasolar planet occurred in 1992 when two bodies were found to be orbiting the millisecond pulsar PSR 1257+12 (Wolszczan and Frail, 1992). The first detection of an extrasolar planet orbiting a solar-type star occurred in 1994 with the claim of a Jupiter-type planet orbiting 51 Pegasi (Mayor and Queloz, 1995). As of January 2010, we currently know of 429 planets orbiting solar-type stars The vast majority of these detections have occurred via the radial velocity method (Udry & Santos 2007), although other methods such as that of transiting photometry and microlensing may become increasingly important in future planet searches as we seek to detect terrestrial-sized planetary bodies and utilize space- based observing programs.

Israelian, Garik

2010-11-01

258

DENSITY WAVES EXCITED BY LOW-MASS PLANETS IN PROTOPLANETARY DISKS. I. LINEAR REGIME  

SciTech Connect

Density waves excited by planets embedded in protoplanetary disks play a central role in planetary migration and gap opening processes. We carry out two-dimensional shearing sheet simulations to study the linear regime of wave evolution with the grid-based code Athena and provide detailed comparisons with theoretical predictions. Low-mass planets (down to {approx}0.03 M{sub Circled-Plus} at 1 AU) and high spatial resolution (256 grid points per scale height) are chosen to mitigate the effects of wave nonlinearity. To complement the existing numerical studies, we focus on the primary physical variables such as the spatial profile of the wave, torque density, and the angular momentum flux carried by the wave, instead of secondary quantities such as the planetary migration rate. Our results show percent level agreement with theory in both physical and Fourier spaces. New phenomena such as the change of the toque density sign far from the planet are discovered and discussed. Also, we explore the effect of the numerical algorithms and find that a high order of accuracy, high resolution, and an accurate planetary potential are crucial to achieve good agreement with the theory. We find that the use of a too large time step without properly resolving the dynamical timescale around the planet produces incorrect results and may lead to spurious gap opening. Global simulations of planet migration and gap opening violating this requirement may be affected by spurious effects resulting in, e.g., the incorrect planetary migration rate and gap opening mass.

Dong, Ruobing; Stone, James M.; Petrovich, Cristobal; Rafikov, Roman R., E-mail: rdong@astro.princeton.edu, E-mail: rrr@astro.princeton.edu, E-mail: jstone@astro.princeton.edu, E-mail: cpetrovi@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2011-11-01

259

An Equation of State for Low-Mass Stars and Giant Planets  

Microsoft Academic Search

We present new equations of state (EOS) for hydrogen and helium, intended for applications to low-mass stars (M < 1 Msun), brown dwarfs, and giant planets. They cover the range 2.10

D. Saumon; G. Chabrier; H. M. van Horn

1995-01-01

260

The Final Report: Detecting Terrestrial Mass Planets Around M-dwarfs: Is SIM's performance competitive?  

Microsoft Academic Search

Here, we present our final report on our SIM Science Study to determine the effect of intrinsic stellar jitter on our ability to detect terrestrial planets around low-mass stars with micro-arcsecond astrometry. The study has had two primary goals: 1) To assess the astrophysical limits of ultra-precision astrometric measurements of M-dwarfs compared to those of other detection methods and 2)

Angelle M. Tanner; N. Law; P. Plavchan; J. Catanzarite

2010-01-01

261

The Terrestrial Planets Formation in the Solar-System Analogs  

NASA Astrophysics Data System (ADS)

In this work, we numerically studied the terrestrial planets formation in the Solar-Systems Analogs using MERCURY (Chambers 1999). The Solar-System Analogs are herein defined as a solar-system like planetary system, where the system consists of two wide-separated Jupiter-like planets (e.g., 47 UMa, Ji et al. 2005) move about the central star on nearly circular orbits with low inclinations, then low-mass terrestrial planets can be formed there, and life would be possibly evolved. We further explored the terrestrial planets formation due to the current uncertainties of the eccentricities for two giant planets. In addition, we place a great many of the planetesimals between two Jupiter-like planets to investigate the potential asteroidal structure in such systems. We showed that the secular resonances and mean motion resonances can play an important role in shaping the asteroidal structure. We acknowledge the financial support by National Natural Science Foundation of China (Grant No.10573040, 10233020, 10203005) and Foundation of Minor Planets of Purple Mountain Observatory.

Ji, Jianghui; Liu, L.; Chambers, J. E.; Butler, R. P.

2006-09-01

262

Planet Formation  

NASA Astrophysics Data System (ADS)

1. Historical notes on planet formation Bodenheimer; 2. The formation and evolution of planetary systems Bouwman et al.; 3. Destruction of protoplanetary disks by photoevaporation Richling, Hollenbach and Yorke; 4. Turbulence in protoplanetary accretion disks Klahr, Rozyczka, Dziourkevitch, Wunsch and Johansen; 5. The origin of solids in the early solar system Trieloff and Palme; 6. Experiments on planetesimal formation Wurm and Blum; 7. Dust coagulation in protoplanetary disks Henning, Dullemond, Wolf and Dominik; 8. The accretion of giant planet cores Thommes and Duncan; 9. Planetary transits: direct vision of extrasolar planets Lecavelier des Etangs and Vidal-Madjar; 10. The core accretion - gas capture model Hubickyj; 11. Properties of exoplanets Marcy, Fischer, Butler and Vogt; 12. Giant planet formation: theories meet observations Boss; 13. From hot Jupiters to hot Neptures … and below Lovis, Mayor and Udry; 14. Disk-planet interaction and migration Masset and Kley; 15. The Brown Dwarf - planet relation Bate; 16. From astronomy to astrobiology Brandner; 17. Overview and prospective Lin.

Klahr, Hubert; Brandner, Wolfgang

2011-02-01

263

The Chemistry of the Planets.  

ERIC Educational Resources Information Center

Introduces knowledge of planetary chemistry for possible use in teaching. Discusses the chemical composition of the planets; the atmosphere and clouds of Venus, Jupiter and its moons, and Titan. Includes diagrams of the greenhouse effects in the solar system, elemental abundances, and the chemical composition of Jupiter. (RT)

Blake, Peter

1988-01-01

264

The Chemistry of the Planets.  

ERIC Educational Resources Information Center

|Introduces knowledge of planetary chemistry for possible use in teaching. Discusses the chemical composition of the planets; the atmosphere and clouds of Venus, Jupiter and its moons, and Titan. Includes diagrams of the greenhouse effects in the solar system, elemental abundances, and the chemical composition of Jupiter. (RT)|

Blake, Peter

1988-01-01

265

Jupiter's obliquity and a long-lived circumplanetary disk  

NASA Astrophysics Data System (ADS)

It has been claimed [Canup, R.M., Ward, W.R., 2002. Astron. J. 124, 3404-3423; Ward, W.R., 2003. In: AGU, Fall Meeting 2003] that a long-lived minimum mass circumplanetary gas disk is inconsistent with Jupiter's low obliquity. Here we find that while Jupiter's obliquity may constrain its characteristics it does not rule out a long-lived massive (compared to the mass of the Galilean satellites) disk. This is because the argument assumes a Solar System much like that of the present day with the one exception of a circumjovian disk which is then allowed to dissipate on a long timescale ( 10-10 yr). Given that the sequence of events in Solar System history that fit known constraints is non-unique, we choose for the sake of clarity of exposition the orbital architecture framework of Tsiganis et al. [Tsiganis, K., Gomes, R., Morbidelli, A., Levison, H.F., 2005. Nature 435, 459-461], in which Jupiter and Saturn were once in compact, nearly coplanar orbits, and show that in this case Jupiter's low obliquity is consistent with the SEMM (solids-enhanced minimum mass) satellite formation model of Mosqueira and Estrada [Mosqueira, I., Estrada, P.R., 2003a. Icarus 163, 198-231; Mosqueira, I., Estrada, P.R., 2003b. Icarus 163, 232-255]. We suggest that a low inclination starting condition may apply, but stress that our SEMM satellite formation model could be compatible with Jupiter's obliquity even for mutually inclined giant planets.

Mosqueira, Ignacio; Estrada, Paul R.

2006-01-01

266

5 Micron of beta Pictoris B at a Sub-Jupiter Projected Separation: Evidence for a Misalignment Between the Planet and the Inner, Warped Disk.  

National Technical Information Service (NTIS)

We present and analyze a new M' detection of the young exoplanet Beta Pictoris b from 2008 VLT/NaCo data at a separation of approx. = 4 AU and a high signal-to-noise rereduction of L' data taken in December 2Q09. Based on our orbital analysis, the planet'...

A. Burrows C. Thalmann M. Kuchner N. Madhusudhan S. Matsumura T. Currie

2011-01-01

267

Types of gaseous envelopes of "hot Jupiter" exoplanets  

NASA Astrophysics Data System (ADS)

As a rule, the orbital velocities of "hot Jupiters," i.e., exoplanets with masses comparable to the mass of Jupiter and orbital semi-major axes less than 0.1 AU, are supersonic relative to the stellar wind, resulting in the formation of a bow shock. Gas-dynamical modeling shows that the gaseous envelopes around hot Jupiters can belong to two classes, depending on the position of the collision point. if the collision point is inside the Roche lobe of the planet, the envelopes have the almost spherical shapes of classical atmospheres, slightly distorted by the influence of the star and interactions with the stellar-wind gas; if the collision point is located outside the Roche lobe, outflows from the vicinity of the Lagrangian points L1 and L2 arise, and the envelope becomes substantially asymmetrical. The latter class of objects can also be divided into two types. If the dynamical pressure of the stellar-wind gas is high enough to stop the most powerful outflow from the vicinity of the inner Lagrangian point L1, a closed quasi-spherical envelope with a complex shape forms in the system. If the wind is unable to stop the outflow from L1, an open aspherical envelope forms. The possible existence of atmospheres of these three types is confirmed by 3D numerical modeling. Using the typical hot Jupiter HD 209458b as an example, it is shown that all three types of atmospheres could exist within the range of estimated parameters of this planet. Since different types of envelopes have different observational manifestations, determining the type of envelope in HD 209458b could apply additional constrains on the parameters of this exoplanet.

Bisikalo, D. V.; Kaigorodov, P. V.; Ionov, D. E.; Shematovich, V. I.

2013-10-01

268

Estimates of the Planet Yield from Ground-based High-contrast Imaging Observations as a Function of Stellar Mass  

NASA Astrophysics Data System (ADS)

We use Monte Carlo simulations to estimate the number of extrasolar planets that are directly detectable in the solar neighborhood using current and forthcoming high-contrast imaging instruments. Our calculations take into consideration the important factors that govern the likelihood for imaging a planet, including the statistical properties of stars in the solar neighborhood, correlations between star and planet properties, observational effects, and selection criteria. We consider several different ground-based surveys, both biased and unbiased, and express the resulting planet yields as a function of stellar mass. Selecting targets based on their youth and visual brightness, we find that strong correlations between star mass and planet properties are required to reproduce high-contrast imaging results to date (i.e., HR 8799, ? Pic). Using the most recent empirical findings for the occurrence rate of gas-giant planets from radial velocity (RV) surveys, our simulations indicate that naive extrapolation of the Doppler planet population to semimajor axes accessible to high-contrast instruments provides an excellent agreement between simulations and observations using present-day contrast levels. In addition to being intrinsically young and sufficiently bright to serve as their own beacon for adaptive optics correction, A-stars have a high planet occurrence rate and propensity to form massive planets in wide orbits, making them ideal targets. The same effects responsible for creating a multitude of detectable planets around massive stars conspire to reduce the number orbiting low-mass stars. However, in the case of a young stellar cluster, where targets are approximately the same age and situated at roughly the same distance, MK-stars can easily dominate the number of detections because of an observational bias related to small number statistics. The degree to which low-mass stars produce the most planet detections in this special case depends upon whether multiple formation mechanisms are at work. Upon relaxing our assumption that planets in ultra-wide (a > 100 AU) orbits resemble the RV sample, our simulations suggest that the companions found orbiting late-type stars (AB Pic, 1RXSJ1609, GSC 06214, etc.) are consistent with a formation channel distinct from that of RV planets. These calculations explain why planets have thus far been imaged preferentially around A-stars and K-, M-stars, but no spectral types in between, despite concerted efforts targeting F-, G-stars.

Crepp, Justin R.; Johnson, John Asher

2011-06-01

269

ESTIMATES OF THE PLANET YIELD FROM GROUND-BASED HIGH-CONTRAST IMAGING OBSERVATIONS AS A FUNCTION OF STELLAR MASS  

SciTech Connect

We use Monte Carlo simulations to estimate the number of extrasolar planets that are directly detectable in the solar neighborhood using current and forthcoming high-contrast imaging instruments. Our calculations take into consideration the important factors that govern the likelihood for imaging a planet, including the statistical properties of stars in the solar neighborhood, correlations between star and planet properties, observational effects, and selection criteria. We consider several different ground-based surveys, both biased and unbiased, and express the resulting planet yields as a function of stellar mass. Selecting targets based on their youth and visual brightness, we find that strong correlations between star mass and planet properties are required to reproduce high-contrast imaging results to date (i.e., HR 8799, {beta} Pic). Using the most recent empirical findings for the occurrence rate of gas-giant planets from radial velocity (RV) surveys, our simulations indicate that naive extrapolation of the Doppler planet population to semimajor axes accessible to high-contrast instruments provides an excellent agreement between simulations and observations using present-day contrast levels. In addition to being intrinsically young and sufficiently bright to serve as their own beacon for adaptive optics correction, A-stars have a high planet occurrence rate and propensity to form massive planets in wide orbits, making them ideal targets. The same effects responsible for creating a multitude of detectable planets around massive stars conspire to reduce the number orbiting low-mass stars. However, in the case of a young stellar cluster, where targets are approximately the same age and situated at roughly the same distance, MK-stars can easily dominate the number of detections because of an observational bias related to small number statistics. The degree to which low-mass stars produce the most planet detections in this special case depends upon whether multiple formation mechanisms are at work. Upon relaxing our assumption that planets in ultra-wide (a > 100 AU) orbits resemble the RV sample, our simulations suggest that the companions found orbiting late-type stars (AB Pic, 1RXSJ1609, GSC 06214, etc.) are consistent with a formation channel distinct from that of RV planets. These calculations explain why planets have thus far been imaged preferentially around A-stars and K-, M-stars, but no spectral types in between, despite concerted efforts targeting F-, G-stars.

Crepp, Justin R.; Johnson, John Asher, E-mail: jcrepp@astro.caltech.edu [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); NASA Exoplanet Science Institute (NExScI), California Institute of Technology, Mail Code 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)

2011-06-01

270

The formation of Uranus and Neptune in the Jupiter-Saturn region of the Solar System.  

PubMed

Planets are believed to have formed through the accumulation of a large number of small bodies. In the case of the gas-giant planets Jupiter and Saturn, they accreted a significant amount of gas directly from the protosolar nebula after accumulating solid cores of about 5-15 Earth masses. Such models, however, have been unable to produce the smaller ice giants Uranus and Neptune at their present locations, because in that region of the Solar System the small planetary bodies will have been more widely spaced, and less tightly bound gravitationally to the Sun. When applied to the current Jupiter-Saturn zone, a recent theory predicts that, in addition to the solid cores of Jupiter and Saturn, two or three other solid bodies of comparable mass are likely to have formed. Here we report the results of model calculations that demonstrate that such cores will have been gravitationally scattered outwards as Jupiter, and perhaps Saturn, accreted nebular gas. The orbits of these cores then evolve into orbits that resemble those of Uranus and Neptune, as a result of gravitational interactions with the small bodies in the outer disk of the protosolar nebula. PMID:10604469

Thommes, E W; Duncan, M J; Levison, H F

1999-12-01

271

Metallicity of M dwarfs. III. Planet-metallicity and planet-stellar mass correlations of the HARPS GTO M dwarf sample  

NASA Astrophysics Data System (ADS)

Aims: The aim of this work is the study of the planet-metallicity and the planet-stellar mass correlations for M dwarfs from the HARPS GTO M dwarf subsample. Methods: We use a new method that takes advantage of the HARPS high-resolution spectra to increase the precision of metallicity, using previous photometric calibrations of [Fe/H] and effective temperature as starting values. Results: In this work we use our new calibration (rms = 0.08 dex) to study the planet-metallicity relation of our sample. The well-known correlation for giant planet FGKM hosts with metallicity is present. Regarding Neptunians and smaller hosts no correlation is found but there is a hint that an anti-correlation with [Fe/H] may exist. We combined our sample with the California Planet Survey late-K and M-type dwarf sample to increase our statistics but found no new trends. We fitted a power law to the frequency histogram of the Jovian hosts for our sample and for the combined sample, fp = C10? [Fe/H] , using two different approaches: a direct bin fitting and a Bayesian fitting procedure. We obtained a value for C between 0.02 and 0.04 and for ? between 1.26 and 2.94. Regarding stellar mass, an hypothetical correlation with planets was discovered, but was found to be the result of a detection bias. Based on observations made with the HARPS instrument on the ESO 3.6-m telescope at La Silla Observatory under programme ID 072.C-0488.Tables 2, 8, and Appendix A are available in electronic form at http://www.aanda.org

Neves, V.; Bonfils, X.; Santos, N. C.; Delfosse, X.; Forveille, T.; Allard, F.; Udry, S.

2013-03-01

272

Value of Hipparcos Catalogue shown by planet assessments  

NASA Astrophysics Data System (ADS)

The first detailed findings from Hipparcos, recently published in Astronomy and Astrophysics Letters, confirm the existence of planets around other stars. Hipparcos astronomers plucked out their data on three stars suspected of possessing attendant planets. Their distances, measured far more accurately than ever before, enables the astronomers to rule out, in two cases, the possibility that the supposed planets might be small stars. The discovery of alien planets in the first astronomical step towards fashioning a proper science out of the speculations about life beyond the solar system. Hipparcos makes a decisive contribution by setting an upper limit to their masses. Astronomers at the Geneva Observatory caused a sensation last year when they reported slight motions in the star 51 Pegasi, due to a massive planet orbiting around it. With a ground-based telescope they detected small shifts in the wavelength of light as 51 Pegasi moved slowly under the influence of its invisible companion. This year, astronomers at San Francisco State University confirmed the discovery and have subsequently reported two similar cases, in the stars 47 Ursae Majoris and 70 Virginis. Uncertainties about the orientation of the planets' orbits and the distances of the stars left a wide margin of doubt about the masses of the candidate planets. Accurate rangefinding by Hipparcos puts the star 47 Ursae Majoris at a distance of 46 light-years. Calculations then set an upper limit on the mass of the companion at 7 to 22 times the mass of Jupiter, the Sun's largest planet. The Sun itself is a thousand times more massive that Jupiter, and theorists believe that the smallest true star would have a mass of 80 Jupiters. Below that mass, the object cannot burn hydrogen in the nuclear fashion, which is the most characteristic source of energy for stars. In the range between 17 and 80 Jupiter masses an object is called a brown dwarf. It can in theory derive a little energy by burning heavy hydrogen, or deuterium. Even the "worst-case" mass quoted here for the companion of 47 Ursae Majoris, 22 Jupiter masses, is only a maximum, not a measurement. So the companion is almost certainly a true planet with less than 17 times the mass of Jupiter. For the star 70 Virginis, the distance newly established by Hipparcos is 59 light-years. Even on the least favourable assumptions about its orbit, the companion cannot have more than 65 Jupiter masses. It could be brown dwarf rather than a planet, but not a true star. Much more ambiguous is the result for 51 Pegasi. Its distance is 50 light-years and theoretically the companion could have more than 500 Jupiter masses, or half the mass of the Sun. This is a peculiar case anyway, because the companion is very close to 51 Pegasi. Small planets of the size of the Earth might be more promising as abodes of life than the large planets detectable by present astronomical methods. Space scientists are now reviewing methods of detecting the presence of life on alien planets by detecting the infrared signature of ozone in a planet's atmosphere. Ozone is a by-product of oxygen gas, which in turn is supposed to be generated only by life similar to that on the Earth. Meanwhile the detection of planets of whatever size is a tour de force for astronomers, and by analogy with the Solar System one may suppose that large planets are often likely to be accompanied by smaller ones. "Hipparcos was not conceived to look for planets," comments Michael Perryman, ESA's project scientist for Hipparcos, "and this example of assistance to our fellow-astronomers involves a very small sample of our measurements. But it is a timely result when we are considering planet-hunting missions for the 21st Century. The possibilities include a super-Hipparcos that could detect directly the wobbles in nearby stars due to the presence of planets." Hipparcos Catalogue ready for use The result from Hipparcos on alien planets coincides with the completion of the Hipparcos Catalogue and the distribution of the data to collaborating scie

1996-08-01

273

A Framework For Characterizing The Atmospheres Of GJ 1214b-type Low-mass Low-density Transiting Planets  

NASA Astrophysics Data System (ADS)

The atmosphere of the low-mass low-density transiting planet GJ 1214b has been extensively characterized via transmission spectroscopy. Observations include spectra and photometric points from blue to mid-infrared wavelengths. The transmission spectrum appears relatively featureless, indicating an atmosphere that does not show strong molecular absorption features. It has been suggested that this ``flat" spectrum could be due to an obscuring grey cloud/haze layer, or due to a high mean molecular weight (MMW) atmosphere. If the planet is similar to a scaled down version of Uranus or Neptune, as suggested by Nettelmann et al. (2011), both explanations could well be viable. To lift the degeneracy of these explanations, one can imagine characterizing a range of similar planets, which are now being found. Here we examine the structure and atmospheres of volatile-rich planets from 5-20 Earth masses and T_eq from 100 - 1500 K. Based on population synthesis models of core-accretion planet formation, we examine the expected Z_atmosphere and MMW these low mass planets. We examine how atmospheric escape of the outermost layers of such planets may expose deeper atmospheric layers with less hydrogen and a higher Z_atmosphere and MMW. We note that the hottest variants of these planets should feature atmospheres rich in CO, rather than CH4, potentially eliminating a pathway to photochemical haze formation. We provide a synthesis of these physical effects over a range of mass, temperature, and metallicity parameters. We highlight where in parameter space these GJ 1214b and Neptune-like planets are likely to have atmospheres that are most amenable to characterization from transmission spectroscopy.

Fortney, Jonathan J.; Nettelmann, N.; Kempton, E.; Mordasini, C.; Zahnle, K.; Lopez, E.; Morley, C. V.; Marley, M. S.

2012-10-01

274

Early Giant Planet Migration in the Solar System: Geochemical and Cosmochemical Implications for Terrestrial Planet Formation  

NASA Astrophysics Data System (ADS)

A new terrestrial planet formation model (Walsh et al., this meeting) explores the effects of a two-stage, inward-then-outward migration of Jupiter and Saturn, as found in numerous hydrodynamical simulations of giant planet formation (Masset & Snellgrove 2001, Morbidelli & Crida 2007, Pierens & Nelson 2008). Walsh et al. show that the inward migration of Jupiter truncates the disk of planetesimals and embryos in the terrestrial planet region. Subsequent accretion in that region then forms a realistic system of terrestrial planets, in particular giving a low-mass Mars, which has been difficult to reproduce in simulations with a self-consistent set of initial conditions (see, eg. Raymond et al. 2009). Additionally, the outward migration of the giant planets populates the asteroid belt with distinct populations of bodies, with the inner belt filled by bodies originating inside of 3 AU, and the outer belt filled with bodies originating from beyond the giant planets. From a geochemical and cosmochemical point of view, this scenario differs significantly from the "standard model" in which essentially all of the material in the inner Solar System initially formed there. Specifically, the assumption that the current radial distribution of material in the inner Solar System is reflective of the primordial distribution of material in that region is no longer necessary. This is important for understanding the chemical and isotopic diversity of the inner Solar System as inferred from studies of the terrestrial planets, asteroids, and meteorites, as well as for understanding the origin of Earth's water. We will discuss the geochemical and cosmochemical implications of this model in relation to available constraints, as well as to previous models of terrestrial planet formation. Masset & Snellgrove (2001), MNRAS 320, L55. Morbidelli & Crida (2007), Icarus 191, 158. Pierens & Nelson (2008), A&A 482, 333. Raymond et al. (2009), Icarus 203, 644.

O'Brien, David P.; Walsh, K. J.; Morbidelli, A.; Raymond, S. N.; Mandell, A. M.; Bond, J. C.

2010-10-01

275

Seven transiting hot Jupiters from WASP-South, Euler and TRAPPIST: WASP-47b, WASP-55b, WASP-61b, WASP-62b, WASP-63b, WASP-66b and WASP-67b  

NASA Astrophysics Data System (ADS)

We present seven new transiting hot Jupiters from the WASP-South survey. The planets are all typical hot Jupiters orbiting stars from F4 to K0 with magnitudes of V = 10.3-12.5. The orbital periods are all in the range of 3.9-4.6 d, the planetary masses range from 0.4 to 2.3 MJup and the radii from 1.1 to 1.4 RJup. In line with known hot Jupiters, the planetary densities range from Jupiter-like to inflated (? = 0.13-1.07?Jup). We use the increasing numbers of known hot Jupiters to investigate the distribution of their orbital periods and the 3-4 d 'pile-up'.

Hellier, Coel; Anderson, D. R.; Collier Cameron, A.; Doyle, A. P.; Fumel, A.; Gillon, M.; Jehin, E.; Lendl, M.; Maxted, P. F. L.; Pepe, F.; Pollacco, D.; Queloz, D.; Ségransan, D.; Smalley, B.; Smith, A. M. S.; Southworth, J.; Triaud, A. H. M. J.; Udry, S.; West, R. G.

2012-10-01

276

Liquid metallic hydrogen and the structure of brown dwarfs and giant planets  

Microsoft Academic Search

Electron-degenerate, pressure-ionized hydrogen (usually referred to as metallic hydrogen) is the principal constituent of brown dwarfs, the long-sought objects which lie in the mass range between the lowest-mass stars (about eighty times the mass of Jupiter) and the giant planets. The thermodynamics and transport properties of metallic hydrogen are important for understanding the properties of these objects, which, unlike stars,

W. B. Hubbard; T. Guillot; J. I. Lunine; A. Burrows; D. Saumon; M. S. Marley; R. S. Freedman

1997-01-01

277

Jupiter Magnetospheric Orbiter and Trojan Asteroid Explorer in EJSM (Europa Jupiter System Mission)  

NASA Astrophysics Data System (ADS)

Europa Jupiter System Mission (EJSM) is an international mission to explore and Jupiter, its satellites and magnetospheric environment in 2020s. EJSM consists of (1) The Jupiter Europa Orbiter (JEO) by NASA, (2) the Jupiter Ganymede Orbiter (JGO) by ESA, and (3) the Jupiter Magnetospheric Orbiter (JMO) studied by JAXA (Japan Aerospace Exploration Agency). In February 2009, NASA and ESA decided to continue the study of EJSM as a candidate of the outer solar system mission. JMO will have magnetometers, low-energy plasma spectrometers, medium energy particle detectors, energetic particle detectors, electric field / plasma wave instruments, an ENA imager, an EUV spectrometer, and a dust detector. Collaborating with plasma instruments on board JEO and JGO, JMO will investigate the fast and huge rotating magnetosphere to clarify the energy procurement from Jovian rotation to the magnetosphere, to clarify the interaction between the solar wind the magnetosphere. Especially when JEO and JGO are orbiting around Europa and Ganymede, respectively, JMO will measure the outside condition in the Jovian magnetosphere. JMO will clarify the characteristics of the strongest accelerator in the solar system with the investigation of the role of Io as a source of heavy ions in the magnetosphere. JAXA started a study of a solar power sail for deep space explorations. Together with a solar sail (photon propulsion), it will have very efficient ion engines where electric power is produced solar panels within the sail. JAXA has already experienced ion engine in the successful Hayabusa mission, which was launched in 2003 and is still in operation in 2010. For the purpose of testing solar power sail technology, an engineering mission IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) will be launched in 2010 together with Venus Climate Orbiter PLANET-C. The shape of the IKAROS' membrane is square, with a diagonal distance of 20m. It is made of polyimide film only 0.0075mm thick. Currently we are studying a mission to Jupiter and one (or two) of Trojan asteroids using a large (100m-scale) solar power sail that can transfer large payload mass as far as Jupiter. Trojan asteroids are primitive bodies with information of the early solar system as well as raw solid materials of Jovian system. According to the mission plan, as the main spacecraft flies by Jupiter, it will deploy a JMO spinner around Jupiter. Proposed instruments on board Trojan spacecraft are cameras, IR spectrometers, XRS, a laser altimeter, and a surface vehicle (if rendezvous with the target is possible). An instrument for measuring cosmic background is also proposed. Currently JEO and JGO will be launched in 2020 and the Trojan spacecraft with JMO shall be launched at the same window. The mission (Trojan-JMO) will take 6 years to Jupiter and 5 years more to a Trojan asteroid around L4. The mission study team also includes J. Kawaguchi, Y. Kawakatsu, and M. Morimoto of JAXA.

Sasaki, Sho; Fujimoto, Masaki; Takashima, Takeshi; Yano, Hajime; Kasaba, Yasumasa; Takahashi, Yukihiro; Kimura, Jun; Tsuda, Yuichi; Funase, Ryu; Mori, Osamu

2010-05-01

278

News and Views: Low-mass stars pull weight in globular clusters; Red dwarf planets are common, too; More planets than stars in the Milky Way? After Bullet comes Musket Ball; Planets survive red giant phase  

NASA Astrophysics Data System (ADS)

Gravitational microlensing techniques have uncovered the first low-mass star found in a globular cluster, suggesting that previously undetectable stars may contribute to cluster masses, meaning that there is less dark matter to find. Data from NASA's Kepler mission suggest that small rocky planets may be common orbiting red dwarf stars - and because red dwarfs are common types of star, this means that rocky planets may be commonplace in the Milky Way. A survey using gravitational microlensing suggest that exoplanets are the exception rather than the rule in the Milky Way - and that small planets like Earth are more common than gas and ice giants. The Bullet Cluster famously allows mapping of the dark matter distribution during the merger of two clusters. Now a merging cluster named the Musket Ball shows a later stage in the process. Planets are not necessarily vaporized when a red giant star expands; the cores of gas giants may survive, but they would not be pleasant places to live. Data from NASA's Kepler mission has revealed two small planets orbiting a star after its red giant phase.

2012-02-01

279

An extrasolar giant planet in a close triple-star system.  

PubMed

Hot Jupiters are gas-giant planets orbiting with periods of 3-9 days around Sun-like stars. They are believed to form in a disk of gas and condensed matter at or beyond approximately 2.7 astronomical units (au-the Sun-Earth distance) from their parent star. At such distances, there exists a sufficient amount of solid material to produce a core capable of capturing enough gas to form a giant planet. Subsequently, they migrate inward to their present close orbits. Here I report the detection of an unusual hot Jupiter orbiting the primary star of a triple stellar system, HD 188753. The planet has an orbital period of 3.35 days and a minimum mass of 1.14 times that of Jupiter. The primary star's mass is 1.06 times that of the Sun, 1.06 M(\\circ). The secondary star, itself a binary stellar system, orbits the primary at an average distance of 12.3 au with an eccentricity of 0.50. The mass of the secondary pair is 1.63 M(\\circ). Such a close and massive secondary would have truncated a disk around the primary to a radius of only approximately 1.3 AU (ref. 4) and might have heated it up to temperatures high enough to prohibit giant-planet formation, leaving the origin of this planet unclear. PMID:16015323

Konacki, Maciej

2005-07-14

280

An auroral flare at Jupiter.  

PubMed

Jupiter's aurora is the most powerful in the Solar System. It is powered largely by energy extracted from planetary rotation, although there seems also to be a contribution from the solar wind. This contrasts with Earth's aurora, which is generated through the interaction of the solar wind with the magnetosphere. The major features of Jupiter's aurora (based on far-ultraviolet, near-infrared and visible-wavelength observations) include a main oval that generally corotates with the planet and a region of patchy, diffuse emission inside the oval on Jupiter's dusk side. Here we report the discovery of a rapidly evolving, very bright and localized emission poleward of the northern main oval, in a region connected magnetically to Jupiter's outer magnetosphere. The intensity of the emission increased by a factor of 30 within 70 s, and then decreased on a similar timescale, all captured during a single four-minute exposure. This type of flaring emission has not previously been reported for Jupiter (similar, but smaller, transient events have been observed at Earth), and it may be related directly to changes in the solar wind. PMID:11298440

Waite, J H; Gladstone, G R; Lewis, W S; Goldstein, R; McComas, D J; Riley, P; Walker, R J; Robertson, P; Desai, S; Clarke, J T; Young, D T

2001-04-12

281

Terrestrial planet formation in extra-solar planetary systems  

NASA Astrophysics Data System (ADS)

Terrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions, turbulent concentration of solids, and gravitational collapse from micron-sized dust grains in the thin disk midplane. Second, planetesimals coalesce to form Moon- to Mars-sized protoplanets, also called “planetary embryos”. Finally, full-sized terrestrial planets accrete from protoplanets and planetesimals. This final stage of accretion lasts about 10-100 Myr and is strongly affected by gravitational perturbations from any gas giant planets, which are constrained to form more quickly, during the 1-10 Myr lifetime of the gaseous component of the disk. It is during this final stage that the bulk compositions and volatile (e.g., water) contents of terrestrial planets are set, depending on their feeding zones and the amount of radial mixing that occurs. The main factors that influence terrestrial planet formation are the mass and surface density profile of the disk, and the perturbations from giant planets and binary companions if they exist. Simple accretion models predicts that low-mass stars should form small, dry planets in their habitable zones. The migration of a giant planet through a disk of rocky bodies does not completely impede terrestrial planet growth. Rather, “hot Jupiter” systems are likely to also contain exterior, very water-rich Earth-like planets, and also “hot Earths”, very close-in rocky planets. Roughly one third of the known systems of extra-solar (giant) planets could allow a terrestrial planet to form in the habitable zone.

Raymond, Sean N.

2008-05-01

282

Tornados and Hurricanes in Planet Formation  

NASA Astrophysics Data System (ADS)

We study the formation of a giant gas planet by the core-accretion gas-capture process, with numerical simulations, under the assumption that the planetary core forms in the center of an anti-cyclonic vortex. The presence of the vortex concentrates particles of centimeter to meter size from the surrounding disk, and speeds up the core formation process. Assuming that a planet of Jupiter mass is forming at 5 AU from the star, the vortex enhancement results in considerably shorter formation times than are found in standard core-accretion gas-capture simulations. Also, formation of a gas giant is possible in a disk with mass comparable to that of the minimum mass solar nebula (MMSN).

Klahr, H.; Bodenheimer, P.

2004-12-01

283

Galileo Probe Mass Spectrometer Measurements of the Chemical Composition of the Atmosphere of Jupiter  

NASA Astrophysics Data System (ADS)

The chemical and isotopic composition of the Jovian atmosphere was measured by the Galileo Probe Mass Spectrometer (GPMS). This data was obtained on December 7, 1995 over a time period of approximately 1 hour during the probe descent in the 0.5 to 20 bar pressure region and transmitted to Earth over a period of several weeks. The sampling was either of atmospheric gases directly introduced into the ion source of the mass spectrometer through one of 2 capillary leak arrays or of gas which had been processed in enrichment cells to enhance the sensitivity of the measurement to trace species or heavy noble gases. Mixing ratios or limits were previously reported [Niemann et al., 1996] for atmospheric hydrogen, helium, methane, water, ammonia, hydrogen sulfide, neon, argon, krypton, and xenon. Ratios for isotopes of He, Ne, Ar, Kr, Xe, C, and H were also obtained. Additional molecules detected at the present stage of analysis include ethane, ethylene, propane, and hydrogen chloride as well as benzene and carbon/nitrogen compounds. The GPMS Flight Unit was not calibrated for some of these molecules and laboratory studies continue on an Engineering Unit. A substantial increase was observed in the mixing ratio of water, hydrogen sulfide, ethane and other species with increasing depth into the atmosphere over the 8 bar to 23 bar pressure regime. It has been suggested [Atreya et al., 1996] that the lower than expected abundance of many species in the early part of the descent and the observed increase with depth may be the signature of a large downdraft. H. B. Niemann et al., Science 272, 781 (1996). S. K. Atreya et al., Paper presented at the European Geophysical Society Meeting, The Hague, Netherlands, May 6, 1996, EGS Bull. 58, 197 (1996).

Niemann, H. B.; Haberman, J. A.; Harpold, D. N.; Hartle, R. E.; Kasprzak, W. T.; Mahaffy, P. R.; Atreya, S. K.; Carignan, G. R.; Donahue, T. M.; Hunten, D. M.; Owen, T. C.; Spencer, N. W.

1996-09-01

284

Disk structure and planet formation around young low-mass stars and brown dwarfs  

NASA Astrophysics Data System (ADS)

We propose to obtain IRS complete (5-40 micron) low-resolution spectra of a sample of 41 young low-mass stars and brown dwarfs, to study the characteristics of their disks and to search for evidence of ongoing planet formation. We also propose to use IRAC to observe an additional 43 newly-identified brown dwarfs in Taurus and Chamaeleon, for future IRS spectroscopic followup. This guaranteed-time observing program has a total of 50.1 hours, with 14 hours provided by IRAC PI Giovanni Fazio, and 36.1 hours by IRS PI Jim Houck.

Houck, James R.; Luhman, Kevin; Allen, Lori; Calvet, Nuria; Chen, Christine; Fazio, Giovanni; Forrest, Bill; Furlan, Elise; Hartmann, Lee; Jura, Mike; Keller, Luke; Mainzer, Amy; Markwick-Kemper, Ciska; Marley, Mark; Megeath, Tom; Muzerolle, James; Najita, Joan; Roellig, Tom; Sloan, Greg; Uchida, Keven; Watson, Dan; D'Alessio, Paola

2006-05-01

285

A New Planet Around an M Dwarf: Revealing a Correlation Between Exoplanets and Stellar Mass  

Microsoft Academic Search

We report precise Doppler measurements of GJ317 (M3.5V) that reveal the\\u000apresence of a planet with a minimum mass Msini = 1.2 Mjup in an eccentric,\\u000a692.9 day orbit. GJ317 is only the third M dwarf with a Doppler-detected Jovian\\u000aplanet. The residuals to a single-Keplerian fit show evidence of a possible\\u000asecond orbital companion. The inclusion of an additional

John Asher Johnson; R. Paul Butler; Geoffrey W. Marcy; Debra A. Fischer; Steven S. Vogt; Jason T. Wright; Kathryn M. G. Peek

2007-01-01

286

SPECTRAL AND PHOTOMETRIC DIAGNOSTICS OF GIANT PLANET FORMATION SCENARIOS  

SciTech Connect

Gas-giant planets that form via core accretion might have very different characteristics from those that form via disk instability. Disk-instability objects are typically thought to have higher entropies, larger radii, and (generally) higher effective temperatures than core-accretion objects. In this paper, we provide a large set of models exploring the observational consequences of high-entropy (hot) and low-entropy (cold) initial conditions, in the hope that this will ultimately help to distinguish between different physical mechanisms of planet formation. However, the exact entropies and radii of newly formed planets due to these two modes of formation cannot, at present, be precisely predicted. It is possible that the distribution of properties of core-accretion-formed planets and the distribution of properties of disk-instability-formed planets overlap. We, therefore, introduce a broad range of 'warm-start' gas-giant planet models. Between the hottest and the coldest models that we consider, differences in radii, temperatures, luminosities, and spectra persist for only a few million to a few tens of millions of years for planets that are a few times Jupiter's mass or less. For planets that are {approx}five times Jupiter's mass or more, significant differences between hottest-start and coldest-start models persist for on the order of 100 Myr. We find that out of the standard infrared bands (J, H, K, L', M, N) the K and H bands are the most diagnostic of the initial conditions. A hottest-start model can be from {approx}4.5 mag brighter (at Jupiter's mass) to {approx}9 mag brighter (at 10 times Jupiter's mass) than a coldest-start model in the first few million years. In more massive objects, these large differences in luminosity and spectrum persist for much longer than in less massive objects. Finally, we consider the influence of atmospheric conditions on spectra, and find that the presence or absence of clouds, and the metallicity of an atmosphere, can affect an object's apparent brightness in different bands by up to several magnitudes.

Spiegel, David S. [Institute for Advanced Study, Princeton, NJ 08540 (United States); Burrows, Adam, E-mail: dave@ias.edu, E-mail: burrows@astro.princeton.edu [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States)

2012-02-01

287

A Detailed Model Grid for Solid Planets from 0.1 through 100 Earth Masses  

NASA Astrophysics Data System (ADS)

This article describes a new grid for the mass--radius relation of three-layer exoplanets within the mass range of 0.1-100 M?. The three layers are: Fe (?-phase of iron), MgSiO3 (including both the perovskite phase, post-perovskite phase, and its dissociation at ultrahigh pressures), and H2O (including Ices Ih, III, V, VI, VII, X, and the superionic phase along the melting curve). We discuss the current state of knowledge about the equations of state (EOS) that influence these calculations and the improvements used in the new grid. For the two-layer model, we demonstrate the utility of contours on the mass--radius diagrams. Given the mass and radius input, these contours can be used to quickly determine the important physical properties of a planet including its p0 (central pressure), p1/p0 (core--mantle boundary pressure over central pressure), CMF (core mass fraction) or CRF (core radius fraction). For the three-layer model, a curve segment on the ternary diagram represents all possible relative mass proportions of the three layers for a given mass--radius input. These ternary diagrams are tabulated with the intent to make comparison to observations easier. How the presence of Fe in the mantle affects the mass--radius relations is also discussed in a separate section. A dynamic and interactive tool to characterize and illustrate the interior structure of exoplanets built upon models in this article is available online.

Zeng, Li; Sasselov, Dimitar

2013-03-01

288

Hiding in the Shadows: Searching for Planets in Pre-transitional and Transitional Disks  

NASA Astrophysics Data System (ADS)

Transitional and pre-transitional disks can be explained by a number of mechanisms. This work aims to find a single observationally detectable marker that would imply a planetary origin for the gap and, therefore, indirectly indicate the presence of a young planet. N-body simulations were conducted to investigate the effect of an embedded planet of one Jupiter mass on the production of instantaneous collisional dust derived from a background planetesimal disk. Our new model allows us to predict the dust distribution and resulting observable markers with greater accuracy than previous works. Dynamical influences from a planet on a circular orbit are shown to enhance dust production in the disk interior and exterior to the planet orbit, while removing planetesimals from the orbit itself, creating a clearly defined gap. In the case of an eccentric planet, the gap opened by the planet is not as clear as the circular case, but there is a detectable asymmetry in the dust disk.

Dobinson, Jack; Leinhardt, Zoë M.; Dodson-Robinson, Sarah E.; Teanby, Nick A.

2013-11-01

289

The Juno New Frontiers Jupiter Polar Orbiter Mission  

Microsoft Academic Search

The Juno mission is currently in Phase A Concept Study as a candidate for the next NASA New Frontiers program investigation. The overarching scientific goal of the Juno mission is to understand the origin and evolution of Jupiter. As the archetype of giant planets, Jupiter can provide the knowledge we need to understand the origin of our own solar system

O. Toby; B. Scott; M. Allison; J. Anderson; S. Atreya; F. Bagenal; M. Blanc; J. Bloxham; J. Connerney; A. Coradini; S. Cowley; D. Gautier; R. Gladstone; T. Guillot; S. Gulkis; C. Hansen; B. Hubbard; A. Ingersoll; M. Janssen; M. Klein; B. Kurth; S. Levin; J. Lunine; B. Mauk; D. McComas; E. Smith; D. Stevenson; E. Stone; R. Thorne

2004-01-01

290

The Juno New Frontiers Jupiter polar orbiter mission  

Microsoft Academic Search

The Juno mission, currently in Phase B, was selected in June 2005, by NASA to be the second mission in the New Frontiers Program. The overarching scientific goal of the Juno mission is to understand the origin and evolution of Jupiter. As the archetype of giant planets, Jupiter can provide the knowledge we need to understand the origin of our

S. Bolton

2006-01-01

291

Polar Lightning and Decadal-Scale Cloud Variability on Jupiter  

Microsoft Academic Search

Although lightning has been seen on other planets, including Jupiter, polar lightning has been known only on Earth. Optical observations from the New Horizons spacecraft have identified lightning at high latitudes above Jupiter up to 80°N and 74°S. Lightning rates and optical powers were similar at each pole, and the mean optical flux is comparable to that at nonpolar latitudes,

Kevin H. Baines; Amy A. Simon-Miller; Glenn S. Orton; Harold A. Weaver; Allen Lunsford; Thomas W. Momary; John Spencer; Andrew F. Cheng; Dennis C. Reuter; Donald E. Jennings; G. R. Gladstone; Jeffrey Moore; S. Alan Stern; Leslie A. Young; Henry Throop; Padma Yanamandra-Fisher; Brendan M. Fisher; Joseph Hora; Michael E. Ressler

2007-01-01

292

Estimations of changes of the Sun's mass and the gravitation constant from the modern observations of planets and spacecraft  

Microsoft Academic Search

More than 635 000 positional observations (mostly radiotechnical) of planets and spacecraft (1961-2010), have been used for estimating possible changes of the gravitation constant, the solar mass, and semi-major axes of planets, as well as the value of the astronomical unit, related to them. The analysis of the observations has been performed on the basis of the EPM2010 ephemerides of

E. V. Pitjeva; N. P. Pitjev

2011-01-01

293

Images of a fourth planet orbiting HR 8799.  

PubMed

High-contrast near-infrared imaging of the nearby star HR 8799 has shown three giant planets. Such images were possible because of the wide orbits (>25?astronomical units, where 1?au is the Earth-Sun distance) and youth (<100?Myr) of the imaged planets, which are still hot and bright as they radiate away gravitational energy acquired during their formation. An important area of contention in the exoplanet community is whether outer planets (>10?au) more massive than Jupiter form by way of one-step gravitational instabilities or, rather, through a two-step process involving accretion of a core followed by accumulation of a massive outer envelope composed primarily of hydrogen and helium. Here we report the presence of a fourth planet, interior to and of about the same mass as the other three. The system, with this additional planet, represents a challenge for current planet formation models as none of them can explain the in situ formation of all four planets. With its four young giant planets and known cold/warm debris belts, the HR 8799 planetary system is a unique laboratory in which to study the formation and evolution of giant planets at wide (>10?au) separations. PMID:21150902

Marois, Christian; Zuckerman, B; Konopacky, Quinn M; Macintosh, Bruce; Barman, Travis

2010-12-08

294

The HARPS search for southern extra-solar planets. XXVII. Up to seven planets orbiting HD 10180: probing the architecture of low-mass planetary systems  

Microsoft Academic Search

Context. Low-mass extrasolar planets are presently being discovered at an\\u000aincreased pace by radial velocity and transit surveys, opening a new window on\\u000aplanetary systems. Aims. We are conducting a high-precision radial velocity\\u000asurvey with the HARPS spectrograph which aims at characterizing the population\\u000aof ice giants and super-Earths around nearby solar-type stars. This will lead\\u000ato a better understanding

C. Lovis; D. Ségransan; M. Mayor; S. Udry; W. Benz; J.-L. Bertaux; F. Bouchy; A. C. M. Correia; J. Laskar; G. Lo Curto; C. Mordasini; F. Pepe; D. Queloz; N. C. Santos

2010-01-01

295

The HARPS search for southern extra-solar planets. XXVIII. Up to seven planets orbiting HD 10180: probing the architecture of low-mass planetary systems  

Microsoft Academic Search

Context. Low-mass extrasolar planets are presently being discovered at an increased pace by radial velocity and transit surveys, which opens a new window on planetary systems. Aims: We are conducting a high-precision radial velocity survey with the HARPS spectrograph, which aims at characterizing the population of ice giants and super-Earths around nearby solar-type stars. This will lead to a better

C. Lovis; D. Ségransan; M. Mayor; S. Udry; W. Benz; J.-L. Bertaux; F. Bouchy; A. C. M. Correia; J. Laskar; G. Lo Curto; C. Mordasini; F. Pepe; D. Queloz; N. C. Santos

2011-01-01

296

A Decreased Probability of Habitable Planet Formation around Low-Mass Stars  

Microsoft Academic Search

Smaller terrestrial planets (<~0.3 M?) are less likely to retain the substantial atmospheres and ongoing tectonic activity probably required to support life. A key element in determining whether sufficiently massive sustainably habitable planets can form is the availability of solid planet-forming material. We use dynamical simulations of terrestrial planet formation from planetary embryos and simple scaling arguments to explore the

Sean N. Raymond; John Scalo; Victoria S. Meadows

2007-01-01

297

"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)

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.

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

2011-01-01

298

Planets' magnetic environments  

SciTech Connect

The magnetospheres of Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and comets and the heliomagnetosphere are examined. The orientations of the planetary spin and magnetic axes, the size of the magnetospheres, and the magnetic properties and the radio emissions of the planets are compared. Results from spacecraft studies of the planets are included. Plans for the Voyager 2 mission and its expected study of the Neptune magnetosphere are considered.

Lanzerotti, L.J.; Uberoi, C.

1989-02-01

299

Discovery of the distant cool sub-Neptune mass planet OGLE 2005-BLG-390Lb by microlensing  

SciTech Connect

The favoured theoretical explanation for planetary systems formation is the core-accretion model in which solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars, the most common stars of our Galaxy, this model favours the formation of Earth- to Neptune-mass planets in a few million years with orbital sizes of 1 to 10 AU, which is consistent with the small number of detections of giant planets with M-dwarf host stars. More than 170 extrasolar planets have been discovered so far with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not previously been detected at separations of more than 0.15 AU from normal stars. Here we report the discovery of a 5.5{sub -2.7}{sup +5.5} Earthmass planetary companion at a separation of 2.6{sub -0.6}{sup +1.5}AU from a 0.22{sub -0.11}{sup +0.21} M{sub e} M-dwarf star, which is the lens star for gravitational microlensing event OGLE 2005-BLG-390. This is the lowest mass ever reported for an extrasolar planet orbiting a main sequence star, although the error bars overlap those for the mass of GJ876d. Our detection suggests that such cool, sub-Neptune mass planets may be common than gas giant planets, as predicted by the core accretion theory.

Beaulieu, J P; Bennett, D P; Fouque, P; Williams, A; Dominik, M; Jorgensen, U G; Kubas, D; Cassan, A; Coutures, C; Greenhill, J; Hill, K; Menzies, J; Sackett, P D; Albrow, M; Brillant, S; Caldwell, J R; Calitz, J J; Cook, K H; Corrales, E; Desort, M; Dieters, S; Dominis, D; Donatowicz, J; Hoffman, M; Kane, S; Marquette, J B; Martin, R; Meintjes, P; Pollard, K; Sahu, K; Vinter, C; Wambsganss, J; Woller, K; Horne, K; Steele, I; Bramich, D M; Burgdorf, M; Snodgrass, C; Bode, M; Udalski, A; Szymanski, M K; Kubiak, M; Wieckowski, T; Pietrzynski, G; Soszynski, I; Szewczyk, O; Wyrzykowski, L; Paczynski, B; Abe, F; Bond, I A; Britton, T R; Gilmore, A C; Hearnshaw, J B; Itow, Y; Kamiya, K; Kilmartin, P M; Korpela, A V; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okada, C; Ohnishi, K; Rattenbury, N J; Sako, T; Sato, S; Sasaki, M; Sekiguchi, T; Sullivan, D J; Tristram, P J; Yock, P M; Yoskioka, T

2005-11-07

300

Weighing the Non-transiting Hot Jupiter ? Boo b  

NASA Astrophysics Data System (ADS)

We report the detection of the orbital velocity of non-transiting hot Jupiter ? Boo b. By employing high-resolution ground-based spectroscopy around 2.3 ?m during one half-night, we are able to detect carbon monoxide absorption lines produced in the planet atmosphere, which shift significantly in wavelength during the course of the observations due to the orbital motion of the planet. This detection of the planetary signal results in the determination of the orbital inclination as being i = 47+7 - 6 deg and, furthermore, allows us to solve for the exact planetary mass, m p = 5.6 ± 0.7 M Jup. This clearly confirms the planetary nature of the non-transiting companion to ? Boo.

Rodler, F.; Lopez-Morales, M.; Ribas, I.

2012-07-01

301

Jovian Planet Finder optical system  

NASA Astrophysics Data System (ADS)

The Jovian Planet Finder (JPF) is a proposed NASA MIDEX mission to place a highly optimized coronagraphic telescope on the International Space Station (ISS) to image Jupiter-like planets around nearby stars. The optical system is an off-axis, unobscured telescope with a 1.5 m primary mirror. A classical Lyot coronagraph with apodized occulting spots is used to reduce diffracted light from the central star. In order to provide the necessary contrast for detection of a planet, scattered light from mid-spatial-frequency errors is reduced by using super-smooth optics. Recent advances in polishing optics for extreme-ultraviolet lithography have shown that a factor of >30 reduction in midfrequency errors relative to those in the Hubble Space Telescope is possible (corresponding to a reduction in scattered light of nearly 1000x). The low level of scattered and diffracted light, together with a novel utilization of field rotation introduced by the alt-azimuth ISS telescope mounting, will provide a relatively low-cost facility for not only imaging extrasolar planets, but also circumstellar disks, host galaxies of quasars, and low-mass substellar companions such as brown dwarfs.

Krist, John E.; Clampin, Mark; Petro, Larry; Woodruff, Robert A.; Ford, Holland C.; Illingworth, Garth D.; Ftaclas, Christ

2003-02-01

302

The Exosphere of a Newly Discovered Transiting Planet  

NASA Astrophysics Data System (ADS)

We propose to use HST to directly detect the atmosphere and extended envelope {exosphere} of a recently discovered planet that transits the relatively bright star HD 149026. Absorption of background stellar Lyman-alpha emission is an extremely sensitive exospheric diagnostic that only HST can measure. If the HD 149026 planet is evaporating, then hydrogen in the exosphere should fill or overfill the Roche lobe, which has a size 4 times the diameter of Jupiter. If we do not detect a decrease in Lyman-alpha flux during several transits, then the hydrogen exosphere does not fill the Roche lobe of the planet and significant evaporation is unlikely. This would be a surprise, given that Vidal-Madjar et al. {2003} detected the exosphere of the planet that transits HD 209458, and the models of Lecavelier des Etangs et al. {2004} predict an order of magnitude more evaporation for the planet around HD 149026, due to its lower mass and smaller orbital distance. The newly discovered planet has 3 times the mean density and at least 3 times the core mass of the planet that transits HD 209458, which is consistent with significant exospheric evaporation in the past. We will also use ACS/PR200L observations to measure stellar limb darkening in the NUV, to detect Mg in the lower atmosphere of the planet, and to search for evidence of a moon or planetary rings.

Valenti, Jeff

2005-07-01

303

Evaporation of extrasolar planets  

NASA Astrophysics Data System (ADS)

This article presents a review on the observations and theoretical modeling of the evaporation of extrasolar planets. The observations and the resulting constraints on the upper atmosphere (thermosphere and exosphere) of the ``hot-Jupiters'' are described. The early observations of the first discovered transiting extrasolar planet, HD209458b, allowed the discovery that this planet has an extended atmosphere of escaping hydrogen. Subsequent observations showed the presence of oxygen and carbon at very high altitude. These observations give unique constraints on the escape rate and mechanism in the atmosphere of hot-Jupiters. The most recent Lyman-alpha HST observations of HD189733b and MgII observations of Wasp-12b allow for the first time a comparison of the evaporation from different planets in different environments. Models to quantify the escape rate from the measured occultation depths, and an energy diagram to describe the evaporation state of hot-Jupiters are presented. Using this diagram, it is shown that few already known planets like GJ876d or CoRot-7b could be remnants of formerly giant planets.

Lecavelier Des Etangs, A.

2010-12-01

304

The life, death, and composition of exoterrestrial planets around intermediate mass stars  

NASA Astrophysics Data System (ADS)

This thesis attempts to comprehensively address the life, death, and composition of terrestrial-like planets orbiting around intermediate-mass stars. All-sky optical and infrared catalogs were cross-correlated to identify new main sequence stellar systems with evidence for terrestrial planet zone formation and evolution events. One such system is identified and its mid- infrared spectral energy distribution is characterized. In the course of cross- correlating the all-sky catalogs a new class of dusty, accreting, first-ascent giant star was discovered. Rough characterization of this new class of giants in the optical and infrared is provided with an emphasis on two giant-disk systems. The final throes of planetary systems around intermediate mass stars were investigated through the study of three gas-disk hosting white dwarfs. A dusty component to one white dwarf is identified, and the physical parameters regarding all three disks are determined. A model for the gas disk heating mechanism is suggested. By examining the pollution of the white dwarf photosphere by infalling disk material the first-ever bulk composition of an extra-solar rocky body is determined.

Melis, Carl Anthony

305

Benefits of Nuclear Electric Propulsion for Outer Planet Exploration.  

National Technical Information Service (NTIS)

Nuclear electric propulsion (NEP) offers significant benefits to missions for outer planet exploration. Reaching outer planet destinations, especially beyond Jupiter, is a struggle against time and distance. For relatively near missions, such as a Europa ...

L. Kos L. Johnson J. Jones A. Trausch B. Eberle G. Woodcock

2002-01-01

306

The HARPS search for southern extra-solar planets. XXVIII. Up to seven planets orbiting HD 10180: probing the architecture of low-mass planetary systems  

NASA Astrophysics Data System (ADS)

Context. Low-mass extrasolar planets are presently being discovered at an increased pace by radial velocity and transit surveys, which opens a new window on planetary systems. Aims: We are conducting a high-precision radial velocity survey with the HARPS spectrograph, which aims at characterizing the population of ice giants and super-Earths around nearby solar-type stars. This will lead to a better understanding of their formation and evolution, and will yield a global picture of planetary systems from gas giants down to telluric planets. Methods: Progress has been possible in this field thanks in particular to the sub-m s-1 radial velocity precision achieved by HARPS. We present here new high-quality measurements from this instrument. Results: We report the discovery of a planetary system comprising at least five Neptune-like planets with minimum masses ranging from 12 to 25 M?, orbiting the solar-type star HD 10180 at separations between 0.06 and 1.4 AU. A sixth radial velocity signal is present at a longer period, probably caused by a 65-M? object. Moreover, another body with a minimum mass as low as 1.4 M? may be present at 0.02 AU from the star. This is the most populated exoplanetary system known to date. The planets are in a dense but still well separated configuration, with significant secular interactions. Some of the orbital period ratios are fairly close to integer or half-integer values, but the system does not exhibit any mean-motion resonances. General relativity effects and tidal dissipation play an important role to stabilize the innermost planet and the system as a whole. Numerical integrations show long-term dynamical stability provided true masses are within a factor ~3 from minimum masses. We further note that several low-mass planetary systems exhibit a rather "packed" orbital architecture with little or no space left for additional planets. In several cases, semi-major axes are fairly regularly spaced on a logarithmic scale, giving rise to approximate Titius-Bode-like (i.e. exponential) laws. These dynamical architectures can be interpreted as the signature of formation scenarios where type I migration and interactions between protoplanets play a major role. However, it remains challenging to explain the presence of so many Neptunes and super-Earths on non-resonant, well-ordered orbits within ~1-2 AU of the central star. Finally, we also confirm the marked dependence of planet formation on both metallicity and stellar mass. Very massive systems are all found around metal-rich stars more massive than the Sun, while low-mass systems are only found around metal-deficient stars less massive than the Sun. Based on observations made with the HARPS instrument on the ESO 3.6-m telescope at La Silla Observatory (Chile), under program IDs 072.C-0488 and 183.C-0972.Radial velocities are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/528/A112

Lovis, C.; Ségransan, D.; Mayor, M.; Udry, S.; Benz, W.; Bertaux, J.-L.; Bouchy, F.; Correia, A. C. M.; Laskar, J.; Lo Curto, G.; Mordasini, C.; Pepe, F.; Queloz, D.; Santos, N. C.

2011-04-01

307

THE NASA-UC ETA-EARTH PROGRAM. II. A PLANET ORBITING HD 156668 WITH A MINIMUM MASS OF FOUR EARTH MASSES  

SciTech Connect

We report the discovery of HD 156668 b, an extrasolar planet with a minimum mass of M{sub P} sin i = 4.15 M{sub +}. This planet was discovered through Keplerian modeling of precise radial velocities from Keck-HIRES and is the second super-Earth to emerge from the NASA-UC Eta-Earth Survey. The best-fit orbit is consistent with circular and has a period of P = 4.6455 days. The Doppler semi-amplitude of this planet, K = 1.89 m s{sup -1}, is among the lowest ever detected, on par with the detection of GJ 581 e using HARPS. A longer period (P {approx} 2.3 years), low-amplitude signal of unknown origin was also detected in the radial velocities and was filtered out of the data while fitting the short-period planet. Additional data are required to determine if the long-period signal is due to a second planet, stellar activity, or another source. Photometric observations using the Automated Photometric Telescopes at Fairborn Observatory show that HD 156668 (an old, quiet K3 dwarf) is photometrically constant over the radial velocity period to 0.1 mmag, supporting the existence of the planet. No transits were detected down to a photometric limit of {approx}3 mmag, ruling out transiting planets dominated by extremely bloated atmospheres, but not precluding a transiting solid/liquid planet with a modest atmosphere.

Howard, Andrew W.; Marcy, Geoffrey W.; Isaacson, Howard [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Johnson, John Asher [Department of Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Fischer, Debra A. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Wright, Jason T. [Center for Exoplanets and Habitable Worlds, Pennsylvania State University, University Park, PA 16802 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Valenti, Jeff A.; Anderson, Jay [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Piskunov, Nikolai E., E-mail: howard@astro.berkeley.edu [Department of Astronomy and Space Physics, Uppsala University, Box 515, 751 20 Uppsala (Sweden)

2011-01-10

308

The mass function of primordial rogue planet MACHOs in quasar nano-lensing  

NASA Astrophysics Data System (ADS)

The recent Sumi et al (2010 Astrophys. J. 710 1641; 2011 Nature 473 349) detection of free roaming planet mass MACHOs in cosmologically significant numbers recalls their original detection in quasar microlening studies (Colley and Schild 2003 Astrophys. J. 594 97; Schild R E 1996 Astrophys. J. 464 125). We consider the microlensing signature of such a population, and find that the nano-lensing (microlensing) would be well characterized by a statistical microlensing theory published previously by Refsdal and Stabell (1991 Astron. Astrophys. 250 62) Comparison of the observed First Lens microlensing amplitudes with the theoretical prediction gives close agreement and a methodology for determining the slope of the mass function describing the population. Our provisional estimate of the power law exponent in an exponential approximation to this distribution is 2.98+1.0-0.5, where a Salpeter slope is 2.35.

Schild, Rudolph E.; Nieuwenhuizen, Theo M.; Gibson, Carl H.

2012-11-01

309

WASP-12b as a prolate, inflated and disrupting planet from tidal dissipation.  

PubMed

The class of exotic Jupiter-mass planets that orbit very close to their parent stars were not explicitly expected before their discovery. The recently discovered transiting planet WASP-12b has a mass M = 1.4 +/- 0.1 Jupiter masses (M(J)), a mean orbital distance of only 3.1 stellar radii (meaning it is subject to intense tidal forces), and a period of 1.1 days. Its radius 1.79 +/- 0.09R(J) is unexpectedly large and its orbital eccentricity 0.049 +/- 0.015 is even more surprising because such close orbits are usually quickly circularized. Here we report an analysis of its properties, which reveals that the planet is losing mass to its host star at a rate of about 10(-7)M(J) per year. The planet's surface is distorted by the star's gravity and the light curve produced by its prolate shape will differ by about ten per cent from that of a spherical planet. We conclude that dissipation of the star's tidal perturbation in the planet's convective envelope provides the energy source for its large volume. We predict up to 10 mJy CO band-head (2.292 mum) emission from a tenuous disk around the host star, made up of tidally stripped planetary gas. It may also contain a detectable resonant super-Earth, as a hypothetical perturber that continually stirs up WASP-12b's eccentricity. PMID:20182506

Li, Shu-Lin; Miller, N; Lin, Douglas N C; Fortney, Jonathan J

2010-02-25

310

SOPHIE velocimetry of Kepler transit candidates. IV. KOI-196b: a non-inflated hot Jupiter with a high albedo  

NASA Astrophysics Data System (ADS)

We report the discovery of a new hot-Jupiter, KOI-196b, transiting a solar-type star with an orbital period of 1.855558 days ± 0.6 s thanks to public photometric data from the Kepler space mission and new radial velocity observations obtained by the SOPHIE spectrograph mounted on the 1.93-m telescope at the Observatoire de Haute-Provence, France. The planet KOI-196b, with a radius of 0.89 ± 0.05 RJup and a mass of 0.55 ± 0.09 MJup, orbits a G6V star with R? = 1.02 ± 0.03 R?, M? = 1.12 ± 0.07 M?, [Fe/H] = 0.29 ± 0.16 dex, Teff = 5620 ± 140 K, and an age of 650 +2500-300} Myr. KOI-196b is one of the rare close-in hot Jupiters with a radius smaller than Jupiter suggesting that it is a non-inflated planet. The high precision of the Kepler photometry permits us to detect the secondary transit with a depth of 64 +10-12} ppm as well as the optical phase variation. We find a geometric albedo of Ag = 0.30 ± 0.08, which is higher than most of the transiting hot Jupiters with a measured Ag. Assuming no heat recirculation, we find a day-side temperature of Tday = 1730 ± 400 K. The planet KOI-196b seems to be one of the rare hot Jupiters located in the short-period hot-Jupiter desert. Based on observations made with SOPHIE on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS), France.

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

2011-12-01

311

Observational Evidence for Tidal Effects in Hot Jupiters  

NASA Astrophysics Data System (ADS)

Several hundred hot Jupiters are now known to orbit very close to their host star, where tidal effects are expected to have a significant impact on the planet's evolution. We search for evidence of tidal effects in the sample of known transiting planets by analysing new radial velocity measurements using the HARPS and SOPHIE spectrographs, as well as re-analysing existing radial velocity measurements and photometric constraints on the orbital elements from the literature. We show that the orbital eccentricities and the projected spin-orbit alignment angles as measured from the Rossiter McLaughlin effect for known transiting planets, where available, are in fact fully compatible with classical tidal theory, without having recourse to special scenarios such as eccentricity pumping from a second companion in the system, etc. We also show that planets on circular orbits gather in a well-defined region in the mass-period plane at the shortest possible period for a given mass, and we reexamine the recent hypothesis that the presence of a convective stellar envelope leads to a spin-orbit alignment.

Husnoo, Nawal; Pont, F.; Mazeh, T.; Fabrycky, D.; Hebrard, G.; Bouchy, F.; Moutou, C.; Shporer, A.

2011-09-01

312

Mantle Convection in the Earth and Planets  

Microsoft Academic Search

Mantle Convection in the Earth and Planets is a comprehensive synthesis of all aspects of mantle convection within the Earth, the terrestrial planets, the Moon, and the Galilean satellites of Jupiter. The authors include up-to-date discussions of the latest research developments that have revolutionized our understanding of the Earth and the planets. The book features a comprehensive index, an extensive

Gerald Schubert; Donald L. Turcotte; Peter Olson

2001-01-01

313

Extrasolar Trojan planets close to habitable zones  

Microsoft Academic Search

We investigate the stability regions of hypothetical terrestrial planets around the Lagrangian equilibrium points L4 and L5 in some specific extrasolar planetary systems. The problem of their stability can be treated in the framework of the restricted three body problem where the host star and a massive Jupiter-like planet are the primary bodies and the terrestrial planet is regarded as

R. Dvorak; E. Pilat-Lohinger; R. Schwarz; F. Freistetter

2004-01-01

314

A planet around the evolved intermediate-mass star HD 110014  

NASA Astrophysics Data System (ADS)

Context: We found evidence for a sub-stellar companion around the K giant star HD 110014. This cool evolved star, with a spectral type K2III and an estimated mass between 1.9 and 2.4 M?, is slightly metal rich with [Fe/H] = 0.19 and a rotational velocity V sin i = 2.0 km s-1. Aims: To search for extrasolar planets around intermediate-mass stars and to improve our knowledge of the nature of radial velocity variations shown by G and K giant stars. Methods: Based on radial velocity analysis, we found evidence for a substellar companion with a planetary mass and long orbital period. The Radial velocity variation of HD 110014 has been monitored from 2000 until 2007 with FEROS at 1.5 m ESO and at the 2.2 m MPG/ESO, HARPS at the 3.6 m ESO and Coralie at 1.2 m Leonard Euler swiss telescopes in La Silla observatory. The radial velocities were computed by using a cross-correlation technique. Line bisector, Hipparcos photometry and chromospheric lines were analyzed to exclude other root-causes for the radial velocity variability. Results: We report the presence of an extrasolar planet around the giant star HD 110014, with an orbital period of 835.48 ± 6.04 days. A Keplerian orbit, with an eccentricity e = 0.462± 0.069, yields a minimum mass M sin i = 11.09 MJup. The analysis of the residuals shows evidence for a second RV variability with a period of 130 days and an amplitude of ±100 ms-1 . Its nature is not completely clear, but a second planet is a possible explanation. Based on observations collected at the 1.52-m ESO telescope (1999 to 2002), at the 2.2-m MPG/ESO telescope (2003 to 2007), at the 3.60 ESO telescope and at the Euler swiss telescope, at the La Silla Observatory, Chile. Radial velocity measurements are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/504/617

de Medeiros, J. R.; Setiawan, J.; Hatzes, A. P.; Pasquini, L.; Girardi, L.; Udry, S.; Döllinger, M. P.; da Silva, L.

2009-09-01

315

Formation of Giant Planets  

NASA Astrophysics Data System (ADS)

The observed properties of giant planets, models of their evolution, and observations of protoplanetary disks provide constraints on the formation of gas giant planets. The four largest planets in our solar system contain considerable quantities of hydrogen and helium; these gases could not have condensed into solid planetesimals within the protoplanetary disk. Jupiter and Saturn are mostly hydrogen and helium, but have larger abundances of heavier elements than does the Sun. Neptune and Uranus are primarily composed of heavier elements. The transiting extrasolar planet HD149026b, which is slightly more massive than Saturn, appears to have comparable amounts of light gases and heavy elements. The other observed transiting exoplanets are primarily hydrogen and helium, but may contain supersolar abundances of heavy elements. Spacecraft flybys and observations of satellite orbits provide estimates of the gravitational moments of the giant planets in our solar system, which in turn provide information on the internal distribution of matter within Jupiter, Saturn, Uranus, and Neptune. Atmospheric thermal structure and heat flow measurements constrain the interior temperatures of these planets. Internal processes may cause giant planets to become more compositionally differentiated or alternatively more homogeneous; high-pressure laboratory experiments provide data useful for modeling these processes. The preponderance of evidence supports the core nucleated gas accretion model. According to this model, giant planets begin their growth by the accumulation of small solid bodies, as do terrestrial planets. However, unlike terrestrial planets, the giant planet cores grow massive enough to accumulate substantial amounts of gas before the protoplanetary disk dissipates. The primary question regarding the core nucleated growth model is under what conditions can planets develop cores sufficiently massive to accrete gas envelopes within the lifetimes of gaseous protoplanetary disks.

Lissauer, J. J.; Stevenson, D. J.

316

Temporary satellite captures of comets by Jupiter  

NASA Astrophysics Data System (ADS)

Recent numerical researches on the dynamics of close approaches of short period comets to Jupiter have confirmed that in several cases objects of this kind can be captured by the planet as temporary satellites. This phenomenon seems to occur rather frequently and provides new insights on the orbital evolutionary patterns of short period comets.

Carusi, A.; Valsecchi, G. B.

1981-02-01

317

The Sub-Saturn Mass Transiting Planet HAT-P-12b  

NASA Astrophysics Data System (ADS)

We present new photometric data of the transiting planet HAT-P-12b observed in 2011. Our three transit curves are modeled using the JKTEBOP code and adopting the quadratic limb-darkening law. Including our measurements, 18 transit times spanning about 4.2 yr were used to determine the improved ephemeris with a transit epoch of 2,454,187.85560 ± 0.00011 BJD and an orbital period of 3.21305961 ± 0.00000035 days. The physical properties of the star-planet system are computed using empirical calibrations from eclipsing binary stars and stellar evolutionary models, combined with both our transit parameters and previously known spectroscopic results. We found that the absolute dimensions of the host star are M A = 0.73 ± 0.02 M ?, R A = 0.70 ± 0.01 R ?, log g A = 4.61 ± 0.02, ?A = 2.10 ± 0.09 ??, and L A = 0.21 ± 0.01 L ?. The planetary companion has M b = 0.21 ± 0.01 M Jup, R b = 0.94 ± 0.01 R Jup, log g b = 2.77 ± 0.02, ?b = 0.24 ± 0.01 ?Jup, and T eq = 960 ± 14 K. Our results agree well with standard models of irradiated gas giants with a core mass of 11.3 M ?.

Lee, Jae Woo; Youn, Jae-Hyuck; Kim, Seung-Lee; Lee, Chung-Uk; Hinse, Tobias Cornelius

2012-04-01

318

ON THE HORSESHOE DRAG OF A LOW-MASS PLANET. II. MIGRATION IN ADIABATIC DISKS  

SciTech Connect

We evaluate the horseshoe drag exerted on a low-mass planet embedded in a gaseous disk, assuming the disk's flow in the co-orbital region to be adiabatic. We restrict this analysis to the case of a planet on a circular orbit, and we assume a steady flow in the corotating frame. We also assume that the corotational flow upstream of the U-turns is unperturbed, so that we discard saturation effects. In addition to the classical expression for the horseshoe drag in barotropic disks, which features the vortensity gradient across corotation, we find an additional term which scales with the entropy gradient, and whose amplitude depends on the perturbed pressure at the stagnation point of the horseshoe separatrices. This additional torque is exerted by evanescent waves launched at the horseshoe separatrices, as a consequence of an asymmetry of the horseshoe region. It has a steep dependence on the potential's softening length, suggesting that the effect can be extremely strong in the three-dimensional case. We describe the main properties of the co-orbital region (the production of vortensity during the U-turns, the appearance of vorticity sheets at the downstream separatrices, and the pressure response), and we give torque expressions suitable to this regime of migration. Side results include a weak, negative feedback on migration, due to the dependence of the location of the stagnation point on the migration rate, and a mild enhancement of the vortensity-related torque at a large entropy gradient.

Masset, F. S.; Casoli, J., E-mail: frederic.masset@cea.f, E-mail: jules.casoli@cea.f, E-mail: frederic.masset@cea.f [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d'Astrophysique, Bat. 709, CEA/Saclay, 91191 Gif-sur-Yvette (France)

2009-09-20

319

The Influence of Giant Planets Near a Mean Motion Resonance on Earth-like Planets in the Habitable Zone of Sun-like Stars  

Microsoft Academic Search

We present a numerical study of several two-planet systems based on the motions of Jupiter and Saturn, in which the two giant planets move in low eccentric orbits close to a mean motion resonance. It is more likely to find two planets with similar characteristics in a system than a clone of the Jupiter-Saturn pair of our solar system. Therefore,

E. Pilat-Lohinger; Á. Süli; P. Robutel; F. Freistetter

2008-01-01

320

Speculating on Additional Planets and Debris in the OGLE-2006-BLG-109L System  

NASA Astrophysics Data System (ADS)

The multiple-planet extrasolar system OGLE-2006-BLG-109L, discovered by gravitational microlensing, is possibly the closest analog to the solar system yet known (1): the two detected planets have mass ratios, semimajor axis ratios, and equilibrium temperatures that are similar to those of Jupiter and Saturn; the mass of the host star is only 0.5 solar mass, and the system is more compact than our own Solar system. The gravity of the two detected planets limits the regions in this system where additional planets and debris belts may exist. Test particle orbital stability analysis indicates that this system may readily harbor two debris belts, one interior and one exterior to the two Jovian planets, analogous to the Solar system's asteroid belt and Kuiper belt. Orbital stability in the habitable zone of this system is very sensitive to the stellar mass and the jovian planets' masses and orbital parameters: stable orbits may be possible if the Jovian planets' have anti-aligned apsides or are librating in a 2:1 mean motion resonance, otherwise a strong secular resonance would excite large orbital eccentricities and force an Earth-mass planet out of the habitable zone (2,3). However, an additional inner planet of at least 0.3 earth-mass quenches the instability in the habitable zone (2). Thus, our orbital stability considerations lead to this speculative conclusion: with two terrestrial planets, two jovian planets and two debris belts, the planetary architecture of a potentially habitable OGLE-2006-BLG-109L planetary system could bear even closer resemblance to our own Solar system than the two detected planets alone suggest. References: (1) Gaudi, B.S., et al., Science, 319, 927 (2008); (2) Malhotra, R., Minton, D.A., ApJ-Letts, 683:L67-L70 (2008); (3) Migaszewski, C., et al., MNRAS, in press.

Malhotra, Renu; Minton, D. A.

2009-05-01

321

Gravitational signature of Jupiter's internal dynamics  

NASA Astrophysics Data System (ADS)

Telescopic observations and space missions to Jupiter have provided vast information about Jupiter's cloud level winds, but the depth to which these winds penetrate has remained an ongoing mystery. Scheduled to be launched in 2011, the Jupiter orbiter Juno will make high-resolution observations of Jupiter's gravity field. In this paper we show that these measurements are sensitive to the depth of the internal winds. We use dynamical models ranging from an idealized thermal wind balance analysis, using the observed cloud-top winds, to a full general circulation model (GCM). We relate the depth of the dynamics to the external gravity spectrum for different internal wind structure scenarios. In particular, we predict that substantial Jovian winds below a depth of 500 km would lead to detectable (milligal-level) gravity anomalies with respect to the expected gravity for a planet in solid body rotation.

Kaspi, Yohai; Hubbard, William B.; Showman, Adam P.; Flierl, Glenn R.

2010-01-01

322

The HARPS search for southern extra-solar planets. XVII. Super-Earth and Neptune-mass planets in multiple planet systems HD47186 and HD181433  

Microsoft Academic Search

This paper reports on the detection of two new multiple planet systems around\\u000asolar-like stars HD47186 and HD181433. The first system includes a hot Neptune\\u000aof 22.78 M_Earth at 4.08-days period and a Saturn of 0.35 M_Jup at 3.7-years\\u000aperiod. The second system includes a Super-Earth of 7.5 M_Earth at 9.4-days\\u000aperiod, a 0.64 M$_Jup at 2.6-years period as well

F. Bouchy; M. Mayor; C. Lovis; S. Udry; W. Benz; J.-L. Bertaux; X. Delfosse; C. Mordasini; F. Pepe; D. Queloz; D. Segransan

2008-01-01

323

SUPER-ECCENTRIC MIGRATING JUPITERS  

SciTech Connect

An important class of formation theories for hot Jupiters involves the excitation of extreme orbital eccentricity (e = 0.99 or even larger) followed by tidal dissipation at periastron passage that eventually circularizes the planetary orbit at a period less than 10 days. In a steady state, this mechanism requires the existence of a significant population of super-eccentric (e > 0.9) migrating Jupiters with long orbital periods and periastron distances of only a few stellar radii. For these super-eccentric planets, the periastron is fixed due to conservation of orbital angular momentum and the energy dissipated per orbit is constant, implying that the rate of change in semi-major axis a is a-dot {proportional_to}a{sup 1/2} and consequently the number distribution satisfies dN/d log a{proportional_to}a{sup 1/2}. If this formation process produces most hot Jupiters, Kepler should detect several super-eccentric migrating progenitors of hot Jupiters, allowing for a test of high-eccentricity migration scenarios.

Socrates, Aristotle; Katz, Boaz; Dong Subo; Tremaine, Scott [Institute for Advanced Study, Princeton, NJ 08540 (United States)

2012-05-10

324

Comparison of periodic substorms at Jupiter and Earth  

NASA Astrophysics Data System (ADS)

The Energetic Particles Detector and magnetometer measurements on Galileo showed that the Jovian magnetosphere undergoes reconfiguration processes which are very similar to the characteristics of a terrestrial substorm. At Jupiter the reconfiguration process occurs quasi-periodically with a repetition period of several days. In the terrestrial magnetosphere periodic substorms have been observed during magnetic storms. The comparison of the periodic magnetospheric disturbances at Jupiter and Earth shows that they are similar in dynamic features as well as in spatial distribution but have different energy sources. In the case of Earth, the well-established energy source is the solar wind. In the case of the Jovian magnetosphere, it is believed that internal energy is supplied by the fast planetary rotation and the moon Io which releases ˜1000 kg s-1 of plasma into the magnetosphere. It is established that the energy accumulation and subsequent release lead to similar features in the magnetospheres of both planets. The particle data show periodic intensity fluctuations and plasma pressure variations. In addition, recurring signatures of stretching and dipolarization are observed in the magnetic field at the terrestrial and Jovian magnetospheres. Furthermore, the release process is associated with an intensification of auroral emissions. The typical phases for terrestrial substorms like growth, expansion and recovery are also found in the periodic substorms at Jupiter. As a lesson taken from the Jovian magnetosphere it is proposed that under certain conditions periodic magnetospheric substorms at Earth can be driven by mass-loading from the plasmasphere.

Kronberg, E. A.; Woch, J.; Krupp, N.; Lagg, A.; Daly, P. W.; Korth, A.

2008-04-01

325

Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits  

NASA Astrophysics Data System (ADS)

To aid in the physical interpretation of planetary radii constrained through observations of transiting planets, or eventually direct detections, we compute model radii of pure hydrogen-helium, water, rock, and iron planets, along with various mixtures. Masses ranging from 0.01 Earth masses to 10 Jupiter masses at orbital distances of 0.02-10 AU are considered. For hydrogen-helium rich planets, our models are the first to couple planetary evolution to stellar irradiation over a wide range of orbital separations (0.02-10 AU) through a nongray radiative-convective equilibrium atmosphere model. Stellar irradiation retards the contraction of giant planets, but its effect is not a simple function of the irradiation level: a planet at 1 AU contracts as slowly as a planet at 0.1 AU. We confirm the assertion of Guillot that very old giant planets under modest stellar irradiation (like that received by Jupiter and Saturn) develop isothermal atmospheric radiative zones once the planet's intrinsic flux drops to a small fraction of the incident flux. For hydrogen-helium planets, we consider cores up to 90% of the total planet mass, comparable to those of Uranus and Neptune. If ``hot Neptunes'' have maintained their original masses and are not remnants of more massive planets, radii of ~0.30-0.45 RJ are expected. Water planets are ~40%-50% larger than rocky planets, independent of mass. Finally, we provide tables of planetary radii at various ages and compositions, and for ice-rock-iron planets we fit our results to analytic functions, which will allow for quick composition estimates, given masses and radii, or mass estimates, given only planetary radii. These results will assist in the interpretation of observations for both the current transiting planet surveys as well as upcoming space missions, including COROT and Kepler.

Fortney, J. J.; Marley, M. S.; Barnes, J. W.

2007-04-01

326

ORBITS AND MASSES OF THE SATELLITES OF THE DWARF PLANET HAUMEA (2003 EL61)  

SciTech Connect

Using precise relative astrometry from the Hubble Space Telescope and the W. M. Keck Telescope, we have determined the orbits and masses of the two dynamically interacting satellites of the dwarf planet (136108) Haumea, formerly 2003 EL61. The orbital parameters of Hi'iaka, the outer, brighter satellite, match well the previously derived orbit. On timescales longer than a few weeks, no Keplerian orbit is sufficient to describe the motion of the inner, fainter satellite Namaka. Using a fully interacting three-point-mass model, we have recovered the orbital parameters of both orbits and the mass of Haumea and Hi'iaka; Namaka's mass is marginally detected. The data are not sufficient to uniquely determine the gravitational quadrupole of the nonspherical primary (described by J {sub 2}). The nearly coplanar nature of the satellites, as well as an inferred density similar to water ice, strengthen the hypothesis that Haumea experienced a giant collision billions of years ago. The excited eccentricities and mutual inclination point to an intriguing tidal history of significant semimajor axis evolution through satellite mean-motion resonances. The orbital solution indicates that Namaka and Haumea are currently undergoing mutual events and that the mutual event season will last for next several years.

Ragozzine, D.; Brown, M. E. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)], E-mail: darin@gps.caltech.edu

2009-06-15

327

The Nine Planets: Mercury  

NSDL National Science Digital Library

This page of Nine Planets highlights details about the planet Mercury. Information includes planet diameter, mass, distance from the Sun, orbit, and mythology. Also covered are composition, surface features, atmosphere and magnetic field data, and the results of exploration spacecraft. The site provides links to images, movies, and more Mercury facts. Unanswered questions about the planet are also discussed.

Arnett, Bill

328

A giant planet around HD95086 ?  

NASA Astrophysics Data System (ADS)

Understanding planetary systems formation and evolution has become one of the challenges in as- tronomy, since the discovery of the first exoplanet around the solar-type star 51 Peg in the 90's. While more than 800 planets (mostly giants) closer than a few AU have been identified with radial velocity and transit techniques, very few have been imaged and definitely confirmed around stars, at separations below a hundred of astronomical units. Direct imaging detection of exoplanet is indeed a major frontier in planetary astrophysics. It surveys a region of semi-major axes (> 5 AU) that is almost inaccessible to other methods. Moreover, the planets imaged so far orbit young stars; indeed the young planets are still hot and the planet-star contrasts are compatible with the detection limits currently achievable, in contrast with similar planets in older systems. Noticeably, the stars are of early-types, and surrounded by debris disks, i.e. disks populated at least by small grains with lifetimes so short that they must be permanently produced, probably by destruction (evaporation, collisions) of larger solid bodies. Consequently, every single discovery has a tremendous impact on the understanding of the formation, the dynamical evolution, and the physics of giant planets. In this context, I will present our recent discovery of one faint companion to a nearby, dusty, and young A-type star (at 56 AU projected separation). Background contaminants are rejected with high confidence level based on both astrometry and photometry with three dataset at more than a year-time-laps and two different wavelength regimes. From the system age (10 to 17 Myr) and from model-dependent luminosity estimates, we derive mass of 4 to 5 Jupiter mass. This planet is therefore the one with the lowest mass ever imaged around a star. Given its orbital and physical properties, I will discuss the implication on its atmosphere with respect to other imaged companions but also on its formation.

Rameau, Julien; Chauvin, Gaël; Lagrange, Anne-Marie; Meshkat, Tiffany; Boccaletti, Anthony; Quanz, Sascha P.; Bonnefoy, Mickaël; Bailey, Vanessa; Kenworthy, Matthew; Currie, Thayne; Girard, Julien H.; Delorme, Philippe; Desidera, Silvano; Dumas, Christophe; Mordasini, Christoph; Klahr, Hubert; Bonavita, Mariangela

2013-07-01

329

ON THE HORSESHOE DRAG OF A LOW-MASS PLANET. I. MIGRATION IN ISOTHERMAL DISKS  

SciTech Connect

We investigate the unsaturated horseshoe drag exerted on a low-mass planet by an isothermal gaseous disk. In the globally isothermal case, we use a formalism, based on the use of a Bernoulli invariant, that takes into account pressure effects, and that extends the torque estimate to a region wider than the horseshoe region. We find a result that is strictly identical to the standard horseshoe drag. This shows that the horseshoe drag accounts for the torque of the whole corotation region, and not only of the horseshoe region, thereby deserving to be called corotation torque. We find that evanescent waves launched downstream of the horseshoe U-turns by the perturbations of vortensity exert a feedback on the upstream region, that render the horseshoe region asymmetric. This asymmetry scales with the vortensity gradient and with the disk's aspect ratio. It does not depend on the planetary mass, and it does not have any impact on the horseshoe drag. Since the horseshoe drag has a steep dependence on the width of the horseshoe region, we provide an adequate definition of the width that needs to be used in horseshoe drag estimates. We then consider the case of locally isothermal disks, in which the temperature is constant in time but depends on the distance to the star. The horseshoe drag appears to be different from the case of a globally isothermal disk. The difference, which is due to the driving of vortensity in the vicinity of the planet, is intimately linked to the topology of the flow. We provide a descriptive interpretation of these effects, as well as a crude estimate of the dependency of the excess on the temperature gradient.

Casoli, J.; Masset, F. S., E-mail: jules.casoli@cea.f, E-mail: frederic.masset@cea.f, E-mail: jules.casoli@cea.f [Also at ICF-UNAM, Av. Universidad s/n, Cuernavaca, Morelos, C.P. 62210 (Mexico)

2009-09-20

330

OHMIC DISSIPATION IN THE INTERIORS OF HOT JUPITERS  

SciTech Connect

We present models of ohmic heating in the interiors of hot Jupiters in which we decouple the interior and the wind zone by replacing the wind zone with a boundary temperature T{sub iso} and magnetic field B{sub {phi}0}. Ohmic heating influences the contraction of gas giants in two ways: by direct heating within the convection zone and by heating outside the convection zone, which increases the effective insulation of the interior. We calculate these effects and show that internal ohmic heating is only able to slow the contraction rate of a cooling gas giant once the planet reaches a critical value of internal entropy. We determine the age of the gas giant when ohmic heating becomes important as a function of mass, T{sub iso}, and induced B{sub {phi}0}. With this survey of parameter space complete, we then adopt the wind zone scalings of Menou and calculate the expected evolution of gas giants with different levels of irradiation. We find that, with this prescription of magnetic drag, it is difficult to inflate massive planets or those with strong irradiation using ohmic heating, meaning that we are unable to account for many of the observed hot Jupiter radii. This is in contrast to previous evolutionary models that assumed that a constant fraction of the irradiation is transformed into ohmic power.

Huang Xu [Department of Astrophysical Sciences, 4 Ivy Lane, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Cumming, Andrew, E-mail: xuhuang@princeton.edu, E-mail: cumming@physics.mcgill.ca [Department of Physics, McGill University, 3600 Rue University, Montreal, QC H3A 2T8 (Canada)

2012-09-20

331

Map of Jupiter's moon Io  

NASA Astrophysics Data System (ADS)

Map of Jupiter's moon Io The first global geologic map of the Jovian satellite Io has been published by the U.S. Geological Survey (USGS), the agency announced on 19 March. “More than 130 years after the USGS first began producing quality geologic maps here on Earth, it is exciting to have the reach of our science extend across 400 million miles to this volcanically active moon of Jupiter,” said USGS director Marcia McNutt. “Somehow it makes the vast expanse of space seem less forbidding to know that similar geologic processes which have shaped our planet are active elsewhere.” The map illustrates the geologic character of the unique and active volcanoes on Io, a planetary body that has about 25 times more volcanic activity than Earth does, according to USGS.

Showstack, Randy

2012-04-01

332

The gravity signature of internal dynamics on Jupiter, Saturn, Uranus and Neptune  

NASA Astrophysics Data System (ADS)

A key question regarding the circulation on the giant planets is how deep do the zonal flows observed at the cloud level extend into the interior. The upcoming Juno mission to Jupiter and extended Cassini mission to Saturn will perform close flybys of these planets enabling them to measure high-order gravity harmonics, which can give information about the depth of the circulation. Here, we systematically determine the gravity signature for a variety of plausible flow configurations, with the goal of determining what constraints can be placed on the flow field from spacecraft determination of the gravity field. For this analysis we use a mix of models including potential-theory models; an anelastic deep general circulation model simulating the fluid motion on the planet and the resulting density perturbations; and a thermal-wind analysis in which we use the observed surface winds and extend them into the interior while varying the depth of the flow along angular momentum surfaces. The latter approach allows a systematic study of the relation between the depth of the winds and the resulting gravity field. For Jupiter the signature of deep winds will appear at gravity harmonic J10 and beyond, which is likely to be measurable by Juno. On the other planets the gravity signature of the circulation is expected to appear at even lower harmonics due to their lower masses, stronger surface winds, and the fact that they have fewer, wider jets (in latitude) than Jupiter. The extreme case is Neptune where if the zonal winds are deep enough they can affect even J4. On Saturn, these results for the lower harmonics can potentially constrain the recent uncertainty in the exact rotation period. We discuss the results for each of the giant planets, the physical constraints they give about the circulation and implications for the Juno and Cassini missions.

Kaspi, Y.; Showman, A. P.; Hubbard, W. B.

2011-10-01

333

Implications of (Less) Accurate Mass-Radius-Measurements for the Habitability of Extrasolar Terrestrial Planets: Why Do We Need PLATO?  

NASA Astrophysics Data System (ADS)

Several space missions (CoRoT, Kepler and others) already provided promising candidates for terrestrial exoplanets (i.e. with masses less than about 10 Earth masses) and thereby triggered an exciting new research branch of planetary modelling to investigate the possible habitability of such planets. Earth analogues (low-mass planets with an Earth-like structure and composition) are likely to be found in the near future with new missions such as the proposed M3 mission PLATO. Planets may be more diverse in the universe than they are in the solar system. Our neighbouring planets in the habitable zone are all terrestrial by the means of being differentiated into an iron core, a silicate mantle and a crust. To reliably determine the interior structure of an exoplanet, measurements of mass and radius have to be sufficiently accurate (around +/-2% error allowed for the radius and +/-5% for the mass). An Earth-size planet with an Earth-like mass but an expected error of ~15% in mass for example may have either a Mercury-like, an Earth-like or a Moon-like (i.e. small iron core) structure [1,2]. Even though the atmospheric escape is not strongly influenced by the interior structure, the outgassing of volatiles and the likeliness of plate tectonics and an ongoing carbon-cycle may be very different. Our investigations show, that a planet with a small silicate mantle is less likely to shift into the plate-tectonics regime, cools faster (which may lead to the loss of a magnetic field after a short time) and outgasses less volatiles than a planet with the same mass but a large silicate mantle and small iron core. To be able to address the habitability of exoplanets, space missions such as PLATO, which can lead up to 2% accuracy in radius [3], are extremely important. Moreover, information about the occurrence of different planetary types helps us to better understand the formation of planetary systems and to further constrain the Drake's equation, which gives an estimate of the expected number of potentially habitable exoplanets in the universe.

Noack, L.; Wagner, F. W.; Plesa, A.-C.; Höning, D.; Sohl, F.; Breuer, D.; Rauer, H.

2012-04-01

334

Conjunctions of Jupiter and Saturn  

NASA Astrophysics Data System (ADS)

This year's Jupiter-Saturn conjunction is an astronomical event that has been noted in yearbooks, even though it occurred too close to the Sun to be readily visible. Astronomical conjunctions are often loosely defined. Four questions need to be answered: Which two astronomical bodies are involved? What co-ordinate system is used to define the conjunction? From what astronomical body is the event observed? Is the event described apparent or real? Jupiter-Saturn conjunctions are among the most impressive such events, occurring about every 20 years and involving the two outermost visible planets. The timing of apparent retrograde motion of the two planets can also produce an apparent triple conjunction, as happened in 1980-81. Triple conjunctions occur at irregular multiples of the conjunction interval. Occasionally a close grouping of Jupiter, Saturn, and Mars is also referred to as a triple conjunction. Successive Jupiter-Saturn conjunctions, slightly more than 240 deg apart, develop an interesting pattern as they step around the ecliptic, a rotating triangle with legs about 120 deg apart. In relation to the fixed stars, it takes about 854 or 913 years for the event to return to a point near the start of the sequence. Some scholars have given it as 960 years. Relative to a precessing co-ordinate system, it takes about 800 (794) years. Medieval scholars in Europe and the Near East were impressed by the above conjunction sequence, and tried to relate it to major events in world history. The earliest known attempts come from 8th century Baghdad, but their explanation may have originated in Iran (3rd to 7th centuries). It persisted in Europe into the 17th century.

Etz, Donald V.

2000-08-01

335

Weather and Climate on the Planets.  

National Technical Information Service (NTIS)

Automatic interplanetary station observations and theoretical investigations of weather conditions and climate on Venus, Mars and Jupiter are discussed, which are opening up good prospects for the development of the comparative meteorology of the planets....

K. Y. Kondratyev

1975-01-01

336

The formation and habitability of terrestrial planets in the presence of close-in giant planets  

Microsoft Academic Search

‘Hot jupiters,’ giant planets with orbits very close to their parent stars, are thought to form farther away and migrate inward via interactions with a massive gas disk. If a giant planet forms and migrates quickly, the planetesimal population has time to re-generate in the lifetime of the disk and terrestrial planets may form [P.J. Armitage, A reduced efficiency of

Sean N. Raymond; Thomas Quinn; Jonathan I. Lunine

2005-01-01

337

Are Giant Planet Satellites Mini-solar Systems?  

NASA Astrophysics Data System (ADS)

The regular satellites of Jupiter and Saturn exhibit a number of characteristics strongly suggestive of formation in a thin (aspect ratio H/r ˜ 0.1) circumplanetary gas disk (Mosqueira and Estrada 2003a). Also, the mass ratio of the largest satellites to the primary ? ˜ 10-4 lead one to think of these satellite systems as scaled-down solar systems. Yet, the larger mass ratio for the giant planets to the primary ? ˜ 10-3 appears to limit the usefulness of the planet-satellite analogy. If gap-opening determines the final size of at least Jupiter (Lin and Papaloizou 1993), then significantly smaller objects would be unable to truncate the disk. There are, however, at least two significant difficulties with this point of view. First, the non-linear or thermal gap-opening criterion (Lin and Papaloizou 1993) does not yield a Jupiter mass. Second, the migration timescale due to planet-disk interactions (Ward 1997) is too fast for the formation of giant planets through the core accretion process (Pollack et. al 1996) despite recent work which has lengthened it by up to an order of magnitude (Tanaka et al. 2002, D'Angelo et al. 2002, Bate et al. 2003). An alternative viewpoint has accretion taking place in a weakly turbulent disk, and the survival of both planets and satellites a direct consequence of gap-opening. In this view at least the largest satellites (Mosqueira and Estrada 2003b) and planetary cores ( ˜ 10 M? ; Rafikov 2002) were able to open gaps in the disk. However, because the waves launched by such pertubers do not become non-linear immediately, the gap begins to form a distance away from the perturber given by the shocking length of acoustic waves (Goodman and Rafikov 2001; Rafikov 2002). Estrada and Mosqueira (2003) have suggested that the annulus of material adjacent to the proto-planet that immediately precedes the runaway gas accretion phase (Pollack et al. 1996) can be used to provide the mass needed to lead to the formation of a giant planet. If so, the dilemma posed by Type I migration (Ward 1997) is mitigated, and the analogy between satellites and planets gains currency. It is possible to argue that an alternative solution to this issue may involve lowering the migration rate even further, but one should keep in mind that slower migration might allow even smaller objects to open gaps. Here we look into the issues raised by this annulus of material in the satellite context, and argue that it may not prevent satellite survival. This work was supported by a NASA PGG grant and the NRC.

Mosqueira, I.; Estrada, P. R.

2003-12-01

338

Low-mass Planets in Protoplanetary Disks with Net Vertical Magnetic Fields: The Planetary Wake and Gap Opening  

NASA Astrophysics Data System (ADS)

Some regions in protoplanetary disks are turbulent, while some regions are quiescent (e.g. the dead zone). In order to study how planets open gaps in both inviscid hydrodynamic disk (e.g. the dead zone) and the disk subject to magnetorotational instability (MRI), we carried out both shearing box two-dimensional inviscid hydrodynamical simulations and three-dimensional unstratified magnetohydrodynamical (MHD) simulations (having net vertical magnetic fields) with a planet at the box center. We found that, due to the nonlinear wave steepening, even a low mass planet can open gaps in both cases, in contradiction to the "thermal criterion" for gap opening. In order to understand if we can represent the MRI turbulent stress with the viscous ? prescription for studying gap opening, we compare gap properties in MRI-turbulent disks to those in viscous HD disks having the same stress, and found that the same mass planet opens a significantly deeper and wider gap in net vertical flux MHD disks than in viscous HD disks. This difference arises due to the efficient magnetic field transport into the gap region in MRI disks, leading to a larger effective ? within the gap. Thus, across the gap, the Maxwell stress profile is smoother than the gap density profile, and a deeper gap is needed for the Maxwell stress gradient to balance the planetary torque density. Comparison with previous results from net toroidal flux/zero flux MHD simulations indicates that the magnetic field geometry plays an important role in the gap opening process. We also found that long-lived density features (termed zonal flows) produced by the MRI can affect planet migration. Overall, our results suggest that gaps can be commonly produced by low mass planets in realistic protoplanetary disks, and caution the use of a constant ?-viscosity to model gaps in protoplanetary disks.

Zhu, Zhaohuan; Stone, James M.; Rafikov, Roman R.

2013-05-01

339

Assimilation of planets by red giant stars  

NASA Astrophysics Data System (ADS)

The typical red giant star rotates slowly. This characteristic is expected from the conservation of angular momentum as these stars expand during their evolution. Nevertheless, a small percentage of red giant stars are rapidly rotating. One possible source of these stars' excess angular momenta is the orbital angular momentum of a planetary companion. The transfer of orbital angular momentum to the stellar envelope decays the planet's orbit, ultimately leading to the rapid in-spiral of the planet into the star. Using the known sample of exoplanets around main sequence host stars, I simulated both the future evolution of these stars and the expected interactions with their planets and found that Jupiter-mass planets residing at inner solar system distances---relatively common in exoplanetary systems---can contribute enough angular momentum to cause rapid rotation in their host stars during the red giant phase. Gas giant planets are also massive enough to alter the chemical composition of their host stars' envelopes when they are accreted. The central experiment of this thesis is to search for abundance anomalies in the rapid rotators that could be indicative of planet accretion. Hypothetical anomalies include the replenishment of light elements that are diluted by giant stars during first dredge-up (such as the stellar surface abundance of lithium), changes in isotopic abundance ratios that were altered by nucleosynthesis (such as increasing the stellar surface 12C/13C), and the preferential enhancement of refractory elements (indicative of the accretion of chemically fractionated material such as a planet). To increase the total number of known rapid rotators, I measured rotational velocities in a large database of spectra collected for the Grid Giant Star Survey developed for NASA's Space Interferometry Mission's astrometric grid. The 28 new rapid rotators discovered in this sample were combined with rapid rotators from the literature and a control sample of slow rotators to form a new sample for the abundance experiment. This thesis presents evidence that the accretion of planets of a few Jupiter masses with "normal" planetary compositions can reproduce both the observed rotational velocities and abundances of red giant rapid rotators.

Carlberg, Joleen Karen

340

Interaction of free-floating planets with a star-planet pair  

NASA Astrophysics Data System (ADS)

The recent discovery of free-floating planets and their theoretical interpretation as celestial bodies, either condensed independently or ejected from parent stars in tight clusters, introduced an intriguing possibility. Namely, that some exoplanets are not condensed from the protoplanetary disk of their parent star. In this novel scenario a free-floating planet interacts with an already existing planetary system, created in a tight cluster, and is captured as a new planet. In the present work we study this interaction process by integrating trajectories of planet-sized bodies, which encounter a binary system consisting of a Jupiter-sized planet revolving around a Sun-like star. To simplify the problem we assume coplanar orbits for the bound and the free-floating planet and an initially parabolic orbit for the free-floating planet. By calculating the uncertainty exponent, a quantity that measures the dependence of the final state of the system on small changes of the initial conditions, we show that the interaction process is a fractal classical scattering. The uncertainty exponent is in the range (0.2-0.3) and is a decreasing function of time. In this way we see that the statistical approach we follow to tackle the problem is justified. The possible final outcomes of this interaction are only four, namely flyby, planet exchange, capture or disruption. We give the probability of each outcome as a function of the incoming planet's mass. We find that the probability of exchange or capture (in prograde as well as retrograde orbits and for very long times) is non-negligible, a fact that might explain the possible future observations of planetary systems with orbits that are either retrograde (see e.g. Queloz et al. Astron. Astrophys. 417, L1, 2010) or tight and highly eccentric.

Varvoglis, Harry; Sgardeli, Vasiliki; Tsiganis, Kleomenis

2012-08-01

341

Galileo in-situ dust measurements in Jupiter’s gossamer rings  

Microsoft Academic Search

Galileo was the first artificial satellite to orbit Jupiter. During its late orbital mission the spacecraft made two passages through the giant planet’s gossamer ring system. The impact-ionization dust detector on board successfully recorded dust impacts during both ring passages and provided the first in-situ measurements from a dusty planetary ring. During the first passage—on 5 November 2002 while Galileo

Harald Krüger; Douglas P. Hamilton; Richard Moissl; Eberhard Grün

2009-01-01

342

A NEW HYBRID N-BODY-COAGULATION CODE FOR THE FORMATION OF GAS GIANT PLANETS  

SciTech Connect

We describe an updated version of our hybrid N-body-coagulation code for planet formation. In addition to the features of our 2006-2008 code, our treatment now includes algorithms for the one-dimensional evolution of the viscous disk, the accretion of small particles in planetary atmospheres, gas accretion onto massive cores, and the response of N-bodies to the gravitational potential of the gaseous disk and the swarm of planetesimals. To validate the N-body portion of the algorithm, we use a battery of tests in planetary dynamics. As a first application of the complete code, we consider the evolution of Pluto-mass planetesimals in a swarm of 0.1-1 cm pebbles. In a typical evolution time of 1-3 Myr, our calculations transform 0.01-0.1 M{sub sun} disks of gas and dust into planetary systems containing super-Earths, Saturns, and Jupiters. Low-mass planets form more often than massive planets; disks with smaller {alpha} form more massive planets than disks with larger {alpha}. For Jupiter-mass planets, masses of solid cores are 10-100 M{sub +}.

Bromley, Benjamin C. [Department of Physics, University of Utah, 201 JFB, Salt Lake City, UT 84112 (United States); Kenyon, Scott J., E-mail: bromley@physics.utah.edu, E-mail: skenyon@cfa.harvard.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-04-20

343

Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars  

NASA Astrophysics Data System (ADS)

We present an analysis of ~5 years of Lick Observatory radial velocity measurements targeting a uniform sample of 31 intermediate-mass (IM) subgiants (1.5 lsim M */M sunlsim 2.0) with the goal of measuring the occurrence rate of Jovian planets around (evolved) A-type stars and comparing the distributions of their orbital and physical characteristics to those of planets around Sun-like stars. We provide updated orbital solutions incorporating new radial velocity measurements for five known planet-hosting stars in our sample; uncertainties in the fitted parameters are assessed using a Markov-Chain Monte Carlo method. The frequency of Jovian planets interior to 3 AU is 26+9 -8%, which is significantly higher than the 5%-10% frequency observed around solar-mass stars. The median detection threshold for our sample includes minimum masses down to {0.2, 0.3, 0.5, 0.6, 1.3} M Jup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. To compare the properties of planets around IM stars to those around solar-mass stars we synthesize a population of planets based on the parametric relationship dN vprop M ? P ? dlnMdlnP, the observed planet frequency, and the detection limits we derived. We find that the values of ? and ? for planets around solar-type stars from Cumming et al. fail to reproduce the observed properties of planets in our sample at the 4? level, even when accounting for the different planet occurrence rates. Thus, the properties of planets around A stars are markedly different than those around Sun-like stars, suggesting that only a small (~50%) increase in stellar mass has a large influence on the formation and orbital evolution of planets. Based on observations obtained at the Lick Observatory, which is operated by the University of California.

Bowler, Brendan P.; Johnson, John Asher; Marcy, Geoffrey W.; Henry, Gregory W.; Peek, Kathryn M. G.; Fischer, Debra A.; Clubb, Kelsey I.; Liu, Michael C.; Reffert, Sabine; Schwab, Christian; Lowe, Thomas B.

2010-01-01

344

Cold Friends of Hot Jupiters: NIRSPEC Survey  

NASA Astrophysics Data System (ADS)

Previous surveys have shown that half of all stars occur in binary systems. Although most exoplanet surveys exclude systems with known binary companions, it is likely that many known planetary systems contain distant, low-mass stellar companions that went unnoticed in the initial survey selection. Such companions may have important effects on the formation and migration of planets (and especially hot Jupiters) around the primary star via three-body interactions such as Kozai-driven migration. The Cold Friends project uses three observing techniques to make a robust determination of the occurrence rate of exoplanets in binary systems: radial velocity monitoring, adaptive optics imaging (see presentation on the AO Survey by H. Ngo et al.), and near-infrared spectroscopy. In this presentation, we focus on the results of the spectroscopy portion of the Cold Friends project. Using NIRSPEC at Keck Observatory, we have obtained high-resolution spectra of roughly fifty exoplanet-hosting stars near 2.3 microns, where low-mass companions will show deep CO absorption features superimposed on the primary stellar spectrum. This method allows for the detection of binary companions located within 50 to 200 AU of the host star. At this location, such a binary companion could conceivably influence the formation and migration of exoplanets orbiting the main star. We describe our method for removing the signal due to the main-sequence FGK host stars and searching for the distinctive spectral features of a low-mass stellar companion.

Piskorz, Danielle; Knutson, H. A.; Muirhead, P. S.; Batygin, K.; Crepp, J. R.; Hinkley, S.; Howard, A. W.; Johnson, J. A.; Morton, T. D.

2013-10-01

345

External Resource: Planet Impact!  

NSDL National Science Digital Library

This interactive resource from the Space Telescope Science Institute allows students to discover the fierce force of gravity and pelt Jupiter with comets. Topics: mass, trajectory, comets, speed, gravity.

1900-01-01

346

One or more bound planets per Milky Way star from microlensing observations.  

PubMed

Most known extrasolar planets (exoplanets) have been discovered using the radial velocity or transit methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17-30% (refs 4, 5) of solar-like stars host a planet. Gravitational microlensing, on the other hand, probes planets that are further away from their stars. Recently, a population of planets that are unbound or very far from their stars was discovered by microlensing. These planets are at least as numerous as the stars in the Milky Way. Here we report a statistical analysis of microlensing data (gathered in 2002-07) that reveals the fraction of bound planets 0.5-10?AU (Sun-Earth distance) from their stars. We find that 17(+6)(-9)% of stars host Jupiter-mass planets (0.3-10?M(J), where M(J) = 318?M(?) and M(?) is Earth's mass). Cool Neptunes (10-30?M(?)) and super-Earths (5-10?M(?)) are even more common: their respective abundances per star are 52(+22)(-29)% and 62(+35)(-37)%. We conclude that stars are orbited by planets as a rule, rather than the exception. PMID:22237108

Cassan, A; Kubas, D; Beaulieu, J-P; Dominik, M; Horne, K; Greenhill, J; Wambsganss, J; Menzies, J; Williams, A; Jørgensen, U G; Udalski, A; Bennett, D P; Albrow, M D; Batista, V; Brillant, S; Caldwell, J A R; Cole, A; Coutures, Ch; Cook, K H; Dieters, S; Prester, D Dominis; Donatowicz, J; Fouqué, P; Hill, K; Kains, N; Kane, S; Marquette, J-B; Martin, R; Pollard, K R; Sahu, K C; Vinter, C; Warren, D; Watson, B; Zub, M; Sumi, T; Szyma?ski, M K; Kubiak, M; Poleski, R; Soszynski, I; Ulaczyk, K; Pietrzy?ski, G; Wyrzykowski, L

2012-01-11

347

Star-planet magnetic interaction and evaporation of planetary atmospheres  

NASA Astrophysics Data System (ADS)

Context. Stars interact with their close-in planets through radiation, gravitation and magnetic fields. Aims: We investigate the energy input to a planetary atmosphere by reconnection between stellar and planetary magnetic fields and compare it to the energy input of the extreme ultraviolet (EUV) radiation field of the star. Methods: We quantify the power released by magnetic reconnection at the boundary of the planetary magnetosphere that is conveyed to the atmosphere by accelerated electrons. We introduce simple models to evaluate the energy spectrum of the accelerated electrons and the energy dissipated in the atmospheric layers in the polar region of the planet upon which they impinge. A simple transonic isothermal wind flow along field lines is considered to estimate the increase in mass loss rate in comparison with a planet irradiated only by the EUV flux of its host star. Results: We find that energetic electrons can reach levels down to column densities of 1023-1025 m-2, comparable with or deeper than EUV photons, and increase the mass loss rate up to a factor of 30-50 in close-in (< 0.10 AU), massive (?1.5 Jupiter masses) planets. Mass loss rates up to (0.5-1.0) × 109 kg s-1 are found for atmospheres heated by electrons accelerated by magnetic reconnection at the boundary of planetary magnetospheres. On the other hand, average mass loss rates up to (0.3-1.0) × 1010 kg s-1 are found in the case of magnetic loops interconnecting the planet with the star. Conclusions: The star-planet magnetic interaction provides a remarkable source of energy for planetary atmospheres, generally comparable with or exceeding that of stellar EUV radiation for close-in planets. Therefore, it must be included in models of chemical evolution or evaporation of planetary atmospheres as well as in modelling of light curves of transiting planets at UV wavelengths.

Lanza, A. F.

2013-09-01

348

Terrestrial planet formation  

PubMed Central

Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (?106 y), followed by planetesimals to embryos (lunar to Mars-sized objects; few × 106 y), and finally embryos to planets (107–108 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

Righter, K.; O'Brien, D. P.

2011-01-01

349

Four new WASP transiting close-in giant planets (Hebrard+, 2013)  

NASA Astrophysics Data System (ADS)

We present the discovery of four new transiting hot jupiters, detected mainly from SuperWASP-North and SOPHIE observations. These new planets, WASP-52b, WASP-58b, WASP-59b, and WASP-60b, have orbital periods ranging from 1.7 to 7.9-days, masses between 0.46 and 0.94MJup, and radii between 0.73 and 1.49 RJup. (2 data files).

Hebrard, G.; Collier, Cameron A.; Brown, D. J. A.; Diaz, R. F.; Faedi, F.; Smalley, B.; Anderson, D. R.; Armstrong, D.; Barros, S. C. C.; Bento, J.; Bouchy, F.; Doyle, A. P.; Enoch, B.; Gomez Maqueo Chew, Y.; Hebrard, E. M.; Hellier, C.; Lendl, M.; Lister, T. A.; Maxted, P. F. L.; McCormac, J.; Moutou, C.; Pollacco, D.; Queloz, D.; Santerne, A.; Skillen, I.; Southworth, J.; Tregloan-Reed, J.; Triaud, A. H. M. J.; Udry, S.; Vanhuysse, M.; Watson, C. A.; West, R. G.; Wheatley, P. J.

2012-11-01

350

Implications of the TTV-detection of close-in terrestrial planets around M stars for their origin and dynamical evolution  

NASA Astrophysics Data System (ADS)

It has been shown that an Earth-size planet or a super-Earth, in resonance with a transiting Jupiter-like body around an M star, can create detectable TTV signals (Kirste & Haghighipour, 2011). Given the low masses of M stars and their circumstellar disks, it is expected that the transiting giant planet to have formed at large distances and migrated to its close-in orbit. That implies, the terrestrial planet has to form during the migration of the giant planet, be captured in resonances, and migrate with the giant body to short-period orbits. To determine the possibility of this scenario, we have studied the dynamics of a disk of protoplanetary embryos and the formation of terrestrial planets during the migration of a Jupiter-like planet around an M star. Results suggest that unless the terrestrial planet was also formed at large distances and carried to its close-in resonant orbit by the giant planet, it is unlikely for this object to form in small orbits. We present the details of our simulations and discuss the implication of the results for the origin of the terrestrial planet.

Haghighipour, N.; Rastegar, S.

2011-02-01

351

UV emissions of Hot Jupiters  

NASA Astrophysics Data System (ADS)

In the solar system, the giant planets Jupiter and Saturn have bright aurorae due to particle precipitation in the upper atmospheres. The brightest optical auroral emissions are emitted by H and H2 in the UV and by H3+ in the IR. Due to the short distance to the parent stars, hot Jupiters are likely to be bombarded by intense stellar winds and UV fluxes and have strong emissions at the same wavelengths. When detected, their UV emissions could bring helpful information to characterize the upper atmospheres of the exoplanets. The first question to address is : are these emissions bright enough to be observed from Earth and distinguished from the stellar UV emissions ? We focus on Jupiter-like atmospheres, composed of H, H2 and He. Kinetic calculations allow to estimate the electron flux throughout the atmosphere and to calculate excitation rates of the upper levels of UV transitions of H and H2. Radiative transfer calculations are then done to estimate the intensity of the emergent lines and the profile of the H Lyman alpha line. Using the Yelle (2004) atmosphere model for HD209458b, we evaluate the H Lyman alpha dayglow of the planet. We also evaluate UV emissions of the planet caused by the precipitation of particles with and without an intrinsec magnetic field. We find that the Lyman alpha emission of the planet could reach 1/1000 of that of the star. It has been shown that the profile of the H Lyman alpha line is very sensitive to the atmospheric model and to the energy of the precipitating electrons (Menager et al. 2010). We see here a way to constrain the upper atmosphere of exoplanets and their particle environment, that could be used by future UV telescopes. References R. Yelle, Aeronomy of extra-solar giant planets at small orbital distances, Icarus, volume 170, 2004 H. Menager, M. Barthélemy, and J. Lilensten, H Lyman alpha line in Jovian aurorae : electron transport and radiative transfer coupled modelling, Astronomy & Astrophysics, accepted

Ménager, Hélène; Mathieu, Barthélemy; Jean, Lilensten

2010-05-01

352

Detecting Terrestrial Mass Planets Around M-dwarfs: Is SIM Competitive?  

Microsoft Academic Search

In the past few years, there have been public claims that SIM is unnecessary as a terrestrial planet search tool since radial velocity studies will be able to reach sensitivities of 10 cm\\/s. This is adequate to detect terrestrial planets in the habitable zones of M and K dwarfs. However, it has not been demonstrated that the RV technique will

Angelle M. Tanner; N. Law; P. Plavchan; J. Catanzarite

2009-01-01

353

The Deuterium Test for Exo-Planet Candidates Detected Directly  

NASA Astrophysics Data System (ADS)

In the near future, direct images will be obtained for massive planets orbiting around other stars. Most likely, the first such objects detected directly will have masses near the proposed limit between brown dwarfs and planets, i.e., around 13 Jupiter masses, because the more massive planets are the brightest. Hence, it may be dubious in these first few cases, whether the detected object is a brown dwarf or a real planet. To solve this problem, one can perform the deuterium test, i.e., one can distinguish between a brown dwarf (defined as an object able to fuse all deuterium) and an real planet (defined as an object not being able to fuse any deuterium) by whether or not deuterium can be identified in a spectrum. Any such object, brown dwarf or planet, would have spectral type T, defined as those with strong methane lines in the infrared. We present a model spectrum with the CH3D line at ~ 4.5 ?m which can be obtained for such objects with CRIRES at the VLT.

Neuhäuser, Ralph; Seifahrt, Andreas; Hauschildt, Peter; Alves, Joao; Guenther, Eike

354

Towards detecting and characterizing Earth-like extrasolar planets  

NASA Astrophysics Data System (ADS)

Extrasolar planet detection methods have recently advanced to the point where planets only slightly larger than the Earth, both in mass and size, are detectable with currently available instruments. The newly discovered class of planets known as "super-Earths" with masses in the range 1-10 M (+) afford scientists the ability to study planets and planet formation scenarios in a mass regime that does not exist in our solar system. This thesis describes work aimed at both detecting and characterizing these low-mass planets. If a transiting planet is found to vary in its measured orbital period over a series of transits, the resulting transit timing variations (TTVs) may be due to the gravitational pull of an additional planet in the system. The first part of this thesis (Chapters 2-4) describes some of the first efforts to use the TTV method to detect low-mass planets in known transiting systems. In Chapters 2 and 3 we present transit timing measurements for both the HD 209458 and HD 189733 systems, using data from the Canadian MOST space telescope. We additionally study the effects of HID 189733's large surface star spots on measuring accurate transit times in Chapter 4. While we find no evidence of low-mass companion planets in either of these transiting hot Jupiter systems, the null results from our TTV analyses serve to provide strong constraints on planet formation theories. Characterization of super-Earth atmospheres will be possible with future instruments, such as those aboard the James Webb Space Telescope. However, the interpretation of any such observations will necessitate direct comparison against theoretical atmosphere models. To this end, we have developed a planetary atmosphere model specifically for the study of super-Earths, and we present this model and some of its applications in Chapters 5-7. In Chapter 5 we determine how to best constrain the atmospheric hydrogen content of a super- Earth atmosphere through observations of the planetary emission and transmission spectrum. In Chapter 6 we turn our attention to the problem of direct detection of low-mass planets with next generation ELTs. We conclude this thesis in Chapter 7, where we describe the recent addition of a self- consistent temperature correction routine to the model atmosphere.

Miller-Ricci, Eliza

355

The frequency of giant planets around metal-poor stars  

NASA Astrophysics Data System (ADS)

Context. The discovery of about 700 extrasolar planets, so far, has lead to the first statistics concerning extrasolar planets. The presence of giant planets seems to depend on stellar metallicity and mass. For example, they are more frequent around metal-rich stars, with an exponential increase in planet occurrence rates with metallicity. Aims: We analyzed two samples of metal-poor stars (-2.0 ? [Fe/H] ? 0.0) to see if giant planets are indeed rare around these objects. Radial velocity datasets were obtained with two different spectrographs (HARPS and HIRES). Detection limits for these data, expressed in minimum planetary mass and period, are calculated. These produce trustworthy numbers for the planet frequency. Methods: A general Lomb-Scargle (GLS) periodogram analysis was used together with a bootstrapping method to produce the detection limits. Planet frequencies were calculated based on a binomial distribution function within metallicity bins. Results: Almost all hot Jupiters and most giant planets should have been found in these data. Hot Jupiters around metal-poor stars have a frequency lower than 1.0% at one sigma. Giant planets with periods up to 1800 days, however, have a higher frequency of fp = 2.63-0.8+2.5%. Taking into account the different metallicities of the stars, we show that giant planets appear to be very frequent (fp = 4.48-1.38+4.04%) around stars with [Fe/H] > - 0.7, while they are rare around stars with [Fe/H] ? - 0.7 ( ? 2.36% at one sigma). Conclusions: Giant planet frequency is indeed a strong function of metallicity, even in the low-metallicity tail. However, the frequencies are most likely higher than previously thought. The data presented herein are based on observations collected at the La Silla Parana Observatory, ESO (Chile) with the HARPS spectrograph at the 3.6-m telescope (ESO runs ID 72.C-0488, 082.C-0212, and 085.C-0063) and at the W. M. Keck Observatory that is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. This Observatory was made possible by the generous financial support of the W. M. Keck Foundation.Full Table 1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/543/A45Appendix A is available in electronic form at http://www.aanda.org

Mortier, A.; Santos, N. C.; Sozzetti, A.; Mayor, M.; Latham, D.; Bonfils, X.; Udry, S.

2012-07-01

356

Energetic neutral atoms from a trans-Europa gas torus at Jupiter.  

PubMed

The space environments--or magnetospheres--of magnetized planets emit copious quantities of energetic neutral atoms (ENAs) at energies between tens of electron volts to hundreds of kiloelectron volts (keV). These energetic atoms result from charge exchange between magnetically trapped energetic ions and cold neutral atoms, and they carry significant amounts of energy and mass from the magnetospheres. Imaging their distribution allows us to investigate the structure of planetary magnetospheres. Here we report the analysis of 50-80 keV ENA images of Jupiter's magnetosphere, where two distinct emission regions dominate: the upper atmosphere of Jupiter itself, and a torus of emission residing just outside the orbit of Jupiter's satellite Europa. The trans-Europa component shows that, unexpectedly, Europa generates a gas cloud comparable in gas content to that associated with the volcanic moon Io. The quantity of gas found indicates that Europa has a much greater impact than hitherto believed on the structure of, and the energy flow within, Jupiter's magnetosphere. PMID:12606993

Mauk, B H; Mitchell, D G; Krimigis, S M; Roelof, E C; Paranicas, C P

2003-02-27

357

Formation of Saturn and Jupiter and their Atmospheres  

NASA Astrophysics Data System (ADS)

The heavy elements (> 4He) in the well-mixed atmosphere are key to understanding the formation of Saturn and Jupiter and the origin and evolution of their atmospheres. The conventional model of the giant planet formation, known as the core accretion model, requires first the formation of a substantial core of 10-15 Earth masses, followed by gravitational capture of the most volatile of gases, hydrogen, helium and neon. The core is made from gradual agglomeration of grains of rock, metal, ice and the volatiles trapped in them. During accretionary heating, volatiles are released from the core and form the atmosphere together with hydrogen, helium and neon. The above formation scenario implies solar abundances of heavy elements, as does the gravitational instability model. However, the heavy elements (relative to H) in Jupiter's atmosphere were determined by the Galileo probe to be enriched by a factor of 4±2 compared to the sun. Galileo is the only probe ever to enter a giant planet to make in situ composition measurements. Moreover, the inter-elemental ratios were uneven, hence non-solar. One key elemental ratio, O/H, could not be determined as the probe entered a meteorologically anomalous region that was exceptionally dry. The O/H ratio is a key missing piece of the formation puzzle, however, as water was presumably the original carrier of heavy elements that formed the core and could have made up more than half of the core mass. This situation will be rectified in 2016 when the Juno microwave radiometer (MWR) experiment measures and maps Jupiter's water abundance to pressure levels of several hundred bars, hence the O/H ratio. Unlike Jupiter, the only reliable data presently available for Saturn are on C/H from methane, and P/H from phosphine in the upper troposphere/stratosphere by remote sensing. However, P/H in this region is not a good indicator of either the deep P/H or the enrichment of other heavy elements in Saturn, since phosphine is in thermochemical disequilibrium in the upper atmosphere. If Saturn's O/H is subsolar, a measurement of water even at shallow depths could allow its determination. CO could also provide a handle on O/H, but requires a knowledge of vertical mixing in Saturn's interior. The measurement of water and phosphine, respectively by the MWR and the Jovian InfraRed Auroral Mapper (JIRAM) on Juno, together with prior data on CO at Jupiter will provide a useful guide for determining convective mixing in Saturn as well. As in the case of Jupiter, an entry probe is essential for determining the bulk composition in Saturn's atmosphere, especially the elemental abundances of He, Ne, Ar, Kr, Xe, O, N and S and the critical isotopes, D/H, 3He/4He, 18O/16O, 13C/12C, 15N/14N, 34S/32S and the isotopes of the heavy noble gases. This would enable the type of comparative study of Saturn and Jupiter that is crucial to unraveling the mystery of the formation and evolution of the solar system and, by extension, extrasolar systems. [www.umich.edu/~atreya to download pdf's of related publications

Atreya, S. K.; Lunine, J. I.; Simon-Miller, A. A.; Atkinson, D. H.; Brinckerhoff, W. B.; Coustenis, A.; Mahaffy, P. R.; Spilker, T. R.; Colaprete, A.; Reh, K.

2012-04-01

358

Gas Accretion by Giant Planets: 3D Simulations of Gap Opening and Dynamics of the Circumplanetary Disk  

NASA Astrophysics Data System (ADS)

What sets the terminal mass of a giant planet once the latter enters into a runaway gas-accretion phase? The formation of a gap around the planet's orbit may be an answer, provided that the gap is wide and deep enough. A wide-spread idea is that this happens if the viscosity in the circumstellar disk is small, i.e. if planets form in the "dead zone". With 3D hydrodynamical simulations we study the formation of a gap in details. We find an interesting 4-step meridional loop in the gas dynamics: (1) the gas flows into the gap at the top layer of the disk; (2) then it falls towards the disk's midplane; (3) the planet keeps the gap open by pushing this infalling gas back into the disk; (4) the gas rises back to the disk's surface, which closes the loop. The gas flow in this loop is governed by the viscous timescale at the surface of the disk. It is generally accepted that the surface layer of the disk is MRI-active and viscous, even if a dead zone is present near the midplane. Thus, there should always be enough gas flowing into the gap for a Jupiter-mass planet to accrete at a fast rate, in absence of other regulation mechanisms. However, only a very small portion of the gas flowing into the gap is directly accreted by the planet. Most of the gas falling towards the planet forms a circumplanetary disk (CPD), due to angular momentum conservation. If the CPD is MRI-inactive, as suggested by Turner et al. (2010) and Fujii et al. (2011), it can act as a bottle-neck for planet accretion. We find that the main mechanism that allows the CPD to lose angular momentum is the torque exerted by the star via a spiral density wave. We compute that this promotes the accretion of 0.025% of the mass of the CPD per year, for a Jupiter mass planet at 5.2 AU, independent of viscosity. By balancing the pressure of the vertical inflow with that internal to the CPD, we estimate that the CPD should contain less than 1% of the planet's mass. This leads to a mass-doubling timescale for Jupiter longer than half a My, i.e. of the order of the timescale of existence of circumstellar disks. A wide variety of giant planets terminal masses can result from the equivalence of these two timescales.

Morbidelli, Alessandro; Szulagyi, J.; Crida, A.; Tanigawa, T.; Lega, E.; Masset, F.; Bitsch, B.

2013-10-01

359

Solar Stars and Planets in Open Clusters*  

NASA Astrophysics Data System (ADS)

The study of open clusters stars is essential for our understanding of several open questions related to stars with planets and to planetary formation. We aim to investigate the dependence of planet formation on stellar mass and to compare in detail the chemical composition of stars with and without planets in a cluster of solar metallicity and age. Precise stellar radial velocities are used to search for massive (Jupiter masses or higher) exo-planets around stars of the Open Cluster M67. We observed a sample of 88 main-sequence stars, subgiants, and giants all with proper motion membership probability higher than 60%, using four telescopes and instrument combinations: the HARPS spectrograph at the ESO 3.6m, the SOPHIE spectrograph at OHP, the CORALIE spectrograph at the Euler Swiss telescope, and the HRS spectrograph at HET. 680 single observations, spanning a period of up to 8 years, have been recorded (Dec. 2011) and analyzed obtaining radial velocities with precision as good as ? 10 m/s. After reducing all the observations to the HARPS zero point, the radial velocity (RV) measurements for each star are used to evaluate the RV variability along the cluster. We found 11 new previously unknown binary candidates, although the sample was pre-selected against binaries, other 11 stars clearly stand out with higher RV variability: 9 are interesting candidates for long term substellar companions, 2 stars present RV velocity variation too high to host a planet. The RV variance (including the stellar intrinsic variability and the observational error) for the bulk of stars is almost constant with stellar magnitude (therefore stellar gravity), at ? = 20 m/s. The high scatter of radial velocities, in excess to the measurement errors, may indicate that more stars are suitable candidates for hosting planets.

Brucalassi, A.; Pasquini, L.; Ruiz, M. T.; Bonifacio, P.; Lovis, C.; Saglia, R.; Melo, C.; Biazzo, K.; Randich, S.; Bedin, L.

2013-04-01

360

Characterizing the Cool Kepler Objects of Interests. New Effective Temperatures, Metallicities, Masses, and Radii of Low-mass Kepler Planet-candidate Host Stars  

NASA Astrophysics Data System (ADS)

We report stellar parameters for late-K and M-type planet-candidate host stars announced by the Kepler Mission. We obtained medium-resolution, K-band spectra of 84 cool (T eff <~ 4400 K) Kepler Objects of Interest (KOIs) from Borucki et al. We identified one object as a giant (KOI 977); for the remaining dwarfs, we measured effective temperatures (T eff) and metallicities [M/H] using the K-band spectral indices of Rojas-Ayala et al. We determine the masses (M sstarf) and radii (R sstarf) of the cool KOIs by interpolation onto the Dartmouth evolutionary isochrones. The resultant stellar radii are significantly less than the values reported in the Kepler Input Catalog and, by construction, correlate better with T eff. Applying the published KOI transit parameters to our stellar radius measurements, we report new physical radii for the planet candidates. Recalculating the equilibrium temperatures of the planet-candidates assuming Earth's albedo and re-radiation fraction, we find that three of the planet-candidates are terrestrial sized with orbital semimajor axes that lie within the habitable zones of their host stars (KOI 463.01, KOI 812.03, and KOI 854.01). The stellar parameters presented in this Letter serve as a resource for prioritization of future follow-up efforts to validate and characterize the cool KOI planet candidates.

Muirhead, Philip S.; Hamren, Katherine; Schlawin, Everett; Rojas-Ayala, Bárbara; Covey, Kevin R.; Lloyd, James P.

2012-05-01

361

Finding Earth clones with SIM: the most promising near-term technique to detect, find masses for, and determine three-dimensional orbits of nearby habitable planets  

NASA Astrophysics Data System (ADS)

SIM is a space astrometric interferometer capable of better than one-microarcsecond ( as) single measurement accuracy, providing the capability to detect stellar "wobble" resulting from planets in orbit around nearby stars. While a search for exoplanets can be optimized in a variety of ways, a SIM five-year search optimized to detect Earth analogs (0.3 to 10 Earth masses) in the middle of the habitable zone (HZ) of nearby stars would yield the masses, without M*sin(i) ambiguity, and three-dimensional orbital parameters for planets around ~70 stars, including those in the HZ and further away from those same stars. With >200 known planets outside our solar system, astrophysical theorists have built numerical models of planet formation that match the distribution of Jovian planets discovered to date and those models predict that the number of terrestrial planets (< 10 M(+) ) would far exceed the number of more massive Jovian planets. Even so, not every star will have an Earth analog in the middle of its HZ. This paper describes the relationship between SIM and other planet detection methods, the SIM planet observing program, expected results, and the state of technical readiness for the SIM mission.

Shao, Michael; Unwin, Stephen C.; Beichman, Charles; Catanzarite, Joseph; Edberg, Stephen J.; Marr, James C., IV; Marcy, Geoffrey

2007-09-01

362

Discovery of the distant cool sub-Neptune mass planet OGLE 2005-BLG-390Lb by microlensing  

Microsoft Academic Search

The favoured theoretical explanation for planetary systems formation is the core-accretion model in which solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars, the most common stars of our Galaxy, this model favours the formation of Earth- to Neptune-mass planets in a few million years with orbital sizes

J P Beaulieu; D P Bennett; P Fouque; A Williams; M Dominik; U G Jorgensen; D Kubas; A Cassan; C Coutures; J Greenhill; K Hill; J Menzies; P D Sackett; M Albrow; S Brillant; J R Caldwell; J J Calitz; K H Cook; E Corrales; M Desort; S Dieters; D Dominis; J Donatowicz; M Hoffman; S Kane; J B Marquette; R Martin; P Meintjes; K Pollard; K Sahu; C Vinter; J Wambsganss; K Woller; K Horne; I Steele; D M Bramich; M Burgdorf; C Snodgrass; M Bode; A Udalski; M K Szymanski; M Kubiak; T Wieckowski; G Pietrzynski; I Soszynski; O Szewczyk; L Wyrzykowski; B Paczynski; F Abe; I A Bond; T R Britton; A C Gilmore; J B Hearnshaw; Y Itow; K Kamiya; P M Kilmartin; A V Korpela; K Masuda; Y Matsubara; M Motomura; Y Muraki; S Nakamura; C Okada; K Ohnishi; N J Rattenbury; T Sako; S Sato; M Sasaki; T Sekiguchi; D J Sullivan; P J Tristram; P M Yock; T Yoskioka

2005-01-01

363

Uranus and Neptune: Refugees from the Jupiter-Saturn zone?  

NASA Astrophysics Data System (ADS)

Plantesimal accretion models of planet formation have been quite successful at reproducing the terrestrial region of the Solar System. However, in the outer Solar System these models run into problems, and it becomes very difficult to grow bodies to the current mass of the ``ice giants," Uranus and Neptune. Here we present an alternative scenario to in-situ formation of the ice giants. In addition to the Jupiter and Saturn solid cores, several more bodies of mass ~ 10 MEarth or more are likely to have formed in the region between 4 and 10 AU. As Jupiter's core, and perhaps Saturn's, accreted nebular gas, the other nearby bodies must have been scattered outward. Dynamical friction with the trans-Saturnian part of the planetesimal disk would have acted to decouple these ``failed cores" from their scatterer, and to circularize their orbits. Numerical simulations presented here show that systems very similar to our outer Solar System (including Uranus, Neptune, the Kuiper belt, and the scattered disk) are a natural product of this process.

Thommes, E. W.; Duncan, M. J.; Levison, H. F.

1999-09-01

364

Magnetosphere-ionosphere coupling at Jupiter: A parameter space study  

NASA Astrophysics Data System (ADS)

Jupiter's main auroral emission is a signature of the current system that transfers angular momentum from the planet to radially outward moving Iogenic plasma. Ray et al. (2010) developed a steady state model of this current system which self-consistently included the effects of a field-aligned potential, ??, and an ionospheric conductance modified by precipitating electrons. The presented parameter space study extends their model to explore how variations in the auroral cavity density and temperature, magnetospheric mass loading rate, and background ionospheric Pedersen conductance affect the current system and resulting auroral emission. We show that while the solutions found by Ray et al. (2010) vary with changes in the system parameters, the gross general trends remain similar to the original solutions. We find that, for an outer constraint of I100 = 86 MA, the high-latitude electron temperature and density have a lower limit of ˜1.5 keV and an upper limit of ˜0.01 cm-3, respectively, in order for solutions to be consistent with observations of Jupiter's auroral emission. For increases in the radial mass transport rate and an outer constraint of ??Max = 75 kV the auroral emission brightness increases.

Ray, L. C.; Ergun, R. E.; Delamere, P. A.; Bagenal, F.

2012-01-01

365

How giant planets cool  

NASA Astrophysics Data System (ADS)

Understanding how giant planets cool is key to the study of their interior structure, composition and hence formation. I will review how the observed luminosities of Jupiter, Saturn, Uranus and Neptune may be accounted for, mostly by convective transport of heat limited by the atmospheric lip, but with several complications (sedimentation of helium droplets, gradients of composition...). Conversely, I will show that the the cooling of strongly irradiated giant planets ("Pegasids") is limited by heat transport in a thick external radiative zone with a possibility of a significant dissipation of heat due to tides. In all cases, both radiative transport and atmospheric/interior dynamics play crucial roles and require further studies.

Guillot, T.

2006-12-01

366

Sprites on other planets  

NASA Astrophysics Data System (ADS)

Lightning discharges have been observed or inferred in several planets in the solar system, and so it seems reasonable to expect that like on Earth, some form of accompanying transient luminous events (TLEs, e.g. sprites, halos, elves) will occur in the atmospheres of these planets. We present simple calculations of the necessary lightning induced charge-moment changes and possible atmospheric heights for the occurrence of sprites on Venus, Mars, Titan and the gas giants Jupiter and Saturn. The types of thunderstorms and the postulated locations of charge centers are based on published spacecraft data and cloud models. We calculated the values of the conventional breakdown field over a wide range of pressures and temperatures in each planet's atmosphere, based on the parameters for each composition given by Sentman (2004). Assuming that sprites occur below the base of the ionosphere and above the upper-most planetary cloud layer, we show that for reasonable amounts of charge, sprites can be formed in Venus, Jupiter and Saturn, but not in Mars or Titan. For Venus, an intracloud flash with a charge-moment change of 500 C km occurring between the two lower cloud layers (presumably separated by 5 km), a sprite can be triggered approximately at an altitude 90 km above ground, ~20 km above the tops of the upper most cloud layer. For Jupiter, the results suggest that for a charge of 1000C located 30 km below the 1-bar pressure level, a sprite can be ignited at an altitude approximately 100 km above the top visible ammonia cloud layer. The observation methodology for sprites on other planets by orbiting spacecraft is limb observations above the nocturnal hemisphere (Venus, Jupiter) or even nadir view when the lightning light is obscured in the deep atmosphere (Venus, Saturn). The emission lines for planetary sprites were studied in laboratory experiments with appropriate gas mixtures, and are presented in a separate talk.

Yair, Y.; Takahashi, Y.; Ebert, U.; Price, C. G.; Yaniv, R.; Dubrovin, D.; Nijdam, S.; van Veldhuizen, E.

2009-12-01

367

Mid-IR Atmospheric Tracers of Jupiter's Storm Oval BA  

Microsoft Academic Search

The 2005-2006 reddening of a major anticyclonic storm, known as Oval BA, in Jupiter's turbulent atmosphere may well be a paradigm for the formation of red-colored vortices on the giant planets, including Jupiters Great Red Spot. Mid-infrared observations can be effectively used to determine physical and chemical properties of the atmosphere, and we present the results of mid-infrared thermal imaging

Matthew J. Shannon; G. Orton; L. Fletcher

2010-01-01

368

Nine Planets: Planetary Picture List  

NSDL National Science Digital Library

This section of The Nine Planets provides links to internet solar system images of the nine planets and their moons. Images include the Sun, Mercury, Venus, the Earth and Moon, Mars (Phobos, Deimos), Jupiter (Amalthea, Io, Europa, Ganymede, Callisto), Saturn (Pan, Atlas, Prometheus, Pandora, Epimetheus, Janus, Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion, Iapetus, Phoebe), Uranus (Puck, Miranda, Ariel, Umbriel, Titania, Oberon), Neptune (Triton, Proteus), and Pluto with Charon. Miscellanous images include asteroids, comets, meteorites, and spacecraft.

369

The formation of systems with closely spaced low-mass planets and the application to Kepler-36  

NASA Astrophysics Data System (ADS)

The Kepler-36 system consists of two planets that are spaced unusually close together, near the 7:6 mean motion resonance. While it is known that mean motion resonances can easily form by convergent migration, Kepler-36 is an extreme case due to the close spacing and the relatively high planet masses of four and eight times that of the Earth. In this paper, we investigate whether such a system can be obtained by interactions with the protoplanetary disc. These discs are thought to be turbulent and exhibit density fluctuations which might originate from the magnetorotational instability. We adopt a realistic description for stochastic forces due to these density fluctuations and perform both long-term hydrodynamical and N-body simulations. Our results show that planets in the Kepler-36 mass range can be naturally assembled into a closely spaced planetary system for a wide range of migration parameters in a turbulent disc similar to the minimum-mass solar nebula. The final orbits of our formation scenarios tend to be Lagrange stable, even though large parts of the parameter space are chaotic and unstable.

Paardekooper, Sijme-Jan; Rein, Hanno; Kley, Willy

2013-10-01

370

The Young Planet-mass Object 2M1207b: A Cool, Cloudy, and Methane-poor Atmosphere  

NASA Astrophysics Data System (ADS)

The properties of 2M1207b, a young (~8 Myr) planet-mass companion, have lacked a satisfactory explanation for some time. The combination of low luminosity, red near-IR colors, and L-type near-IR spectrum (previously consistent with T eff ~ 1600 K) implies an abnormally small radius. Early explanations for the apparent underluminosity of 2M1207b invoked an edge-on disk or the remnant of a recent protoplanetary collision. The discovery of a second planet-mass object (HR8799b) with similar luminosity and colors as 2M1207b indicates that a third explanation, one of a purely atmospheric nature, is more likely. By including clouds, non-equilibrium chemistry, and low gravity, an atmosphere with effective temperature consistent with evolution cooling-track predictions is revealed. Consequently, 2M1207b, and others like it, requires no new physics to explain nor do they belong to a new class of objects. Instead they most likely represent the natural extension of cloudy substellar atmospheres down to low T eff and log (g). If this atmosphere only explanation for 2M1207b is correct, then very young planet-mass objects with near-IR spectra similar to field T dwarfs may be rare.

Barman, Travis S.; Macintosh, Bruce; Konopacky, Quinn M.; Marois, Christian

2011-07-01

371

THE YOUNG PLANET-MASS OBJECT 2M1207b: A COOL, CLOUDY, AND METHANE-POOR ATMOSPHERE  

SciTech Connect

The properties of 2M1207b, a young ({approx}8 Myr) planet-mass companion, have lacked a satisfactory explanation for some time. The combination of low luminosity, red near-IR colors, and L-type near-IR spectrum (previously consistent with T{sub eff} {approx} 1600 K) implies an abnormally small radius. Early explanations for the apparent underluminosity of 2M1207b invoked an edge-on disk or the remnant of a recent protoplanetary collision. The discovery of a second planet-mass object (HR8799b) with similar luminosity and colors as 2M1207b indicates that a third explanation, one of a purely atmospheric nature, is more likely. By including clouds, non-equilibrium chemistry, and low gravity, an atmosphere with effective temperature consistent with evolution cooling-track predictions is revealed. Consequently, 2M1207b, and others like it, requires no new physics to explain nor do they belong to a new class of objects. Instead they most likely represent the natural extension of cloudy substellar atmospheres down to low T{sub eff} and log (g). If this atmosphere only explanation for 2M1207b is correct, then very young planet-mass objects with near-IR spectra similar to field T dwarfs may be rare.

Barman, Travis S. [Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff, AZ 86001 (United States); Macintosh, Bruce; Konopacky, Quinn M. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Marois, Christian, E-mail: barman@lowell.edu [National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)

2011-07-10