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1

The Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of GPI has been tuned for maximum sensitivity to faint planets near bright stars. GPI has undergone a year of commissioning, verification, and calibration work. We have achieved an estimated H-band contrast (5-sigma) of 106 at 0.75 arcseconds and 105 at 0.35 arcseconds in spectral mode, and suppression of unpolarized starlight by a factor of 800 in imaging polarimetry mode. Early science observations include study of the spectra of ? Pic b and HR 8799, orbital investigations of ? Pic b and PZ Tel, and observations of the debris disk systems associated with ? Pic, AU Mic, and HR 4796A. An 890-hour exoplanet survey with GPI is scheduled to begin in late 2014. A status report for the campaign will be presented.

Graham, James R.; Macintosh, Bruce; Perrin, Marshall D.; Ingraham, Patrick; Konopacky, Quinn M.; Marois, Christian; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam Seth; Cardwell, Andrew; Chilcote, Jeffrey K.; De Rosa, Robert John J.; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James E.; Maire, Jerome; Marchis, Franck; Marley, Mark S.; McBride, James; Millar-Blanchaer, Max; Morzinski, Kathleen M.; Nielsen, Eric L.; Norton, Andew; Oppenheimer, Rebecca; Palmer, David; Patience, Jenny; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemeyer, Leslie; Savransky, Dmitry; Serio, Andrew W.; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wang, Jason; Wiktorowicz, Sloane; Wolff, Schulyer; Gpi/Gpies Team

2015-01-01

2

First light of the Gemini Planet imager.  

PubMed

The Gemini Planet Imager is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of the Gemini Planet Imager has been tuned for maximum sensitivity to faint planets near bright stars. During first-light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-? contrast of 10(6) at 0.75 arcseconds and 10(5) at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-s exposure with minimal postprocessing. Beta Pictoris b is observed at a separation of 434 ± 6 milliarcseconds (mas) and position angle 211.8 ± 0.5°. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions. The planet orbits at a semimajor axis of [Formula: see text] near the 3:2 resonance with the previously known 6-AU asteroidal belt and is aligned with the inner warped disk. The observations give a 4% probability of a transit of the planet in late 2017. PMID:24821792

Macintosh, Bruce; Graham, James R; Ingraham, Patrick; Konopacky, Quinn; Marois, Christian; Perrin, Marshall; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam S; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James; Maire, Jerome; Marchis, Franck; Marley, Mark S; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, B R; Palmer, David; Patience, Jennifer; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J Kent; Wiktorowicz, Sloane; Wolff, Schuyler

2014-09-01

3

First light of the Gemini Planet Imager  

PubMed Central

The Gemini Planet Imager is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of the Gemini Planet Imager has been tuned for maximum sensitivity to faint planets near bright stars. During first-light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-? contrast of 106 at 0.75 arcseconds and 105 at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-s exposure with minimal postprocessing. Beta Pictoris b is observed at a separation of 434 ± 6 milliarcseconds (mas) and position angle 211.8 ± 0.5°. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions. The planet orbits at a semimajor axis of 9.0?0.4+0.8?AU near the 3:2 resonance with the previously known 6-AU asteroidal belt and is aligned with the inner warped disk. The observations give a 4% probability of a transit of the planet in late 2017. PMID:24821792

Macintosh, Bruce; Graham, James R.; Ingraham, Patrick; Konopacky, Quinn; Marois, Christian; Perrin, Marshall; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam S.; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J.; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James; Maire, Jerome; Marchis, Franck; Marley, Mark S.; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, B. R.; Palmer, David; Patience, Jennifer; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wiktorowicz, Sloane; Wolff, Schuyler

2014-01-01

4

The Gemini Planet Imager Exoplanet Survey  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a next-generation coronagraph constructed for the Gemini Observatory. GPI will see first light this fall. It will be the most advanced planet-imaging system in operation - an order of magnitude more sensitive than any current instrument, capable of detecting and spectroscopically characterizing young Jovian planets 107 times fainter than their parent star at separations of 0.2 arcseconds. GPI was built from the beginning as a facility-class survey instrument, and the observatory will employ it that way. Our team has been selected by Gemini Observatory to carry out an 890-hour program - the GPI Exoplanet Survey (GPIES) campaign from 2014-2017. We will observe 600 stars spanning spectral types A-M. We will use published young association catalogs and a proprietary list in preparation that adds several hundred new young (<100 Myr, <75 pc) and adolescent (<300 Myr, <35 pc) stars. The range of separations studied by GPI is completely inaccessible to Doppler and transit techniques (even with Kepler or TESS)— GPI offers a new window into planet formation. We will use GPI to produce the first-ever robust census of giant planet populations in the 5-50 AU range, allowing us to: 1) illuminate the formation pathways of Jovian planets; 2) reconstruct the early dynamical evolution of systems, including migration mechanisms and the interaction with disks and belts of debris; and 3) bridge the gap between Jupiter and the brown dwarfs with the first examples of cool low- gravity planetary atmospheres. Simulations predict this survey will discover approximately 50 exoplanets, increasing the number of exoplanet images by an order of magnitude, enough for statistical investigation. This Origins of Solar Systems proposal will support the execution of the GPI Exoplanet Survey campaign. We will develop tools needed to execute the survey efficiently. We will refine the existing GPI data pipeline to a final version that robustly removes residual speckle artifacts and provides accurate and calibrated recovery of exoplanet spectra. We will produce a complete archive of all reduced GPI data products (supplementing the existing Gemini archive of raw data) for use by our collaboration, and release that archive to the public on an 18-month cycle. Most importantly, we will execute the GPI observations, initially through classical telescope visits, transitioning to remote and queue modes as our techniques are refined. As the first direct-imaging planet search with statistical depth comparable to Doppler planet detection and the first to probe into the snow line, the GPI Exoplanet Survey will provide strong constraints on paradigms for planet formation, completing the picture of the giant planet distribution throughout other solar systems, and also illuminating its evolution with stellar age and mass. We will deliver a catalog of detected exoplanets— the principal legacy of this campaign—released for follow-up by the astronomical community within 18 months of observation, as well as searchable archive of fully reduced images and detection limits for all stars surveyed. For each detected planet, we will produce estimated effective temperatures, luminosities, and semi-major axes: for a subset, high-SNR fiducial spectra, orbital eccentricities, and dynamical characterization through polarimetric imaging of attendant debris disks. GPI will complete final acceptance testing this month (May 2013) and is now ready to ship to Chile for first light in September 2013. The GPI survey will provide the best-yet view of the nature of wide-orbit planetary companions, informing our knowledge of solar system formation to guide future NASA planet hunting missions, while simultaneously offering a real- world program using the techniques - from integral field spectroscopy to advanced coronagraphy - that will someday be used to directly image Earthlike planets from space.

Macintosh, Bruce

5

Wavefront control for the Gemini Planet Imager  

SciTech Connect

The wavefront control strategy for the proposed Gemini Planet Imager, an extreme adaptive optics coronagraph for planet detection, is presented. Two key parts of this strategy are experimentally verified in a testbed at the Laboratory for Adaptive Optics, which features a 32 x 32 MEMS device. Detailed analytic models and algorithms for Shack-Hartmann wavefront sensor alignment and calibration are presented. It is demonstrated that with these procedures, the spatially filtered WFS and the Fourier Transform reconstructor can be used to flatten to the MEMS to 1 nm RMS in the controllable band. Performance is further improved using the technique of modifying the reference slopes using a measurement of the static wavefront error in the science leg.

Poyneer, L A; Veran, J; Dillon, D; Severson, S; Macintosh, B

2006-04-14

6

Gemini Planet Imager Coronagraph Testbed Results  

SciTech Connect

The Gemini Planet Imager (GPI) is an extreme AO coronagraphic integral field unit YJHK spectrograph destined for first light on the 8m Gemini South telescope in 2011. GPI fields a 1500 channel AO system feeding an apodized pupil Lyot coronagraph, and a nIR non-common-path slow wavefront sensor. It targets detection and characterizion of relatively young (<2GYr), self luminous planets up to 10 million times as faint as their primary star. We present the coronagraph subsystem's in-lab performance, and describe the studies required to specify and fabricate the coronagraph. Coronagraphic pupil apodization is implemented with metallic half-tone screens on glass, and the focal plane occulters are deep reactive ion etched holes in optically polished silicon mirrors. Our JH testbed achieves H-band contrast below a million at separations above 5 resolution elements, without using an AO system. We present an overview of the coronagraphic masks and our testbed coronagraphic data. We also demonstrate the performance of an astrometric and photometric grid that enables coronagraphic astrometry relative to the primary star in every exposure, a proven technique that has yielded on-sky precision of the order of a milliarsecond.

Sivaranmakrishnan, A.; Carr, G.; Soummer, R.; Oppenheimer, B.R.; Mey, J.L.; Brenner, D.; Mandeville, C.W.; Zimmerman, N. Macintosh, B.A.; Graham, J.R.; Saddlemyer, L.; Bauman, B.; Carlotti, A.; Pueyo, L.; Tuthill, P.G.; Dorrer, C.; Roberts, R.; Greenbaum, A.

2010-12-08

7

Gemini Planet Imager: Preliminary Design Report  

SciTech Connect

For the first time in history, direct and indirect detection techniques have enabled the exploration of the environments of nearby stars on scales comparable to the size of our solar system. Precision Doppler measurements have led to the discovery of the first extrasolar planets, while high-contrast imaging has revealed new classes of objects including dusty circumstellar debris disks and brown dwarfs. The ability to recover spectrophotometry for a handful of transiting exoplanets through secondary-eclipse measurements has allowed us to begin to study exoplanets as individual entities rather than points on a mass/semi-major-axis diagram and led to new models of planetary atmospheres and interiors, even though such measurements are only available at low SNR and for a handful of planets that are automatically those most modified by their parent star. These discoveries have galvanized public interest in science and technology and have led to profound new insights into the formation and evolution of planetary systems, and they have set the stage for the next steps--direct detection and characterization of extrasolar Jovian planets with instruments such as the Gemini Planet Imager (GPI). As discussed in Volume 1, the ability to directly detect Jovian planets opens up new regions of extrasolar planet phase space that in turn will inform our understanding of the processes through which these systems form, while near-IR spectra will advance our understanding of planetary physics. Studies of circumstellar debris disks using GPI's polarimetric mode will trace the presence of otherwise-invisible low-mass planets and measure the build-up and destruction of planetesimals. To accomplish the science mission of GPI will require a dedicated instrument capable of achieving contrast of 10{sup -7} or more. This is vastly better than that delivered by existing astronomical AO systems. Currently achievable contrast, about 10{sup -5} at separations of 1 arc second or larger, is completely limited by quasi-static wave front errors, so that contrast does not improve with integration times longer than about 1 minute. Using the rotation of the Earth to distinguish companions from artifacts or multiwavelength imaging improves this somewhat, but GPI will still need to surpass the performance of existing systems by one to two orders of magnitude--an improvement comparable to the transition from photographic plates to CCDs. This may sound daunting, but other areas of optical science have achieved similar breakthroughs, for example, the transition to nanometer-quality optics for extreme ultraviolet lithography, the development of MEMS wave front control devices, and the ultra-high contrast demonstrated by JPL's High Contrast Imaging Test-bed. In astronomy, the Sloan Digital Sky Survey, long baseline radio interferometry, and multi-object spectrographs have led to improvements of similar or greater order of magnitude. GPI will be the first project to apply these revolutionary techniques to ground-based astronomy, with a systems engineering approach that studies the impact of every design decision on the key metric--final detectable planet contrast.

Macintosh, B

2007-05-10

8

Gemini planet imager observational calibrations II: detector performance and calibration  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager is a newly commissioned facility instrument designed to measure the near-infrared spectra of young extrasolar planets in the solar neighborhood and obtain imaging polarimetry of circumstellar disks. GPI's science instrument is an integral field spectrograph that utilizes a HAWAII-2RG detector with a SIDECAR ASIC readout system. This paper describes the detector characterization and calibrations performed by the GPI Data Reduction Pipeline to compensate for effects including bad/hot/cold pixels, persistence, non- linearity, vibration induced microphonics and correlated read noise.

Ingraham, Patrick; Perrin, Marshall D.; Sadakuni, Naru; Ruffio, Jean-Baptiste; Maire, Jérôme; Chilcote, Jeff; Larkin, James; Marchis, Franck; Galicher, Raphael; Weiss, Jason

2014-07-01

9

The Gemini planet imager: first light and commissioning  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a facility extreme-AO high-contrast instrument - optimized solely for study of faint companions - on the Gemini telescope. It combines a high-order MEMS AO system (1493 active actuators), an apodized pupil Lyot coronagraph, a high-accuracy IR post-coronagraph wavefront sensor, and a near-infrared integral field spectrograph. GPI incorporates several other novel features such as ultra-high quality optics, a spatially-filtered wavefront sensor, and new calibration techniques. GPI had first light in November 2013. This paper presnets results of first-light and performance verification and optimization and shows early science results including extrasolar planet spectra and polarimetric detection of the HR4696A disk. GPI is now achieving contrasts approaching 10-6 at 0.5" in 30 minute exposures.

Macintosh, Bruce A.; Anthony, Andre; Atwood, Jenny; Bauman, Brian; Cardwell, Andrew; Caputa, Kris; Chilcote, Jeffery; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erickson, Darren; Fitzgerald, Michael P.; Gavel, Donald T.; Galvez, Ramon; Goodsell, Stephen; Graham, James; Greenbaum, Alexandra Z.; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Kerley, Dan; Konopacky, Quinn; Labrie, Kathleen; Larkin, James; Maire, Jerome; Marchis, Franck; Marois, Christian; Millar-Blanchaer, Max; Morzinski, Katie; Nunez, Arturo; Oppenheimer, Rebecca; Palmer, David; Pazder, John; Perrin, Marshall; Poyneer, Lisa A.; Pueyo, Laurent; Quiroz, Carlos; Rantakyro, Fredrik; Reshetov, Vlad; Saddlemyer, Les; Sadakuni, Naru; Savransky, Dmitry; Serio, Andrew; Sivaramakrishnan, Anand; Smith, Malcolm; Soummer, Remi; Thomas, Sandrine; Wallace, J. K.; Wang, Jason; Weiss, Jason; Wiktorowicz, Sloane; Wolff, Schuyler G.

2014-08-01

10

GPI Pipeline: Gemini Planet Imager Data Pipeline  

NASA Astrophysics Data System (ADS)

The GPI data pipeline allows users to reduce and calibrate raw GPI data into spectral and polarimetric datacubes, and to apply various PSF subtraction methods to those data. Written in IDL and available in a compiled version, the software includes an integrated calibration database to manage reference files and an interactive data viewer customized for high contrast imaging that allows exploration and manipulation of data.

GPI instrument Collaboration

2014-11-01

11

Non-Redundant Masking Science on the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

Non-Redundant Mask Interferometry (NRM) transforms a fully transmissive pupil into an interferometer by masking all but a set of holes that form unique baselines. The interferometric resolution and dynamic range makes the technique suitable for probing potential planet forming regions. So called "transition disks" may or may not have perturbing bodies in the process of changing the disk morphology (cleared gaps, etc.) and require close-in imaging to peer inside disk clearings and spot companions that are several orders of magnitude fainter than the host star. Improvements in contrast for NRM rely on both the wavefront quality as well as the data reduction methods. Image plane modeling of the NRM point-spread function avoids ringing and windowing effects that result in Fourier domain analysis of bad pixel and restricted field of view data. The Gemini Planet Imager (GPI), an extreme adaptive optics system and integral field spectrograph, is equipped with a 10-hole NRM. We present recent results from GPI NRM I&T data using the image plane approach to measure visibilities as an early prediction of performance. We additionally discuss the feasibility of measuring visibility amplitudes from ground-based studies and their implications for NRM science with GPI.

Greenbaum, Alexandra; Cheetham, Anthony; Sivaramakrishnan, A.; Pueyo, L.; Wolff, S.; Perrin, M. D.; Ingraham, P.; Thomas, S.; Norris, B.; Tuthill, P.

2014-01-01

12

The integral field spectrograph for the Gemini planet imager  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a complex optical system designed to directly detect the self-emission of young planets within two arcseconds of their host stars. After suppressing the starlight with an advanced AO system and apodized coronagraph, the dominant residual contamination in the focal plane are speckles from the atmosphere and optical surfaces. Since speckles are diffractive in nature their positions in the field are strongly wavelength dependent, while an actual companion planet will remain at fixed separation. By comparing multiple images at different wavelengths taken simultaneously, we can freeze the speckle pattern and extract the planet light adding an order of magnitude of contrast. To achieve a bandpass of 20%, sufficient to perform speckle suppression, and to observe the entire two arcsecond field of view at diffraction limited sampling, we designed and built an integral field spectrograph with extremely low wavefront error and almost no chromatic aberration. The spectrograph is fully cryogenic and operates in the wavelength range 1 to 2.4 microns with five selectable filters. A prism is used to produce a spectral resolution of 45 in the primary detection band and maintain high throughput. Based on the OSIRIS spectrograph at Keck, we selected to use a lenslet-based spectrograph to achieve an rms wavefront error of approximately 25 nm. Over 36,000 spectra are taken simultaneously and reassembled into image cubes that have roughly 192x192 spatial elements and contain between 11 and 20 spectral channels. The primary dispersion prism can be replaced with a Wollaston prism for dual polarization measurements. The spectrograph also has a pupil-viewing mode for alignment and calibration.

Larkin, James E.; Chilcote, Jeffrey K.; Aliado, Theodore; Bauman, Brian J.; Brims, George; Canfield, John M.; Cardwell, Andrew; Dillon, Daren; Doyon, René; Dunn, Jennifer; Fitzgerald, Michael P.; Graham, James R.; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Johnson, Christopher A.; Kress, Evan; Konopacky, Quinn M.; Macintosh, Bruce A.; Magnone, Kenneth G.; Maire, Jerome; McLean, Ian S.; Palmer, David; Perrin, Marshall D.; Quiroz, Carlos; Rantakyrö, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Serio, Andrew; Thibault, Simon; Thomas, Sandrine J.; Vallee, Philippe; Weiss, Jason L.

2014-07-01

13

PDS 66 Resolved in Polarimetry with the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

We present H band polarimetry data for the PDS 66 circumstellar disk obtained as part of commissioning tests for the Gemini Planet Imager. GPI's high contrast AO system and coronagraph combined with differential polarimetry provide a clear view of the disk. The disk has an apparent outer radius of ~ 70 AU which is in agreement with previous HST scattered light imaging. We achieve an inner working angle of ~ 0.3'' which surpasses the ~ 0.4'' result accomplished with HST STIS. PDS 66 is a classical T Tauri star and a member of Lower Centaurus Crux with an age of 13 Myrs. The PDS 66 disk appears un-evolved for it's age with a higher than average accretion rate indicative of a near transition disk morphology. Evidence for grain growth within the disk has been seen in both the FIR and millimeter. Early radiative transfer modeling results will also be presented. By comparing the observed polarization fraction to radiative transfer models we can probe the geometry (degree of flaring) and grain distributions (size, density) of the disk.

Wolff, Schuyler; Perrin, Marshall D.; Wang, Jason; Graham, James R.; Pueyo, Laurent; Millar-Blanchaer, Max; Kalas, Paul; Gpies Team

2015-01-01

14

Gemini Planet Imager Spectroscopy of the HR 8799 Planets c and d  

NASA Astrophysics Data System (ADS)

During the first-light run of the Gemini Planet Imager we obtained K-band spectra of exoplanets HR 8799 c and d. Analysis of the spectra indicates that planet d may be warmer than planet c. Comparisons to recent patchy cloud models and previously obtained observations over multiple wavelengths confirm that thick clouds combined with horizontal variation in the cloud cover generally reproduce the planets' spectral energy distributions. When combined with the 3 to 4 ?m photometric data points, the observations provide strong constraints on the atmospheric methane content for both planets. The data also provide further evidence that future modeling efforts must include cloud opacity, possibly including cloud holes, disequilibrium chemistry, and super-solar metallicity.

Ingraham, Patrick; Marley, Mark S.; Saumon, Didier; Marois, Christian; Macintosh, Bruce; Barman, Travis; Bauman, Brian; Burrows, Adam; Chilcote, Jeffrey K.; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald; Goodsell, Stephen J.; Graham, James R.; Hartung, Markus; Hibon, Pascale; Kalas, Paul G.; Konopacky, Quinn; Larkin, James A.; Maire, Jérôme; Marchis, Franck; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie M.; Norton, Andrew; Oppenheimer, Rebecca; Palmer, Dave W.; Patience, Jenny; Perrin, Marshall D.; Poyneer, Lisa A.; Pueyo, Laurent; Rantakyrö, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Soummer, Rémi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wiktorowicz, Sloane J.; Wolff, Schuyler G.

2014-10-01

15

Interpreting Gemini Planet Imager Spectroscopy of the Young Giant Planets HR 8799 c and d  

NASA Astrophysics Data System (ADS)

During the first-light run of the Gemini Telescope’s newest facility instrument, the Gemini Planet Imager (GPI), K-band spectra of exoplanets HR 8799 c and d were obtained. Combined with previous ground based multi-band photometry and spectroscopy, the new datasets place strong constraints on the atmospheric composition, cloud properties, and thermal profile of these two giant planets. Comparison of the data to our newest atmospheric models confirms that thick clouds combined with horizontal variation in the cloud cover is required to best reproduce the planets’ spectral energy distributions. The data also provide further evidence that future modeling efforts must include cloud opacity, possibly including cloud holes, disequilibrium chemistry, and super-solar metallicity. In short there is now little doubt these planets are as complex and dynamic as the giants of our own solar system. In our presentation we will not only discuss the challenges of characterizing these objects but will also look forward to the future of exoplanet direct imaging by both GPI and SPHERE.

Marley, Mark S.; Ingraham, Patrick; Saumon, Didier; Marois, Christian

2014-11-01

16

Direct observation of extrasolar planets and the development of the gemini planet imager integral field spectrograph  

NASA Astrophysics Data System (ADS)

This thesis is focused on the development and testing of a new instrument capable of finding and characterizing recently-formed Jupiter-sized planets orbiting other stars. To observe these planets, I present the design, construction and testing of the Gemini Planet Imager (GPI) Integral Field Spectrograph (IFS). GPI is a facility class instrument for the Gemini Observatory with the primary goal of directly detecting young Jovian planets. The GPI IFS utilizes an infrared transmissive lenslet array to sample a rectangular 2.7 x 2.7 arcsecond field of view and provide low-resolution spectra across five bands between 1 and 2.5 mum. The dispersing element can be replaced with a Wollaston prism to provide broadband polarimetry across the same five filter bands. The IFS construction was based at the University of California, Los Angeles in collaboration with the Universite de Montreal, Immervision and Lawrence Livermore National Laboratory. I will present performance results, from in-lab testing, of the Integral Field Spectrograph (IFS) for the Gemini Planet Imager (GPI). The IFS is a large, complex, cryogenic, optical system requiring several years of development and testing. I will present the design and integration of the mechanical and optical performance of the spectrograph optics. The IFS passed its pre-ship review in 2011 and was shipped to University of California, Santa Cruz for integration with the remaining sub-systems of GPI. The UCLA built GPI IFS was integrated with the rest of GPI and is delivering high quality spectral datacubes of GPI's coronagraphic field. Using the NIRC2 instrument located at the Keck Observatory, my collaborators and I observed the planetary companion to beta Pictoris in L' (3.5--4.1mum). Observations taken in the fall of 2009 and 2012 are used to find the location and inclination of the planet relative to the massive debris disk orbiting beta Pictoris. We find that the planet's orbit has a position angle on the sky of 211.9+/-0.4 degrees, making the planet misaligned by 2.9+/-0.5 degrees from the main disk, consistent with other observations that beta Pic b is misaligned with the main disk, and part of the misaligned inner disk. In 2009 & 2012 we find a projected orbital separation of 312.8 +/- 18.3 and 466.35 +/- 8.4 milliarcseconds consistent with an orbital period of ˜ 20 years, and a semi-major axis of ˜ 9 AU as found by Macintosh et al. (2014). During the first commissioning observations with the Gemini Planet Imager (GPI), my collaborators and I took the first H-band spectrum of the planetary companion to the nearby young star beta Pictoris. The spectrum has a resolving power of ˜ 45 and demonstrates the distinctive triangular shape of a cool substellar object with low surface gravity. Using atmospheric models, we find an effective temperature of 1650 +/- 50K and a surface gravity of log(g) = 4.0 +/- 0.25 (cgs units). These values agree well with predictions from planetary evolution models for a gas giant with mass between 10 and 12 MJup and age between 10 and 20 Myrs. The spectrum is very similar to a known low mass field brown dwarf but has more flux at the long wavelength end of the filters compared to models. Given the very high signal-to-noise of our spectrum this likely indicates additional physics such as patchy clouds that need to be included in the model.

Chilcote, Jeffrey Kaplan

17

Calibrating IR optical densities for the Gemini Planet Imager Extreme Adaptive Optics Coronagraph apodizers  

E-print Network

Calibrating IR optical densities for the Gemini Planet Imager Extreme Adaptive Optics Coronagraph. INTRODUCTION Astronomy is at a new frontier of comparative planetary science. Recent advances in adaptive optics (or AO, which corrects atmospheric disturbances to stellar light in real-time), combined

18

A Gemini Planet Imager investigation of the atmosphere of the HD 95086b planet  

NASA Astrophysics Data System (ADS)

We present Gemini Planet Imager (GPI) near-infrared observations of the ~5 Mjup companion to the young, dusty A-type star HD 95086, observed during the course of the verification and commissioning of the instrument. By combining binned low-resolution H and K-band IFS spectra from GPI, with literature near and mid-IR photometry, we have undertaken the most comprehensive analysis of the spectral energy distribution of HD 95086 b to-date. Comparing these observational results with atmospheric models, we constrain key parameters such as the effective temperature and surface gravity, and place the results in the context of analyses of other directly imaged planetary-mass companions (e.g. HR 8799 bcde, ? Pic b), and other substellar companions at a similar age (e.g. HD 106906 b, GQ Lup b). We also comment on the sensitivity of companions interior and exterior to HD 95086 b. Lastly, we present the color-corrections derived during the course of this study that are required to transform photometry obtained with GPI in the K1 and K2 filters into both the MKO and 2MASS photometric systems, essential for the propoer interpretation of K-band photometry measurements obtained with GPI.

De Rosa, Robert J.; Pueyo, Laurent; Patience, Jenny; Graham, James R.; Gemini Planet Imager Team

2015-01-01

19

Development and Commissioning of the Integral Field Spectrograph for the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is one of a new generation of instruments being built to directly image extrasolar planets in the outer solar systems of young main sequence stars. By combining a 1700-actuactor adaptive optics system, an apodized-pupil Lyot coronagraph, a precision interferometric infrared wavefront sensor, and an integral field spectrograph (IFS), GPI’s goal is more than an order of magnitude improvement in contrast compared to existing high contrast systems. This presentation focuses on the performance and characterization of the GPI IFS which is based on concepts from the OSIRIS instrument employed at Keck. Like OSIRIS, the IFS utilizes an infrared transmissive lenslet array to sample an approximate 2.7 x 2.7 arcsecond field of view at the diffraction limit of the Gemini Telescopes. The IFS provides over 36,000 simultaneous low-resolution (R ~ 45) spectra across five bands between 1 and 2.5?m. Alternatively, the dispersing element can be replaced with a Wollaston prism to provide broadband polarimetry of the same five filter bands. The IFS construction was based at the University of California, Los Angeles in collaboration with the Université de Montreal, Immervision and Lawrence Livermore National Laboratory. The IFS was integrated with the other components of GPI in the fall of 2011. GPI has recently finished Integration & Testing at the University of California, Santa Cruz, and has been shipped to Gemini South where it is undergoing post delivery acceptance testing.

Chilcote, Jeffrey K.; Larkin, J. E.; Planet Imager instrument, Gemini; science Teams

2014-01-01

20

The use of a high-order MEMS deformable mirror in the Gemini Planet Imager  

SciTech Connect

We briefly review the development history of the Gemini Planet Imager's 4K Boston Micromachines MEMS deformable mirror. We discuss essential calibration steps and algorithms to control the MEMS with nanometer precision, including voltage-phase calibration and influence function characterization. We discuss the integration of the MEMS into GPI's Adaptive Optics system at Lawrence Livermore and present experimental results of 1.5 kHz closed-loop control. We detail mitigation strategies in the coronagraph to reduce the impact of abnormal actuators on final image contrast.

Poyneer, L A; Bauman, B; Cornelissen, S; Jones, S; Macintosh, B; Palmer, D; Isaacs, J

2010-12-17

21

Gemini planet imager observational calibrations VI: photometric and spectroscopic calibration for the integral field spectrograph  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a new facility instrument for the Gemini Observatory designed to provide direct detection and characterization of planets and debris disks around stars in the solar neighborhood. In addition to its extreme adaptive optics and coronagraphic systems which give access to high angular resolution and high-contrast imaging capabilities, GPI contains an integral field spectrograph providing low resolution spectroscopy across five bands between 0.95 and 2.5 ?m. This paper describes the sequence of processing steps required for the spectro-photometric calibration of GPI science data, and the necessary calibration files. Based on calibration observations of the white dwarf HD 8049 B we estimate that the systematic error in spectra extracted from GPI observations is less than 5%. The flux ratio of the occulted star and fiducial satellite spots within coronagraphic GPI observations, required to estimate the magnitude difference between a target and any resolved companions, was measured in the H-band to be ?m = 9.23 +/- 0.06 in laboratory measurements and ?m = 9.39 +/- 0.11 using on-sky observations. Laboratory measurements for the Y, J , K1 and K2 filters are also presented. The total throughput of GPI, Gemini South and the atmosphere of the Earth was also measured in each photometric passband, with a typical throughput in H-band of 18% in the non-coronagraphic mode, with some variation observed over the six-month period for which observations were available. We also report ongoing development and improvement of the data cube extraction algorithm.

Maire, Jérôme; Ingraham, Patrick J.; De Rosa, Rob J.; Perrin, Marshall D.; Rajan, Abhijith; Savransky, Dmitry; Wang, Jason J.; Ruffio, Jean-Baptiste; Wolff, Schuyler G.; Chilcote, Jeffrey K.; Doyon, René; Graham, James R.; Greenbaum, Alexandra Z.; Konopacky, Quinn M.; Larkin, James E.; Macintosh, Bruce A.; Marois, Christian; Millar-Blanchaer, Max; Patience, Jennifer; Pueyo, Laurent A.; Sivaramakrishnan, Anand; Thomas, Sandrine J.; Weiss, Jason L.

2014-07-01

22

Performance of the integral field spectrograph for the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

We present performance results, from in-lab testing, of the Integral Field Spectrograph (IFS) for the Gemini Planet Imager (GPI). GPI is a facility class instrument for the Gemini Observatory with the primary goal of directly detecting young Jovian planets. The GPI IFS is based on concepts from the OSIRIS instrument at Keck and utilizes an infrared transmissive lenslet array to sample a rectangular 2.8 x 2.8 arcsecond field of view. The IFS provides low-resolution spectra across five bands between 1 and 2.5?m. Alternatively, the dispersing element can be replaced with a Wollaston prism to provide broadband polarimetry across the same five filter bands. The IFS construction was based at the University of California, Los Angeles in collaboration with the Université de Montr eal, Immervision and Lawrence Livermore National Laboratory. During its construction, we encountered an unusual noise source from microphonic pickup by the Hawaii-2RG detector. We describe this noise and how we eliminated it through vibration isolation. The IFS has passed its preship review and was shipped to University of California, Santa Cruz at the end of 2011 for integration with the remaining sub-systems of GPI. The IFS has been integrated with the rest of GPI and is delivering high quality spectral datacubes of GPI's coronagraphic field.

Chilcote, Jeffrey K.; Larkin, James E.; Maire, Jérôme; Perrin, Marshall D.; Fitzgerald, Michael P.; Doyon, René; Thibault, Simon; Bauman, Brian; Macintosh, Bruce A.; Graham, James R.; Saddlemyer, Les

2012-09-01

23

Gemini Planet Imager observational calibrations I: Overview of the GPI data reduction pipeline  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) has as its science instrument an infrared integral field spectrograph/polarimeter (IFS). Integral field spectrographs are scientificially powerful but require sophisticated data reduction systems. For GPI to achieve its scientific goals of exoplanet and disk characterization, IFS data must be reconstructed into high quality astrometrically and photometrically accurate datacubes in both spectral and polarization modes, via flexible software that is usable by the broad Gemini community. The data reduction pipeline developed by the GPI instrument team to meet these needs is now publicly available following GPI's commissioning. This paper, the first of a series, provides a broad overview of GPI data reduction, summarizes key steps, and presents the overall software framework and implementation. Subsequent papers describe in more detail the algorithms necessary for calibrating GPI data. The GPI data reduction pipeline is open source, available from planetimager.org, and will continue to be enhanced throughout the life of the instrument. It implements an extensive suite of task primitives that can be assembled into reduction recipes to produce calibrated datasets ready for scientific analysis. Angular, spectral, and polarimetric differential imaging are supported. Graphical tools automate the production and editing of recipes, an integrated calibration database manages reference files, and an interactive data viewer customized for high contrast imaging allows for exploration and manipulation of data.

Perrin, Marshall D.; Maire, Jérôme; Ingraham, Patrick; Savransky, Dmitry; Millar-Blanchaer, Max; Wolff, Schuyler G.; Ruffio, Jean-Baptiste; Wang, Jason J.; Draper, Zachary H.; Sadakuni, Naru; Marois, Christian; Rajan, Abhijith; Fitzgerald, Michael P.; Macintosh, Bruce; Graham, James R.; Doyon, René; Larkin, James E.; Chilcote, Jeffrey K.; Goodsell, Stephen J.; Palmer, David W.; Labrie, Kathleen; Beaulieu, Mathilde; De Rosa, Robert J.; Greenbaum, Alexandra Z.; Hartung, Markus; Hibon, Pascale; Konopacky, Quinn; Lafreniere, David; Lavigne, Jean-Francois; Marchis, Franck; Patience, Jenny; Pueyo, Laurent; Rantakyrö, Fredrik T.; Soummer, Rémi; Sivaramakrishnan, Anand; Thomas, Sandrine; Ward-Duong, Kimberly; Wiktorowicz, Sloane

2014-07-01

24

On-sky performance during verification and commissioning of the Gemini Planet Imager's adaptive optics system  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager instrument's adaptive optics (AO) subsystem was designed specifically to facilitate high-contrast imaging. It features several new technologies, including computationally efficient wavefront reconstruction with the Fourier transform, modal gain optimization every 8 seconds, and the spatially filtered wavefront sensor. It also uses a Linear-Quadratic-Gaussian (LQG) controller (aka Kalman filter) for both pointing and focus. We present on-sky performance results from verification and commissioning runs from December 2013 through May 2014. The efficient reconstruction and modal gain optimization are working as designed. The LQG controllers effectively notch out vibrations. The spatial filter can remove aliases, but we typically use it oversized by about 60% due to stability problems.

Poyneer, Lisa A.; De Rosa, Robert J.; Macintosh, Bruce; Palmer, David W.; Perrin, Marshall D.; Sadakuni, Naru; Savransky, Dmitry; Bauman, Brian; Cardwell, Andrew; Chilcote, Jeffrey K.; Dillon, Daren; Gavel, Donald; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Rantakyrö, Fredrik T.; Thomas, Sandrine; Veran, Jean-Pierre

2014-07-01

25

Gemini planet imager observational calibrations IX: least-squares inversion flux extraction  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is an instrument designed to directly image planets and circumstellar disks from 0.9 to 2.5 microns (the YJHK infrared bands) using high contrast adaptive optics with a lenslet-based integral field spectrograph. We develop an extraction algorithm based on a least-squares method to disentangle the spectra and systematic noise contributions simultaneously. We utilize two approaches to adjust for the effect of flexure of the GPI optics which move the position of light incident on the detector. The first method is to iterate the extraction to achieve minimum residual and the second is to cross-correlate the detector image with a model image in iterative extraction steps to determine an offset. Thus far, this process has made clear qualitative improvements to the cube extraction by reducing the Moiré pattern. There are also improvements to the automated routines for finding flexure offsets which are reliable to with ~ 0.5 pixel accuracy compared to pixel accuracy prior. Further testing and optimization will follow before implementation into the GPI pipeline.

Draper, Zachary H.; Marois, Christian; Wolff, Schuyler; Perrin, Marshall; Ingraham, Patrick J.; Ruffio, Jean-Baptiste; Rantakyro, Fredrik T.; Hartung, Markus; Goodsell, Stephen J.

2014-07-01

26

The First H-band Spectrum of the Massive Gas Giant Planet beta Pictoris b with the Gemini Planet Imager  

E-print Network

Using the recently installed Gemini Planet Imager (GPI), we have taken the first H-band spectrum of the planetary companion to the nearby young star beta Pictoris. GPI is designed to image and provide low-resolution spectra of Jupiter sized, self-luminous planetary companions around young nearby stars. These observations were taken covering the H-band (1.65 microns). The spectrum has a resolving power of $\\sim$ 45 and demonstrates the distinctive triangular shape of a cool substellar object with low surface gravity. Using atmospheric models, we find an effective temperature of $1650 \\pm 50$ K and a surface gravity of $\\log(g) = 4.0 \\pm 0.25$ (cgs units). These values agree well with predictions from planetary evolution models for a gas giant with mass between 10 and 12 $M_{\\rm Jup}$ and age between 10 and 20 Myrs.

Chilcote, Jeffrey; Fitzgerald, Michael P; Graham, James R; Larkin, James E; Macintosh, Bruce; Bauman, Brian; Burrows, Adam S; Cardwell, Andrew; De Rosa, Robert J; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Gavel, Donald; Goodsell, Stephen J; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Kalas, Paul; Konopacky, Quinn; Maire, Jérôme; Marchis, Franck; Marley, Mark S; Marois, Christian; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, B R; Palmer, David; Patience, Jennifer; Perrin, Marshall D; Poyneer, Lisa; Pueyo, Laurent; Rantakyrö, Fredrik; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Sivaramakrishnan, Anand; Song, Inseok; Soummer, Remi; Thomas, Sandrine; Wallace, J Kent; Wiktorowicz, Sloane J; Wolff, Schuyler

2014-01-01

27

Gemini planet imager observational calibrations VIII: characterization and role of satellite spots  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) combines extreme adaptive optics, an integral field spectrograph, and a high performance coronagraph to directly image extrasolar planets in the near-infrared. Because the coronagraph blocks most of the light from the star, it prevents the properties of the host star from being measured directly. Instead, satellite spots, which are created by diffraction from a square grid in the pupil plane, can be used to locate the star and extract its spectrum. We describe the techniques implemented into the GPI Data Reduction Pipeline to measure the properties of the satellite spots and discuss the precision of the reconstructed astrometry and spectrophotometry of the occulted star. We find the astrometric precision of the satellite spots in an H-band datacube to be 0.05 pixels and is best when individual satellite spots have a signal to noise ratio (SNR) of > 20. In regards to satellite spot spectrophotometry, we find that the total flux from the satellite spots is stable to ~7% and scales linearly with central star brightness and that the shape of the satellite spot spectrum varies on the 2% level.

Wang, Jason J.; Rajan, Abhijith; Graham, James R.; Savransky, Dmitry; Ingraham, Patrick J.; Ward-Duong, Kimberly; Patience, Jennifer; De Rosa, Robert J.; Bulger, Joanna; Sivaramakrishnan, Anand; Perrin, Marshall D.; Thomas, Sandrine J.; Sadakuni, Naru; Greenbaum, Alexandra Z.; Pueyo, Laurent; Marois, Christian; Oppenheimer, Ben R.; Kalas, Paul; Cardwell, Andrew; Goodsell, Stephen; Hibon, Pascale; Rantakyrö, Fredrik T.

2014-07-01

28

The Gemini NICI Planet-Finding Campaign  

Microsoft Academic Search

Our team is carrying out a multi-year observing program to directly image and characterize young extrasolar planets using the Near-Infrared Coronagraphic Imager (NICI) on the Gemini-South 8.1-meter telescope. NICI is the first instrument on a large telescope designed from the outset for high-contrast imaging, comprising a high-performance curvature adaptive optics (AO) system with a simultaneous dual-channel coronagraphic imager. Combined with

Michael C. Liu; Zahed Wahhaj; Beth A. Biller; Eric L. Nielsen; Mark Chun; Laird M. Close; Christ Ftaclas; Markus Hartung; Thomas L. Hayward; Fraser Clarke; I. Neill Reid; Evgenya L. Shkolnik; Niranjan Thatte; Silvia Alencar; Pawel Artymowicz; Alan Boss; Adam Burrows; Elisabethe de Gouveia Dal Pino; Jane Gregorio-Hetem; Shigeru Ida; Marc J. Kuchner; Douglas Lin; Douglas Toomey

2010-01-01

29

Gemini planet imager observational calibrations III: empirical measurement methods and applications of high-resolution microlens PSFs  

NASA Astrophysics Data System (ADS)

The newly commissioned Gemini Planet Imager (GPI) combines extreme adaptive optics, an advanced coronagraph, precision wavefront control and a lenslet-based integral field spectrograph (IFS) to measure the spectra of young extrasolar giant planets between 0.9-2.5 ?m. Each GPI detector image, when in spectral model, consists of ~37,000 microspectra which are under or critically sampled in the spatial direction. This paper demonstrates how to obtain high-resolution microlens PSFs and discusses their use in enhancing the wavelength calibration, flexure compensation and spectral extraction. This method is generally applicable to any lenslet-based integral field spectrograph including proposed future instrument concepts for space missions.

Ingraham, Patrick; Ruffio, Jean-Baptiste; Perrin, Marshall D.; Wolff, Schuyler G.; Draper, Zachary H.; Maire, Jerome; Marchis, Franck; Fesquet, Vincent

2014-07-01

30

Gemini Planet Imager Polarimetry of the Circumstellar Ring around HR 4796A  

NASA Astrophysics Data System (ADS)

Using the Gemini Planet Imager we have obtained imaging polarimetry of the circumstellar ring around HR 4796A, revealing surprisingly complex morphology that challenges models and has forced us to drastically revise our understanding of the physical properties of this disk.GPI's differential polarimetry mode not only provides an increase in contrast for better detection of dust-scattered light, but also provides new insights into the properties of the scattering dust through measurement of the polarized scattering phase function. In polarized light, the disk is seen all the way in to its semi-minor axis for the first time, and exhibits surprisingly strong asymmetry in polarized intensity. Based on a synthesis of the total and polarized intensities, our revised model now envisions an optically thick ring composed of relatively large silicate dust particles, with the west side closer to us, contrary to most prior interpretations. These findings suggest that the ring is geometrically narrow and dynamically cold, perhaps shepherded by larger bodies in the same manner as Saturn's F ring. Deep multiwavelength observations from J to K bands are allowing further tests of this model.

Perrin, Marshall D.; Duchene, Gaspard; Fitzgerald, Michael P.; Millar-Blanchaer, Max; Graham, James R.; Wiktorowicz, Sloane; Kalas, Paul; Macintosh, Bruce; Gemini Planet Imager Team

2015-01-01

31

Near-infrared detection and characterization of the exoplanet HD 95086 b with the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

HD 95086 is an intermediate-mass debris-disk-bearing star. VLT/NaCo 3.8 ?m observations revealed it hosts a 5 ± 2 MJup companion (HD 95086 b) at ?56 AU. Follow-up observations at 1.66 and 2.18 ?m yielded a null detection, suggesting extremely red colors for the planet and the need for deeper direct-imaging data. In this Letter, we report H-(1.7 ?m) and K1-(2.05 ?m) band detections of HD 95086 b from Gemini Planet Imager (GPI) commissioning observations taken by the GPI team. The planet position in both spectral channels is consistent with the NaCo measurements and we confirm it to be comoving. Our photometry yields colors of H - L' = 3.6 ± 1.0 mag and K1 - L' = 2.4 ± 0.7 mag, consistent with previously reported 5-? upper limits in H and Ks. The photometry of HD 95086 b best matches that of 2M 1207 b and HR 8799 cde. Comparing its spectral energy distribution with the BT-SETTL and LESIA planet atmospheric models yields Teff ~ 600-1500 K and log g ~ 2.1-4.5. Hot-start evolutionary models yield M = 5 ± 2 MJup. Warm-start models reproduce the combined absolute fluxes of the object for M = 4-14 MJup for a wide range of plausible initial conditions (Sinit = 8-13 kB/baryon). The color-magnitude diagram location of HD 95086 b and its estimated Teff and log g suggest that the planet is a peculiar L - T transition object with an enhanced amount of photospheric dust. Based on public data taken at the GPI commissioning.

Galicher, R.; Rameau, J.; Bonnefoy, M.; Baudino, J.-L.; Currie, T.; Boccaletti, A.; Chauvin, G.; Lagrange, A.-M.; Marois, C.

2014-05-01

32

A Combined Very Large Telescope and Gemini Study of the Atmosphere of the Directly Imaged Planet, ? Pictoris b  

NASA Astrophysics Data System (ADS)

We analyze new/archival VLT/NaCo and Gemini/NICI high-contrast imaging of the young, self-luminous planet ? Pictoris b in seven near-to-mid IR photometric filters, using advanced image processing methods to achieve high signal-to-noise, high precision measurements. While ? Pic b's near-IR colors mimic those of a standard, cloudy early-to-mid L dwarf, it is overluminous in the mid-infrared compared to the field L/T dwarf sequence. Few substellar/planet-mass objects—i.e., ? And b and 1RXJ 1609B—match ? Pic b's JHKsL' photometry and its 3.1 ?m and 5 ?m photometry are particularly difficult to reproduce. Atmosphere models adopting cloud prescriptions and large (~60 ?m) dust grains fail to reproduce the ? Pic b spectrum. However, models incorporating thick clouds similar to those found for HR 8799 bcde, but also with small (a few microns) modal particle sizes, yield fits consistent with the data within the uncertainties. Assuming solar abundance models, thick clouds, and small dust particles (langarang = 4 ?m), we derive atmosphere parameters of log (g) = 3.8 ± 0.2 and T eff = 1575-1650 K, an inferred mass of 7^{+4}_{-3} MJ , and a luminosity of log(L/L ?) ~-3.80 ± 0.02. The best-estimated planet radius, ?1.65 ± 0.06 RJ , is near the upper end of allowable planet radii for hot-start models given the host star's age and likely reflects challenges constructing accurate atmospheric models. Alternatively, these radii are comfortably consistent with hot-start model predictions if ? Pic b is younger than ?7 Myr, consistent with a late formation well after its host star's birth ~12^{+8}_{-4} Myr ago.

Currie, Thayne; Burrows, Adam; Madhusudhan, Nikku; Fukagawa, Misato; Girard, Julien H.; Dawson, Rebekah; Murray-Clay, Ruth; Kenyon, Scott; Kuchner, Marc; Matsumura, Soko; Jayawardhana, Ray; Chambers, John; Bromley, Ben

2013-10-01

33

A Combined Very Large Telescope and Gemini Study of the Atmosphere of the Directly Imaged Planet, Beta Pictoris b  

NASA Technical Reports Server (NTRS)

We analyze new/archival VLT/NaCo and Gemini/NICI high-contrast imaging of the young, self-luminous planet Beta Pictoris b in seven near-to-mid IR photometric filters, using advanced image processing methods to achieve high signal-to-noise, high precision measurements. While Beta Pic b's near-IR colors mimic those of a standard, cloudy early-to-mid L dwarf, it is overluminous in the mid-infrared compared to the field L/T dwarf sequence. Few substellar/planet-mass objects-i.e., ? And b and 1RXJ 1609B-match Beta Pic b's JHKsL photometry and its 3.1 micron and 5 micron photometry are particularly difficult to reproduce. Atmosphere models adopting cloud prescriptions and large (approx. 60 micron)dust grains fail to reproduce the Beta Pic b spectrum. However, models incorporating thick clouds similar to those found forHR8799 bcde, but also with small (a fewmicrons) modal particle sizes, yield fits consistent with the data within the uncertainties. Assuming solar abundance models, thick clouds, and small dust particles (a = 4 micron), we derive atmosphere parameters of log(g) = 3.8 +/- 0.2 and Teff = 1575-1650 K, an inferred mass of 7+4 -3 MJ, and a luminosity of log(L/L) approx. -3.80 +/- 0.02. The best-estimated planet radius, is approx. equal to 1.65 +/- 0.06 RJ, is near the upper end of allowable planet radii for hot-start models given the host star's age and likely reflects challenges constructing accurate atmospheric models. Alternatively, these radii are comfortably consistent with hot-start model predictions if Beta Pic b is younger than is approx. equal to 7 Myr, consistent with a late formation well after its host star's birth approx. 12+8 -4 Myr ago.

Currie, Thayne; Burrows, Adam; Madhusudhan, Nikku; Fukagawa, Misato; Girard, Julien H.; Dawson, Rebekah; Murray-Clay, Ruth; Kenyon, Scott; Kuchner, Marc J.; Matsumura, Soko; Jayawardhana, Ray; Chambers, John; Bromley, Ben

2013-01-01

34

A COMBINED VERY LARGE TELESCOPE AND GEMINI STUDY OF THE ATMOSPHERE OF THE DIRECTLY IMAGED PLANET, ? PICTORIS b  

SciTech Connect

We analyze new/archival VLT/NaCo and Gemini/NICI high-contrast imaging of the young, self-luminous planet ? Pictoris b in seven near-to-mid IR photometric filters, using advanced image processing methods to achieve high signal-to-noise, high precision measurements. While ? Pic b's near-IR colors mimic those of a standard, cloudy early-to-mid L dwarf, it is overluminous in the mid-infrared compared to the field L/T dwarf sequence. Few substellar/planet-mass objects—i.e., ? And b and 1RXJ 1609B—match ? Pic b's JHK{sub s}L' photometry and its 3.1 ?m and 5 ?m photometry are particularly difficult to reproduce. Atmosphere models adopting cloud prescriptions and large (?60 ?m) dust grains fail to reproduce the ? Pic b spectrum. However, models incorporating thick clouds similar to those found for HR 8799 bcde, but also with small (a few microns) modal particle sizes, yield fits consistent with the data within the uncertainties. Assuming solar abundance models, thick clouds, and small dust particles ((a) = 4 ?m), we derive atmosphere parameters of log (g) = 3.8 ± 0.2 and T{sub eff} = 1575-1650 K, an inferred mass of 7{sup +4}{sub -3} M{sub J} , and a luminosity of log(L/L{sub ?}) ?–3.80 ± 0.02. The best-estimated planet radius, ?1.65 ± 0.06 R{sub J} , is near the upper end of allowable planet radii for hot-start models given the host star's age and likely reflects challenges constructing accurate atmospheric models. Alternatively, these radii are comfortably consistent with hot-start model predictions if ? Pic b is younger than ?7 Myr, consistent with a late formation well after its host star's birth ?12{sup +8}{sub -4} Myr ago.

Currie, Thayne; Jayawardhana, Ray [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544 (United States); Madhusudhan, Nikku [Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States); Fukagawa, Misato [Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043 (Japan); Girard, Julien H. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Cassilla 19001, Santiago (Chile); Dawson, Rebekah; Murray-Clay, Ruth; Kenyon, Scott [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 10, Cambridge, MA 02138 (United States); Kuchner, Marc [NASA-Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory Code 667, Greenbelt, MD 20771 (United States); Matsumura, Soko [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Chambers, John [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW Washington, DC 20015-1305 (United States); Bromley, Ben [Department of Physics, University of Utah, Salt Lake City, UT (United States)

2013-10-10

35

The Gemini Deep Planet Survey - GDPS  

SciTech Connect

We present the results of the Gemini Deep Planet Survey, a near-infrared adaptive optics search for giant planets and brown dwarfs around nearby young stars. The observations were obtained with the Altair adaptive optics system at the Gemini North telescope and angular differential imaging was used to suppress the speckle noise of the central star. Detection limits for the 85 stars observed are presented, along with a list of all faint point sources detected around them. Typically, the observations are sensitive to angular separations beyond 0.5-inch with 5{sigma} contrast sensitivities in magnitude difference at 1.6 {micro}m of 9.6 at 0.5-inch, 12.9 at 1-inch, 15 at 2-inch, and 16.6 at 5-inch. For the typical target of the survey, a 100 Myr old K0 star located 22 pc from the Sun, the observations are sensitive enough to detect planets more massive than 2 M{sub Jup} with a projected separation in the range 40-200 AU. Depending on the age, spectral type, and distance of the target stars, the minimum mass that could be detected with our observations can be {approx}1 M{sub Jup}. Second epoch observations of 48 stars with candidates (out of 54) have confirmed that all candidates are unrelated background stars. A detailed statistical analysis of the survey results, which provide upper limits on the fractions of stars with giant planet or low mass brown dwarf companions, is presented. Assuming a planet mass distribution dn/dm {proportional_to} m{sup -1.2} and a semi-major axis distribution dn/da {proportional_to} a{sup -1}, the upper limits on the fraction of stars with at least one planet of mass 0.5-13 M{sub Jup} are 0.29 for the range 10-25 AU, 0.13 for 25-50 AU, and 0.09 for 50-250 AU, with a 95% confidence level; this result is weakly dependent on the semi-major axis distribution power-law index. Without making any assumption on the mass and semi-major axis distributions, the fraction of stars with at least one brown dwarf companion having a semi-major axis in the range 25-200 AU is 0.018{sub -0.014}{sup +0.078}, with a 95% confidence level. The observations made as part of this survey have resolved the stars HD 14802, HD 135363, HD 160934, HD 166181, and HD 213845 into close binaries for the first time.

Lafreniere, D; Doyon, R; Marois, C; Nadeau, D; Oppenheimer, B R; Roche, P F; Rigaut, F; Graham, J R; Jayawardhana, R; Johnstone, D; Kalas, P G; Macintosh, B; Racine, R

2007-06-01

36

Polarimetry with the Gemini Planet Imager: Methods, Performance at First Light, and the Circumstellar Ring around HR 4796A  

NASA Astrophysics Data System (ADS)

We present the first results from the polarimetry mode of the Gemini Planet Imager (GPI), which uses a new integral field polarimetry architecture to provide high contrast linear polarimetry with minimal systematic biases between the orthogonal polarizations. We describe the design, data reduction methods, and performance of polarimetry with GPI. Point-spread function (PSF) subtraction via differential polarimetry suppresses unpolarized starlight by a factor of over 100, and provides sensitivity to circumstellar dust reaching the photon noise limit for these observations. In the case of the circumstellar disk around HR 4796A, GPI's advanced adaptive optics system reveals the disk clearly even prior to PSF subtraction. In polarized light, the disk is seen all the way in to its semi-minor axis for the first time. The disk exhibits surprisingly strong asymmetry in polarized intensity, with the west side >~ 9 times brighter than the east side despite the fact that the east side is slightly brighter in total intensity. Based on a synthesis of the total and polarized intensities, we now believe that the west side is closer to us, contrary to most prior interpretations. Forward scattering by relatively large silicate dust particles leads to the strong polarized intensity on the west side, and the ring must be slightly optically thick in order to explain the lower brightness in total intensity there. These findings suggest that the ring is geometrically narrow and dynamically cold, perhaps shepherded by larger bodies in the same manner as Saturn's F ring.

Perrin, Marshall D.; Duchene, Gaspard; Millar-Blanchaer, Max; Fitzgerald, Michael P.; Graham, James R.; Wiktorowicz, Sloane J.; Kalas, Paul G.; Macintosh, Bruce; Bauman, Brian; Cardwell, Andrew; Chilcote, Jeffrey; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Gavel, Donald; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Kerley, Daniel; Konapacky, Quinn; Larkin, James E.; Maire, Jérôme; Marchis, Franck; Marois, Christian; Mittal, Tushar; Morzinski, Katie M.; Oppenheimer, B. R.; Palmer, David W.; Patience, Jennifer; Poyneer, Lisa; Pueyo, Laurent; Rantakyrö, Fredrik T.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Soummer, Rémi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wang, Jason J.; Wolff, Schuyler G.

2015-02-01

37

Astrometric Calibration of the Gemini NICI Planet-Finding Campaign  

NASA Astrophysics Data System (ADS)

We describe the astrometric calibration of the Gemini NICI Planet-Finding Campaign. The Campaign requires a relative astrometric accuracy of ?20 mas across multiyear timescales in order to distinguish true companions from background stars by verifying common proper motion and parallax with their parent stars. The calibration consists of a correction for instrumental optical image distortion, plus on-sky imaging of astrometric fields to determine the pixel scale and image orientation. We achieve an accuracy of ?7 mas between the center and edge of the 18? NICI field, meeting the 20 mas requirement. Most of the Campaign data in the Gemini Science Archive are accurate to this level but we identify a number of anomalies and present methods to correct the errors.

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

2014-12-01

38

The Gemini NICI Planet-Finding Campaign: The Frequency of Giant Planets around Young B and A Stars  

NASA Astrophysics Data System (ADS)

We have carried out high contrast imaging of 70 young, nearby B and A stars to search for brown dwarf and planetary companions as part of the Gemini NICI Planet-Finding Campaign. Our survey represents the largest, deepest survey for planets around high-mass stars (~1.5-2.5 M?) conducted to date and includes the planet hosts ? Pic and Fomalhaut. Despite detecting two new brown dwarfs, our observations did not detect new planets around our target stars, and we present upper limits on the fraction of high-mass stars that can host giant planets that are consistent with our null result.

Nielsen, Eric L.; Liu, Michael C.; Wahhaj, Zahed; Biller, Beth A.; Hayward, Thomas L.; Hayward

2014-01-01

39

Final A&T stages of the Gemini Planet Finder  

NASA Astrophysics Data System (ADS)

The Gemini Planet Finder (GPI) is currently in its final Acceptance & Testing stages at the University of Santa Cruz, California. GPI is an XAO system based on a tweeter & woofer architecture (43 & 9 actuators across the pupil), with the tweeter being a Boston Michromachines 64^2 MEMS device. The XAO AO system is tightly integrated with a Lyot apodizing coronagraph. Acceptance has started in February 2013. After the conclusive acceptance review shipment is scheduled mid 2013 to ensure readiness for commissioning at the Gemini South telescope on Cerro Pachon, Chile, end of 2013, matching the summer window of the southern hemisphere. According to current estimates the 3 year (~800 allocated hours) planet finding campaign might discover, image, and spectroscopically analyze 20 to 40 new exo-planets.Final acceptance testing of the integrated instrument can always emerge a number of unforeseen challenges as we are eventually using cold chamber and flexure rig installations. The latest developments will be reported. Also, we will give an overview of GPI's lab performance, the interplay between subsystems such as the calibration unit (CAL) with the AO bench. (The CAL principal purpose is to maintain a clean and centered XAO PSF on the coronagraph.) We report on-going optimizations on the AO controler loop to filter vibrations and last but not least achieved contrast performance applying speckle nulling. Furthermore, we will give an outlook of possible but challenging future upgrades as the implementation of a predictive controler or exchanging the conventional 48x48 SH WFS with a pyramid. With the ELT area arising, GPI will proof as a versatile and path-finding testbed for AO technologies on the next generation of ground-based telescopes.

Hartung, Markus; Macintosh, Bruce; Poyneer, Lisa; Savransky, Dimitri; Gavel, Donald; Palmer, Dave; Thomas, Sandrine; Dillon, Daren; Chilcote, Jeffrey; Ingraham, Patrick; Sadakuni, Naru; Wallace, Kent; Perrin, Marshall; Marois, Christian; Maire, Jerome; Rantakyro, Fredrik; Hibon, Pascale; Saddlemyer, Les; Goodsell, Stephen

2013-12-01

40

THE GEMINI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF GIANT PLANETS AROUND DEBRIS DISK STARS  

SciTech Connect

We have completed a high-contrast direct imaging survey for giant planets around 57 debris disk stars as part of the Gemini NICI Planet-Finding Campaign. We achieved median H-band contrasts of 12.4 mag at 0.''5 and 14.1 mag at 1'' separation. Follow-up observations of the 66 candidates with projected separation <500 AU show that all of them are background objects. To establish statistical constraints on the underlying giant planet population based on our imaging data, we have developed a new Bayesian formalism that incorporates (1) non-detections, (2) single-epoch candidates, (3) astrometric and (4) photometric information, and (5) the possibility of multiple planets per star to constrain the planet population. Our formalism allows us to include in our analysis the previously known {beta} Pictoris and the HR 8799 planets. Our results show at 95% confidence that <13% of debris disk stars have a {>=}5 M{sub Jup} planet beyond 80 AU, and <21% of debris disk stars have a {>=}3 M{sub Jup} planet outside of 40 AU, based on hot-start evolutionary models. We model the population of directly imaged planets as d {sup 2} N/dMda{proportional_to}m {sup {alpha}} a {sup {beta}}, where m is planet mass and a is orbital semi-major axis (with a maximum value of a{sub max}). We find that {beta} < -0.8 and/or {alpha} > 1.7. Likewise, we find that {beta} < -0.8 and/or a{sub max} < 200 AU. For the case where the planet frequency rises sharply with mass ({alpha} > 1.7), this occurs because all the planets detected to date have masses above 5 M{sub Jup}, but planets of lower mass could easily have been detected by our search. If we ignore the {beta} Pic and HR 8799 planets (should they belong to a rare and distinct group), we find that <20% of debris disk stars have a {>=}3 M{sub Jup} planet beyond 10 AU, and {beta} < -0.8 and/or {alpha} < -1.5. Likewise, {beta} < -0.8 and/or a{sub max} < 125 AU. Our Bayesian constraints are not strong enough to reveal any dependence of the planet frequency on stellar host mass. Studies of transition disks have suggested that about 20% of stars are undergoing planet formation; our non-detections at large separations show that planets with orbital separation >40 AU and planet masses >3 M{sub Jup} do not carve the central holes in these disks.

Wahhaj, Zahed [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago (Chile); Liu, Michael C.; Nielsen, Eric L.; Ftaclas, Christ; Chun, Mark [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Biller, Beth A. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Hayward, Thomas L. [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Close, Laird M.; Males, Jared R.; Skemer, Andrew [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Thatte, Niranjan; Tecza, Matthias [Department of Astronomy, University of Oxford, DWB, Keble Road, Oxford OX1 3RH (United Kingdom); Shkolnik, Evgenya L. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Kuchner, Marc [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Greenbelt, MD 20771 (United States); Reid, I. Neill [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); De Gouveia Dal Pino, Elisabete M.; Gregorio-Hetem, Jane [Departamento de Astronomia, Universidade de Sao Paulo, IAG/USP, Rua do Matao 1226, 05508-900 Sao Paulo, SP (Brazil); Alencar, Silvia H. P. [Departamento de Fisica-ICEx-UFMG, Av. Antonio Carlos 6627, 30270-901 Belo Horizonte, MG (Brazil); Boss, Alan [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States); Lin, Douglas N. C. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States); and others

2013-08-20

41

The Gemini Planet-finding Campaign: The Frequency Of Giant Planets around Debris Disk Stars  

NASA Astrophysics Data System (ADS)

We have completed a high-contrast direct imaging survey for giant planets around 57 debris disk stars as part of the Gemini NICI Planet-Finding Campaign. We achieved median H-band contrasts of 12.4 mag at 0.''5 and 14.1 mag at 1'' separation. Follow-up observations of the 66 candidates with projected separation <500 AU show that all of them are background objects. To establish statistical constraints on the underlying giant planet population based on our imaging data, we have developed a new Bayesian formalism that incorporates (1) non-detections, (2) single-epoch candidates, (3) astrometric and (4) photometric information, and (5) the possibility of multiple planets per star to constrain the planet population. Our formalism allows us to include in our analysis the previously known ? Pictoris and the HR 8799 planets. Our results show at 95% confidence that <13% of debris disk stars have a >=5 M Jup planet beyond 80 AU, and <21% of debris disk stars have a >=3 M Jup planet outside of 40 AU, based on hot-start evolutionary models. We model the population of directly imaged planets as d 2 N/dMdavpropm ? a ?, where m is planet mass and a is orbital semi-major axis (with a maximum value of a max). We find that ? < -0.8 and/or ? > 1.7. Likewise, we find that ? < -0.8 and/or a max < 200 AU. For the case where the planet frequency rises sharply with mass (? > 1.7), this occurs because all the planets detected to date have masses above 5 M Jup, but planets of lower mass could easily have been detected by our search. If we ignore the ? Pic and HR 8799 planets (should they belong to a rare and distinct group), we find that <20% of debris disk stars have a >=3 M Jup planet beyond 10 AU, and ? < -0.8 and/or ? < -1.5. Likewise, ? < -0.8 and/or a max < 125 AU. Our Bayesian constraints are not strong enough to reveal any dependence of the planet frequency on stellar host mass. Studies of transition disks have suggested that about 20% of stars are undergoing planet formation; our non-detections at large separations show that planets with orbital separation >40 AU and planet masses >3 M Jup do not carve the central holes in these disks. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

Wahhaj, Zahed; Liu, Michael C.; Nielsen, Eric L.; Biller, Beth A.; Hayward, Thomas L.; Close, Laird M.; Males, Jared R.; Skemer, Andrew; Ftaclas, Christ; Chun, Mark; Thatte, Niranjan; Tecza, Matthias; Shkolnik, Evgenya L.; Kuchner, Marc; Reid, I. Neill; de Gouveia Dal Pino, Elisabete M.; Alencar, Silvia H. P.; Gregorio-Hetem, Jane; Boss, Alan; Lin, Douglas N. C.; Toomey, Douglas W.

2013-08-01

42

Results from the Gemini NICI Planet-Finding Campaign  

NASA Astrophysics Data System (ADS)

From 2008 December to 2012 September, the NICI (Near-Infrared Coronagraphic Imager at the Gemini-South 8.1-m) Planet-Finding Campaign (Liu et al. 2010) obtained deep, high-contrast AO imaging of a carefully selected sample of over 200 young, nearby stars. In the course of the campaign, we discovered four co-moving brown dwarf companions: PZ Tel B (36+/-6 MJup, 16.4+/-1.0 AU), CD-35 2722B (31+/-8 MJup, 67+/-4 AU), HD 1160B (33+12 -9 MJup, 81+/- AU), and HIP 79797Bb (55+20-19MJup, 3 AU from the previously known brown dwarf companion HIP 79797Ba), as well as numerous stellar binaries. Three survey papers have been published to date, covering: 1) high mass stars (Nielsen et al. 2013), 2) debris disk stars (Wahhaj et al. 2013), and 3) stars which are members of nearby young moving groups (Biller et al. 2013). In addition, the Campaign has yielded new orbital constraints for the ~8-10 MJup planet Pic ? (Nielsen et al. 2014) and a high precision measurement of the star-disk offset for the well-known disk around HR 4796A (Wahhaj et al. 2014). Here we discuss constraints placed on the distribution of wide giant exoplanets from the NICI Campaign, new substellar companion discoveries, and characterization both of exoplanets and circumstellar disks.

Biller, Beth A.; Liu, Michael C.; Wahhaj, Zahed; Nielsen, Eric L.; Hayward, Thomas L.; Chun, Mark R.; Close, Laird M.; Ftaclas, Christ; Males, Jared R.; Hartung, Markus; Reid, I. N.; Shkolnik, Evgenya; Skemer, Andrew J.; Tecza, Matthias; Thatte, Niranjan A.; Clarke, Fraser; Toomey, Douglas

2014-08-01

43

The Gemini Near-Infrared Imager (NIRI)  

Microsoft Academic Search

This paper presents the basic design of the Gemini Near-Infrared Imager (NIRI) and discusses its capabilities. NIRI offers three different pixel scales to match different operating modes of the Gemini telescope and allows polarimetric and spectroscopic observations. It is equipped with an infrared on-instrument wave-front sensor (OIWFS) to allow tip-tilt and focus correction even in highly obscured regions. The science

Klaus W. Hodapp; Joseph B. Jensen; Everett M. Irwin; Hubert Yamada; Randolph Chung; Kent Fletcher; Louis Robertson; Joseph L. Hora; Douglas A. Simons; Wendy Mays; Robert Nolan; Matthieu Bec; Michael Merrill; Albert M. Fowler

2003-01-01

44

Gemini near-infrared imager (NIRI)  

Microsoft Academic Search

The NIRI for the Gemini North telescope is now undergoing acceptance testing. NIRI is the main near-IR facility camera on the Gemini North telescope and is designed to fully exploit the excellent characteristics of the site and the expected high performance o the telescope. NIRI offers 3 different pixel scales for wide-field, tip-tilt corrected and diffraction-limited imaging. It is equipped

Klaus-Werner Hodapp; J. Hora; E. Graves; Everett M. Irwin; Hubert Yamada; Jeffrey W. Douglass; Tony T. Young; Louis Robertson

2000-01-01

45

The Gemini NICI Planet-Finding Campaign: The Frequency of Planets around Young Moving Group Stars  

E-print Network

We report results of a direct imaging survey for giant planets around 80 members of the Beta Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of \\Delta H=13.9 mag at 1" in combined CH4 narrowband ADI+SDI mode and median contrasts of \\Delta H=15.1 mag at 2" in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with NICI all other candidates that lay within 400 AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI campaign followup. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36+-6 MJup, 16.4+-1.0 AU, Biller et al. 2010), CD -35 2722B (31+-8 MJup, 67+-...

Biller, Beth A; Wahhaj, Zahed; Nielsen, Eric L; Hayward, Thomas L; Males, Jared R; Skemer, Andrew; Close, Laird M; Chun, Mark; Ftaclas, Christ; Clarke, Fraser; Thatte, Niranjan; Shkolnik, Evgenya L; Reid, I Neill; Hartung, Markus; Boss, Alan; Lin, Douglas; Alencar, Silvia H P; Pino, Elisabete de Gouveia Dal; Gregorio-Hetem, Jane; Toomey, Douglas

2013-01-01

46

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

47

THE GEMINI NICI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF GIANT PLANETS AROUND YOUNG B AND A STARS  

SciTech Connect

We have carried out high contrast imaging of 70 young, nearby B and A stars to search for brown dwarf and planetary companions as part of the Gemini NICI Planet-Finding Campaign. Our survey represents the largest, deepest survey for planets around high-mass stars (?1.5-2.5 M{sub ?}) conducted to date and includes the planet hosts ? Pic and Fomalhaut. We obtained follow-up astrometry of all candidate companions within 400 AU projected separation for stars in uncrowded fields and identified new low-mass companions to HD 1160 and HIP 79797. We have found that the previously known young brown dwarf companion to HIP 79797 is itself a tight (3 AU) binary, composed of brown dwarfs with masses 58{sup +21}{sub -20} M{sub Jup} and 55{sup +20}{sub -19} M{sub Jup}, making this system one of the rare substellar binaries in orbit around a star. Considering the contrast limits of our NICI data and the fact that we did not detect any planets, we use high-fidelity Monte Carlo simulations to show that fewer than 20% of 2 M{sub ?} stars can have giant planets greater than 4 M{sub Jup} between 59 and 460 AU at 95% confidence, and fewer than 10% of these stars can have a planet more massive than 10 M{sub Jup} between 38 and 650 AU. Overall, we find that large-separation giant planets are not common around B and A stars: fewer than 10% of B and A stars can have an analog to the HR 8799 b (7 M{sub Jup}, 68 AU) planet at 95% confidence. We also describe a new Bayesian technique for determining the ages of field B and A stars from photometry and theoretical isochrones. Our method produces more plausible ages for high-mass stars than previous age-dating techniques, which tend to underestimate stellar ages and their uncertainties.

Nielsen, Eric L.; Liu, Michael C.; Chun, Mark; Ftaclas, Christ [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Wahhaj, Zahed [European Southern Observatory, Alonso de Córdova 3107, Vitacura, Santiago (Chile); Biller, Beth A. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Hayward, Thomas L.; Hartung, Markus [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Close, Laird M.; Males, Jared R.; Skemer, Andrew J. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Alencar, Silvia H. P. [Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 30270-901 Belo Horizonte, MG (Brazil); Artymowicz, Pawel [University of Toronto at Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4 (Canada); Boss, Alan [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, N.W., Washington, DC 20015 (United States); Clarke, Fraser [Department of Astronomy, University of Oxford, DWB, Keble Road, Oxford OX1 3RH (United Kingdom); De Gouveia Dal Pino, Elisabete; Gregorio-Hetem, Jane [Departamento de Astronomia, Universidade de Sao Paulo, IAG/USP, Rua do Matao 1226, 05508-900 Sao Paulo, SP (Brazil); Ida, Shigeru [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Kuchner, Marc [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Greenbelt, MD 20771 (United States); Lin, Douglas N. C. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States); and others

2013-10-10

48

The Gemini/NICI Planet-Finding Campaign: The Frequency of Planets around Young Moving Group Stars  

NASA Astrophysics Data System (ADS)

We report results of a direct imaging survey for giant planets around 80 members of the ? Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini/NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ?H = 13.9 mag at 1'' in combined CH4 narrowband ADI+SDI mode and median contrasts of ?H = 15.1 mag at 2'' in H-band ADI mode. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36 ± 6 MJup, 16.4 ± 1.0 AU), CDñ35 2722B (31 ± 8 M Jup, 67 ± 4 AU), HD 12894B (0.46 ± 0.08 M., 15.7 ± 1.0 AU), and BD+07 1919C (0.20 ± 0.03 M., 12.5 ± 1.4 AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 MJup companions at semi-major axes from 10-150 AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars.

Biller, B.; Liu, M.; Wahhaj, Z.; Nielsen, E.; NICI Campaign Team

2014-03-01

49

The Gemini NICI planet-finding campaign: The offset ring of HR 4796 A  

NASA Astrophysics Data System (ADS)

We present J,H, CH4 short (1.578 ?m), CH4 long (1.652 ?m) and Ks-band images of the dust ring around the 10 Myr old star HR 4796 A obtained using the Near Infrared Coronagraphic Imager (NICI) on the Gemini-South 8.1 m Telescope. Our images clearly show for the first time the position of the star relative to its circumstellar ring thanks to NICI's translucent focal plane occulting mask. We employ a Bayesian Markov chain Monte Carlo method to constrain the offset vector between the two. The resulting probability distribution shows that the ring center is offset from the star by 16.7 ± 1.3 milliarcseconds along a position angle of 26 ± 3°, along the PA of the ring, 26.47 ± 0.04°. We find that the size of this offset is not large enough to explain the brightness asymmetry of the ring. The ring is measured to have mostly red reflectivity across the JHKs filters, which seems to indicate micron-sized grains. Just like Neptune's 3:2 and 2:1 mean-motion resonances delineate the inner and outer edges of the classical Kuiper belt, we find that the radial extent of the HR 4796 A and the Fomalhaut rings could correspond to the 3:2 and 2:1 mean-motion resonances of hypothetical planets at 54.7 AU and 97.7 AU in the two systems, respectively. A planet orbiting HR 4796 A at 54.7 AU would have to be less massive than 1.6 MJup so as not to widen the ring too much by stirring. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).Tables 5 and 6 are available in electronic form at http://www.aanda.org

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

2014-07-01

50

The Gemini/NICI Planet-Finding Campaign: The Frequency of Planets around Young Moving Group Stars  

NASA Astrophysics Data System (ADS)

We report results of a direct imaging survey for giant planets around 80 members of the ? Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini/NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ?H = 13.9 mag at 1'' in combined CH4 narrowband ADI+SDI mode and median contrasts of ?H = 15.1 mag at 2'' in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with Near-Infrared Coronagraphic Imager (NICI) all other candidates that lay within 400 AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI Campaign followup. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36 ± 6 M Jup, 16.4 ± 1.0 AU), CD-35 2722B (31 ± 8 M Jup, 67 ± 4 AU), HD 12894B (0.46 ± 0.08 M ?, 15.7 ± 1.0 AU), and BD+07 1919C (0.20 ± 0.03 M ?, 12.5 ± 1.4 AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-150 AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. Our results strongly constrain the frequency of planets within semi-major axes of 50 AU as well. We restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-50 AU to <21% at a 95.4% confidence level using DUSTY models and to <7% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

Biller, Beth A.; Liu, Michael C.; Wahhaj, Zahed; Nielsen, Eric L.; Hayward, Thomas L.; Males, Jared R.; Skemer, Andrew; Close, Laird M.; Chun, Mark; Ftaclas, Christ; Clarke, Fraser; Thatte, Niranjan; Shkolnik, Evgenya L.; Reid, I. Neill; Hartung, Markus; Boss, Alan; Lin, Douglas; Alencar, Silvia H. P.; de Gouveia Dal Pino, Elisabete; Gregorio-Hetem, Jane; Toomey, Douglas

2013-11-01

51

THE GEMINI/NICI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF PLANETS AROUND YOUNG MOVING GROUP STARS  

SciTech Connect

We report results of a direct imaging survey for giant planets around 80 members of the ? Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini/NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ?H = 13.9 mag at 1'' in combined CH{sub 4} narrowband ADI+SDI mode and median contrasts of ?H = 15.1 mag at 2'' in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with Near-Infrared Coronagraphic Imager (NICI) all other candidates that lay within 400 AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI Campaign followup. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36 ± 6 M{sub Jup}, 16.4 ± 1.0 AU), CD–35 2722B (31 ± 8 M{sub Jup}, 67 ± 4 AU), HD 12894B (0.46 ± 0.08 M{sub ?}, 15.7 ± 1.0 AU), and BD+07 1919C (0.20 ± 0.03 M{sub ?}, 12.5 ± 1.4 AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 M{sub Jup} companions at semi-major axes from 10-150 AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. Our results strongly constrain the frequency of planets within semi-major axes of 50 AU as well. We restrict the frequency of 1-20 M{sub Jup} companions at semi-major axes from 10-50 AU to <21% at a 95.4% confidence level using DUSTY models and to <7% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars.

Biller, Beth A.; Ftaclas, Christ [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69115 Heidelberg (Germany); Liu, Michael C.; Wahhaj, Zahed; Nielsen, Eric L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Hayward, Thomas L.; Hartung, Markus [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Males, Jared R.; Skemer, Andrew; Close, Laird M. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Chun, Mark [Institute for Astronomy, 640 North Aohoku Place, 209, Hilo, HI 96720-2700 (United States); Clarke, Fraser; Thatte, Niranjan [Department of Astronomy, University of Oxford, DWB, Keble Road, Oxford OX1 3RH (United Kingdom); Shkolnik, Evgenya L. [Lowell Observatory, 1400 West Mars Hill Road Flagstaff, AZ 86001 (United States); Reid, I. Neill [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Boss, Alan [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States); Lin, Douglas [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Alencar, Silvia H. P. [Departamento de Fisica-ICEx-Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, 30270-901 Belo Horizonte, MG (Brazil); De Gouveia Dal Pino, Elisabete; Gregorio-Hetem, Jane [Universidade de Sao Paulo, IAG/USP, Departamento de Astronomia, Rua do Matao 1226, 05508-900 Sao Paulo, SP (Brazil); and others

2013-11-10

52

Instrumentation at Gemini Observatory  

NASA Astrophysics Data System (ADS)

Gemini South's instrument suite has been completely transformed since our last biennial update. We commissioned the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and its associated Gemini South Adaptive Optics Imager (GSAOI) as well as Flamingos-2, our long-slit and multi-object infrared imager and spectrograph, and the Gemini Planet Imager (GPI). We upgraded the CCDs in GMOS-S, our multi-object optical imager and spectrograph, with the GMOS-N CCD upgrade scheduled for 2015. Our next instrument, the Gemini High-resolution Optical SpecTrograph (GHOST) is in its preliminary design stage and we are making plans for the instrument to follow:Gen4#3.

Kleinman, S. J.; Boccas, Maxime; Goodsell, Stephen J.; Gomez, Percy; Murowinski, Rick; Chené, André-Nicolas; Henderson, David

2014-07-01

53

The Gemini NICI Planet-finding Campaign: Discovery of a Close Substellar Companion to the Young Debris Disk Star PZ Tel  

Microsoft Academic Search

We report the discovery of a tight substellar companion to the young solar analog PZ Tel, a member of the beta Pic moving group observed with high-contrast adaptive optics imaging as part of the Gemini Near-Infrared Coronagraphic Imager Planet-Finding Campaign. The companion was detected at a projected separation of 16.4 ± 1.0 AU (0farcs33 ± 0farcs01) in 2009 April. Second-epoch

Beth A. Biller; Michael C. Liu; Zahed Wahhaj; Eric L. Nielsen; Laird M. Close; Trent J. Dupuy; Thomas L. Hayward; Adam Burrows; Mark Chun; Christ Ftaclas; Fraser Clarke; Markus Hartung; Jared Males; I. Neill Reid; Evgenya L. Shkolnik; Andrew Skemer; Matthias Tecza; Niranjan Thatte; Silvia H. P. Alencar; Pawel Artymowicz; Alan Boss; Elisabete de Gouveia Dal Pino; Jane Gregorio-Hetem; Shigeru Ida; Marc J. Kuchner; Douglas Lin; Douglas Toomey

2010-01-01

54

Searching for, Finding, and Imaging Young Extrasolar Planets with HST/NICMOS G. Schneider (Steward Obs., UofA), I. Song, J. Farihi, (Gemini Obs.), B. Zuckerman, E. Becklin  

E-print Network

-to-star contrast ratios. Since the detection of the extrasolar giant planet (EGP) companion to 51 Peg [1 an explosion of indirect detections of EGP companions to solar-like stars through radial velocity surveys [2 of a bona fide EGP by imaging (and spectroscopy) remained elusive as recently developed technical

Schneider, Glenn

55

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

56

Direct Imaging of Multiple Planets Orbiting the Star HR 8799  

E-print Network

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; Barman, T; Zuckerman, B; Song, I; Patience, J; Lafrenière, D; Doyon, R; 10.1126/science.1166585

2008-01-01

57

The Planet Formation Imager  

NASA Astrophysics Data System (ADS)

Among the most fascinating and hotly-debated areas in contemporary astrophysics are the means by which planetary systems are assembled from the large rotating disks of gas and dust which attend a stellar birth. Although important work is being done both in theory and observation, a full understanding of the physics of planet formation can only be achieved by opening observational windows able to directly witness the process in action. The key requirement is then to probe planet-forming systems at the natural spatial scales over which material is being assembled. By definition, this is the so-called Hill Sphere which delineates the region of influence of a gravitating body within its surrounding environment. The Planet Formation Imager project has crystallized around this challenging goal: to deliver resolved images of Hill-Sphere-sized structures within candidate planet-hosting disks in the nearest star-forming regions. In this contribution we outline the primary science case of PFI and discuss how PFI could significantly advance our understanding of the architecture and potential habitability of planetary systems. We present radiation-hydrodynamics simulations from which we derive preliminary specifications that guide the design of the facility. Finally, we give an overview about the interferometric and non-interferometric technologies that we are investigating in order to meet the specifications.

Kraus, S.; Buscher, D. F.; Monnier, J. D.; PFI Science, the; Technical Working Group

2014-04-01

58

The Gemini NICI Planet-Finding Campaign: The Orbit of the Young Exoplanet ? Pictoris b  

NASA Astrophysics Data System (ADS)

We present new astrometry for the young (12-21 Myr) exoplanet ? Pictoris b taken with the Gemini/NICI and Magellan/MagAO instruments between 2009 and 2012. The high dynamic range of our observations allows us to measure the relative position of ? Pic b with respect to its primary star with greater accuracy than previous observations. Based on a Markov Chain Monte Carlo analysis, we find the planet has an orbital semi-major axis of 9.1+5.3-0.5 AU and orbital eccentricity <0.15 at 68% confidence (with 95% confidence intervals of 8.2-48 AU and 0.00-0.82 for semi-major axis and eccentricity, respectively, due to a long narrow degenerate tail between the two). We find that the planet has reached its maximum projected elongation, enabling higher precision determination of the orbital parameters than previously possible, and that the planet's projected separation is currently decreasing. With unsaturated data of the entire ? Pic system (primary star, planet, and disk) obtained thanks to NICI's semi-transparent focal plane mask, we are able to tightly constrain the relative orientation of the circumstellar components. We find the orbital plane of the planet lies between the inner and outer disks: the position angle (P.A.) of nodes for the planet's orbit (211.8 ± 0.°3) is 7.4? greater than the P.A. of the spine of the outer disk and 3.2? less than the warped inner disk P.A., indicating the disk is not collisionally relaxed. Finally, for the first time we are able to dynamically constrain the mass of the primary star ? Pic to 1.76+0.18-0.17 M ?.

Nielsen, Eric L.; Liu, Michael C.; Wahhaj, Zahed; Biller, Beth A.; Hayward, Thomas L.; Males, Jared R.; Close, Laird M.; Morzinski, Katie M.; Skemer, Andrew J.; Kuchner, Marc J.; Rodigas, Timothy J.; Hinz, Philip M.; Chun, Mark; Ftaclas, Christ; Toomey, Douglas W.

2014-10-01

59

Gemini near-infrared imager (NIRI): a discussion of its design features and performance  

Microsoft Academic Search

The Gemini Near-Infrared Imager (NIRI) has now been completed and is in operation at the telescope. This paper discusses the basic design of the instrument and a number of particularly interesting technical issues. NIRI offers three different pixel scales to match different operating modes of the Gemini telescope and allows polarimetric and spectroscopic observations. It is equipped with an infrared

Klaus-Werner Hodapp; Everett M. Irwin; Hubert Yamada; Randall Chung; Kent Fletcher; Joe Jensen; Wendy Mays; Robert Nolan; Douglas A. Simons; Colin Aspin

2003-01-01

60

THE GEMINI NICI PLANET-FINDING CAMPAIGN: DISCOVERY OF A MULTIPLE SYSTEM ORBITING THE YOUNG A STAR HD 1160  

SciTech Connect

We report the discovery of two low-mass companions to the young A0V star HD 1160 at projected separations of 81 {+-} 5 AU (HD 1160 B) and 533 {+-} 25 AU (HD 1160 C) by the Gemini NICI Planet-Finding Campaign. Very Large Telescope images of the system taken over a decade for the purpose of using HD 1160 A as a photometric calibrator confirm that both companions are physically associated. By comparing the system to members of young moving groups and open clusters with well-established ages, we estimate an age of 50{sup +50}{sub -40} Myr for HD 1160 ABC. While the UVW motion of the system does not match any known moving group, the small magnitude of the space velocity is consistent with youth. Near-IR spectroscopy shows HD 1160 C to be an M3.5 {+-} 0.5 star with an estimated mass of 0.22{sup +0.03}{sub -0.04} M{sub Sun }, while NIR photometry of HD 1160 B suggests a brown dwarf with a mass of 33{sup +12}{sub -9} M{sub Jup}. The very small mass ratio (0.014) between the A and B components of the system is rare for A star binaries, and would represent a planetary-mass companion were HD 1160 A to be slightly less massive than the Sun.

Nielsen, Eric L.; Liu, Michael C.; Wahhaj, Zahed; Bowler, Brendan; Kraus, Adam; Chun, Mark; Ftaclas, Christ [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Biller, Beth A. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Hayward, Thomas L. [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Boss, Alan [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, N.W., Washington, DC 20015 (United States); Shkolnik, Evgenya L. [Lowell Observatory, 1400 West Mars Road, Flagstaff, AZ 86001 (United States); Tecza, Matthias; Clarke, Fraser [Department of Astronomy, University of Oxford, DWB, Keble Road, Oxford OX1 3RH (United Kingdom); Close, Laird M.; Hartung, Markus; Males, Jared R.; Skemer, Andrew J. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Reid, I. Neill [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Alencar, Silvia H. P. [Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 30270-901, Belo Horizonte, MG (Brazil); Burrows, Adam [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); and others

2012-05-01

61

THE GEMINI NICI PLANET-FINDING CAMPAIGN: DISCOVERY OF A CLOSE SUBSTELLAR COMPANION TO THE YOUNG DEBRIS DISK STAR PZ Tel  

SciTech Connect

We report the discovery of a tight substellar companion to the young solar analog PZ Tel, a member of the {beta} Pic moving group observed with high-contrast adaptive optics imaging as part of the Gemini Near-Infrared Coronagraphic Imager Planet-Finding Campaign. The companion was detected at a projected separation of 16.4 {+-} 1.0 AU (0.''33 {+-} 0.''01) in 2009 April. Second-epoch observations in 2010 May demonstrate that the companion is physically associated and shows significant orbital motion. Monte Carlo modeling constrains the orbit of PZ Tel B to eccentricities >0.6. The near-IR colors of PZ Tel B indicate a spectral type of M7 {+-} 2 and thus this object will be a new benchmark companion for studies of ultracool, low-gravity photospheres. Adopting an age of 12{sup +8} {sub -4} Myr for the system, we estimate a mass of 36 {+-} 6 M {sub Jup} based on the Lyon/DUSTY evolutionary models. PZ Tel B is one of the few young substellar companions directly imaged at orbital separations similar to those of giant planets in our own solar system. Additionally, the primary star PZ Tel A shows a 70 {mu}m emission excess, evidence for a significant quantity of circumstellar dust that has not been disrupted by the orbital motion of the companion.

Biller, Beth A.; Liu, Michael C.; Wahhaj, Zahed; Dupuy, Trent J.; Ftaclas, Christ [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Nielsen, Eric L.; Close, Laird M.; Males, Jared; Skemer, Andrew [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Hayward, Thomas L.; Hartung, Markus [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Burrows, Adam [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Chun, Mark [Institute for Astronomy, 640 North Aohoku Place, 209, Hilo, HI 96720-2700 (United States); Clarke, Fraser; Tecza, Matthias; Thatte, Niranjan [Department of Astronomy, University of Oxford, DWB, Keble Road, Oxford OX1 3RH (United Kingdom); Reid, I. Neill [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Shkolnik, Evgenya L. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States); Alencar, Silvia H. P. [Departamento de Fisica-ICEx-Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 30270-901, Belo Horizonte, MG (Brazil); Artymowicz, Pawel [University of Toronto at Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4 (Canada)

2010-09-01

62

The Gemini NICI Planet-Finding Campaign: Discovery of a Substellar L Dwarf Companion to a Nearby Young M Dwarf  

Microsoft Academic Search

We present the discovery of a substellar companion to a nearby M dwarf member of a young moving group. We detected the companion, at a separation of 75 AU, using the Near-Infrared Coronagraphic Imager (NICI) on the Gemini-South Telescope. Two epochs of NICI observations confirm that the companion is physically associated with the primary. Its ZJHK-band colors are similar to

Zahed Wahhaj; M. C. Liu; B. A. Biller; F. Clarke; E. L. Nielsen; L. M. Close; M. Cushing; T. Dupuy; T. L. Hayward; M. Tecza; N. Thatte; M. Chun; C. Ftaclas; M. Hartung; I. Reid; E. L. Shkolnik; S. H. P. Alencar; P. Artymowicz; A. Boss; A. Burrows; E. Mamajek; E. de Gouveia Dal Pino; J. Gregorio-Hetem; S. Ida; M. Kuchner; D. Lin; D. W. Toomey

2011-01-01

63

Adaptive Wavefront Calibration and Control for the Gemini Planet Imager  

SciTech Connect

Quasi-static errors in the science leg and internal AO flexure will be corrected. Wavefront control will adapt to current atmospheric conditions through Fourier modal gain optimization, or the prediction of atmospheric layers with Kalman filtering.

Poyneer, L A; Veran, J

2007-02-02

64

Current and future facility instruments at the Gemini Observatory  

NASA Astrophysics Data System (ADS)

At the present time, several new Gemini instruments are being delivered and commissioned. The Near-Infrared Coronagraph has been extensively tested and commissioned on the Gemini-South telescope, and will soon begin a large survey to discover extrasolar planets. The FLAMINGOS-2 near-IR multi-object spectrograph is nearing completion at the University of Florida, and is expected to be delivered to Gemini-South by the end of 2008. Gemini's Multi-Conjugate Adaptive Optics bench has been successfully integrated and tested in the lab, and now awaits integration with the laser system and the Gemini-South AO Imager on the telescope. We also describe our efforts to repair thermal damage to the Gemini Near-IR Spectrograph that occurred last year. Since the last update, progress has been made on several of Gemini's next generation of ambitious "Aspen" instruments. The Gemini Planet Imager is now in the final design phase, and construction is scheduled to begin shortly. Two competitive conceptual design studies for the Wide-Field Fiber Multi-Object Spectrometer have now started. The Mauna Kea ground layer monitoring campaign has collected data for well over a year in support of the planning process for a future Ground Layer Adaptive Optics system.

Jensen, Joseph B.; Kleinman, Scot J.; Simons, Douglas A.; Lazo, Manuel; Rigaut, François; White, John K.

2008-07-01

65

Recovery of the Candidate Protoplanet HD 100546 b with Gemini/NICI and Detection of Additional (Planet-induced?) Disk Structure at Small Separations  

NASA Astrophysics Data System (ADS)

We report the first independent, second epoch (re-)detection of a directly imaged protoplanet candidate. Using L' high-contrast imaging of HD 100546 taken with the Near-Infrared Coronagraph and Imager on Gemini South, we recover "HD 100546 b" with a position and brightness consistent with the original Very Large Telescope/NAos-COnica detection from Quanz et al., although data obtained after 2013 will be required to decisively demonstrate common proper motion. HD 100546 b may be spatially resolved, up to ?12-13 AU in diameter, and is embedded in a finger of thermal IR-bright, polarized emission extending inward to at least 0.''3. Standard hot-start models imply a mass of ?15 MJ . However, if HD 100546 b is newly formed or made visible by a circumplanetary disk, both of which are plausible, its mass is significantly lower (e.g., 1-7 MJ ). Additionally, we discover a thermal IR-bright disk feature, possibly a spiral density wave, at roughly the same angular separation as HD 100546 b but 90° away. Our interpretation of this feature as a spiral arm is not decisive, but modeling analyses using spiral density wave theory implies a wave launching point exterior to ?0.''45 embedded within the visible disk structure: plausibly evidence for a second, hitherto unseen, wide-separation planet. With one confirmed protoplanet candidate and evidence for one to two others, HD 100546 is an important evolutionary precursor to intermediate-mass stars with multiple super-Jovian planets at moderate/wide separations like HR 8799.

Currie, Thayne; Muto, Takayuki; Kudo, Tomoyuki; Honda, Mitsuhiko; Brandt, Timothy D.; Grady, Carol; Fukagawa, Misato; Burrows, Adam; Janson, Markus; Kuzuhara, Masayuki; McElwain, Michael W.; Follette, Katherine; Hashimoto, Jun; Henning, Thomas; Kandori, Ryo; Kusakabe, Nobuhiko; Kwon, Jungmi; Mede, Kyle; Morino, Jun-ichi; Nishikawa, Jun; Pyo, Tae-Soo; Serabyn, Gene; Suenaga, Takuya; Takahashi, Yasuhiro; Wisniewski, John; Tamura, Motohide

2014-12-01

66

Infrared imaging of extrasolar planets  

NASA Technical Reports Server (NTRS)

An optical system for direct detection, in the infrared, of planets orbiting other stars is described. The proposed system consists of a large aperture (about 16 m) space-based telescope to which is attached a specialized imaging instrument containing a set of optical signal processing elements to suppress diffracted light from the central star. Starlight suppression is accomplished using coronagraphic apodization combined with rotational shearing interferometry. The possibility of designing the large telescope aperture to be of a deployable, multiarm configuration is examined, and it is shown that there is some sacrifice in performance relative to a filled, circular aperture.

Diner, David J.; Tubbs, Eldred F.; Gaiser, Steven L.; Korechoff, Robert P.

1991-01-01

67

How do Most Planets Form? -- Constraints on Disk Instability from Direct Imaging  

E-print Network

Core accretion and disk instability have traditionally been regarded as the two competing possible paths of planet formation. In recent years, evidence have accumulated in favor of core accretion as the dominant mode, at least for close-in planets. However, it might be hypothesized that a significant population of wide planets formed by disk instabilities could exist at large separations, forming an invisible majority. In previous work, we addressed this issue through a direct imaging survey of B2--A0-type stars, and concluded that <30% of such stars form and retain planets and brown dwarfs through disk instability, leaving core accretion as the likely dominant mechanism. In this paper, we extend this analysis to FGKM-type stars by applying a similar analysis to the Gemini Deep Planet Survey (GDPS) sample. The results strengthen the conclusion that substellar companions formed and retained around their parent stars by disk instabilities are rare. Specifically, we find that the frequency of such companions ...

Janson, Markus; Klahr, Hubert; Lafreniere, David

2011-01-01

68

Comparing Dynamical Ranges of Direct Imaging Planet Detection  

NASA Astrophysics Data System (ADS)

Direct imaging of extra-solar planets in orbit around stars is difficult because of the problem of dynamic range: Planets are much fainter then their parent stars and very close to them. One way around this problem is searching for giant planets around young nearby stars, where the planets are still self-luminous due to their own thermal emssion because of on-going contraction and accretion. We are activelly searching for young planets around young (up to 100 Myrs) nearby (up to 100 pc) stars using space- and ground-based facilities. Previously, we did detect one planet candidate near TWA-7, which could have been a few jupiter mass companion, if at the same distance and age as TWA-7. However, our follow-up H-band ISAAC/VLT spectrum has shown that this object is a background K-type star. Then, we also confirmed two brown dwarfs as companions to TWA-5 and HR 7329 by both spectroscopy and proper motion. We will show and compare the dynamical ranges (detected or detectable magnitude difference versus separation from the primary star) for HST WFPC, HST Nicmos (without coronograph), Calar Alto 3.5m ALFA (AO), ESO 3.6m Adonis (AO, with and without coronograph), ESO 3.5m NTT with the MPE speckle camera SHARP 1, ESO 3.5m NTT with the IR camera SOFI, ESO 8.2m VLT with IR camera ISAAC, and Hbar okbar upa'a (AO) at the 8.3m Gemini-North on Mauna Kea. We will also discuss the capabilities of CONICA-NAOS, soon to be available at the VLT.

Neuhäuser, R.; Huélamo, N.; Ott, T.; Guenther, E. W.; Brandner, W.; Alves, J.; Comerón, F.; Eckart, A.; Potter, D.

69

High Contrast Imaging of Extrasolar Planets  

E-print Network

Gaussian aperture pupil masks (GAPMs) can in theory achieve the contrast requisite for directly imaging an extrasolar planet. We use lab tests and simulations to further study their possible place as a high contrast imaging technique. We present lab comparisons with traditional Lyot coronagraphs and simulations of GAPMs and other high contrast imaging techniques on HST.

John H. Debes; Jian Ge

2003-01-03

70

THE INNER ENVELOPE AND DISK OF L1527 REVEALED: GEMINI L'-BAND-SCATTERED LIGHT IMAGING  

SciTech Connect

We present high-resolution L'-band imaging of the inner scattered light structure of Class 0 protostar L1527 IRS (IRAS 04368+2557) taken with the Gemini North telescope. The central point-source-like feature seen in Spitzer Space Telescope IRAC images is resolved in the Gemini image into a compact bipolar structure with a narrow dark lane in the center. Two scattered light lobes are extended {approx}1.''8 (200 AU) perpendicular to the direction of the outflow and {approx}2.''5 (350 AU) along the outflow axis; the narrow dark lane between the scattered light lobes is {approx}0.''45 (60 AU) thick. The observations are consistent with our initial modeling of a bright inner cavity separated by a dark lane due to extinction along the line of sight of the central protostar by the disk. The bright, compact scattered light might be due to complex inner structure generated by the outflow, as suggested in our first paper, or it may more likely be the upper layers of the disk forming from infalling matter.

Tobin, John J.; Hartmann, Lee [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Loinard, Laurent, E-mail: jjtobin@umich.ed [Centro de Radioastronomia y Astrofisica, UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacan (Mexico)

2010-10-10

71

Direct Imaging of Warm Extrasolar Planets  

SciTech Connect

One of the most exciting scientific discoveries in the last decade of the twentieth century was the first detection of planets orbiting a star other than our own. By now more than 130 extrasolar planets have been discovered indirectly, by observing the gravitational effects of the planet on the radial velocity of its parent star. This technique has fundamental limitations: it is most sensitive to planets close to their star, and it determines only a planet's orbital period and a lower limit on the planet's mass. As a result, all the planetary systems found so far are very different from our own--they have giant Jupiter-sized planets orbiting close to their star, where the terrestrial planets are found in our solar system. Such systems have overturned the conventional paradigm of planet formation, but have no room in them for habitable Earth-like planets. A powerful complement to radial velocity detections of extrasolar planets will be direct imaging--seeing photons from the planet itself. Such a detection would allow photometric measurements to determine the temperature and radius of a planet. Also, direct detection is most sensitive to planets in wide orbits, and hence more capable of seeing solar systems resembling our own, since a giant planet in a wide orbit does not preclude the presence of an Earth-like planet closer to the star. Direct detection, however, is extremely challenging. Jupiter is roughly a billion times fainter than our sun. Two techniques allowed us to overcome this formidable contrast and attempt to see giant planets directly. The first is adaptive optics (AO) which allows giant earth-based telescopes, such as the 10 meter W.M. Keck telescope, to partially overcome the blurring effects of atmospheric turbulence. The second is looking for young planets: by searching in the infrared for companions to young stars, we can see thermal emission from planets that are still warm with the heat of their formation. Together with a UCLA team that leads the field of young-star identification, we carried out a systematic near-infrared search for young planetary companions to {approx}200 young stars. We also carried out targeted high-sensitivity observations of selected stars surrounded by circumstellar dust rings. We developed advanced image processing techniques to allow detection of even fainter sources buried in the noisy halo of scattered starlight. Even with these techniques, around most of our targets our search was only sensitive to planets in orbits significantly wider than our solar system. With some carefully selected targets--very young dusty stars in the solar neighborhood--we reach sensitivities sufficient to see solar systems like our own. Although we discovered no unambiguous planets, we can significantly constrain the frequency of such planets in wide (>50 AU) orbits, which helps determine which models of planet formation remain plausible. Successful modeling of our observations has led us to the design of a next-generation AO system that will truly be capable of exploring solar systems resembling our own.

Macintosh, B

2005-04-11

72

The LAOG-Planet Imaging Surveys  

E-print Network

With the development of high contrast imaging techniques and infrared detectors, vast efforts have been devoted during the past decade to detect and characterize lighter, cooler and closer companions to nearby stars, and ultimately image new planetary systems. Complementary to other observing techniques (radial velocity, transit, micro-lensing, pulsar-timing), this approach has opened a new astrophysical window to study the physical properties and the formation mechanisms of brown dwarfs and planets. I here will briefly present the observing challenge, the different observing techniques, strategies and samples of current exoplanet imaging searches that have been selected in the context of the LAOG-Planet Imaging Surveys. I will finally describe the most recent results that led to the discovery of giant planets probably formed like the ones of our solar system, offering exciting and attractive perspectives for the future generation of deep imaging instruments.

Chauvin, G; Mouillet, D; Beuzit, J -L; Beust, H; Ehrenreich, D; Bonnefoy, M; Allard, F; Bessel, M; Bonavita, M; Desidera, S; Dumas, C; Farihi, J; Fusco, T; Gratadour, D; Lowrance, P; Mayor, M; Rouan, D; Song, I; Udry, S; Zuckerman, B

2009-01-01

73

Polarization of Directly Imaged Young Giant Planets as a Probe of Mass, Rotation, and Clouds  

NASA Technical Reports Server (NTRS)

Young, hot gas giant planets at large separations from their primaries have been directly imaged around several nearby stars. More such planets will likely be detected by ongoing and new imaging surveys with instruments such as the Gemini Planet Imager (GPI). Efforts continue to model the spectra of these planets in order to constrain their masses, effective temperatures, composition, and cloud structure. One potential tool for analyzing these objects, which has received relatively less attention, is polarization. Linear polarization of gas giant exoplanets can arise from the combined influences of light scattering by atmospheric dust and a rotationally distorted shape. The oblateness of gas giant planet increases of course with rotation rate and for fixed rotation also rises with decreasing gravity. Thus young, lower mass gas giant planets with youthful inflated radii could easily have oblateness greater than that of Saturn s 10%. We find that polarizations of over 1% may easily be produced in the near-infrared in such cases. This magnitude of polarization may be measurable by GPI and other instruments. Thus if detected, polarization of a young Jupiter places constraints on the combination of its gravity, rotation rate, and degree of cloudiness. We will present results of our multiple scattering analysis coupled with a self-consistent dusty atmospheric models to demonstrate the range of polarizations that might be expected from resolved exoplanets and the range of parameter space that such observations may inform.

Marley, Mark Scott; Sengupta, Sujan

2012-01-01

74

A deep dive into NGC 604 with Gemini/NIRI imaging  

E-print Network

The giant HII region NGC 604 constitutes a complex and rich population to studying detail many aspects of massive star formation, such as their environments and physical conditions, the evolutionary processes involved, the initial mass function for massive stars and star-formation rates, among many others. Here, we present our first results of a near-infrared study of NGC 604 performed with NIRI images obtained with Gemini North. Based on deep JHK photometry, 164 sources showing infrared excess were detected, pointing to the places where we should look for star-formation processes currently taking place. In addition, the color-color diagram reveals a great number of objects that could be giant/supergiant stars or unresolved, small, tight clusters. A extinction map obtained based on narrow-band images is also shown.

Farina, Cecilia; Barba, Rodolfo H

2009-01-01

75

Imaging Spectroscopy for Extrasolar Planet Detection  

E-print Network

Coronagraphic imaging in combination with moderate to high spectral resolution may prove more effective in both detecting extrasolar planets and characterizing them than a standard coronagraphic imaging approach. We envisage an integral-field spectrograph coupled to a coronagraph to produce a 3D datacube. For the idealised case where the spectrum of the star is well-known and unchanging across the field, we discuss the utility of cross-correlation to seek the extrasolar planet signal, and describe a mathematical approach to completely eliminate stray light from the host star (although not its Poisson noise). For the case where the PSF is dominated by diffraction and scattering effects, and comprises a multitude of speckles within an Airy pattern typical of a space-based observation, we turn the wavelength dependence of the PSF to advantage and present a general way to eliminate the contribution from the star while preserving both the flux and spectrum of the extrasolar planet. We call this method `spectral deconvolution'. We illustrate the dramatic gains by showing an idealized simulation that results in a 20-sigma detection of a Jovian planet at 2 pc with a 2-m coronagraphic space telescope, even though the planet's peak flux is only 1% that of the PSF wings of the host star. This scales to detection of a terrestrial extrasolar planet at 2 pc with an 8-m coronagraphic Terrestrial Planet Finder (TPF) in ~7 hr (or less with appropriate spatial filtering). Data on the spectral characteristics of the extrasolar planet and hence on its atmospheric constituents and possible biomarkers are obtained naturally as part of this process.

William B. Sparks; Holland C. Ford

2002-09-04

76

Imaging Spectroscopy for Extrasolar Planet Detection  

Microsoft Academic Search

Coronagraphic imaging in combination with moderate to high spectral\\u000aresolution may prove more effective in both detecting extrasolar planets and\\u000acharacterizing them than a standard coronagraphic imaging approach. We envisage\\u000aan integral-field spectrograph coupled to a coronagraph to produce a 3D\\u000adatacube. For the idealised case where the spectrum of the star is well-known\\u000aand unchanging across the field, we

William B. Sparks; Holland C. Ford

2002-01-01

77

Gemini H-band imaging of the field of a z=10 candidate  

E-print Network

We present a deep H-band image of the field of a candidate z=10 galaxy magnified by the foreground (z=0.25) cluster A1835. The image was obtained with NIRI on Gemini North to better constrain the photometry and investigate the morphology of the source. The image is approximately one magnitude deeper and has better spatial resolution (seeing was 0.4-0.5 arcsec) than the existing H-band image obtained with ISAAC on the VLT by Pello' et al. 2004. The object is not detected in our new data. Given the published photometry (H(AB)=25.0), we would have expected it to have been detected at more than ~7 sigma in a 1.4 arcsec diameter aperture. We obtain a limit of H(AB)>26.0 (3 sigma) for the object. A major part of the evidence that this object is at z=10 was the presence of a strong continuum break between the J and H band, attributed to absorption of all continuum shortward of 1216 Ang in the rest-frame of the object. Our H-band non-detection substantially reduces the magnitude of any break and therefore weakens the...

Bremer, M N; Lehnert, M D; Förster-Schreiber, N M; Douglas, L; Jensen, Joseph B.; Douglas, Laura

2004-01-01

78

The Gemini Frontier Field: Multi-conjugate Adaptive Optics Ks-band imaging of selected HST Frontier Field galaxy clusters  

NASA Astrophysics Data System (ADS)

We use the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and the Gemini South Adaptive Optics Imager (GSAOI) at the Gemini South telescope to image three of the six Hubble Space Telescope (HST) Frontier Field targets. These observations cover the gap between the HST observations beyond 1.7 microns and the 3.6 micron provided by Spitzer. GeMS is the first multi-conjugate adaptive optics system in use at an 8meter telescope. It delivers and uniform, close to diffraction-limited near-infrared images over a 2? field of view. In this presentation we describe the release of 100'' x 100'' high resolution wide-field images obtained for the galaxy clusters MACS J0416.1-2403 and Abell 2744 in Ks-band. The angular resolution achieved is between 70 to 110 mas, twice as high as HST/WFC3, using a single natural guide star only. This is a demonstration that even for fields at high galactic latitude, where natural guide stars are scarce, current multi-conjugated adaptive optics technology at 8m-telescopes has opened a new window on the distant Universe.

Sivo, Gaetano; Rodrigo Carrasco, Mischa Schirmer, Peter Pessev, Claudia Winge, Vincent Garrel, Benoit Neichel, Fabrice Vidal

2015-01-01

79

Gemini Imaging of Mid-IR Emission from the Nuclear Region of Centaurus A  

E-print Network

We present high spatial resolution mid-IR images of the nuclear region of NGC 5128 (Centaurus A). Images were obtained at 8.8 micron, N-band (10.4 micron), and 18.3 micron using the mid-IR imager/spectrometer T-ReCS on Gemini South. These images show a bright unresolved core surrounded by low-level extended emission. We place an upper limit to the size of the unresolved nucleus of 3.2 pc (0.19") at 8.8 micron and 3.5 pc (0.21") at 18.3 micron at the level of the FWHM. The most likely source of nuclear mid-IR emission is from a dusty torus and possibly dusty narrow line region with some contribution from synchrotron emission associated with the jet as well as relatively minor starburst activity. Clumpy tori models are presented which predict the mid-IR size of this torus to be no larger than 0.05" (0.85pc). Surrounding the nucleus is extensive low-level mid-IR emission. Previously observed by ISO and Spitzer, this paper presents to date the highest spatial resolution mid-IR images of this extended near nuclear structure. Much of the emission is coincident with Pa-alpha sources seen by HST implying emission from star forming areas, however evidence for jet induced star formation, synchrotron emission from the jet, a nuclear bar/ring, and an extended dusty narrow emission line region is also discussed.

James T. Radomski; Christopher Packham; N. A. Levenson; Eric Perlman; Lerothodi L. Leeuw; Henry Matthews; Rachel Mason; James M. De Buizer; Charles M. Telesco; Manuel Orduna

2008-02-28

80

Characterization and monitoring of Flamingos-II, a near-IR imager and spectrograph at Gemini South  

NASA Astrophysics Data System (ADS)

We present results of the characterization and continual monitoring of the Flamingos-II instrument. Currently installed at Gemini South Observatory, Flamingos-II is a near-IR imager and longslit/multi-object spectrograph. In addition to the characterization of the detector, methodologies and results of the Science Verification pipeline, Telluric corrections, and Multi-Object Spectrograph (MOS) mask design software are presented.

Krogsrud, David; Diaz, Ruben; Ferrero, Gabriel; Mora, Marcelo; Navarete, Felipe; Schirmer, Mischa

2015-01-01

81

Gemini H-band imaging of the field of a z=10 candidate  

E-print Network

We present a deep H-band image of the field of a candidate z=10 galaxy magnified by the foreground (z=0.25) cluster A1835. The image was obtained with NIRI on Gemini North to better constrain the photometry and investigate the morphology of the source. The image is approximately one magnitude deeper and has better spatial resolution (seeing was 0.4-0.5 arcsec) than the existing H-band image obtained with ISAAC on the VLT by Pello' et al. 2004. The object is not detected in our new data. Given the published photometry (H(AB)=25.0), we would have expected it to have been detected at more than ~7 sigma in a 1.4 arcsec diameter aperture. We obtain a limit of H(AB)>26.0 (3 sigma) for the object. A major part of the evidence that this object is at z=10 was the presence of a strong continuum break between the J and H band, attributed to absorption of all continuum shortward of 1216 Ang in the rest-frame of the object. Our H-band non-detection substantially reduces the magnitude of any break and therefore weakens the case that this object is at z=10. Without a clear continuum break, the identification of an emission line at 1.33745um as Ly-alpha at z~10 is less likely. We show that the width and flux of this line are consistent with an alternative emission line such as [OIII]5007 from an intermediate redshift HII/dwarf galaxy.

M. N. Bremer; Joseph B. Jensen; M. D. Lehnert; N. M. Foerster Schreiber; Laura Douglas

2004-09-21

82

The M31 Dwarf Spheroidal Companion And V: g', r', and i' Imaging with GMOS on Gemini North  

E-print Network

g', r', and i' images obtained with the Gemini Multi-Object Spectrograph (GMOS) on Gemini North are used to investigate the metallicity and stellar content of the M31 dwarf spheroidal companion galaxy And V. Red giant branch (RGB) stars are traced out to radii in excess of 126 arcsec from the galaxy center, indicating that And V extends over a diameter approaching 1 kpc. The mean g'-i' color of the RGB does not change with radius. Based on the slope of the RGB in the (i', g'-i') color-magnitude diagram we conclude that [Fe/H] = -2.2 +/- 0.1. This metallicity is lower than earlier estimates, and places And V squarely on the relation between metallicity and integrated brightness defined by other dwarf spheroidal and dwarf elliptical galaxies. We also fail to find a statistically significant population of luminous asymptotic giant branch stars near the center of the galaxy.

T. J. Davidge; G. S. Da Costa; I. Jorgensen; J. R. Allington-Smith

2002-07-04

83

Gemini/GMOS Imaging of Globular Clusters in the Virgo Galaxy NGC 4649 (M60)  

E-print Network

We present Sloan g and i imaging from the GMOS instrument on the Gemini North telescope for the globular cluster (GC) system around the Virgo galaxy NGC 4649 (M60). Our three pointings, taken in good seeing conditions, cover an area of about 90 sq. arcmins. We detect 2,151 unresolved sources. Applying colour and magnitude selection criteria to this source list gives 995 candidate GCs that is greater than 90% complete to a magnitude of i = 23.6, with little contamination from background galaxies. We find fewer than half a dozen potential Ultra Compact Dwarf galaxies around NGC 4649. Foreground extinction from the nearby spiral NGC 4647 is limited to be A_V < 0.1. We confirm the bimodality in the GC colour distribution found by earlier work using HST/WFPC2 imaging. As is commonly seen in other galaxies, the red GCs are concentrated towards the centre of the galaxy, having a steeper number density profile than the blue GC subpopulation. The varying ratio of red-to-blue GCs with radius can largely explain the overall GC system colour gradient. The underlying galaxy starlight has a similar density profile slope and colour to the red GCs. This suggests a direct connection between the galaxy field stars and the red GC subpopulation. We estimate a total GC population of 3700 +/- 900, with the uncertainty dominated by the extrapolation to larger radii than observed. This total number corresponds to a specific frequency S_N = 4.1 +/- 1.0. Future work will present properties derived from GMOS spectra of the NGC 4649 GCs.

Duncan A. Forbes; Favio Raul Faifer; Juan Carlos Forte; Terry Bridges; Michael A. Beasley; Karl Gebhardt; David A. Hanes; Ray Sharples; Stephen E. Zepf

2004-08-23

84

Planet Detection Algorithm using Multiple Images with Independent Speckle Patterns  

NASA Astrophysics Data System (ADS)

Current observations in the context of exoplanet searches with coronagraphic instruments have shown that one of the main limitations to high-contrast imaging is due to residual quasi-static speckles. Speckles look like the image of a planet, but they have a different spectral behavior and are optically coherent with the star. All speckles are formed from the same coherent source, the star, and are incoherent with the planet. Moving the DM (or other changes to the optical layout) causes interference and therefore changes in the speckle pattern as seen on the camera. Since the planet light does not interfere with the speckles, the image of the planet remains untouched (except that speckles may appear on top of the planet). This fundamental coherence property of the speckles (and incoherence with the planet light) guides us to develop methods to take advantage of a changing speckle pattern to distinguish a planet from a speckle. We present a model of estimating the intensity of a planet given a point spread function (PSF), and assuming an unknown and locally constant background source as well as photon noise. We use this model to develop a planet detection algorithm similar to matched filtering of the PSF. We are extending the work of image analysis from one image to multiple images presuming an independent source of aberrations between images.

Young, Elizabeth; Kasdin, N. J.; Carlotti, A.

2012-01-01

85

HOW DO MOST PLANETS FORM?-CONSTRAINTS ON DISK INSTABILITY FROM DIRECT IMAGING  

SciTech Connect

Core accretion and disk instability have traditionally been regarded as the two competing possible paths of planet formation. In recent years, evidence has accumulated in favor of core accretion as the dominant mode, at least for close-in planets. However, it might be hypothesized that a significant population of wide planets formed by disk instabilities could exist at large separations, forming an invisible majority. In previous work, we addressed this issue through a direct imaging survey of B2-A0-type stars and concluded that <30% of such stars form and retain planets and brown dwarfs through disk instability, leaving core accretion as the likely dominant mechanism. In this paper, we extend this analysis to FGKM-type stars by applying a similar analysis to the Gemini Deep Planet Survey sample. The results strengthen the conclusion that substellar companions formed and retained around their parent stars by disk instabilities are rare. Specifically, we find that the frequency of such companions is <8% for FGKM-type stars under our most conservative assumptions, for an outer disk radius of 300 AU, at 99% confidence. Furthermore, we find that the frequency is always <10% at 99% confidence independently of outer disk radius, for any radius from 5 to 500 AU. We also simulate migration at a wide range of rates and find that the conclusions hold even if the companions move substantially after formation. Hence, core accretion remains the likely dominant formation mechanism for the total planet population, for every type of star from M-type through B-type.

Janson, Markus [Department of Astrophysics, Princeton University, Peyton Hall, 4 lvy Lane, Princeton, NJ 08544 (United States); Bonavita, Mariangela [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George St, Toronto, ON M5S 3H8 (Canada); Klahr, Hubert [Max Planck Institute for Astronomy, Konigstuhl 17, Heidelberg 69117 (Germany); Lafreniere, David, E-mail: janson@astro.princeton.edu [Department of Physics, University of Montreal, C.P. 6128, Succursale Centre-Ville, Montreal, QC H3C 3J7 (Canada)

2012-01-20

86

New, Near-to-Mid Infrared High-Contrast Imaging of the Young Extrasolar Planets, HR 8799 bcde  

NASA Astrophysics Data System (ADS)

We present new thermal IR imaging for the young, planet-hosting star HR 8799 obtained with Keck/NIRC2, VLT/NaCo and Subaru/IRCS. We easily detect all four HR 8799 planets but fail to identify a fifth planet, "HR 8799 f", at r < 15 AU at a 5-sigma confidence level. We rule out an HR 8799 f with mass of 5 MJ (7 MJ), 7 MJ (10 MJ), and 12 MJ (13 MJ) at rproj ? 12 AU, 9 AU, and 5 AU, respectively. All four HR 8799 planets have red early T dwarf-like L? - [4.05] colors. Atmosphere models assuming thick, patchy clouds appear to better match HR 8799 bcde's photometry than models assuming a uniform cloud layer. While non-equilibrium carbon chemistry is required to explain HR 8799 bc's photometry/spectra, evidence for it from HR 8799 de's photometry is weaker. Pending execution of upcoming observations, we will also present unpublished imaging of HR 8799 with the Gemini Planet Imager (GPI) and Subaru Coronagraphic Extreme Adaptive Optics project (SCExAO): two of a new generation of dedicated extreme-AO facilities.

Currie, Thayne M.; Burrows, Adam Seth; Girard, Julien; Cloutier, Ryan; Fukagawa, Misato; Sorahana, Satoko; Kuchner, Marc J.; Kenyon, Scott; Madhusudhan, Nikku; Itoh, Yoichi; Jayawardhana, Ray; Matsumura, Soko; Pyo, Tae-Soo

2015-01-01

87

Experience with a new approach for instrument software at Gemini  

NASA Astrophysics Data System (ADS)

Gemini Observatory is using a new approach with instrument software that takes advantage of the strengths of our instrument builders and at the same time better supports our own operational needs. A lightweight software library in conjunction with modern agile software development methodologies is being used to ameliorate the problems encountered with the development of the first and second-generation Gemini instruments. Over the last two years, Gemini and the team constructing the software for the Gemini Planet Imager (GPI) have been using an agile development process to implement the Gemini Instrument Application Interface (GIAPI) and the highlevel control software for the GPI instrument. The GPI is being tested and exercised with the GIAPI, and this has allowed us to perform early end-to-end testing of the instrument software. Early in 2009 for the first time in our development history, we were able to move instrument mechanisms with Gemini software during early instrument construction. As a result of this approach, we discovered and fixed software interface issues between Gemini and GPI. Resolving these problems at this stage is simpler and less expensive than when the full instrument is completed. GPI is currently approaching its integration and testing phase, which will occur in 2010. We expect that utilizing this new approach will yield a more robust software implementation resulting in smoother instrument integration, testing, and commissioning phases. In this paper we describe the key points of our approach and results of applying the new instrument API approach together with agile development methodologies. The paper concludes with lessons learned and suggestions for adapting agile approaches in other astronomy development projects.

Núñez, Arturo; Walker, Shane; Goodsell, Stephen; Dunn, Jennifer; Gillies, Kim

2010-07-01

88

FLAMINGOS-2: the facility near-infrared wide-field imager and multi-object spectrograph for Gemini  

Microsoft Academic Search

We report on the design and status of the FLAMINGOS-2 instrument - a fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048×2048-pixel HAWAII-2 0.9-2.4 mum detector array. A slit\\/decker wheel mechanism allows the selection of up to 9 multi-object

Stephen Eikenberry; Richard Elston; S. Nicholas Raines; Jeff Julian; Kevin Hanna; David Hon; Roger Julian; R. Bandyopadhyay; J. Greg Bennett; Aaron Bessoff; Matt Branch; Richard Corley; John-David Eriksen; Skip Frommeyer; Anthony Gonzalez; Michael Herlevich; Antonio Marin-Franch; Jose Marti; Charlie Murphey; David Rashkin; Craig Warner; Brian Leckie; W. Rusty Gardhouse; Murray Fletcher; Jennifer Dunn; Robert Wooff; Tim Hardy

2006-01-01

89

Stable flexure mounting of a MEMS deformable mirror for the GPI Planet Imager  

NASA Astrophysics Data System (ADS)

Small deformable mirrors (DMs) produced using microelectromechanical systems (MEMS) techniques have been used in thermally stable, bench-top laboratory environments. With advances in MEMS DM technology, a variety of field applications are becoming more common, such as the Gemini Planet Imager's (GPI) adaptive optics system. Instruments at the Gemini Observatory operate in conditions where fluctuating ambient temperature, varying gravity orientations and humidity and dust can have a significant affect on DM performance. As such, it is crucial that the mechanical design of the MEMS DM be tailored to the environment. GPI's approach has been to mount the MEMS DM using high performance optical mounting techniques rather than a typical laboratory set-up. This paper discusses the design of the opto-mechanical mounting scheme for a 4096 actuator MEMS DM, developed by Boston Micromachines Corporation for use in the GPI adaptive optics system. Flexures have been incorporated into the DM mount to reduce deformations on the optical surface due to thermal fluctuations. These flexures have also been sized to maintain alignment under varying gravity vector orientations. Finally, a system for environmentally sealing the mirror has been designed to prevent degradation due to humidity effects. A plan for testing the mechanical mount to ensure that it meets GPI's performance and environmental requirements is also presented.

Hill, Alexis; Erickson, Darren; Fitzsimmons, Joeleff; Bierden, Paul; Cornelissen, Steven; Palmer, Dave

2008-07-01

90

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

2010-12-23

91

A UNIFORM ANALYSIS OF 118 STARS WITH HIGH-CONTRAST IMAGING: LONG-PERIOD EXTRASOLAR GIANT PLANETS ARE RARE AROUND SUN-LIKE STARS  

SciTech Connect

We expand on the results of Nielsen et al., using the null result for giant extrasolar planets around the 118 target stars from the Very Large Telescope (VLT) NACO H- and Ks-band planet search (conducted by Masciadri and collaborators in 2003 and 2004), the VLT and MMT Simultaneous Differential Imager survey, and the Gemini Deep Planet Survey to set constraints on the population of giant extrasolar planets. Our analysis is extended to include the planet luminosity models of Fortney et al., as well as the correlation between stellar mass and frequency of giant planets found by Johnson et al. Doubling the sample size of FGKM stars strengthens our conclusions: a model for extrasolar giant planets with power laws for mass and semimajor axis as given by Cumming et al. cannot, with 95% confidence, have planets beyond 65 AU, compared to the value of 94 AU reported by Nielsen et al., using the models of Baraffe et al. When the Johnson et al. correction for stellar mass (which gives fewer Jupiter-mass companions to M stars with respect to solar-type stars) is applied, however, this limit moves out to 82 AU. For the relatively new Fortney et al. models, which predict fainter planets across most of parameter space, these upper limits, with and without a correction for stellar mass, are 182 and 234 AU, respectively.

Nielsen, Eric L.; Close, Laird M., E-mail: enielsen@as.arizona.ed [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

2010-07-10

92

Project Gemini online digital archive  

NASA Astrophysics Data System (ADS)

An archive containing the first high-resolution digital scans of the original flight films from Project Gemini, the second U.S. human spaceflight program, was unveiled by the NASA Johnson Space Center and Arizona State University's (ASU) School of Earth and Space Exploration on 6 January. The archive includes images from 10 flights. Project Gemini, which ran from 1964 to 1966, followed Project Mercury and preceded the Apollo spacecraft. Mercury and Apollo imagery are also available through ASU. For more information, see http://tothemoon.ser.asu.edu/gallery/gemini and http://apollo.sese.asu.edu/index.html.

Showstack, Randy

2012-01-01

93

FLAMINGOS-2: The Facility Near-Infrared Wide-field Imager & Multi-Object Spectrograph for Gemini  

E-print Network

We report on the design and status of the FLAMINGOS-2 instrument - a fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048-pixel HAWAII-2 0.9-2.4 mm detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide resolutions from $\\sim$ 1300 to $\\sim $3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-Instrument WaveFront Sensor subsystems. We also present the current status of the project, currently in final testing in mid-2006.

Stephen Eikenberry; Richard Elston; S. Nicholas Raines; Jeff Julian; Kevin Hanna; David Hon; Roger Julian; R. Bandyopadhyay; J. Greg Bennett; Aaron Bessoff; Matt Branch; Richard Corley; John-David Eriksen; Skip Frommeyer; Anthony Gonzalez; Michael Herlevich; Antonio Marin-Franch; Jose Marti; Charlie Murphey; David Rashkin; Craig Warner; Brian Leckie; W. Rusty Gardhouse; Murray Fletcher; Jennifer Dunn; Robert Wooff; Tim Hardy

2006-04-27

94

FLAMINGOS-2: the facility near-infrared wide-field imager and multi-object spectrograph for Gemini  

NASA Astrophysics Data System (ADS)

We report on the design, on-sky performance, and status of the FLAMINGOS-2 instrument - the fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048- pixel HAWAII-2 0.9-2.4 ?m detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide resolutions from ~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-Instrument WaveFront Sensor subsystems. We also present the on-sky performance measured during acceptance testing in 2009, as well as current status of the project and future plans.

Eikenberry, Stephen; Bandyopadhyay, Reba; Bennett, J. Greg; Bessoff, Aaron; Branch, Matt; Charcos, Miguel; Corley, Richard; Dewitt, Curtis; Eriksen, John-David; Elston, Richard; Frommeyer, Skip; Gonzalez, Anthony; Hanna, Kevin; Herlevich, Michael; Hon, David; Julian, Jeff; Julian, Roger; Lasso, Nestor; Marin-Franch, Antonio; Marti, Jose; Murphey, Charlie; Raines, S. N.; Rambold, William; Rashkind, David; Warner, Craig; Leckie, Brian; Gardhouse, W. R.; Fletcher, Murray; Hardy, Tim; Dunn, Jennifer; Wooff, Robert; Pazder, John

2012-09-01

95

FLAMINGOS-2: The Facility Near-Infrared Wide-field Imager & Multi-Object Spectrograph for Gemini  

E-print Network

We report on the design and status of the FLAMINGOS-2 instrument - a fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048-pixel HAWAII-2 0.9-2.4 mm detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide resolutions from $\\sim$ 1300 to $\\sim $3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-Instrument WaveFront Sensor subsystems. We also present the current status of the pro...

Eikenberry, S; Bennett, J G; Bessoff, A; Branch, M; Corley, R; Dunn, J; Elston, R; Eriksen, J D; Fletcher, M; Frommeyer, S; Gardhouse, W R; González, A; Hanna, K; Hardy, T; Herlevich, M; Hon, D; Julian, J; Julian, R; Leckie, B; Marin-Franch, A; Martí, J; Murphey, C; Raines, S N; Rashkin, D; Warner, C; Wooff, R; Bessoff, Aaron; Branch, Matt; Corley, Richard; Dunn, Jennifer; Eikenberry, Stephen; Elston, Richard; Eriksen, John-David; Fletcher, Murray; Frommeyer, Skip; Gonzalez, Anthony; Hanna, Kevin; Hardy, Tim; Herlevich, Michael; Hon, David; Julian, Jeff; Julian, Roger; Leckie, Brian; Marin-Franch, Antonio; Marti, Jose; Murphey, Charlie; Rashkin, David; Warner, Craig; Wooff, Robert

2006-01-01

96

FLAMINGOS-2: the facility near-infrared wide-field imager and multi-object spectrograph for Gemini  

NASA Astrophysics Data System (ADS)

We report on the design and status of the FLAMINGOS-2 instrument - a fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048×2048-pixel HAWAII-2 0.9-2.4 ?m detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6×2-arcminute field of view, and selectable grisms provide resolutions from ~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi- Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3×1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On- Instrument WaveFront Sensor subsystems. We also present the current status of the project and future plans, including on-sky delivery planned for late 2008.

Eikenberry, Stephen; Elston, Richard; Raines, S. Nicholas; Julian, Jeff; Hanna, Kevin; Warner, Craig; Julian, Roger; Bandyopadhyay, Reba; Bennett, J. Greg; Bessoff, Aaron; Branch, Matt; Corley, Richard; Dewitt, Curtis; Eriksen, John-David; Frommeyer, Skip; Gonzalez, Anthony; Herlevich, Michael; Hon, David; Marin-Franch, Antonio; Marti, Jose; Murphey, Charlie; Rambold, William; Rashkin, David; Leckie, Brian; Gardhouse, W. Rusty; Fletcher, Murray; Hardy, Tim; Dunn, Jennifer; Wooff, Robert

2008-07-01

97

Planet signatures in collisionally active debris discs: scattered light images  

NASA Astrophysics Data System (ADS)

Context. Planet perturbations have been often invoked as a potential explanation for many spatial structures that have been imaged in debris discs. So far this issue has been mostly investigated with pure N-body numerical models, which neglect the crucial effect collisions within the disc can have on the disc's response to dynamical perturbations. Aims: We numerically investigate how the coupled effect of collisions and radiation pressure can affect the formation and survival of radial and azimutal structures in a disc perturbed by a planet. We consider two different set-ups: a planet embedded within an extended disc and a planet exterior to an inner debris ring. One important issue we want to address is under which conditions a planet's signature can be observable in a collisionally active disc. Methods: We use our DyCoSS code, which is designed to investigate the structure of perturbed debris discs at dynamical and collisional steady-state, and derive synthetic images of the system in scattered light. The planet's mass and orbit, as well as the disc's collisional activity (parameterized by its average vertical optical depth ?0) are explored as free parameters. Results: We find that collisions always significantly damp planet-induced spatial structures. For the case of an embedded planet, the planet's signature, mostly a density gap around its radial position, should remain detectable in head-on images if Mplanet ? MSaturn. If the system is seen edge-on, however, inferring the presence of the planet is much more difficult, as only weak asymmetries remain in a collisionally active disc, although some planet-induced signatures might be observable under very favourable conditions. For the case of an inner ring and an external planet, planetary perturbations cannot prevent collision-produced small fragments from populating the regions beyond the ring. The radial luminosity profile exterior to the ring is in most cases close to the one it should have in the absence of the external planet. The most significant signature left by a Jovian planet on a circular orbit are precessing azimutal structures that can be used to indirectly infer its presence. For a planet on an eccentric orbit, we show that the ring becomes elliptic and that the well known pericentre glow effect is visible despite of collisions and radiation pressure, but that detecting such features in observed discs is not an unambiguous indicator of the presence of an outer planet. Movies are available in electronic form at http://www.aanda.org

Thebault, P.; Kral, Q.; Ertel, S.

2012-11-01

98

Laboratory tests of planet signal extraction in high contrast images  

NASA Astrophysics Data System (ADS)

Understanding the formation, evolution and surprising diversity of exoplanetary system is recognized as one of the few major challenges of current astrophysics. While a large number of planets are discovered thanks to techniques like radial velocity and transits, only a few of them have clear measurements of their atmospheric components. Besides, these latter have been studied on transiting planets with very short orbits. Study of planets at larger separations requires direct imaging, which has enabled detection of a handful of exoplanets. This number will dramatically increase with the arrival in 2013 of SPHERE and GPI instruments that will give access to a large class of self-luminous young exoplanets. Characterization of mature planets or even massive rocky planets is expected for the next generation of planet finders that will be installed on Extremely Large Telescopes (ELT).On ELT, even with Adaptive Optics (AO) working at their best, using smart wavefront sensor and correction strategy, it is expected that the residual speckles in the images will still be a factor 100 brighter than the planet signal. This level composed of slow quasi static speckles not detected by the wavefront sensor and the rapidly varying wavefront errors that cannot be corrected by the AO loop frequency. Solutions are actually studied to calibrate these speckles and make sure that we can differentiate them from planet signal. One of the best solution is to use the signal of focal plane wavefront sensors that can help suppressing the quasi-static speckles but also help to extract the planet signal in the final images.After describing the benefit of focal plane wavefront sensor for data extraction, we will describe our laboratory test bench which uses the Self-Coherent Camera as focal plane wavefront sensor. The principle of the data processing used to extract the planet signal will be presented together with laboratory results on very high contrast images.

Baudoz, Pierre; Mazoyer, Johan; Galicher, Raphael

2013-12-01

99

Gemini 10 insignia  

NASA Technical Reports Server (NTRS)

Color design of the emblem of the Gemini 10 space flight. Roman numeral indicates the tenth flight in the Gemini series. The two spacecraft and their orbital paths symbolize the rendezvous and docking mission of the Gemini and Agena.

1966-01-01

100

Exozodiacal Dust and Direct Imaging of Extrasolar Planets  

NASA Technical Reports Server (NTRS)

Direct imaging of extrasolar planets means contending with dust from extrasolar asteroids and comets. This 'exozodiacal dust' creates a structured background light that can easily outshine the light from an exoEarth and confuse a planet-search mission like TPF or TOPS. But exozodiacal dust can be both friend and foe: planets can stir dust clouds into patterns that reveal the presence of the planet and constrain its mass and orbit. I'll describe some recent research on this topic: 3-D dynamical models of dust clouds with planets and searches for exozodiacal dust with the Keck Interferometer. The author also offers a prediction for the typical zodiacal dust background found around solar analogs, based on seafloor sediment data.

Kuchner, Marc

2008-01-01

101

An Imaging Nulling Interferometer to Study Extrasolar Planets  

Microsoft Academic Search

Interferometric techniques oÜer two advantages for the detection and analysis of thermal radiation from planets: destructive interference to strongly suppress the stellar emission, and the possibility of high-resolution imaging to resolve planets and distinguish them from dust emission. This paper presents a new interferometric con—guration in which the con—icting requirements for these goals are reconciled. It realizes a very strong,

J. R. P. Angel; N. J. Woolf

1997-01-01

102

The International Outer Planets Watch atmospheres node database of giant-planet images  

NASA Astrophysics Data System (ADS)

The Atmospheres Node of the International Outer Planets Watch (IOPW) is aimed to encourage the observations and study of the atmospheres of the Giant Planets. One of its main activities is to provide an interaction between the professional and amateur astronomical communities maintaining an online and fully searchable database of images of the giant planets obtained from amateur astronomers and available to both professional and amateurs [1]. The IOPW database contains about 13,000 image observations of Jupiter and Saturn obtained in the visible range with a few contributions of Uranus and Neptune. We describe the organization and structure of the database as posted in the Internet and in particular the PVOL software (Planetary Virtual Observatory & Laboratory) designed to manage the site and based in concepts from Virtual Observatory projects.

Hueso, R.; Legarreta, J.; Sánchez-Lavega, A.; Rojas, J. F.; Gómez-Forrellad, J. M.

2011-10-01

103

Characterization and testing of FLAMINGOS-2: the Gemini facility near-infrared multi-object spectrometer and wide-field imager  

NASA Astrophysics Data System (ADS)

FLAMINGOS-2 is a near-infrared wide-field imager and fully cryogenic multi-object spectrometer for Gemini Observatory being built by the University of Florida. FLAMINGOS-2 can simultaneously carry 9 custom cryogenic multi-object slit masks exchangeable without thermally cycling the entire instrument. Three selectable grisms provide resolving powers which are ~1300 to ~3000 over the entire spectrograph bandpass of 0.9-2.5 microns. We present and discuss characterization data for FLAMINGOS-2 including imaging throughput, image quality, spectral performance, and noise performance. After a lengthy integration process, we expect that FLAMINGOS-2 will be in the midst of commissioning at Gemini South by the fall of 2008.

Raines, Steven N.; Eikenberry, Stephen S.; Bandyopadhyay, Reba M.; Julian, Jeffrey A.; Hanna, Kevin T.; Warner, Craig D.; Julian, Roger E.; Bennett, J. Greg; DeWitt, Curtis N.; Frommeyer, Skip; Gonzalez, Anthony; Herlevich, Michael D.; Murphey, Charles

2008-07-01

104

Gemini Space Program emblem  

NASA Technical Reports Server (NTRS)

The insignia of the Gemini space program is a disc of dark blue as a background for a gold Zodiac Gemini symbol. A white star on each of the two vertical curves of the Gemini symbol represent the Gemini twins, Pollux and Castor.

1965-01-01

105

eXtreme Adaptive Optics Planet Imager: Overview and status  

SciTech Connect

As adaptive optics (AO) matures, it becomes possible to envision AO systems oriented towards specific important scientific goals rather than general-purpose systems. One such goal for the next decade is the direct imaging detection of extrasolar planets. An 'extreme' adaptive optics (ExAO) system optimized for extrasolar planet detection will have very high actuator counts and rapid update rates - designed for observations of bright stars - and will require exquisite internal calibration at the nanometer level. In addition to extrasolar planet detection, such a system will be capable of characterizing dust disks around young or mature stars, outflows from evolved stars, and high Strehl ratio imaging even at visible wavelengths. The NSF Center for Adaptive Optics has carried out a detailed conceptual design study for such an instrument, dubbed the eXtreme Adaptive Optics Planet Imager or XAOPI. XAOPI is a 4096-actuator AO system, notionally for the Keck telescope, capable of achieving contrast ratios >10{sup 7} at angular separations of 0.2-1'. ExAO system performance analysis is quite different than conventional AO systems - the spatial and temporal frequency content of wavefront error sources is as critical as their magnitude. We present here an overview of the XAOPI project, and an error budget highlighting the key areas determining achievable contrast. The most challenging requirement is for residual static errors to be less than 2 nm over the controlled range of spatial frequencies. If this can be achieved, direct imaging of extrasolar planets will be feasible within this decade.

Macintosh, B A; Bauman, B; Evans, J W; Graham, J; Lockwood, C; Poyneer, L; Dillon, D; Gavel, D; Green, J; Lloyd, J; Makidon, R; Olivier, S; Palmer, D; Perrin, M; Severson, S; Sheinis, A; Sivaramakrishnan, A; Sommargren, G; Soumer, R; Troy, M; Wallace, K; Wishnow, E

2004-08-18

106

GMOS: the GEMINI Multiple Object Spectrographs  

Microsoft Academic Search

The two Gemini multiple object spectrographs (GMOS) are being designed and built for use with the Gemini telescopes on Mauna Kea and Cerro Pachon starting in 1999 and 2000 respectively. They have four operating modes: imaging, long slit spectroscopy, aperture plate multiple object spectroscopy and area (or integral field) spectroscopy. The spectrograph uses refracting optics for both the collimator and

Roger L. Davies; Jeremy R. Allington-Smith; P. Bettess; E. Chadwick; G. N. Dodsworth; Roger Haynes; D. Lee; Ian J. Lewis; J. Webster; E. Atad; Steven M. Beard; M. Ellis; Peter R. Hastings; Phil R. Williams; Tim Bond; David Crampton; Timothy J. Davidge; Murray Fletcher; Brian Leckie; Christopher L. Morbey; Richard G. Murowinski; Scott Roberts; Leslie K. Saddlemyer; Jerry Sebesta; James R. Stilburn; Kei Szeto

1997-01-01

107

Mars Imaging Camera (MIC) on board PLANET-B  

Microsoft Academic Search

Mars Imaging Camera (MIC) on board PLANET-B, Japanese Mars mission, is a small, compact and lightweight imager. It features three-color linear CCD aligned with the spacecraft's spin axis and is designed to take two-dimensional images of Mars and its satellites using the spacecraft's spin.The total field of view (FOV) of the camera is 360 degree (around the spin axis) ×

Keiken Ninomiya; Tatsuaki Hashimoto; Akikom Nakamura; Tadashi Mukai; Masato Nakamura; Masahiro Ogasawara; Naoki Yoshizawa; Juro Ishida; Yasuhiko Mizushima; Hiroto Hosoda; Masayo Takano

1999-01-01

108

Unveiling Uranus' Clouds: New Observations From Gemini-North NIFS And NIRI  

Microsoft Academic Search

Observations of Uranus were made in September 2009 with the Gemini-North telescope in Hawaii, using both the NIFS and NIRI instruments. Adaptive optics were used to achieve a spatial resolution of approximately 0.1 arcsec. NIRI images were recorded with three spectral filters to constrain the overall appearance of the planet: J, H-continuum and CH4(long), and long slit spectra (1.49 to

Patrick G. J. Irwin; N. A. Teanby; G. R. Davis; L. N. Fletcher; G. Orton; D. Tice

2010-01-01

109

The international outer planets watch atmospheres node database of giant-planet images  

NASA Astrophysics Data System (ADS)

The Atmospheres Node of the International Outer Planets Watch (IOPW, formerly known as International Jupiter Watch; Russell et al., 1990) intends to encourage and coordinate the imaging observations and study of the atmospheres of the Giant Planets. The main activity of the atmospheres node is to provide an interaction between the professional and amateur astronomical communities maintaining a large database of images of the giant planets (primarily Jupiter and Saturn but with increasing contributions of Uranus and Neptune too). The observational datasets of Jupiter and Saturn correspond to images obtained in the visible range (300 nm-1 ?m), during the last decade, most of them performed by amateur observers. We here describe the organization and structure of the database as posted on the Internet and in particular the PVOL software (Planetary Virtual Observatory Laboratory) designed to manage the site in the spirit of the Virtual Observatory projects. We also describe with examples the important role of the amateur-professional collaboration in the study of the atmospheres of Jupiter and Saturn in an epoch of large telescopes and spacecraft observations of both planets.

Hueso, R.; Legarreta, J.; Pérez-Hoyos, S.; Rojas, J. F.; Sánchez-Lavega, A.; Morgado, A.

2010-08-01

110

The science case for the Planet Formation Imager (PFI)  

NASA Astrophysics Data System (ADS)

Among the most fascinating and hotly-debated areas in contemporary astrophysics are the means by which planetary systems are assembled from the large rotating disks of gas and dust which attend a stellar birth. Although important work has already been, and is still being done both in theory and observation, a full understanding of the physics of planet formation can only be achieved by opening observational windows able to directly witness the process in action. The key requirement is then to probe planet-forming systems at the natural spatial scales over which material is being assembled. By definition, this is the so-called Hill Sphere which delineates the region of influence of a gravitating body within its surrounding environment. The Planet Formation Imager project (PFI; http://www.planetformationimager.org) has crystallized around this challenging goal: to deliver resolved images of Hill-Sphere-sized structures within candidate planethosting disks in the nearest star-forming regions. In this contribution we outline the primary science case of PFI. For this purpose, we briefly review our knowledge about the planet-formation process and discuss recent observational results that have been obtained on the class of transition disks. Spectro-photometric and multi-wavelength interferometric studies of these systems revealed the presence of extended gaps and complex density inhomogeneities that might be triggered by orbiting planets. We present detailed 3-D radiation-hydrodynamic simulations of disks with single and multiple embedded planets, from which we compute synthetic images at near-infrared, mid-infrared, far-infrared, and sub-millimeter wavelengths, enabling a direct comparison of the signatures that are detectable with PFI and complementary facilities such as ALMA. From these simulations, we derive some preliminary specifications that will guide the array design and technology roadmap of the facility.

Kraus, Stefan; Monnier, John; Harries, Tim; Dong, Ruobing; Bate, Matthew; Whitney, Barbara; Zhu, Zhaohuan; Buscher, David; Berger, Jean-Philippe; Haniff, Chris; Ireland, Mike; Labadie, Lucas; Lacour, Sylvestre; Petrov, Romain; Ridgway, Steve; Surdej, Jean; ten Brummelaar, Theo; Tuthill, Peter; van Belle, Gerard

2014-07-01

111

Imaging Young Giant Planets From Ground and Space CHARLES A. BEICHMAN  

E-print Network

the three planets around HR8799 (Mar- ois et al. 2008) and the single planet around Fomalhaut (Kalas et alImaging Young Giant Planets From Ground and Space CHARLES A. BEICHMAN NASA Exoplanet Science gas giant planets around nearby young stars and the closest M stars, complementing radial velocity

112

Design and verification of external occulters for direct imaging of extrasolar planets  

E-print Network

Design and verification of external occulters for direct imaging of extrasolar planets Eric Cady occulters February 10, 2011 1 / 46 #12;Introduction Finding planets 1995: 51 Pegasi b is the first planet found around a Sun-like star (Mayor and Queloz 1995). Since then: over 500 planets found and counting

113

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 ...

Ms. Anderson

2011-04-07

114

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.

115

Imaging plasmas at the Earth and other planets  

NASA Astrophysics Data System (ADS)

The field of space physics, both at Earth and at other planets, was for decades a science based on local observations. By stitching together measurements of plasmas and fields from multiple locations either simultaneously or for similar conditions over time, and by comparing those measurements against models of the physical systems, great progress was made in understanding the physics of Earth and planetary magnetospheres, ionospheres, and their interactions with the solar wind. However, the pictures of the magnetospheres were typically statistical, and the large-scale global models were poorly constrained by observation. This situation changed dramatically with global auroral imaging, which provided snapshots and movies of the effects of field aligned currents and particle precipitation over the entire auroral oval during quiet and disturbed times. And with the advent of global energetic neutral atom (ENA) and extreme ultraviolet (EUV) imaging, global constraints have similarly been added to ring current and plasmaspheric models, respectively. Such global constraints on global models are very useful for validating the physics represented in those models, physics of energy and momentum transport, electric and magnetic field distribution, and magnetosphere-ionosphere coupling. These techniques are also proving valuable at other planets. For example with Hubble Space Telescope imaging of Jupiter and Saturn auroras, and ENA imaging at Jupiter and Saturn, we are gaining new insights into the magnetic fields, gas-plasma interactions, magnetospheric dynamics, and magnetosphere-ionosphere coupling at the giant planets. These techniques, especially ENA and EUV imaging, rely on very recent and evolving technological capabilities. And because ENA and EUV techniques apply to optically thin media, interpretation of their measurements require sophisticated inversion procedures, which are still under development. We will discuss the directions new developments in imaging are taking, what technologies and mission scenarios might best take advantage of them, and how our understanding of the Earth's and other planets' plasma environments may benefit from such advancements.

Mitchell, D. G.

2006-05-01

116

Past, present, and future instrumentation at Gemini Observatory  

NASA Astrophysics Data System (ADS)

First, a status report is given for the on-going (Phase 2) instruments under construction now for Gemini. These instruments will be deployed during 2006 and 2007 at Gemini-South and collectively represent the end of an era of instrument building within the Gemini Partnership. Next, scientific applications and technical details for the next generation of "Aspen" instruments is described. These advanced future instruments will support breakthrough research in areas like extra-solar planets, dark matter, and dark energy. Gemini's ambitious adaptive optics development program in both current and future Aspen instruments is also described. Finally, a look back at some of the trials and tribulations of building instruments at Gemini is presented, with an eye toward the lessons of yesterday, how they helped mold today's program, and how they will likely impact the procurement of future instruments at Gemini.

Simons, Douglas A.; Jensen, Joseph B.; d'Orgeville, Celine; Gray, Peter M.; Lazo, Manuel; Rogers, Rolando; Sheehan, Michael P.; White, John K.

2006-06-01

117

Completing Gemini-South Optical Imaging of ALMA Lensed SMGs Discovered by Herschel  

NASA Astrophysics Data System (ADS)

We propose to complete our program of optical imaging of a sample of candidate strong-lensing galaxies discovered in the Herschel Multi-tiered Extragalactic Survey (HerMES) that was started in GS-2013B-Q-77 ( 80% complete). All of the targets in this proposal have exquisite, high-S/N and high-spatial resolution sub-mm imaging from ALMA that resolves the background source, and many of them have HST/F110W snapshot imaging that pinpoints the position of galaxies along the line of sight that act as gravitational lenses. The ALMA data will permit lens models that measure the mass of the foreground lens and the intrinsic luminosity and size of the background source. We propose to obtain deep (r=24 for a 5-sigma point-source) multi-band (ugriz) wide-field imaging of 7 targets that currently lack optical imaging in one or more optical bands. These data will identify the true optical counterparts to the ALMA sources, measuring their photometric redshifts, stellar masses, star-formation histories.

Bussmann, Robert; Riechers, Dominik; Wardlow, Julie; Fu, Hai; Cooray, Asantha; Perez-Fournon, Ismael; Calanog, Jae; Oliver, Seb; Bock, Jamie

2014-08-01

118

Outer planet Pioneer imaging communications system study. [data compression  

NASA Technical Reports Server (NTRS)

The effects of different types of imaging data compression on the elements of the Pioneer end-to-end data system were studied for three imaging transmission methods. These were: no data compression, moderate data compression, and the advanced imaging communications system. It is concluded that: (1) the value of data compression is inversely related to the downlink telemetry bit rate; (2) the rolling characteristics of the spacecraft limit the selection of data compression ratios; and (3) data compression might be used to perform acceptable outer planet mission at reduced downlink telemetry bit rates.

1974-01-01

119

Eighth-Order Image Masks for Terrestrial Planet Finding  

Microsoft Academic Search

We describe a new series of band-limited image masks for coronagraphy that are insensitive to tip-tilt errors and other low spatial frequency optical aberrations. For a modest cost in throughput, these ``eighth-order'' masks would allow the Terrestrial Planet Finder Coronagraph (TPF-C) to operate with a pointing accuracy no better than that of the Hubble Space Telescope. We also provide eighth-order

Marc J. Kuchner; Justin Crepp; Jian Ge

2005-01-01

120

Direct imaging searches for planets around white dwarf stars  

NASA Astrophysics Data System (ADS)

White dwarfs are excellent targets for direct imaging searches for extra-solar planets, since they are up to 10^4 times fainter than their main sequence progenitors, providing a huge gain in the contrast problem. In addition, the orbits of planetary companions that lie beyond the maximum extent of the Red Giant envelope are expected to widen considerably, improving resolution and further encouraging direct detection. We discuss current searches for planetary companions to white dwarfs, including our own “DODO” programme. At the time of writing, no planetary companion to a white dwarf has been detected. The most sensitive searches have been capable of detecting companions ?5M_{Jup}, and their non-detection is consistent with the conclusions of McCarthy & Zuckerman (2004), that no more than 3% of stars harbour 5-10M_{Jup} planets at orbits between 75-300AU. Extremely Large Telescopes are required to enable deeper searches sensitive to lower mass planets, and to provide larger target samples including more distant and older white dwarfs. ELTs will also enable spectroscopic follow-up for any resolved planets, and follow-up of any planetary companions discovered astrometrically by GAIA and SIM.

Burleigh, Matt; Hogan, Emma; Clarke, Fraser

121

Confirmation of the Planet around HD 95086 by Direct Imaging  

NASA Astrophysics Data System (ADS)

VLT/NaCo angular differential imaging at L' (3.8 ?m) revealed a probable giant planet comoving with the young and early-type HD 95086, also known to harbor an extended debris disk. The discovery was based on the proper motion analysis of two datasets spanning 15 months. However, the second dataset suffered from bad atmospheric conditions, which limited the significance of the re-detection at the 3? level. In this Letter, we report new VLT/NaCo observations of HD 95086 obtained on 2013 June 26 and 27 at L' to recover the planet candidate. We unambiguously re-detect the companion HD 95086 b with multiple independent pipelines at a signal-to-noise ratio greater than or equal to 5. Combined with previously reported measurements, our astrometry decisively shows that the planet is comoving with HD 95086 and inconsistent with a background object. With a revised mass of 5 ± 2 Jupiter masses, estimated from its L' photometry and "hot-start" models at 17 ± 4 Myr, HD 95086 b becomes a new benchmark for further physical and orbital characterization of young giant planets. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under programs number 291.C-5023.

Rameau, J.; Chauvin, G.; Lagrange, A.-M.; Meshkat, T.; Boccaletti, A.; Quanz, S. P.; Currie, T.; Mawet, D.; Girard, J. H.; Bonnefoy, M.; Kenworthy, M.

2013-12-01

122

Direct Imaging of Extrasolar Giant Planets in the Habitable Zone  

NASA Astrophysics Data System (ADS)

Young extrasolar giant planets (EGPs) are initially very luminous as they radiate away gravitational potential energy from formation (Burrows et al., 2001), but they rapidly cool and after a few tens of MYr (depending on mass) are essentially undetectable with typical direct imaging capabilities. Ground-based direct imaging is limited by adaptive optics (AO) performance. As a result of these restrictions direct imaging searches for EGPs have mainly focused on young stars (<~100 MYr) and wide orbital separations (>~10 AU). As AO performance improves we will begin searching for EGPs at much closer separations. Stellar irradiation sets the minimum temperature of a planet atmosphere (depending on albedo), regardless of mass and age. At wide separations this minimum temperature is too low to maintain planet brightness, but closer to the star this minimum temperature is much higher. Furthermore, old EGPs are all roughly the same radius regardless of mass (Fortney et al., 2007). Taken together, these arguments mean that in the habitable zone (HZ) minimum EGP luminosity (proportional to R2T4) is nearly independent of mass and age. We show that this has exciting implications for the thermal-infrared (IR) detectability of EGPs in the HZs of older stars. Similar arguments apply to visible wavelengths as well: in the HZ water clouds significantly increase geometric albedo making EGPs very bright in reflected light. The high performance of second generation adaptive secondary AO systems, employed at the LBT and Magellan, has allowed us to begin searching for EGPs in the HZs of nearby bright stars with current telescopes. The coming generation of giant telescopes will allow us to expand this search to many more stars. Here we present detailed calculations of EGP detectability in the HZ in both the thermal IR and in reflected visible light, describe our observing strategy, and present preliminary results of our search. We also discuss the future of direct imaging in the HZ with giant telescoes.

Males, J. R.; Close, L. M.; Guyon, O.; Barman, T. S.

2014-03-01

123

International Deep Planet Survey, 317 stars to determine the wide-separated planet frequency  

NASA Astrophysics Data System (ADS)

Since 2000, more than 300 nearby young stars were observed for the International Deep Planet Survey with adaptive optics systems at Gemini (NIRI/NICI), Keck (Nirc2), and VLT (Naco). Massive young AF stars were included in our sample whereas they have generally been neglected in first generation surveys because the contrast and target distances are less favorable to image substellar companions. The most significant discovery of the campaign is the now well-known HR 8799 multi-planet system. This remarkable finding allows, for the first time, an estimate of the Jovians planet population at large separations (further than a few AUs) instead of deriving upper limits. During my presentation, I will present the survey showing images of multiple stars and planets. I will then propose a statistic study of the observed stars deriving constraints on the Jupiter-like planet frequency at large separations.

Galicher, R.; Marois, C.; Macintosh, B.; Zuckerman, B.; Song, I.; Barman, T.; Patience, J.

2013-09-01

124

Gemini Detective  

NSDL National Science Digital Library

A collaborative effort of the laboratories of Dr. Judith Brown (University of Arizona) and Dr. Stephen D. Wyatt (Washington State University), this Website serves as a hub of information on whitefly-transmitted geminiviruses in the genus Begomoviridae. Resources provided at the site include Begomovirus descriptive information (general information; worldwide distribution; a hyperlinked list of Begomovirus; and a searchable database of begomovirus isolates by geographic location, virus/ isolate name, symptom, and host) and Core Coat Protein Sequence Database (including PCR sequence technical information and Mini-Blast search). In addition to text, several small color images provide illustrations of the effect (symptoms) of geminivirus-related disease on hosts.

125

Gemini 8-m telescopes  

NASA Astrophysics Data System (ADS)

The paper briefly reviews the scientific rational and scientific systems approach used by the Gemini 8M Telescopes Project in the design, construction and operations of the Gemini telescopes. We report on the progress of the telescopes on both Mauna Kea, Hawaii and Cerro Pachon Chile, give an updated schedule and describe some of the science operations concepts and planning that is going into the Gemini Observatory. In addition, at the end of this paper we give a full bibliography of Gemini papers presented at the numerous sessions of the 1998 SPIE meeting in Kona.

Mountain, C. Matt; Gillett, Fred C.; Oschmann, Jim M.

1998-08-01

126

Eighth-Order Image Masks for Terrestrial Planet Finding  

E-print Network

We describe a new series of band-limited image masks for coronagraphy that are insensitive to pointing errors and other low-spatial-frequency optical aberrations. For a modest cost in throughput, these ``eighth-order'' masks would allow the Terrestrial Planet Finder Coronagraph (TPF-C) to operate with a pointing accuracy no better than that of the Hubble Space Telescope. We also provide eighth-order notch filter masks that offer the same robustness to pointing errors combined with more manageable construction tolerances: binary masks and graded masks with moderate optical density requirements.

Marc J. Kuchner; Justin Crepp; Jian Ge

2005-05-02

127

The Gemini NICI Planet-finding Campaign: Discovery of a Substellar L Dwarf Companion to the Nearby Young M Dwarf CD35 2722  

Microsoft Academic Search

We present the discovery of a wide (67 AU) substellar companion to the nearby (21 pc) young solar-metallicity M1 dwarf CD-35 2722, a member of the ≈100 Myr AB Doradus association. Two epochs of astrometry from the NICI Planet-Finding Campaign confirm that CD-35 2722 B is physically associated with the primary star. Near-IR spectra indicate a spectral type of L4±1

Zahed Wahhaj; Michael C. Liu; Beth A. Biller; Fraser Clarke; Eric L. Nielsen; Laird M. Close; Thomas L. Hayward; Eric E. Mamajek; Michael Cushing; Trent Dupuy; Matthias Tecza; Niranjan Thatte; Mark Chun; Christ Ftaclas; Markus Hartung; I. Neill Reid; Evgenya L. Shkolnik; Silvia H. P. Alencar; Pawel Artymowicz; Alan Boss; Elisabethe de Gouveia Dal Pino; Jane Gregorio-Hetem; Shigeru Ida; Marc Kuchner; Douglas N. C. Lin; Douglas W. Toomey

2011-01-01

128

Project Gemini: A Chronology  

NSDL National Science Digital Library

This internet version of an historical NASA (National Aeronautics and Space Administration) publication contains information about Project Gemini, which laid the groundwork for the Apollo missions. The history of this project is told in three parts. Part I, Concept and Design, discusses the formal initiation of Project Gemini (first designated the Mercury Mark II project). Part II, Chronology, Development and Qualification, spans the years 1963 and 1964 when the main task became translating Gemini designs into working machinery reliable enough for manned space flight. Part III, Flight Tests, chronicles the events of 1965 and 1966, dominated by the 10 manned missions which constitute the main part of the Gemini program. To round out this volume, there are several appendices which summarize, tabulate, and make easily accessible some major aspects of Project Gemini.

James Grimwood

129

Image Retrieval of Earth-like Planets from Light Curves  

NASA Astrophysics Data System (ADS)

Surface environment of habitable exoplanets will be important for astrobiologists on exoplanets in near future. Diverse surface environments on the Earth including continents, ocean, and meteorological condition (clouds and rains) serve as the backbone of biodiversity. One of the promising approaches to know the landscape of the terrestrial exoplanets is to use scattered light of the planet through direct imaging. Since spin rotation and orbital revolution change illuminating area on planetary surface and cause time variation to disk-integrated brightness, light curves carry spatial information on the planetary surface. We propose an inversion technique of annual reflected light curves to sketch a two-dimensional albedo map of exoplanets, named the spin-orbit tomography (SOT). Applying the SOT to realistic simulations of the reflected light of an Earth-twin, we demonstrate how the SOT works. The mean cloud and continental distributions can be roughly obtained with single band photometry and difference of two-bands photometry, respectively. The SOT retrieves the planetary image without actually resolving the planet, which can be used to know the habitat of the exoplanets in near future.

Kawahara, Hajime; Fujii, Yuka

2014-04-01

130

MEMS-based extreme adaptive optics for planet detection  

SciTech Connect

The next major step in the study of extrasolar planets will be the direct detection, resolved from their parent star, of a significant sample of Jupiter-like extrasolar giant planets. Such detection will open up new parts of the extrasolar planet distribution and allow spectroscopic characterization of the planets themselves. Detecting Jovian planets at 5-50 AU scale orbiting nearby stars requires adaptive optics systems and coronagraphs an order of magnitude more powerful than those available today--the realm of ''Extreme'' adaptive optics. We present the basic requirements and design for such a system, the Gemini Planet Imager (GPI.) GPI will require a MEMS-based deformable mirror with good surface quality, 2-4 micron stroke (operated in tandem with a conventional low-order ''woofer'' mirror), and a fully-functional 48-actuator-diameter aperture.

Macintosh, B A; Graham, J R; Oppenheimer, B; Poyneer, L; Sivaramakrishnan, A; Veran, J

2005-11-18

131

Imaging exo-solar planetary systems with Terrestrial Planet Finder  

NASA Astrophysics Data System (ADS)

The concept of building a space based telescope capable of directly imaging extra-solar planetary systems has been in existence for more than a decade. While the basic ideas of how such an instrument might work have already been discussed in the literature, specific details of the design have not been addressed that will enable a telescope of this class to be functionally realized. A straw man configuration of the instrument is examined here for its ability to acquire data of sufficient informational content and quality to produce images and spectra of distant planetary systems and to find what technical problems arise from analyzing the interferograms it delivers. Computer programs that simulate the signals expected to be produced by a structurally connected instrument (SCI) version of Terrestrial Planet Finder (TPF) and reconstruct images from those signals will be presented along with programs that extract planetary parameters. An abbreviated radiometric performance analysis will also be provided that will assist astronomers in designing an appropriate mission.

Eatchel, Andrew Lynn

132

ONE-SIDED ACHROMATIC PHASE APODIZATION FOR IMAGING OF EXTRASOLAR PLANETS Weidong Yang and Alexander B. Kostinski  

E-print Network

ONE-SIDED ACHROMATIC PHASE APODIZATION FOR IMAGING OF EXTRASOLAR PLANETS Weidong Yang and Alexander to direct imaging of extrasolar planets: one-sided phase apodization. It is based on a discovery suppression sufficient for imaging of extrasolar planets. Calculations with specific square-pupil (side D

Kostinski, Alex

133

High-Resolution Multi-Band Imaging for Validation and Characterization of Small Kepler Planets  

NASA Astrophysics Data System (ADS)

High-resolution ground-based optical speckle and near-infrared adaptive optics images are taken to search for stars in close angular proximity to host stars of candidate planets identified by the NASA Kepler Mission. Neighboring stars are a potential source of false positive signals. These stars also blend into Kepler light curves, affecting estimated planet properties, and are important for an understanding of planets in multiple star systems. Deep images with high angular resolution help to validate candidate planets by excluding potential background eclipsing binaries as the source of the transit signals. A study of 18 Kepler Object of Interest stars hosting a total of 28 candidate and validated planets is presented. Validation levels are determined for 18 planets against the likelihood of a false positive from a background eclipsing binary. Most of these are validated at the 99% level or higher, including five newly validated planets in two systems: Kepler-430 and Kepler-431. The stellar properties of the candidate host stars are determined by supplementing existing literature values with new spectroscopic characterizations. Close neighbors of seven of these stars are examined using multi-wavelength photometry to determine their nature and influence on the candidate planet properties. Most of the close neighbors appear to be gravitationally bound secondaries, while a few are best explained as closely co-aligned field stars. Revised planet properties are derived for each candidate and validated planet, including cases where the close neighbors are the potential host stars.

Everett, Mark E.; Barclay, Thomas; Ciardi, David R.; Horch, Elliott P.; Howell, Steve B.; Crepp, Justin R.; Silva, David R.

2015-02-01

134

ATMOSPHERIC DYNAMICS OF BROWN DWARFS AND DIRECTLY IMAGED GIANT PLANETS  

SciTech Connect

A variety of observations provide evidence for vigorous motion in the atmospheres of brown dwarfs and directly imaged giant planets. Motivated by these observations, we examine the dynamical regime of the circulation in the atmospheres and interiors of these objects. Brown dwarfs rotate rapidly, and for plausible wind speeds, the flow at large scales will be rotationally dominated. We present three-dimensional, global, numerical simulations of convection in the interior, which demonstrate that at large scales, the convection aligns in the direction parallel to the rotation axis. Convection occurs more efficiently at high latitudes than low latitudes, leading to systematic equator-to-pole temperature differences that may reach ?1 K near the top of the convection zone. The interaction of convection with the overlying, stably stratified atmosphere will generate a wealth of atmospheric waves, and we argue that, as in the stratospheres of planets in the solar system, the interaction of these waves with the mean flow will cause a significant atmospheric circulation at regional to global scales. At large scales, this should consist of stratified turbulence (possibly organizing into coherent structures such as vortices and jets) and an accompanying overturning circulation. We present an approximate analytic theory of this circulation, which predicts characteristic horizontal temperature variations of several to ?50 K, horizontal wind speeds of ?10-300 m s{sup –1}, and vertical velocities that advect air over a scale height in ?10{sup 5}-10{sup 6} s. This vertical mixing may help to explain the chemical disequilibrium observed on some brown dwarfs. Moreover, the implied large-scale organization of temperature perturbations and vertical velocities suggests that near the L/T transition, patchy clouds can form near the photosphere, helping to explain recent observations of brown-dwarf variability in the near-IR.

Showman, Adam P. [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Boulevard, Tucson, AZ 85721 (United States); Kaspi, Yohai, E-mail: showman@lpl.arizona.edu [Center for Planetary Science, Weizmann Institute of Science, Rehovot (Israel)

2013-10-20

135

Design and Verification of External Occulters for Direct Imaging of Extrasolar Planets  

NASA Technical Reports Server (NTRS)

An occulter is an optical element which is placed in front of the telescope to block most of the light from a star before it reaches the optics inside, without blocking the planet.In our case, we use two spacecraft ying in formation: First has its edge shaped to cancel the starlight Second is the telescope which images the star and planet

Cady, Eric

2011-01-01

136

Recent progress on external occulter technology for imaging exosolar planets  

NASA Astrophysics Data System (ADS)

Imaging planets orbiting nearby stars requires a system for suppressing the host starlight by at least ten orders of magnitude. One such approach uses an external occulter, a satellite flying far from the telescope and employing a large screen, or starshade, to suppress the incoming starlight. This trades the added complexity of building the precisely shaped starshade and flying it in formation against simplifications in the telescope since extremely precise wavefront control is no longer necessary. Much progress has been made recently in designing, testing and manufacturing starshade technology. In this paper we describe the design of starshades and report on recent accomplishments in manufacturing and measuring a prototype occulter petal as part of NASA's first Technology Development for Exoplanet Missions (TDEM) program. We demonstrate that the as-built petal is consistent with a full-size occulter achieving better than 10-10 contrast. We also discuss laboratory testing at the Princeton Occulter Testbed. These experiments use sub-scale, long-distance beam propagation to verify the diffraction analysis associated with occulter starlight suppression. We demonstrate roughly 10-10 suppression in the laboratory and discuss the important challenges and limitations.

Kasdin, N. J.; Vanderbei, R. J.; Sirbu, D.; Samuels, J.; Shaklan, S.; Lisman, D.; Thomson, M.; Cady, E.; Martin, S.

137

Deep Near-Infrared Imaging of a Field in the Outer Disk of M82 with the ALTAIR Adaptive Optics System on Gemini North  

E-print Network

Deep H and K' images, recorded with the ALTAIR adaptive optics system and NIRI imager on Gemini North, are used to probe the red stellar content in a field with a projected distance of 1 kpc above the disk plane of the starburst galaxy M82. The data have an angular resolution of 0.08 arcsec FWHM, and individual AGB and RGB stars are resolved. The AGB extends to at least 1.7 mag in K above the RGB-tip, which occurs at K = 21.7. The relative numbers of bright AGB stars and RGB stars are consistent with stellar evolution models, and one of the brightest AGB stars has an H-K color and K brightness that is consistent with it being a C star. The brightnesses of the AGB stars suggest that they formed during intermediate epochs, possibily after the last major interaction with M81. Therefore, star formation in M82 during intermediate epochs may not have been restricted to the plane of the disk.

Davidge, T J; Rigaut, F; Veran, J P; Herriot, G

2003-01-01

138

Deep Near-Infrared Imaging of a Field in the Outer Disk of M82 with the ALTAIR Adaptive Optics System on Gemini North  

E-print Network

Deep H and K' images, recorded with the ALTAIR adaptive optics system and NIRI imager on Gemini North, are used to probe the red stellar content in a field with a projected distance of 1 kpc above the disk plane of the starburst galaxy M82. The data have an angular resolution of 0.08 arcsec FWHM, and individual AGB and RGB stars are resolved. The AGB extends to at least 1.7 mag in K above the RGB-tip, which occurs at K = 21.7. The relative numbers of bright AGB stars and RGB stars are consistent with stellar evolution models, and one of the brightest AGB stars has an H-K color and K brightness that is consistent with it being a C star. The brightnesses of the AGB stars suggest that they formed during intermediate epochs, possibily after the last major interaction with M81. Therefore, star formation in M82 during intermediate epochs may not have been restricted to the plane of the disk.

T. J. Davidge; J. Stoesz; F. Rigaut; J-P Veran; G. Herriot

2003-12-10

139

Probing the Impact of Stellar Duplicity on Planet Occurrence with Spectroscopic and Imaging Observations  

E-print Network

Although it is commonly agreed that the presence of a close stellar companion is likely to affect planet formation and evolution, the precise effects and their actual impact on planet occurrence and properties are still debated. In particular, observational constraints are sparse, a consequence of the discrimination against close binaries in Doppler planet searches. To bring observational constraints on the occurrence and properties of planets in binaries and multiple stars, we have been conducting two dedicated observing programs using both adaptive optics imaging and radial-velocity monitoring. In this chapter we explain our approach and present preliminary results from these two programs. A simplified statistical analysis of the data from our VLT/NACO imaging survey brings the first observational evidence that the occurrence of planets is reduced in binaries closer than ~120 AU. On the radial-velocity side, current results confirm that the use of two-dimensional correlation allows to search for circumprimary giant planets in many types of spectroscopic binaries. Definitive results from our ongoing planet search in spectroscopic binaries should yield important constraints on the closest binaries susceptible of hosting circumprimary giant planets.

A. Eggenberger; S. Udry

2007-05-22

140

Drag-o-llision Models of Extrasolar Planets in Debris Disks  

NASA Technical Reports Server (NTRS)

An extrasolar planet sculpts the famous debris disk around Fomalhaut; probably many other debris disks contain planets that we could locate if only we could better recognize their signatures in the dust that surrounds them. But the interaction between planets and debris disks involves both orbital resonances and collisions among grains and rocks in the disks---difficult processes to model simultaneously. The author describes new 3-D models of debris disk dynamics, Drag-o-llision models, that incorporate both collisions and resonant trapping of dust for the first time. The author also discusses the implications of these models for coronagraphic imaging with Gemini and other telescopes.

Kuchner, Marc

2009-01-01

141

Unveiling Uranus' Clouds: New Observations From Gemini-North NIFS And NIRI  

NASA Astrophysics Data System (ADS)

Observations of Uranus were made in September 2009 with the Gemini-North telescope in Hawaii, using both the NIFS and NIRI instruments. Adaptive optics were used to achieve a spatial resolution of approximately 0.1 arcsec. NIRI images were recorded with three spectral filters to constrain the overall appearance of the planet: J, H-continuum and CH4(long), and long slit spectra (1.49 to 1.79 microns) were obtained with the slit aligned on Uranus’ central meridian. In addition, the NIFS instrument was used to acquire spectra from other points on the planet, stepping the NIFS 3 x 3 arcsec field of view across Uranus’ disc. These observations were combined to yield complete images of Uranus at 2040 wavelengths between 1.476 and 1.803 microns with a spectral resolution of 5000. The observed spectra along Uranus central meridian were analyzed with the NEMESIS retrieval tool and used to infer the vertical/latitudinal variation in cloud optical depth. We find that the 2009 Gemini data perfectly complement our observations/conclusions from UKIRT/UIST observations made in 2006-2008 and show that the north polar zone at 45N has continued to steadily brighten while that at 45S has continued to fade. The improved spatial resolution of the Gemini observations compared with the non-AO UKIRT/UIST data remove many of the earlier ambiguities inherent in the previous analysis. Overall, Uranus appeared to be less convectively active in 2009 than in the previous 3 years, which suggests that now the equinox (which occurred in 2007) is over the atmosphere is settling back into the quiescent state seen by Voyager 2 in 1986. However, one discrete cloud was captured in the NIFS observations and was estimated to lie at a pressure level of 300-400 mbar.

Irwin, Patrick G. J.; Teanby, N. A.; Davis, G. R.; Fletcher, L. N.; Orton, G.; Tice, D.

2010-10-01

142

Observations of Mars and its satellites by the Mars Imaging Camera (MIC) on Planet-B  

Microsoft Academic Search

We present the specifications of the Mars Imaging Camera (MIC) on the Planet-B spin-stabilized spacecraft, and key scientific objectives of MIC observations. A non-sun-synchronous orbit of Planet-B with a large eccentricity of about 0.87 around Mars provides the opportunities (1) to observe the same region of Mars at various times of day and various solar phase angles with spatial resolution

Tadashi Mukai; Tokuhide Akabane; Tatsuaki Hashimoto; Hiroshi Ishimoto; Sho Sasaki; A. Inada; Anthony Toigo; Masato Nakamura; Yutaka Abe; Kei Kurita; Takeshi Imamura

1998-01-01

143

Imaging Extrasolar Planets by Stellar Halo Suppression in Separately Corrected Color Bands  

Microsoft Academic Search

Extrasolar planets have not been imaged directly with existing ground or space telescopes because they are too faint to be seen against the halo of the nearby bright star. Most techniques being explored to suppress the halo are achromatic, with separate correction of diffraction and wave-front errors. Residual speckle structure may be subtracted by differencing images taken through narrowband filters,

Johanan L. Codona; Roger Angel

2004-01-01

144

High-Contrast Imaging using Adaptive Optics for Extrasolar Planet Detection  

SciTech Connect

Direct imaging of extrasolar planets is an important, but challenging, next step in planetary science. Most planets identified to date have been detected indirectly--not by emitted or reflected light but through the effect of the planet on the parent star. For example, radial velocity techniques measure the doppler shift in the spectrum of the star produced by the presence of a planet. Indirect techniques only probe about 15% of the orbital parameter space of our solar system. Direct methods would probe new parameter space, and the detected light can be analyzed spectroscopically, providing new information about detected planets. High contrast adaptive optics systems, also known as Extreme Adaptive Optics (ExAO), will require contrasts of between 10{sup -6} and 10{sup -7} at angles of 4-24 {lambda}/D on an 8-m class telescope to image young Jupiter-like planets still warm with the heat of formation. Contrast is defined as the intensity ratio of the dark wings of the image, where a planet might be, to the bright core of the star. Such instruments will be technically challenging, requiring high order adaptive optics with > 2000 actuators and improved diffraction suppression. Contrast is ultimately limited by residual static wavefront errors, so an extrasolar planet imager will require wavefront control with an accuracy of better than 1 nm rms within the low- to mid-spatial frequency range. Laboratory demonstrations are critical to instrument development. The ExAO testbed at the Laboratory for Adaptive Optics was designed with low wavefront error and precision optical metrology, which is used to explore contrast limits and develop the technology needed for an extrasolar planet imager. A state-of-the-art, 1024-actuator micro-electrical-mechanical-systems (MEMS) deformable mirror was installed and characterized to provide active wavefront control and test this novel technology. I present 6.5 x 10{sup -8} contrast measurements with a prolate shaped pupil and flat mirror demonstrating that the testbed can operate in the necessary contrast regime. Wavefront measurements and simulations indicate that contrast is limited by wavefront error, not diffraction. I demonstrate feasibility of the MEMS deformable mirror for meeting the stringent residual wavefront error requirements of an extrasolar planet imager with closed-loop results of 0.54 nm rms within controllable spatial frequencies. Individual contributors to final wavefront quality have been identified and characterized. I also present contrast measurements of 2 x 10{sup -7} made with the MEMS device and identify amplitude errors as the limiting error source. Closed-loop performance and simulated far-field measurements using a Kolmogorov phase plate to introduce atmosphere-like optical errors are also presented.

Evans, J W

2006-08-18

145

Direct Imaging of Jupiter and Saturn-mass planets in wide orbit around nearby young stars  

NASA Astrophysics Data System (ADS)

The recent discovery of planetary-mass objects on very wide orbits (hundreds of AU and more) around young stars (e.g. Naud et al. 2014) demonstrates that planets can be found even with arcsecond-level resolution imaging. These massive ( 10MJup) companions are likely formed in-situ via hierarchical collapse and it is not yet known whether this mechanism can form lighter objects. However, dynamical modelling of young planetary systems (Veras et al. 2009) and the relatively large fraction of massive planets in eccentric orbits found by radial velocity surveys suggest that a few percent of planetary systems should host planets, comparable in mass to Jupiter and Saturn, on orbits wide enough to be imaged as isolated objects. We propose to obtain deep IRAC observations combined with J-band imaging gathered by our team to search for such planets around all known nearby young stars (< 70 pc, < 120Myr; 172 stellar systems). This survey will be sensitive to planets down to the mass of Jupiter for all systems and down to the mass of Saturn for 80 of them. Planets lighter than 2MJup are much too faint in the near-infrared to be identified from the ground; Spitzer is the only facility where such a survey can be undertaken. This survey is a unique opportunity to bring direct imaging in a new era with the detection of analogs to our own Solar System Giants, is complementary to the work done on the ground with high-contrast imagers such as GPI and Sphere, and is critical to identify new planets that will be optimally characterized with JWST.

Artigau, Etienne; Lafreniere, David; Baron, Frederique; Malo, Lison; Doyon, Rene; Beichman, Charles; Delorme, Philippe; Rameau, Julien; Janson, Markus; Gagne, Jonathan; Naud, Marie-Eve; Albert, Loic

2014-12-01

146

Insignia of the Gemini 9 space flight  

NASA Technical Reports Server (NTRS)

Ensignia of the Gemini 9 space flight. Roman numeral indicates ninth flight in the Gemini series. Two spacecraft symbolize rendezvous and docking of Gemini with Agena. Astronaut and umbilical (tether) line denotes planned extravehicular activity.

1966-01-01

147

A multi-wavelength study of the 2009 impact on Jupiter: Comparison of high resolution images from Gemini, Keck and HST  

NASA Astrophysics Data System (ADS)

Within several days of A. Wesley's announcement that Jupiter was hit by an object on UT 19 July 2009, we observed the impact site with (1) the Hubble Space Telescope (HST) at UV through visible (225-924 nm) wavelengths, (2) the 10-m W.M. Keck II telescope in the near-infrared (1-5 ?m), and (3) the 8-m Gemini-North telescope in the mid-infrared (7.7-18 ?m). All observations reported here were obtained between 22 and 25 July 2009. Observations at visible and near-infrared wavelengths show that large (˜0.75-?m radius) dark (imaginary index of refraction mi ˜ 0.01-0.1) particulates were deposited at atmospheric pressures between 10 and 200-300 mbar; analysis of HST-UV data reveals that in addition smaller-sized (˜0.1 ?m radius) material must have been deposited at the highest altitudes (˜10 mbar). Differences in morphology between the UV and visible/near-IR images suggest three-dimensional variations in particle size and density across the impact site, which probably were induced during the explosion and associated events. At mid-infrared wavelengths the brightness temperature increased due to both an enhancement in the stratospheric NH 3 gas abundance and the physical temperature of the atmosphere. This high brightness temperature coincides with the center part of the impact site as seen with HST. This observation, combined with (published) numerical simulations of the Shoemaker-Levy 9 impacts on Jupiter and the Tunguska airburst on Earth, suggests that the downward jet from the terminal explosion probably penetrated down to the ˜700-mbar level.

de Pater, Imke; Fletcher, Leigh N.; Pérez-Hoyos, Santiago; Hammel, Heidi B.; Orton, Glenn S.; Wong, Michael H.; Luszcz-Cook, Statia; Sánchez-Lavega, Agustin; Boslough, Mark

2010-12-01

148

THE SEEDS DIRECT IMAGING SURVEY FOR PLANETS AND SCATTERED DUST EMISSION IN DEBRIS DISK SYSTEMS  

SciTech Connect

Debris disks around young main-sequence stars often have gaps and cavities which for a long time have been interpreted as possibly being caused by planets. In recent years, several giant planet discoveries have been made in systems hosting disks of precisely this nature, further implying that interactions with planets could be a common cause of such disk structures. As part of the SEEDS high-contrast imaging survey, we are surveying a population of debris-disk-hosting stars with gaps and cavities implied by their spectral energy distributions, in order to attempt to spatially resolve the disk as well as to detect any planets that may be responsible for the disk structure. Here, we report on intermediate results from this survey. Five debris disks have been spatially resolved, and a number of faint point sources have been discovered, most of which have been tested for common proper motion, which in each case has excluded physical companionship with the target stars. From the detection limits of the 50 targets that have been observed, we find that {beta} Pic b-like planets ({approx}10 M{sub jup} planets around G-A-type stars) near the gap edges are less frequent than 15%-30%, implying that if giant planets are the dominant cause of these wide (27 AU on average) gaps, they are generally less massive than {beta} Pic b.

Janson, Markus; Brandt, Timothy D. [Department of Astrophysical Sciences, Princeton University, NJ 08544 (United States); Moro-Martin, Amaya [Department of Astrophysics, CAB (INTA-CSIC), Instituto Nacional de Tecnica Aerospacial, Torrejonde Ardoz, E-28850 Madrid (Spain); Usuda, Tomonori; Kudo, Tomoyuki; Egner, Sebastian [Subaru Telescope, 650 North Aohoku Place, Hilo, HI 96720 (United States); Thalmann, Christian [Astronomical Institute ''Anton Pannekoek'', University of Amsterdam, Science Park 904, 1098-XH Amsterdam (Netherlands); Carson, Joseph C. [Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States); Goto, Miwa [Universitaets-Sternwarte Muenchen, Ludwig-Maximilians-Universitaet, Scheinerstr. 1, D-81679 Munich (Germany); Currie, Thayne [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, M5S 3H4 Toronto, ON (Canada); McElwain, M. W. [Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 2071 (United States); Itoh, Yoichi [Nishi-Harima Astronomical Observatory, Center for Astronomy, University of Hyogo, 407-2 Nishigaichi, Sayo, Hyogo 679-5313 (Japan); Fukagawa, Misato [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Crepp, Justin [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Kuzuhara, Masayuki; Hashimoto, Jun; Kusakabe, Nobuhiko [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Abe, Lyu [Laboratoire Lagrange, UMR7239, University of Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, F-06300 Nice (France); Brandner, Wolfgang; Feldt, Markus, E-mail: janson@astro.princeton.edu [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); and others

2013-08-10

149

The SEEDS Direct Imaging Survey for Planets and Scattered Dust Emission in Debris Disk Systems  

NASA Technical Reports Server (NTRS)

Debris disks around young main-sequence stars often have gaps and cavities which for a long time have been interpreted as possibly being caused by planets. In recent years, several giant planet discoveries have been made in systems hosting disks of precisely this nature, further implying that interactions with planets could be a common cause of such disk structures. As part of the SEEDS high-contrast imaging survey, we are surveying a population of debris disk-hosting stars with gaps and cavities implied by their spectral energy distributions, in order to attempt to spatially resolve the disk as well as to detect any planets that may be responsible for the disk structure. Here we report on intermediate results from this survey. Five debris disks have been spatially resolved, and a number of faint point sources have been discovered, most of which have been tested for common proper motion, which in each case has excluded physical companionship with the target stars. From the detection limits of the 50 targets that have been observed, we find that beta Pic b-like planets (approximately 10M(sub jup) planets around G-A-type stars) near the gap edges are less frequent than 15-30%, implying that if giant planets are the dominant cause of these wide (27 AU on average) gaps, they are generally less massive than beta Pic b.

Janson, Markus; Brandt, Timothy; Moro-Martin, Amaya; Usuda, Tomonori; Thalmann, Christian; Carson, Joseph C.; Goto, Miwa; Currie, Thayne; McElwain, M. W.; Itoh, Yoichi; Fukagawa, Misato; Crepp, Justin; Kuzuhara, Masayuki; Hashimoto, Jun; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Abe, Lyu; Brandner, Wolfgang; Egner, Sebastian; Fedlt, Markus; Grady, Carol A.; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiro; Hayashi, Saeko

2013-01-01

150

Direct imaging search for planets around low-mass stars and spectroscopic characterization of young exoplanets  

NASA Astrophysics Data System (ADS)

Low--mass stars between 0.1--0.6 M? are the most abundant members our galaxy and may be the most common sites of planet formation, but little is known about the outer architecture of their planetary systems. We have carried out a high-contrast adaptive imaging search for gas giant planets between 1--13 MJup around 122 newly identified young M dwarfs in the solar neighborhood ( ? 35 pc). Half of our targets are younger than 145 Myr, and 90% are younger than 580 Myr. After removing 39 resolved stellar binaries, our homogeneous sample of 83 single young M dwarfs makes it the largest imaging search for planets around low--mass stars to date. Our H- and K- band coronagraphic observations with Subaru/HiCIAO and Keck/NIRC2 achieve typical contrasts of 9--13 mag and 12--14 mag at 100, respectively, which corresponds to limiting masses of ˜1--10 M Jup at 10--30 AU for most of our sample. We discovered four brown dwarfs with masses between 25--60 MJup at projected separations of 4--190 AU. Over 100 candidate planets were discovered, nearly all of which were found to be background stars from follow-up second epoch imaging. Our null detection of planets nevertheless provides strong statistical constraints on the occurrence rate of giant planets around M dwarfs. Assuming circular orbits and a logarithmically-flat power law distribution in planet mass and semi--major axis of the form d 2N=(dloga dlogm) infinity m0 a0, we measure an upper limit (at the 95% confidence level) of 8.8% and 12.6% for 1--13 MJup companions between 10--100 AU for hot start and cold start evolutionary models, respectively. For massive gas giant planets in the 5--13 M Jup range like those orbiting HR 8799, GJ 504, and beta Pictoris, we find that fewer than 5.3% (7.8%) of M dwarfs harbor these planets between 10--100 AU for a hot start (cold start) formation scenario. Our best constraints are for brown dwarf companions; the frequency of 13--75 MJup companions between (de--projected) physical separations of 10--100 AU is 2.1+2.1-1.2 %. Altogether, our results show that gas giant planets, especially massive ones, are rare in the outskirts of M dwarf planetary systems. If disk instability is a viable way to form planets, our constraints for the most common type of star imply that overall it is an inefficient mechanism.

Bowler, Brendan Peter

151

ON THE MISALIGNMENT OF THE DIRECTLY IMAGED PLANET {beta} PICTORIS b WITH THE SYSTEM'S WARPED INNER DISK  

SciTech Connect

The vertical warp in the debris disk {beta} Pictoris-an inclined inner disk extending into a flat outer disk-has long been interpreted as the signpost of a planet on an inclined orbit. Direct images spanning 2004-2010 have revealed {beta} Pictoris b, a planet with a mass and orbital distance consistent with this picture. However, it was recently reported that the orbit of planet b is aligned with the flat outer disk, not the inclined inner disk, and thus lacks the inclination to warp the disk. We explore three scenarios for reconciling the apparent misalignment of the directly imaged planet {beta} Pictoris b with the warped inner disk of {beta} Pictoris: observational uncertainty, an additional planet, and damping of planet b's inclination. We find that, at the extremes of the uncertainties, the orbit of {beta} Pictoris b has the inclination necessary to produce the observed warp. We also find that if planet b were aligned with the flat outer disk, it would prevent another planet from creating a warp with the observed properties; therefore planet b itself must be responsible for the warp. Finally, planet b's inclination could have been damped by dynamical friction and still produce the observed disk morphology, but the feasibility of damping depends on disk properties and the presence of other planets. More precise observations of the orbit of planet b and the position angle of the outer disk will allow us to distinguish between the first and third scenarios.

Dawson, Rebekah I.; Murray-Clay, Ruth A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fabrycky, Daniel C., E-mail: rdawson@cfa.harvard.edu [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)

2011-12-10

152

Changes and improvements to the Gemini North Aircraft Avoidance Program at the Gemini North Laser Guide Star facility on Mauna Kea  

Microsoft Academic Search

Since March 2005 Gemini North Observatory routinely propagates a 12W solid state sodium laser into the night sky as part of Adaptive Optics imaging on dimmer portions of the celestial sphere. Gemini along with Keck and Subaru telescopes have created aircraft spotting programs to meet the FAA's rules for aircraft avoidance for outdoor laser propagation. This paper reviews the GN

Jon Archambeau; Richard Oram; Michael Sheehan

2010-01-01

153

Hubble Takes First Image of a Possible Planet Around Another Star and Finds a Runaway World  

NSDL National Science Digital Library

The Hubble Space Telescope has returned an image of what is possibly the first planet outside our solar system. TMR-1C, about 450 light years away in the constellation Taurus, appears to have been "flung away from the vicinity of a newly forming pair of binary stars," as evidenced by a luminescent filament leading from the "planet" back to the stars. "Susan Terebey of the Extrasolar Research Corporation in Pasadena, California, and her team using Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS)," made the discovery. Hubble experts estimate the chance of the object being a background star instead of a planet at one to two percent. This Space Science Telescope Institute site contains the press release, captioned images in several formats and resolutions, and a space science update, a one hour RealPlayer press conference with Dr. Terebey and other astronomers.

1998-01-01

154

High-Contrast Near-Infrared Imaging and Modeling of Planets and Debris Disks  

NASA Astrophysics Data System (ADS)

Planets are thought to form in circumstellar disks, leaving behind planetesimals that collide to produce dusty debris disks. Characterizing the architectures of planetary systems, along with the structures and compositions of debris disks, can therefore help answer questions about how planets form. In this talk, I will present the results of five papers concerning the properties of extrasolar planetary systems and their circumstellar environments. First I will discuss bias affecting radial velocity (RV) orbital eccentricity. For years astronomers have been puzzled about the large number of RV-detected planets that have eccentric orbits (e > 0.1). I will show that this problem can partially be explained by showing that two circular-orbit planets can masquerade as a single planet on an eccentric orbit. I use this finding to predict that planets with mildly eccentric orbits are the most likely to have massive companions on wide orbits, potentially detectable by future direct imaging observations. Next I will present recent high-contrast 2-4 ?m imaging studies of the edge-on debris disks around HD 15115 and HD 32297. HD 15115’s color is found to be gray, implying large grains 1-10 ?m in size reside in stable orbits in the disk. HD 32297’s disk color is red from 1-4 ?m. Cometary material (carbon, silicates, and porous water ice) are a good match at 1-2 ?m but not at L?. Tholins, organic material that is found in outer solar system bodies, or small silicates can explain the disk’s red color but not the short wavelength data. I will then present my work on the dynamics of dust grains in the presence of massive planets. I will show that the width of a debris disk increases proportionally with the mass of its shepherding planet. I use this result to make predictions for the masses and orbits of putative planets in five well-known disks. Finally, I will present recent MagAO/Clio near-infrared imaging results on the debris disk around HR4796A spanning the 0.5-4 um wavelength range. These images reveal the disk at unprecedented detail, allowing detailed compositional and morphological modeling of the dust.

Rodigas, Timothy; Hinz, P.; Weinberger, A. J.; Close, L. M.; Debes, J. H.

2014-01-01

155

Direct imaging and spectroscopy of terrestrial planets with JWST and a starsahde  

Microsoft Academic Search

We present a study for using a starshade with the James Webb Space Telescope (JWST). This concept would enable imaging and spectroscopy of a planet similar to the Earth, the study of its habitability, and the search for signs of alien life. JWST was not specifically designed to observe with a starshade, but its instrumentation and its great sensitivity make

R. Soummer; J. Valenti; R. A. Brown; S. Seager; J. Tumlinson; W. Cash; I. Jordan; M. Postman; T. Glassman; L. Pueyo; A. Roberge

2010-01-01

156

Direct imaging and spectroscopy of habitable planets using JWST and a starshade  

Microsoft Academic Search

A starshade with the James Webb Space Telescope (JWST) is the only possible path forward in the next decade to obtain images and spectra of a planet similar to the Earth, to study its habitability, and search for signs of alien life. While JWST was not specifically designed to observe using a starshade, its near-infrared instrumentation is in principle capable

Rémi Soummer; Jeff Valenti; Robert A. Brown; Sara Seager; Jason Tumlinson; Webster Cash; Ian Jordan; Marc Postman; Tiffany Glassman; Laurent Pueyo; Aki Roberge

2010-01-01

157

Phase-induced amplitude apodization of telescope pupils for extrasolar terrestrial planet imaging  

Microsoft Academic Search

In this paper, an alternative to classical pupil apodization techniques (use of an amplitude pupil mask) is proposed. It is shown that an achromatic apodized pupil suitable for imaging of extrasolar planets can be obtained by reflection of an unapodized flat wavefront on two mirrors. By carefully choosing the shape of these two mirrors, it is possible to obtain a

Olivier Guyon

2003-01-01

158

SPHERE: exo-planets science with the new frontier of high contrast imaging  

NASA Astrophysics Data System (ADS)

ABSTRACT High contrast imaging will be the new frontier of exoplanets search providing the opportunity to have at once a deep glance in the neighborhood of the target star. In addition, coupling integral field spectrographs to extreme adaptive optics module at the focus of 8m telescope class and in future to ELTs, gives also the possibility to have a first order characterization of the exoplanets itself. SPHERE, second generation instrument for VLT, is an exo-solar planet imager, which goal is to detect giant exo-solar planets in the vicinity of bright stars and to characterize them through spectroscopic and polarimetric observations. It is a complete system with a core made of an extreme-Adaptive Optics (AO) turbulence correction, pupil tracker and interferential coronagraphs. At its back end, a differential dual imaging camera (IRDIS) and an integral field spectrograph (IFS) work in the Near Infrared (NIR) Y, J, H and Ks bands (0.95-2.32 ?m) and a high resolution polarization camera (ZIMPOL) covers the visible (0.6 - 0.9 ?m). The three instruments could work simultaneously. As matter of fact, as the instrument has been thought and designed, It should be considered more like an experiment than a typical ancillary instrumentation. The prime objective of SPHERE is the discovery and study of new planets orbiting stars by direct imaging of the circumstellar environment. The challenge consists in the very large contrast of luminosity between the star and the planet (larger than " 12.5 magnitudes or " 105 flux ratio), at very small angular separations, typically inside the seeing halo. The whole design of SPHERE is therefore optimized towards high contrast performance in a limited field of view and at short distances from the central star. Both evolved and young planetary systems will be detected, respectively through their reflected light (mostly by ZIMPOL) and through the intrinsic planet emission (IRDIS+IFS modes). Both components of the near-infrared arm of SPHERE will provide complementary detection capacities and characterization potential, in terms of field of view, contrast, and spectral domain. The number of planets expected to be detected is a very strong function of the (assumed) distribution of planet separation. Extending the semi-major axis distribution up to P=250 yr (about 40 AU) yield a number of planet detections about 3.5 larger than for the same distribution truncated at P=70 yr (about 17 AU). Several tens of planet detection (details depend on target number and selection criteria) are then expected between 20 and 40 AU if planets are there. SPHERE has clearly the potential for an accurate determination of the frequency of planets in wide orbits. Note that while giant planets are not expected to be found in large number at very wide separation (a >50-100 AU), brown dwarfs might instead be present. In this paper a brief description of the whole instrument is given. Furthermore, an analysis of the performances of the instrument with its foreseen ability in discovering and characterize warm planets is also given. Last, but not least, SPHERE and its USA counter part: GPI, open the path towards new high contrast istrumentation for ELT like EPICS.

Claudi, R.; Beuzit, J.-L.; Feldt, M.; Mouillet, D.; Dohlen, K.; Puget, P.; Wildi, F.; Baruffolo, A.; Charton, J.; Antichi, J.; Boccaletti, A.; Desidera, S.; Fusco, T.; Gratton, R.; Langlois, M.; Mesa, D.; Pragt, J.; Raboub, P.; Roelfsema, R.; Saisse, M.; Schmid, H.-M.; Turatto, M.; Moutou, C.; Henning, T.; Udry, S.; Vakili, F.; Waters, R.

2008-09-01

159

Direct and interferometric imaging approaches for detecting earth-like extrasolar planets  

NASA Technical Reports Server (NTRS)

This paper discusses functional requirements of space-based observational systems with sufficient sensitivity, resolution, and dynamic range to image earth-like extrasolar planets within a search radius of 10 parsecs from the sun. Both direct and interferometric systems operating at visible and infrared wavelengths are evaluated, and the methods used to establish the system tolerances are presented. Due to the more favorable star/planet contrast ratio in the infrared, optical tolerance requirements are less stringent than in the visible. However, reduction of thermal radiation from the telescope requires cooling of the primary optics. Other tradeoffs between various approaches are enumerated.

Diner, D. J.; Van Zyl, J.; Jones, D. L.; Tubbs, E.; Wright, V.

1988-01-01

160

Janus and Gemini Nanoplates  

NASA Astrophysics Data System (ADS)

Janus particles were used to make stable Pickering emulsions (emulsions stabilized by particles). Here we demonstrated a novel method to produce high aspect ratio Janus plates with atomic thickness. Gemini plates with only the edges functionalized are also fabricated. These novel nanoplates are observed to have super surface activity. Most importantly, these particles overcome the two opposite effects in the stabilization of Pickering emulsions using spherical particles: stabilization requires particles as small as possible; but smaller particles are easy to escape the interface due to Brownian motion since the adsorption energy to the oil-water interface is proportional to the diameter of the spheres. Our nanoplates have a large aspect ratio due to the extremely thin thickness, which offers extraordinary stability to the liquid film between two emulsions to prevent coalescence. In the meantime, their large lateral surface area offers strong adsorption energy at the oil-water interface.

Cheng, Zhengdong; Mejia, Andres; Chang, Ya-Wen; He, Peng; Diaz, Agustin; Clearfield, Abraham

2011-03-01

161

Gemini-IFU Spectroscopy of HH 111  

NASA Astrophysics Data System (ADS)

We present new optical observations of the Herbig–Haro (HH) 111 jet using the Gemini Multi Object Spectrograph in its Integral Field Unit mode. Eight fields of 5\\prime\\prime × 3\\buildrel{\\prime\\prime}\\over{.} 5 have been positioned along and across the HH 111 jet, covering the spatial region from knot E to L in HH 111 (namely, knots E, F, G, H, J, K, and L). We present images and velocity channel maps for the [O i] 6300+6360, H?, [N ii] 6548+6583, and [S ii] 6716+6730 lines, as well as for the [S ii] 6716/6730 line ratio. We find that the HH 111 jet has an inner region with lower excitation and higher radial velocity, surrounded by a broader region of higher excitation and lower radial velocity. Also, we find higher electron densities at lower radial velocities. These results imply that the HH 111 jet has a fast, axial region with lower velocity shocks surrounded by a lower velocity sheath with higher velocity shocks. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

Cerqueira, A. H.; Vasconcelos, M. J.; Raga, A. C.; Feitosa, J.; Plana, H.

2015-03-01

162

Combining high-dispersion spectroscopy with high contrast imaging: Probing rocky planets around our nearest neighbors  

NASA Astrophysics Data System (ADS)

Context. Ground-based high-dispersion (R ~ 100 000) spectroscopy (HDS) is proving to be a powerful technique with which to characterize extrasolar planets. The planet signal is distilled from the bright starlight, combining ral and time-differential filtering techniques. In parallel, high-contrast imaging (HCI) is developing rapidly, aimed at spatially separating the planet from the star. While HDS is limited by the overwhelming noise from the host star, HCI is limited by residual quasi-static speckles. Both techniques currently reach planet-star contrast limits down to ~10-5, albeit for very different types of planetary systems. Aims: In this work, we discuss a way to combine HDS and HCI (HDS+HCI). For a planet located at a resolvable angular distance from its host star, the starlight can be reduced up to several orders of magnitude using adaptive optics and/or coronography. In addition, the remaining starlight can be filtered out using high-dispersion spectroscopy, utilizing the significantly different (or Doppler shifted) high-dispersion spectra of the planet and star. In this way, HDS+HCI can in principle reach contrast limits of ~10-5 × 10-5, although in practice this will be limited by photon noise and/or sky-background. In contrast to current direct imaging techniques, such as Angular Differential Imaging and Spectral Differential Imaging, it will work well at small working angles and is much less sensitive to speckle noise. For the discovery of previously unknown planets HDS+HCI requires a high-contrast adaptive optics system combined with a high-dispersion R ~ 100 000 integral field spectrograph (IFS). This combination currently does not exist, but is planned for the European Extremely Large Telescope. Methods: We present simulations of HDS+HCI observations with the E-ELT, both probing thermal emission from a planet at infrared wavelengths, and starlight reflected off a planet atmosphere at optical wavelengths. For the infrared simulations we use the baseline parameters of the E-ELT and METIS instrument, with the latter combining extreme adaptive optics with an R = 100 000 IFS. We include realistic models of the adaptive optics performance and atmospheric transmission and emission. For the optical simulation we also assume R = 100 000 IFS with adaptive optics capabilities at the E-ELT. Results: One night of HDS+HCI observations with the E-ELT at 4.8 ?m (?? = 0.07 ?m) can detect a planet orbiting ? Cen A with a radius of R = 1.5 Rearth and a twin-Earth thermal spectrum of Teq = 300 K at a signal-to-noise (S/N) of 5. In the optical, with a Strehl ratio performance of 0.3, reflected light from an Earth-size planet in the habitable zone of Proxima Centauri can be detected at a S/N of 10 in the same time frame. Recently, first HDS+HCI observations have shown the potential of this technique by determining the spin-rotation of the young massive exoplanet ? Pictoris b. Conclusions: The exploration of the planetary systems of our neighbor stars is of great scientific and philosophical value. The HDS+HCI technique has the potential to detect and characterize temperate rocky planets in their habitable zones. Exoplanet scientists should not shy away from claiming a significant fraction of the future ELTs to make such observations possible.

Snellen, I.; de Kok, R.; Birkby, J. L.; Brandl, B.; Brogi, M.; Keller, C.; Kenworthy, M.; Schwarz, H.; Stuik, R.

2015-04-01

163

Speckle Imaging and Spectroscopy of Kepler Exo-planet Transit Candidate Stars  

NASA Astrophysics Data System (ADS)

The NASA Kepler mission was successfully launched on 6 March 2009 and has begun science operations. Commissioning tests done early on in the mission have shown that for the bright sources, 10-15 ppm relative photometry can be achieved. This level assures we will detect Earth- like transits if they are present. ``Hot Jupiter" and similar large planet candidates have already been discovered and will be discussed at the Jan. AAS meeting as well as in a special issue of Science magazine to appear near years end. The plethora of variability observed is astounding and includes a number of eclipsing binaries which appear to have Jupiter and smaller size objects as an orbiting their body. Our proposal consists of three highly related objectives: 1) To continue our highly successful speckle imaging program which is a major component of defense to weed out false positive candidate transiting planets found by Kepler and move the rest to probable or certain exo-planet detections; 2) To obtain low resolution ``discovery" type spectra for planet candidate stars in order to provide spectral type and luminosity class indicators as well as a first look triage to eliminate binaries and rapid rotators; and 3) to obtain ~1Aresolution time ordered spectra of eclipsing binaries that are exo-planet candidates in order to obtain the velocity solution for the binary star, allowing its signal to be modeled and removed from the Keck or HET exo-planet velocity search. As of this writing, Kepler has produced a list of 227 exo-planet candidates which require false positive decision tree observations. Our proposed effort performs much of the first line of defense for the mission.

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

2010-02-01

164

Beyond Kepler: Direct Imaging of Earth-like Planets  

NASA Technical Reports Server (NTRS)

Is there another Earth out there? Is there life on it? People have been asking these questions for over two thousand years, and we finally stand on the verge of answering them. The Kepler space telescope is NASA's first mission designed to study Earthlike exoplanets (exo-Earths), and it will soon tell us how often exo-Earths occur in the habitable zones of their stars. The next natural step after Kepler is spectroscopic characterization of exo-Earths, which would tell us whether they possess an atmosphere, oxygen, liquid water, as well as other biomarkers. In order to do this, directly imaging an exo-Earth may be necessary (at least for Sun-like stars). Directly imaging an exo-Earth is challenging and likely requires a flagship-size optical space telescope with an unprecedented imaging system capable of achieving contrasts of 1(exp 10) very close to the diffraction limit. Several coronagraphs and external occulters have been proposed to meet this challenge and are in development. After first overviewing the history and current state of the field, my talk will focus on the work proceeding at the Ames Coronagraph Experiment (ACE) at the NASA Ames Research Center, where we are developing the Phase Induced Amplitude Apodization (PIAA) coronagraph in a collaboration with JPL. PIAA is a powerful technique with demonstrated aggressive performance that defines the state of the art at small inner working angles. At ACE, we have achieved contrasts of 2(exp -8) with an inner working angle of 2 lambda/D and 1(exp -6) at 1.4 lambda/D. On the path to exo-Earth imaging, we are also pursuing a smaller telescope concept called EXCEDE (EXoplanetary Circumstellar Environments and Disk Explorer), which was recently selected for technology development (Category III) by NASA's Explorer program. EXCEDE will do fundamental science on debris disks as well as serve as a technological and scientific pathfinder for an exo-Earth imaging mission.

Belikov, Ruslan

2012-01-01

165

The Subaru SEEDS Direct Imaging Survey for Planets of Early-Type Stars  

NASA Astrophysics Data System (ADS)

We present results from the Subaru SEEDS sub-program to search for extrasolar planets around early-type (mostly A-type) stars. SEEDS, the Strategic Exploration of Exoplanets and Disks with Subaru, is a multi-year, direct-imaging survey to explore the link between planets and disks, and the evolution of protoplanetary systems and debris disks. With first observations carried out in 2009, the early-type star sub-program uses the Subaru 8-meter Telescope, the AO188 adaptive optics system, the HiCIAO near infrared science camera, and an Angular Differential Imaging observing procedure to distinguish faint orbiting companions from the overwhelming light of the parent star. We summarize progress to date, including the nature of our data processing techniques, improved software sensitivities, and our prior discovery of the 'Super-Jupiter' Kappa Andromedae b.

Lawson, Kellen D.; Carson, Joseph; Thalmann, Christian; Seeds Survey Team

2015-01-01

166

Imaging and Spectroscopy of Outer Planets and Their Satellites with the Spitzer Space Telescope  

NASA Astrophysics Data System (ADS)

The Spitzer Space Telescope, formerly known as SIRTF, is now operational and delivers unprecedented sensitivity for the observation of Solar System targets. Spitzer's imagers and spectrometers cover the 3.6 to 160 micron wavelength range. Guaranteed Time Observer (GTO) programs include the moons of the outer Solar System, Pluto, Centaurs, Kuiper Belt Objects, and comets. For example, the "Moons and Planets" program is now examining the principal satellites of outer Solar System planets, as well as Uranus and Neptune, using all SIRTF instruments. In our poster, we present the early results of the Spitzer Space Telescope "Moons and Planets" program, including but not limited to: 1. Photometry and derived albedos of the rings of Uranus and its principal satellites between 3.6 and 15 microns. 2. Images and spectra of Rhea, Titan, Iapetus, and Phoebe. 3. Images and spectra of Neptune and Triton, if those observations are scheduled between April 29 and the beginning of this conference. and interpretation of these data in terms of surface composition, temperature, and thermal inertia. We will also relate the data presented in item 2 to the data that will be collected by Cassini, which is due to encounter Phoebe and enter orbit around Saturn shortly after this conference. This material is based on work supported by the National Aeronautics and Space Administration under Award No. NAS7-03001, The California Institute of Technology, and Cornell University

Van Cleve, J. E.; Cruikshank, D. P.; Stansberry, J. A.; Burgdorf, M. J.; Devost, D.; Emery, J. P.; Fazio, G.; Fernandez, Y. R.; Glaccum, W.; Grillmair, C.; Houck, J. R.; Meadows, V. S.; Morris, P.; Reach, W.; Reitsema, H.; Rieke, G. H.; Werner, M. W.

2004-05-01

167

PVOL: The Planetary Virtual Observatory & Laboratory. An online database of the Outer Planets images.  

NASA Astrophysics Data System (ADS)

The collaboration between amateurs astronomers and the professional community has been fruitful on many areas of astronomy. The development of the Internet has allowed a better than ever capability of sharing information worldwide and access to other observers data. For many years now the International Jupiter Watch (IJW) Atmospheric discipline has coordinated observational efforts for long-term studies of the atmosphere of Jupiter. The International Outer Planets Watch (IOPW) has extended its labours to the four Outer Planets. Here we present the Planetary Virtual Observatory & Laboratory (PVOL), a website database where we integer IJW and IOPW images. At PVOL observers can submit their data and professionals can search for images under a wide variety of useful criteria such as date and time, filters used, observer, or central meridian longitude. PVOL is aimed to grow as an organized easy to use database of amateur images of the Outer Planets. The PVOL web address is located at http://www.pvol.ehu.es/ and coexists with the traditional IOPW site: http://www.ehu.es/iopw/ Acknowledgements: This work has been funded by Spanish MCYT PNAYA2003-03216, fondos FEDER and Grupos UPV 15946/2004. R. Hueso acknowledges a post-doc fellowship from Gobierno Vasco.

Morgado, A.; Sánchez-Lavega, A.; Rojas, J. F.; Hueso, R.

2005-08-01

168

The SEEDS Direct Imaging Survey for Planets and Scattered Dust Emission in Debris Disk Systems  

E-print Network

Debris disks around young main-sequence stars often have gaps and cavities which for a long time have been interpreted as possibly being caused by planets. In recent years, several giant planet discoveries have been made in systems hosting disks of precisely this nature, further implying that interactions with planets could be a common cause of such disk structures. As part of the SEEDS high-contrast imaging survey, we are surveying a population of debris disk-hosting stars with gaps and cavities implied by their spectral energy distributions, in order to attempt to spatially resolve the disk as well as to detect any planets that may be responsible for the disk structure. Here we report on intermediate results from this survey. Five debris disks have been spatially resolved, and a number of faint point sources have been discovered, most of which have been tested for common proper motion, which in each case has excluded physical companionship with the target stars. From the detection limits of the 50 targets t...

Janson, Markus; Moro-Martin, Amaya; Usuda, Tomonori; Thalmann, Christian; Carson, Joseph C; Goto, Miwa; Currie, Thayne; McElwain, M W; Itoh, Yoichi; Fukagawa, Misato; Crepp, Justin; Kuzuhara, Masayuki; Hashimoto, Jun; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Abe, Lyu; Brandner, Wolfgang; Egner, Sebastian; Feldt, Markus; Grady, Carol A; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiro; Hayashi, Saeko; Henning, Thomas; Hodapp, Klaus W; Ishii, Miki; Iye, Masanori; Kandori, Ryo; Knapp, Gillian R; Kwon, Jungmi; Matsuo, Taro; Miyama, Shoken; Morino, Jun-Ichi; Nishimura, Tetsuro; Pyo, Tae-Soo; Serabyn, Eugene; Suenaga, Takuya; Suto, Hiroshi; Suzuki, Ryuji; Takahashi, Yasuhiro; Takami, Michihiro; Takato, Naruhisa; Terada, Hiroshi; Tomono, Daego; Turner, Edwin L; Watanabe, Makoto; Wisniewski, John; Yamada, Toru; Takami, Hideki; Tamura, Motohide

2013-01-01

169

How Do Images Help Us Learn About Our Planet Earth?  

NSDL National Science Digital Library

Nighttime light patterns on Earth have been recorded using NASA satellites. In this investigation, students will correlate those patterns of lights with the distribution of human populations, and then determine if related statements included in the activity are true or false. Additionally, students will use a world atlas to investigate the physical features and climate of both the populated and unpopulated areas and then use that information to explain the population patterns. The URL opens to the investigation directory, with links to teacher and student materials, lesson extensions, resources, teaching tips, and assessment strategies. This is Investigation 3 of four found in the Grades K-4 Module 3 of Mission Geography. The Mission Geography curriculum integrates data and images from NASA missions with the National Geography Standards. Each of the four investigations in Module 3, while related, can be done independently. Please see Investigation 1 of this module for a two-page module overview and list of all standards addressed.

170

High-resolution imaging of Kepler planet host candidates. A comprehensive comparison of different techniques  

NASA Astrophysics Data System (ADS)

Context. The Kepler mission has discovered thousands of planet candidates. Currently, some of them have already been discarded; more than 200 have been confirmed by follow-up observations (most by radial velocity and few by other methods), and several hundreds have been validated. However, the large majority of the candidates are still awaiting for confirmation. Thus, priorities (in terms of the probability of the candidate being a real planet) must be established for subsequent radial velocity observations. Aims: The motivation of this work is to provide a set of isolated (good) host candidates to be further tested by other techniques that allow confirmation of the planet. As a complementary goal, we aim to identify close companions of the candidates that could have contaminated the light curve of the planet host due to the large pixel size of the Kepler CCD and its typical PSF of around 6 arcsec. Both goals can also provide robust statistics about the multiplicity of the Kepler hosts. Methods: We used the AstraLux North instrument located at the 2.2 m telescope in the Calar Alto Observatory (Almería, Spain) to obtain diffraction-limited images of 174 Kepler objects of interest. A sample of demoted Kepler objects of interest (with rejected planet candidates) is used as a control for comparison of multiplicity statistics. The lucky-imaging technique used in this work is compared to other adaptive optics and speckle imaging observations of Kepler planet host candidates. To that end, we define a new parameter, the blended source confidence level (BSC), to assess the probability of an object to have blended non-detected eclipsing binaries capable of producing the detected transit. Results: We find that 67.2% of the observed Kepler hosts are isolated within our detectability limits, and 32.8% have at least one visual companion at angular separations below 6 arcsec. Indeed, we find close companions (below 3 arcsec) for the 17.2% of the sample. The planet properties of this sample of non-isolated hosts are revised according to the presence of such close companions. We report one possible S-type binary (KOI-3158), where the five planet candidates would orbit one of the components of the system. We also report three possible false positives (KOIs 1230.01, 3649.01, and 3886.01) due to the presence of close companions that modify candidate properties such that they cannot be considered as planets anymore. The BSC parameter is calculated for all the isolated targets and compared to both the value prior to any high-resolution image and, when possible, to observations from previous high-spatial resolution surveys in the Kepler sample. Tables 1, 3, 4, 7, and 11 are available in electronic form at http://www.aanda.org

Lillo-Box, J.; Barrado, D.; Bouy, H.

2014-06-01

171

Gemini G.E.L. online catalogue raisonne  

NSDL National Science Digital Library

The National Gallery of Art presents the Gemini G.E.L. (Graphic Editions Limited) online catalogue raisonne, a listing of prints produced at this Los Angeles studio from 1966 through 1996. At Gemini, artists including Robert Rauschenberg, Ellsworth Kelly, Jasper Johns, David Hockney, Sam Francis, Roy Lichtenstein, Jonathan Borofsky, and Richard Serra worked with master printers to produce editions of prints. Initially the online catalogue raisonne seems difficult to browse, but the search area provides drop-down boxes for artists' names, dates, and series titles, so without prior knowledge that Frank Stella worked at Gemini, one can still retrieve 93 Stella prints. In the essay section, users can read a series of illustrated sections on the history of Gemini, individual artists, and decades, and link to larger images. The guide section explains the metadata fields in each catalog record, such as artist, series, title, and less obvious aspects such as "support," which refers to the support each print is on, almost always paper, or start date (year the artists began collaborating with Gemini) vs. signature date (year the artist signed the edition) vs. publication date (year the edition was made available).

172

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

173

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

174

Planet Earth  

NSDL National Science Digital Library

For those interested in a global view of the weather, Planet Earth is a "real-time 3-D model of the Earth with continuously updating night shadows and clouds." Cloud images are provided by the University of Wisconsin-Madison Space Science and Engineering Center. Planet Earth is shareware with a fee of $29.95.

175

Performance Evaluation of the Philips “Gemini” PET\\/CT System  

Microsoft Academic Search

Methods to test the practical performance of the Philips Gemini PET\\/CT system during clinical imaging are described and results presented. The test methods used were based on the NEMA standards and those suggested by a task group of the Commission of European Communities (EEC). These were performed using the EEC emission phantom, and phantoms provided by Philips. Scans were acquired

Rebecca Gregory; Mike Partridge; Maggie A. Flower

2006-01-01

176

ADAPTIVE OPTICS IMAGES. II. 12 KEPLER OBJECTS OF INTEREST AND 15 CONFIRMED TRANSITING PLANETS  

SciTech Connect

All transiting planet observations are at risk of contamination from nearby, unresolved stars. Blends dilute the transit signal, causing the planet to appear smaller than it really is, or producing a false positive detection when the target star is blended with an eclipsing binary. High spatial resolution adaptive optics images are an effective way of resolving most blends. Here we present visual companions and detection limits for 12 Kepler planet candidate host stars, of which 4 have companions within 4''. One system (KOI 1537) consists of two similar-magnitude stars separated by 0.''1, while KOI 174 has a companion at 0.''5. In addition, observations were made of 15 transiting planets that were previously discovered by other surveys. The only companion found within 1'' of a known planet is the previously identified companion to WASP-2b. An additional four systems have companions between 1'' and 4'': HAT-P-30b (3.''7, {Delta}Ks = 2.9), HAT-P-32b (2.''9, {Delta}Ks = 3.4), TrES-1b (2.''3, {Delta}Ks = 7.7), and WASP-P-33b (1.''9, {Delta}Ks = 5.5), some of which have not been reported previously. Depending on the spatial resolution of the transit photometry for these systems, these companion stars may require a reassessment of the planetary parameters derived from transit light curves. For all systems observed, we report the limiting magnitudes beyond which additional fainter objects located 0.''1-4'' from the target may still exist.

Adams, E. R.; Dupree, A. K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Kulesa, C.; McCarthy, D. [Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States)

2013-07-01

177

Imaging the Sources and Full Extent of the Sodium Tail of the Planet Mercury  

NASA Technical Reports Server (NTRS)

Observations of sodium emission from Mercury can be used to describe the spatial and temporal patterns of sources and sinks in the planet s surface-boundary-exosphere. We report on new data sets that provide the highest spatial resolution of source regions at polar latitudes, as well as the extraordinary length of a tail of escaping Na atoms. The tail s extent of approx.1.5 degrees (nearly 1400 Mercury radii) is driven by radiation pressure effects upon Na atoms sputtered from the surface in the previous approx.5 hours. Wide-angle filtered-imaging instruments are thus capable of studying the time history of sputtering processes of sodium and other species at Mercury from ground-based observatories in concert with upcoming satellite missions to the planet. Plasma tails produced by photo-ionization of Na and other gases in Mercury s neutral tails may be observable by in-situ instruments.

Baumgardner, Jeffrey; Wilson, Jody; Mendillo, Michael

2008-01-01

178

Index maps for Gemini earth photography  

NASA Technical Reports Server (NTRS)

Index maps for the Gemini missions are presented; these are for the Gemini 3 through Gemini 12 missions. The maps are divided into four sections: the whole earth; the Western Hemisphere and eastern Pacific Ocean; Africa, India, and the Near East; and Asia, Australia, and the Pacific Ocean.

Giddings, L. E.

1975-01-01

179

The Nine Planets: Mars  

NSDL National Science Digital Library

This Nine Planets page contains details about the planet Mars. Information includes planet diameter, mass, distance from the Sun, orbit, and mythology. Also covered are planet composition, surface features, atmosphere and magnetic field data, temperature on the planet, and results from exploration spacecraft. Phobos and Deimos (Mars satellites) are also covered in depth. The site provides links to more images, movies, and facts about Mars and its moons, and discusses unanswered questions about the planet.

Bill Arnett

180

A Laboratory Demonstration of the Capability to Image an Earth-like Extrasolar Planet  

NASA Technical Reports Server (NTRS)

The detection and characterization of an Earth-like planet orbiting a nearby star requires a telescope with an extraordinarily large contrast at small angular separations. At visible wavelengths, an Earth-like planet would be 1 times 10-10 times fainter than the star at angular separations of typically 0.1 arcsecond or less. There are several proposed space telescope systems that could, in principle, achieve this. Here we report a laboratory experiment that reaches these limits. We have suppressed the diffracted and scattered light near a star-like source to a level of 6 times 10-10 times the peak intensity in individual coronagraph images. In a series of such images, together with simple image processing, we have effectively reduced this to a residual noise level of about 0.1 times 10-10. This demonstrates that a coronagraphic telescope in space could detect and spectroscopically characterize nearby exoplanetary systems, with the sensitivity to image an 'Earth-twin' orbiting a nearby star.

Trauger, John T.; Wesley, A. Traub

2007-01-01

181

How to Directly Image a Habitable Planet Around Alpha Centauri with a ~30cm Space Telescope  

NASA Astrophysics Data System (ADS)

Several mission concepts are being studied to directly image planets around nearby stars. Direct imaging enables spectroscopic detection of biomarkers such as atmospheric oxygen and methane, which would be highly suggestive of extraterrestrial life. It is commonly thought that directly imaging a potentially habitable exoplanet requires telescopes with apertures of at least 1m, costing at least 1B, and launching no earlier than the 2020s.A notable exception to this is Alpha Centauri (A and B), which is an extreme outlier among FGKM stars in terms of apparent habitable zone size. Specifically, Alpha Centauri habitable zones span about 0.5-1' in stellocentric angle, ~3x wider than around any other FGKM star. This enables a ~30cm visible light space telescope equipped with a modern high performance coronagraph or starshade to resolve the habitable zone at high contrast and directly image any potentially habitable planet that may exist in the system. Due to the extreme apparent brightness of the stars, exposure times can be as short as minutes with ideal components, or days with realistic ones. This makes it possible to do color photometry on potentially habitable planets sufficient to differentiate Venus-like, Earth-like, and Mars-like planets from each other and establish the presence of Earth-pressure atmosphere through Rayleigh scattering.The raw contrast requirements for such an instrument can be relaxed to 1e-8 if the mission spends 2 years collecting tens of thousands of images on the same target, enabling a factor of 500-1000 speckle suppression in post processing. The light leak from both stars is controllable with a special wavefront control algorithm known as Multi-Star Wavefront Control (MSWC), which independently suppresses diffraction and aberrations from both stars using independent modes on the deformable mirror (see Thomas et al. at this conference).The presentation will describe the general studies and calculations in more detail and briefly present examples of small coronagraphic mission concepts currently being developed to take advantage of this opportunity. (For more detail about one such concept, see Bendek et al. at this conference).

Belikov, Ruslan; Acend Team, Acesat Team

2015-01-01

182

Suppressing speckle noise for simultaneous differential extrasolar planet imaging (SDI) at the VLT and MMT  

NASA Astrophysics Data System (ADS)

We discuss data reduction techniques and results from the Simultaneous Differential Imager (SDI) implemented at the VLT (Lenzen et al. 2004a) and the MMT. SDI uses a quad filter to take images simultaneously at 3 wavelengths surrounding the 1.62 ?m methane bandhead found in the spectrum of cool brown dwarfs and gas giants. By performing a difference of images in these filters, speckle noise from the primary can be attenuated by a factor of >102. Non-trivial data reduction tools are necessary to pipeline the simultaneous differential imaging. Here we discuss a custom algorithm implemented in IDL to perform this reduction. The script performs basic data reduction tasks but also precisely aligns images taken in each of the filters using a custom shift and subtract routine. In our commissioning runs at the VLT and MMT, we achieved contrasts up to a factor of 45000 (?H=11.7) at a separation of 0.6" from the primary star. With this degree of attenuation, we should be able to image a 2-4 Jupiter mass planet at 5 AU around a 30 Myr star at 10 pc. We believe that our SDI images are the highest contrast astronomical images ever made from ground or space.

Biller, Beth A.; Close, Laird; Lenzen, Rainer; Brandner, Wolfgang; McCarthy, Donald W.; Nielsen, Eric; Hartung, Markus

2004-10-01

183

Gemini: steps to the Moon  

NASA Astrophysics Data System (ADS)

In Gemini, the author unfolds the story of the origin and development of the programme and the spacecraft from the perspective of the engineers, flight controllers and astronauts involved. It includes chapters on flight tests, Extra Vehicular Activity (EVA) and rendezvous and docking.

Shayler, David J.

184

Multiplicity in transiting planet-host stars. A lucky imaging study of Kepler candidates  

NASA Astrophysics Data System (ADS)

Context. In the exoplanetary era, the Kepler spacecraft is causing a revolution by discovering thousands of new planet candidates. However, a follow-up program is needed to reject false candidates and fully characterize the bona-fide exoplanets. Aims: Our main aims are to 1./ detect and analyze close companions inside the typical Kepler point spread function (PSF) to study whether they are the responsible for the dimming found in Kepler light curves, 2./ study the change in the stellar and planetary parameters caused by an unresolved object, 3./ help validate the Kepler objects of interest (KOI) that do not have any object inside the Kepler PSF, and 4./ study the multiplicity rate of planet-host candidates. Such a large sample of observed planet-host candidates allows us to derive statistics for close (visual or bounded) companions to the harboring star. Methods: We present lucky imaging observations for a total of 98 KOIs. This technique is based on the acquisition of thousands of very-short-exposure-time images. A selection and combination of a small amount of the highest quality frames provides a high resolution image with objects having a 0.1 arcsec PSF. We apply this technique to carry out observations in the Sloan i and z filters of our Kepler candidates. Results: We find blended objects inside the Kepler PSF for a significant percentage of KOIs. On the one hand, only 58.2% of the hosts do not have any object within 6 arcsec. On the other hand, we find 19 companions closer than 3 arcsec in 17 KOIs. According to their magnitudes and i - z colors, 8 of them could be physically bound to the host star.

Lillo-Box, J.; Barrado, D.; Bouy, H.

2012-10-01

185

A Lucky Imaging search for stellar companions to transiting planet host stars  

NASA Astrophysics Data System (ADS)

The presence of stellar companions around planet hosting stars influences the architecture of their planetary systems. To find and characterise these companions and determine their orbits is thus an important consideration to understand planet formation and evolution. For transiting systems even unbound field stars are of interest if they are within the photometric aperture of the light curve measurement. Then they contribute a constant flux offset to the transit light curve and bias the derivation of the stellar and planetary parameters if their existence is unknown. Close stellar sources are, however, easily overlooked by common planet surveys due to their limited spatial resolution. We therefore performed high angular resolution imaging of 49 transiting exoplanet hosts to identify unresolved binaries, characterize their spectral type, and determine their separation. The observations were carried out with the Calar Alto 2.2 m telescope using the Lucky Imaging camera AstraLux Norte. All targets were imaged in i' and z' passbands. We found new companion candidates to WASP-14 and WASP-58, and we re-observed the stellar companion candidates to CoRoT-2, CoRoT-3, CoRoT-11, HAT-P-7, HAT-P-8, HAT-P-41, KIC 10905746, TrES-2, TrES-4, and WASP-2. We deduce from the stellar density around all sources that two companion candidates out of the targets with the first position measurement (CoRoT-11, HAT-P-41, KIC 10905746, WASP-14 and WASP-58) are probably unbound. In addition, we re-analyse the influence of the sources close to WASP-14 and WASP-58 on the planetary parameters given in the literature and find no significant changes. Table 1 is available in electronic form at http://www.aanda.org

Wöllert, Maria; Brandner, Wolfgang; Bergfors, Carolina; Henning, Thomas

2015-03-01

186

The TRENDS High-contrast Imaging Survey. IV. The Occurrence Rate of Giant Planets around M Dwarfs  

NASA Astrophysics Data System (ADS)

Doppler-based planet surveys have discovered numerous giant planets but are incomplete beyond several AU. At larger star-planet separations, direct planet detection through high-contrast imaging has proven successful, but this technique is sensitive only to young planets and characterization relies upon theoretical evolution models. Here we demonstrate that radial velocity measurements and high-contrast imaging can be combined to overcome these issues. The presence of widely separated companions can be deduced by identifying an acceleration (long-term trend) in the radial velocity of a star. By obtaining high spatial resolution follow-up imaging observations, we rule out scenarios in which such accelerations are caused by stellar binary companions with high statistical confidence. We report results from an analysis of Doppler measurements of a sample of 111 M-dwarf stars with a median of 29 radial velocity observations over a median time baseline of 11.8 yr. By targeting stars that exhibit a radial velocity acceleration ("trend") with adaptive optics imaging, we determine that 6.5% ± 3.0% of M-dwarf stars host one or more massive companions with 1 < m/MJ < 13 and 0 < a < 20 AU. These results are lower than analyses of the planet occurrence rate around higher-mass stars. We find the giant planet occurrence rate is described by a double power law in stellar mass M and metallicity F ? [Fe/H] such that f(M,F) = 0.039^{+0.056}_{-0.028} M^{0.8^{+1.1}_{-0.9}} 10^{(3.8 +/- 1.2)F}. Our results are consistent with gravitational microlensing measurements of the planet occurrence rate; this study represents the first model-independent comparison with microlensing observations.

Montet, Benjamin T.; Crepp, Justin R.; Johnson, John Asher; Howard, Andrew W.; Marcy, Geoffrey W.

2014-01-01

187

The Nine Planets: Venus  

NSDL National Science Digital Library

This page contains details about the planet Venus. Information includes planet mass, distance from the Sun, diameter, orbit, and mythology. Also covered is planet composition, surface features, atmosphere and magnetic field data, temperature on the planet, and results of exploration spacecraft. Includes links to images, movies, and additional facts. Discusses unanswered questions about Venus as well.

Bill Arnett

188

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.

Bill Arnett

189

Effect of condensate cycles in driving atmospheric circulation on brown dwarfs and directly imaged giant planets  

NASA Astrophysics Data System (ADS)

Growing observations of brown dwarfs and directly imaged giant planets, including properties of the L/T transition, chemical disequilibrium, brightness variability, and surface maps have provided evidence for strong atmospheric circulation on these worlds. Previous studies that serve to understand the atmospheric circulation of brown dwarfs include modeling of convection from the interior both in a two-dimensional and global fashion, a two-layer shallow water model and a global circulation model with dry thermal perturbation at the bottom of atmosphere. These models show that interactions between the stably stratified layer and the convective interior can drive an atmospheric circulation, including zonal jets and/or vortices. However, these models are dry models, not including the condensation cycles such as silicate and iron in hot dwarfs. Condensation of water has previously been shown to play an important role on driving the zonal jets on four giant planets in our solar system. As such, condensation cycles of various species is believed to be an important source in driving the atmospheric circulation of brown dwarfs and directly imaged planets as well. Here we present results from three-dimensional simulations for the stably stratified atmospheres of brown dwarfs based on a general circulation model that includes the effect of a condensate cycle. Large-scale latent heating and molecular weight effect due to condensation of a single species are treated explicitly in our model. We examine the atmospheric circulation patterns of brown dwarfs caused by large-scale latent heating that results from condensation of silicates in hot dwarfs and water in the cold dwarfs. By varying the parameters such as abundances of condensates, effective temperature and rotational period, we explore possible configurations of the circulation, and determine implications for the observed cloud patchiness and brightness variability for brown dwarfs.

Tan, Xianyu; Showman, Adam

2014-11-01

190

Accepted for publication in ApJ, October 2002 Imaging Spectroscopy for Extrasolar Planet Detection  

E-print Network

of a terrestrial extrasolar planet at 2 pc with an 8­m coronagraphic Terrestrial Planet Finder (TPF) in # 7 hr (or been undertaken to consider com­ peting concepts for the Terrestrial Planet Finder (TPF) whose primary goal is to locate terrestrial extrasolar planets in the habitable zone (where liquid water may

191

Gemini high-resolution optical spectrograph conceptual design  

NASA Astrophysics Data System (ADS)

A multiplexed moderate resolution (R = 34,000) and a single object high resolution (R = 90,000) spectroscopic facility for the entire 340 - 950nm wavelength region has been designed for Gemini. The result is a high throughput, versatile instrument that will enable precision spectroscopy for decades to come. The extended wavelength coverage for these relatively high spectral resolutions is achieved by use of an Echelle grating with VPH cross-dispersers and for the R = 90,000 mode utilization of an image slicer. The design incorporates a fast, efficient, reliable system for acquiring targets over the7 arcmin field of Gemini. This paper outlines the science case development and requirements flow-down process that leads to the configuration of the HIA instrument and describes the overall GHOS conceptual design. In addition, this paper discusses design trades examined during the conceptual design study instrument group of the Herzberg Institute of Astrophysics has been commissioned by the Gemini Observatory as one of the three competing organizations to conduct a conceptual design study for a new Gemini High-Resolution Optical Spectrograph (GHOS). This paper outlines the science case development and requirements flow-down process that leads to the configuration of the HIA instrument and describes the overall GHOS conceptual design. In addition, this paper discusses design trades examined during the conceptual design study.

Szeto, Kei; McConnachie, Alan; Anthony, André; Bohlender, David; Crampton, David; Desaulniers, Pierre; Dunn, Jennifer; Hardy, Tim; Hill, Alexis; Monin, Dmitry; Pazder, John; Schwab, Christian; Spano, Paola; Starkenburg, Else; Thibault, Simon; Walker, Gordon; Venn, Kim; Zhang, Hu

2012-09-01

192

Uranus’ cloud structure and seasonal variability from Gemini-North and UKIRT observations  

NASA Astrophysics Data System (ADS)

Observations of Uranus were made in September 2009 with the Gemini-North telescope in Hawaii, using both the NIFS and NIRI instruments. Observations were acquired in Adaptive Optics mode and have a spatial resolution of approximately 0.1?. NIRI images were recorded with three spectral filters to constrain the overall appearance of the planet: J, H-continuum and CH4(long), and long slit spectroscopy measurements were also made (1.49-1.79 ?m) with the entrance slit aligned on Uranus’ central meridian. To acquire spectra from other points on the planet, the NIFS instrument was used and its 3? × 3? field of view stepped across Uranus’ disc. These observations were combined to yield complete images of Uranus at 2040 wavelengths between 1.476 and 1.803 ?m. The observed spectra along Uranus central meridian were analysed with the NEMESIS retrieval tool and used to infer the vertical/latitudinal variation in cloud optical depth. We find that the 2009 Gemini data perfectly complement our observations/conclusions from UKIRT/UIST observations made in 2006-2008 and show that the north polar zone at 45°N has continued to steadily brighten while that at 45°S has continued to fade. The improved spatial resolution of the Gemini observations compared with the non-AO UKIRT/UIST data removes some of the earlier ambiguities with our previous analyses and shows that the opacity of clouds deeper than the 2-bar level does indeed diminish towards the poles and also reveals a darkening of the deeper cloud deck near the equator, perhaps coinciding with a region of subduction. We find that the clouds at 45°N,S lie at slightly lower pressures than the clouds at more equatorial latitudes, which suggests that they might possibly be composed of a different condensate, presumably CH4 ice, rather than H2S or NH3 ice, which is assumed for the deeper cloud. In addition, analysis of the centre-to-limb curves of both the Gemini/NIFS and earlier UKIRT/UIST IFU observations shows that the main cloud deck has a well-defined top, and also allows us to better constrain the particle scattering properties. Overall, Uranus appeared to be less convectively active in 2009 than in the previous 3 years, which suggests that now the northern spring equinox (which occurred in 2007) is passed the atmosphere is settling back into the quiescent state seen by Voyager 2 in 1986. However, a number of discrete clouds were still observed, with one at 15°N found to lie near the 500 mb level, while another at 30°N, was seen to be much higher at near the 200 mb level. Such high clouds are assumed to be composed of CH4 ice.

Irwin, P. G. J.; Teanby, N. A.; Davis, G. R.; Fletcher, L. N.; Orton, G. S.; Tice, D.; Kyffin, A.

2011-03-01

193

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.

Bill Arnett

194

The Nine Planets: Uranus  

NSDL National Science Digital Library

This page of Nine Planets highlights details about the gas giant planet Uranus and its moons. Information includes planet diameter, mass, distance from the Sun, orbit, and mythology. Also covered are planet composition, surface features, atmosphere and magnetic field data, surface temperature, and results of spacecraft exploration. Uranus' moons and rings are detailed, including Titania, Oberon, Umbriel, Ariel, Miranda, and more. Discussion of unanswered questions about the planet and links to more images, movies, and facts are also provided.

Bill Arnett

195

The Nine Planets: Neptune  

NSDL National Science Digital Library

This Nine Planets page contains details about the gas giant planet Neptune and its moons. Information includes planet diameter, mass, distance from the Sun, orbit, and mythology. Also covered are planet composition, surface features, atmosphere and magnetic field data, surface temperature, and results of spacecraft exploration. Neptune's moons and rings are also detailed, including Nereid, Triton, Proteus, and many others. Unanswered questions about the planet and its moons are covered, and links to more images, movies, and facts are given.

Bill Arnett

196

Gaps in the HD 169142 Protoplanetary Disk Revealed by Polarimetric Imaging: Signs of Ongoing Planet Formation?  

NASA Astrophysics Data System (ADS)

We present H-band Very Large Telescope/NACO polarized light images of the Herbig Ae/Be star HD 169142 probing its protoplanetary disk as close as ~0.''1 to the star. Our images trace the face-on disk out to ~1.''7 (~250 AU) and reveal distinct substructures for the first time: (1) the inner disk (lsim20 AU) appears to be depleted in scattering dust grains; (2) an unresolved disk rim is imaged at ~25 AU; (3) an annular gap extends from ~40 to 70 AU; (4) local brightness asymmetries are found on opposite sides of the annular gap. We discuss different explanations for the observed morphology among which ongoing planet formation is a tempting, but yet to be proven, one. Outside of ~85 AU the surface brightness drops off roughly vpropr -3.3, but describing the disk regions between 85-120 AU and 120-250 AU separately with power laws vpropr -2.6 and vpropr -3.9 provides a better fit hinting toward another discontinuity in the disk surface. The flux ratio between the disk-integrated polarized light and the central star is ~4.1 × 10-3. Finally, combining our results with those from the literature, ~40% of the scattered light in the H band appears to be polarized. Our results emphasize that HD 169142 is an interesting system for future planet formation or disk evolution studies. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under program number 089.C-0611(A).

Quanz, Sascha P.; Avenhaus, Henning; Buenzli, Esther; Garufi, Antonio; Schmid, Hans Martin; Wolf, Sebastian

2013-03-01

197

Direct imaging and spectroscopy of terrestrial planets with JWST and a starsahde  

NASA Astrophysics Data System (ADS)

We present a study for using a starshade with the James Webb Space Telescope (JWST). This concept would enable imaging and spectroscopy of a planet similar to the Earth, the study of its habitability, and the search for signs of alien life. JWST was not specifically designed to observe with a starshade, but its instrumentation and its great sensitivity make it capable of achieving major results in the study of terrestrial-mass exoplanets. However, there are some challenges for the starshade designs mainly due to the very large wavelength sensitivity of the HgCdTe detectors. We discuss the combination of a starshade with internal filters in NIRCam and NIRSpec to optimize both science return and starshade performance. We discuss a possible filter upgrade to enable feasible observations of Earth-like planets and in particular spectroscopic characterization in the near infrared. The new filter would not affect NIRSpec's scientific performance nor its operations, but it would dramatically reduce the risk of adding a starshade to JWST in the future and enhance the performance of any starshade that is built.

Soummer, R.; Valenti, J.; Brown, R. A.; Seager, S.; Tumlinson, J.; Cash, W.; Jordan, I.; Postman, M.; Mountain, M.; Glassman, T.; Pueyo, L.; Roberge, A.; NWP Team

2010-10-01

198

Cryostat design and fabrication for the Gemini NIRI instrument  

Microsoft Academic Search

The Gemini Near IR Imager (NIRI) is a cryogenic instrument cooled by two closed-cycle cryo-coolers. The vacuum jacket is a hexagon shaped vacuum vessel made of three sections. Each section is forged out of aluminum 6061. All the internal structural components are made of aluminum 6061T6 except the supporting trusses, which are made of titanium. All the internal structural members

Tony T. Young; Klaus-Werner Hodapp; Jeffrey W. Douglass; Doug Neill; E. Irvin; Louis Robertson

1998-01-01

199

ExSPO: A Discovery Class Apodized Square Aperture (ASA) Expo-Planet Imaging Space Telescope Concept  

NASA Technical Reports Server (NTRS)

ExSPO is a Discovery Class (approx. 4 meter) apodized square aperture (ASA) space telescope mission designed for direct imaging of extrasolar Earth-like planets, as a precursor to TPF. The ASA telescope concept, instrument design, capabilities, mission plan and science goals are described.

Gezari, D.; Harwit, M.; Lyon, R.; Melnick, G.; Papaliolos, G.; Ridgeway, S.; Woodruff, R.; Nisenson, P.; Oegerle, William (Technical Monitor)

2002-01-01

200

HIGH-CONTRAST IMAGING SEARCH FOR PLANETS AND BROWN DWARFS AROUND THE MOST MASSIVE STARS IN THE SOLAR NEIGHBORHOOD  

SciTech Connect

There has been a long-standing discussion in the literature as to whether core accretion or disk instability is the dominant mode of planet formation. Over the last decade, several lines of evidence have been presented showing that core accretion is most likely the dominant mechanism for the close-in population of planets probed by radial velocity and transits. However, this does not by itself prove that core accretion is the dominant mode for the total planet population, since disk instability might conceivably produce and retain large numbers of planets in the far-out regions of the disk. If this is a relevant scenario, then the outer massive disks of B-stars should be among the best places for massive planets and brown dwarfs to form and reside. In this study, we present high-contrast imaging of 18 nearby massive stars of which 15 are in the B2-A0 spectral-type range and provide excellent sensitivity to wide companions. By comparing our sensitivities to model predictions of disk instability based on physical criteria for fragmentation and cooling, and using Monte Carlo simulations for orbital distributions, we find that {approx}85% of such companions should have been detected in our images on average. Given this high degree of completeness, stringent statistical limits can be set from the null-detection result, even with the limited sample size. We find that <30% of massive stars form and retain disk instability planets, brown dwarfs, and very low mass stars of <100 M{sub jup} within 300 AU, at 99% confidence. These results, combined with previous findings in the literature, lead to the conclusion that core accretion is likely the dominant mode of planet formation.

Janson, Markus; Bonavita, Mariangela; Jayawardhana, Ray [Department of Astronomy, University of Toronto, Toronto, ON (Canada); Klahr, Hubert [Max Planck Institute for Astronomy, Heidelberg (Germany); Lafreniere, David [Department of Physics, University of Montreal, Montreal, ON (Canada); Zinnecker, Hans, E-mail: janson@astro.utoronto.ca [Astrophysikalisches Institut Potsdam, Potsdam (Germany)

2011-08-01

201

The Planet Pipeline: enabling data mining and citizen science with Hubble images of the Solar System  

NASA Astrophysics Data System (ADS)

In 15 years of service, the Wide Field Planetary Camera 2 (WFPC2) onboard the Hubble Space Telescope (HST) obtained over 10,000 frames of Solar System data. Since standard data reduction pipelines are typically not optimized for movingtarget data, our "planet pipeline" will uniformly reprocess and catalog this WFPC2 image collection to make it more immediately science-ready. Some of our processing steps will utilize citizen scientists to perform visual inspections. Our corresponding database will enable robust queries which are more specific to planetary science, helping archival researchers quickly find and utilize the prepared images within our collection for a wide range of scientific analyses. We welcome suggestions (especially from veteran WFPC2 users) on the optimal treatment and organization of this data collection, and also to identify a broad range of analyses that might only be possible with visual inspections by citizen scientists. Our processed images and associated catalogs will be made available as High Level Science Products (HLSP) in the Multimission Archive at STScI (MAST): http://archive.stsci.edu/prepds/planetpipeline

Mutchler, M.; Wong, M. H.; Higgins, J.; Gay, P. L.; Conti, A.; Deustua, S.; Golombek, D.; Grunsfeld, J.; Lerner, T.

2011-10-01

202

Role of spacer lengths of gemini surfactants in the synthesis of silver nanorods in micellar media  

NASA Astrophysics Data System (ADS)

In this work, we have prepared Ag-nanorods using biscationic gemini surfactant micelles as the media by a seed-mediated wet synthesis method. Towards this end, we first synthesized Ag-nanoseeds of diameter ~7 nm stabilized by trisodium citrate (as the capping agent). Then these Ag-nanoseeds were used to synthesize Ag-nanorods of different aspect ratios. With decreasing Ag-nanoseed concentration, the aspect ratios of the Ag-nanorods stabilized by these gemini surfactants increased gradually. Various Ag-nanoseeds and Ag-nanospecies were characterized using UV-Vis spectroscopy (to know the surface plasmon bands), transmission electron microscopy (to find out their particle sizes and distribution), energy-dispersive X-ray spectroscopy and X-ray diffraction. When we used micelles derived from gemini surfactants of shorter spacer -(CH2)n- (n = 2 or 4) to stabilize the Ag-nanorods, the ?max of the longitudinal band shifted more towards the blue region compared to that of the gemini surfactant micelles with a longer spacer -(CH2)n- (n = 5, 12) at a given amount of the Ag-nanoseed solution. So, the growth of Ag-nanorods in the gemini micellar solutions depends on the spacer-chain length of gemini surfactants employed.In this work, we have prepared Ag-nanorods using biscationic gemini surfactant micelles as the media by a seed-mediated wet synthesis method. Towards this end, we first synthesized Ag-nanoseeds of diameter ~7 nm stabilized by trisodium citrate (as the capping agent). Then these Ag-nanoseeds were used to synthesize Ag-nanorods of different aspect ratios. With decreasing Ag-nanoseed concentration, the aspect ratios of the Ag-nanorods stabilized by these gemini surfactants increased gradually. Various Ag-nanoseeds and Ag-nanospecies were characterized using UV-Vis spectroscopy (to know the surface plasmon bands), transmission electron microscopy (to find out their particle sizes and distribution), energy-dispersive X-ray spectroscopy and X-ray diffraction. When we used micelles derived from gemini surfactants of shorter spacer -(CH2)n- (n = 2 or 4) to stabilize the Ag-nanorods, the ?max of the longitudinal band shifted more towards the blue region compared to that of the gemini surfactant micelles with a longer spacer -(CH2)n- (n = 5, 12) at a given amount of the Ag-nanoseed solution. So, the growth of Ag-nanorods in the gemini micellar solutions depends on the spacer-chain length of gemini surfactants employed. Electronic supplementary information (ESI) available: Additional TEM images, characteristics of Ag-nanorods and EDAX analyses. See DOI: 10.1039/c1nr10141b

Bhattacharya, Santanu; Biswas, Joydeep

2011-07-01

203

Welcome to the Gemini Observatory  

NSDL National Science Digital Library

This site covers many aspects of the Gemini Observatory. It discusses where it is located, what it observes, what pictures it takes, and certain issues that pertain to it. In addition, it allows users to take a virtual tour of the campus. In a Quicktime format, a 360 degree picture is taken of the observatory and the surrounding landscape. Users can virtually move about and see the impressive, and the impressively beautiful, landscape. The site also provides links to newsletters, press releases and the clips of the observatory in the news. This is a nice look at the different goals and features of a prominent observatory.

Michaud, Peter

204

The International Deep Planet Survey. I. The frequency of wide-orbit massive planets around A-stars  

NASA Astrophysics Data System (ADS)

Breakthrough direct detections of planetary companions orbiting A-type stars confirm the existence of massive planets at relatively large separations, but dedicated surveys are required to estimate the frequency of similar planetary systems. To measure the first estimation of the giant exoplanetary systems frequency at large orbital separation around A-stars, we have conducted a deep-imaging survey of young (8-400 Myr), nearby (19-84 pc) A- and F-stars to search for substellar companions in the ~10-300 AU range. The sample of 42 stars combines all A-stars observed in previous AO planet search surveys reported in the literature with new AO observations from VLT/NaCo and Gemini/NIRI. It represents an initial subset of the International Deep Planet Survey (IDPS) sample of stars covering M- to B-stars. The data were obtained with diffraction-limited observations in H- and Ks-band combined with angular differential imaging to suppress the speckle noise of the central stars, resulting in typical 5? detection limits in magnitude difference of 12 mag at 1'', 14 mag at 2'' and 16 mag at 5'' which is sufficient to detect massive planets. A detailed statistical analysis of the survey results is performed using Monte Carlo simulations. Considering the planet detections, we estimate the fraction of A-stars having at least one massive planet (3-14 MJup) in the range 5-320 AU to be inside 5.9-18.8% at 68% confidence, assuming a flat distribution for the mass of the planets. By comparison, the brown dwarf (15-75 MJup) frequency for the sample is 2.0-8.9% at 68% confidence in the range 5-320 AU. Assuming power law distributions for the mass and semimajor axis of the planet population, the AO data are consistent with a declining number of massive planets with increasing orbital radius which is distinct from the rising slope inferred from radial velocity (RV) surveys around evolved A-stars and suggests that the peak of the massive planet population around A-stars may occur atseparations between the ranges probed by existing RV and AO observations. Finally, we report the discovery of three new close M-star companions to HIP 104365 and HIP 42334. Based on observations collected at the European Southern Observatory, Chile, ESO programs 081.C-0519, 083.C-0706, 084.C-0605, 087.C-0559, 088.C-0477, and at the Gemini North observatory, Gemini programs GN-2007B-Q-59, GN-2008A-Q-77, GN-2008B-Q-64, GN-2009A-Q-80, GN-2009B-Q-93.Table A.1 is available in electronic form at http://www.aanda.orgTables 1, 3, and A.1 are also 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/544/A9

Vigan, A.; Patience, J.; Marois, C.; Bonavita, M.; De Rosa, R. J.; Macintosh, B.; Song, I.; Doyon, R.; Zuckerman, B.; Lafrenière, D.; Barman, T.

2012-08-01

205

Direct imaging and spectroscopy of habitable planets using JWST and a starshade  

NASA Astrophysics Data System (ADS)

A starshade with the James Webb Space Telescope (JWST) is the only possible path forward in the next decade to obtain images and spectra of a planet similar to the Earth, to study its habitability, and search for signs of alien life. While JWST was not specifically designed to observe using a starshade, its near-infrared instrumentation is in principle capable of doing so and could achieve major results in the study of terrestrialmass exoplanets. However, because of technical reasons associated with broadband starlight suppression and filter red-leak, NIRSpec would need a slight modification to one of its target acquisition filters to enable feasible observations of Earth-like planets. This upgrade would 1) retire the high risk associated with the effects of the current filter red leak which are difficult to model given the current state of knowledge on instrument stray light and line spread function at large separation angles, 2) enable access to the oxygen band at 0.76 ?m in addition to the 1.26 ?m band, 3) enable a smaller starshade by relaxing requirements on bandwidth and suppression 4) reduce detector saturation and associated long recovery times. The new filter would not affect neither NIRSpecs scientific performance nor its operations, but it would dramatically reduce the risk of adding a starshade to JWST in the future and enhance the performance of any starshade that is built. In combination with a starshade, JWST could be the most capable and cost effective of all the exoplanet hunting missions proposed for the next decade, including purpose built observatories for medium-size missions.

Soummer, Rémi; Valenti, Jeff; Brown, Robert A.; Seager, Sara; Tumlinson, Jason; Cash, Webster; Jordan, Ian; Postman, Marc; Mountain, Matt; Glassman, Tiffany; Pueyo, Laurent; Roberge, Aki

2010-07-01

206

Gemini's instrumentation program: latest results and long-range plan  

NASA Astrophysics Data System (ADS)

The Gemini Observatory is going through an extraordinary time with astronomical instrumentation. New powerful capabilities are delivered and are soon entering scientific operations. In parallel, new instruments are being planned and designed to align the strategy with community needs and enhance the competitiveness of the Observatory for the next decade. We will give a broad overview of the instrumentation program, focusing on achievements, challenges and strategies within a scientific, technical and management perspective. In particular we will discuss the following instruments and projects (some will have dedicated detailed papers in this conference): GMOS-CCD refurbishment, FLAMINGOS-2, GeMS (MCAO system and imager GSAOI), GPI, new generation of A&G, GRACES (fiber feed to CFHT ESPaDOnS) and GHOS (Gemini High-resolution Optical Spectrograph), and provide some updates about detector controllers, mid-IR instruments, Altair, GNIRS, GLAO and future workhorse instruments.

Boccas, Maxime; Kleinman, S. J.; Goodsell, Stephen; Tollestrup, Eric; Adamson, Andrew; Arriagada, Gustavo; Christou, Julian; Gonzalez, Patricio; Hanna, Kevin; Hartung, Markus; Lazo, Manuel; Mason, Rachel; Neichel, Benoît; Perez, Gabriel; Simons, Doug; Walls, Brian; White, John

2012-09-01

207

Development of the longwave infrared imager (LIR) onboard PLANET-C  

NASA Astrophysics Data System (ADS)

The Longwave Infrared Camera (LIR), which mounts an uncooled micro-bolometer array (UMBA), is under development for the Japanese Venus orbiter mission, PLANET-C. LIR detects thermal emission from the top of the sulfur dioxide cloud in a wavelength region 8--12 ?m to map the cloud-top temperature which is typically as low as 230 K. The requirement for the noise equivalent temperature difference (NETD) is 0.3 K. Images of blackbody targets in room temperature (~300 K) and low temperature (~230 K) have been acquired in a vacuum environment using a prototype model of LIR, showing that the NETD of 0.2 K and 0.8 K are achieved in ~300 K and ~230 K, respectively. We expect that the requirement of NETD<0.3 K for ~230 K targets will be achieved by averaging several tens of images which are acquired within a few minutes. The vibration test for the UMBA was also carried out and the result showed the UMBA survived without any pixel defects or malfunctions. The tolerance to high-energy protons was tested and verified using a commercial camera in which a same type of UMBA is mounted. Based on these results, a flight model is now being manufactured with minor modifications from the prototype.

Fukuhara, Tetsuya; Taguchi, Makoto; Imamura, Takeshi; Nakamura, Masato; Iwagami, Naomoto; Ueno, Munetaka; Suzuki, Makoto; Hashimoto, George L.; Sato, Mitsuteru; Yamazaki, Atsushi; Kashikawa, Ryoichi; Higashino, Isamu; Noguchi, Kazuhide

2008-04-01

208

High-contrast Imaging Search for Planets and Brown Dwarfs around the Most Massive Stars in the Solar Neighborhood  

E-print Network

There has been a long-standing discussion in the literature as to whether core accretion or disk instability is the dominant mode of planet formation. Over the last decade, several lines of evidence have been presented showing that core accretion is most likely the dominant mechanism for the close-in population of planets probed by radial velocity and transits. However, this does not by itself prove that core accretion is the dominant mode for the total planet population, since disk instability might conceivably produce and retain large numbers of planets in the far-out regions of the disk. If this is a relevant scenario, then the outer massive disks of B-stars should be among the best places for massive planets and brown dwarfs to form and reside. In this study, we present high-contrast imaging of 18 nearby massive stars, of which 15 are in the B2--A0 spectral type range and provide excellent sensitivity to wide companions. By comparing our sensitivities to model predictions of disk instability based on phys...

Janson, Markus; Klahr, Hubert; Lafreniere, David; Jayawardhana, Ray; Zinnecker, Hans

2011-01-01

209

The performance evaluation test for prototype model of Longwave Infrared Imager (LIR) onboard PLANET-C  

NASA Astrophysics Data System (ADS)

The PLANET-C mission, which is one of the future planetary missions of Japan, aims at understanding the atmospheric circulation of Venus. Meteorological information will be obtained by globally mapping clouds and minor constituents successively with four imagers at ultraviolet and infrared wavelengths, and radio occultation experiments will provide vertical profiles of the atmospheric temperature. These systematic, continuous remote observations will provide us with an unprecedented large data set of the Venusian atmospheric dynamics. The Longwave Infrared Imager (LIR), which mounts a commercial uncooled micro-bolometer array (UMBA), is one of four imagers onboard the spacecraft and detects thermal emission from the top of the sulfur dioxide cloud in a rather wide wavelength region of 8-12 µm to map the cloud-top temperature which is typically as low as 230 K. Unlike other imagers, LIR is able to take images of both dayside and nightside with equal quality and accuracy. The cloud-top temperature map will reflect the cloud height distribution in which a few hundred meters of difference in cloud height corresponds to temperature difference of 0.3 K. In order to detect the cloud height difference of a few hundred meters, LIR requires a noise equivalent temperature difference (NETD) of 0.3 K. The commercial UMBA camera is typically used for observing room-temperature targets, and thus the electronics and the driving parameters have been optimized for low temperature-targets. Images of blackbody targets in room temperature (˜300 K) and low temperature (˜230 K) have been acquired in a vacuum environment using a prototype model of LIR, showing that the NETD of 0.2 K and 0.8 K are achieved in room temperature and low temperature, respectively. Although the NETD at the low temperature is 4 times worse than the case for the room temperature, we expect that the requirement of N ET D < 0.3 K for a low-temperature target will be achieved by averaging several tens of images which are acquired continuously. The vibration test for the UMBA was also carried out and the result showed the UMBA survived without any pixel defects or malfunctions. The tolerance to high-energy protons was tested and verified using a commercial camera in which a same type of UMBA is mounted. Based on these results, a flight model is now being manufactured with minor modifications from the prototype. The performance of flight model will be evaluated during 2008-09 in time for the scheduled launch year of 2010.

Fukuhara, Tetsuya; Taguchi, Makoto; Imamura, Takeshi

210

Welcome to the Planets  

NSDL National Science Digital Library

This is a collection of over 200 of the best images from NASA's planetary exploration program. There are captioned images from the major planets, small bodies, and the space craft used for the images.

211

Gemini Observatory Multi-continental Network  

NASA Astrophysics Data System (ADS)

The Gemini Observatory operates two 8-meter IR/optical telescopes: one in Hawaii and the other in Chile. High-speed network connections among all of the mountain telescopes, their sea-level bases, and a support facility in Tucson are essential to their operation, providing video and audio communications, administrative computing systems, remote telescope operation, scientific data management, and many other applications. All the sites have recently been connected via the Abilene network, through collaborations with more than a dozen astronomy facilities near of the various Gemini sites, with Florida International University's AMPATH program, with various providers, and with grant support for the National Science Foundation. While the bandwidth levels required will change over time, Gemini's current objective is a minimum 10 Mbps presence on Internet2 to and from its principal sites. The Gemini North, Gemini South, and Tucson sites are at this level or better. Gemini North has been upgraded to a burst capability up to 155 Mbps to the US Mainland Internet2. Gemini South has burst capability to 10 Mbps, with 6 Mbps guarantied to the US Mainland Internet2.

Kennedy, James R.

2002-11-01

212

Fellow astronauts join Gemini 7 crew for preflight breakfast  

NASA Technical Reports Server (NTRS)

Fellow astronauts join the Gemini 7 prime crew for breakfeast in the Manned Spacecraft Operations Building, Merritt Island, on the day of the Gemini 7 launch. Clockwise around table, starting lower left, are Astronauts James A. Lovell Jr., Gemini 7 prime crew pilot; Walter M. Schirra Jr., Donald K. Slayton, MSC Assistant Director for Flight Crew Operations; Richard F. Gordon Jr., Gemini 8 backup crew pilot; Virgil I. Grissom, Charles Conrad Jr., and Frank Borman, Gemini 7 prime crew command pilot.

1965-01-01

213

Detection and characterization of the atmospheres of the HR 8799 b and c planets with high contrast HST/WFC3 imaging  

NASA Astrophysics Data System (ADS)

We present results from our Hubble Space Telescope program to characterize the atmospheres of two planets, b and c, in the HR8799 system, the only directly imaged multi-planet system currently known. Images were taken in three near-infrared medium-band filters -- F098M, F127M and F137M -- using the Wide Field Camera 3. One of the three filters is sensitive to water absorption bands inaccessible from ground-based observations, providing a unique probe of the thermal emission from the atmospheres of these young, warm giant planets. To enable the detections, we utilized the exquisite pointing accuracy of HST in combination with an innovative pipeline designed to combine the dithered, angular differential imaging data which improved the image resolution while accurately capturing the photometric information. The program spanned 15 orbits and the full data set was analyzed with the Karhunen-Loeve Image Projection (KLIP) routine, an advanced image processing algorithm designed specifically to work with HST data. The results include the first images of the outer-most planet HR 8799 b in the water-band filter, and both the two outer planets in the J-band peak. By probing in regions of the planet spectral energy distribution previously unobservable, we place unique constraints on their atmospheric properties.

Rajan, Abhijith; Barman, Travis; Soummer, Remi; Pueyo, Laurent; Patience, Jenny; Brendan Hagan, J.; Macintosh, Bruce; Marois, Christian; Konopacky, Quinn M.

2015-01-01

214

The Atmospheres of Directly Imaged Planets: Where Has All the Methane Gone?  

NASA Technical Reports Server (NTRS)

Methane and ammonia both first appear at lower effective temperatures in brown dwarf atmospheres than equilibrium chemistry models would suggest. This has traditionally been understood as a consequence of vertical mixing timescales being shorter than chemical equilibration timescales in brown dwarf photospheres. Indeed the eddy diffusivity, a variable accounting for the vigor of vertical mixing, has become a standard part of the description of brown dwarf atmosphere models, along with Teff and log g. While some models have suggested that methane is less favored at lower gravity, the almost complete absence of methane in the atmospheres of directly imaged planets, such as those orbiting HR 8799, even at effective temperatures where methane is readily apparent in brown dwarf spectra, has been puzzling. To better understand the paucity of methane in low gravity atmospheres we have revisited the problem of methane chemistry and mixing. We employed a 1-D atmospheric chemistry code augmented with an updated and complete network of the chemical reactions that link CO to CH4. We find the methane abundance at altitudes at or above the effective photosphere is a strong function of surface gravity because higher g shifts the p-T structure to higher pressures (i.e., a given optical depth is proportional to p/g, a relation mitigated somewhat by pressure broadening). Thus quenching in more massive brown dwarfs occurs at a lower temperature and higher pressure, both favoring CH4. We predict that in the lowest mass young giant planets, methane will appear very late, at effective temperatures as low as 600 K rather than the 1200 K seen among field brown dwarfs. This methane deficiency has important implications for the interpretation of spectra as well as methane-based planetary companion searches, such as the NICI survey. The GPI and SPHERE surveys will test these ideas and probe atmospheric chemistry and composition in an entire new range of parameter space. A caveat is that these calculations presume that the C to O ratio is comfortably less than one; the behavior is quite different if C and O are equally abundant, and of course CH4 is always present if C exceeds O.

Marley, Mark S.; Zahnle, Kevin

2014-01-01

215

Combining high-dispersion spectroscopy (HDS) with high contrast imaging (HCI): Probing rocky planets around our nearest neighbors  

E-print Network

Aims: In this work, we discuss a way to combine High Dispersion Spectroscopy and High Contrast Imaging (HDS+HCI). For a planet located at a resolvable angular distance from its host star, the starlight can be reduced up to several orders of magnitude using adaptive optics and/or coronography. In addition, the remaining starlight can be filtered out using high-dispersion spectroscopy, utilizing the significantly different (or Doppler shifted) high-dispersion spectra of the planet and star. In this way, HDS+HCI can in principle reach contrast limits of ~1e-5 x 1e-5, although in practice this will be limited by photon noise and/or sky-background. Methods: We present simulations of HDS+HCI observations with the E-ELT, both probing thermal emission from a planet at infrared wavelengths, and starlight reflected off a planet atmosphere at optical wavelengths. For the infrared simulations we use the baseline parameters of the E-ELT and METIS instrument, with the latter combining extreme adaptive optics with an R=100,...

Snellen, Ignas; Birkby, Jayne; Brandl, Bernhard; Brogi, Matteo; Keller, Christoph; Kenworthy, Matthew; Schwarz, Henriette; Stuik, Remko

2015-01-01

216

The International Deep Planet Survey I. The frequency of wide-orbit massive planets around A-stars  

E-print Network

Breakthrough direct detections of planetary companions orbiting A-type stars confirm the existence of massive planets at relatively large separations, but dedicated surveys are required to estimate the frequency of similar planetary systems. To measure the first estimation of the giant exoplanetary systems frequency at large orbital separation around A-stars, we have conducted a deep-imaging survey of young (8-400 Myr), nearby (19-84 pc) A- and F-stars to search for substellar companions in the 10-300 AU range. The sample of 42 stars combines all A-stars observed in previous AO planet search surveys reported in the literature with new AO observations from VLT/NaCo and Gemini/NIRI. It represents an initial subset of the International Deep Planet Survey (IDPS) sample of stars covering M- to B-stars. The data were obtained with diffraction-limited observations in H- and Ks-band combined with angular differential imaging to suppress the speckle noise of the central stars, resulting in typical 5-sigma detection li...

Vigan, A; Marois, C; Bonavita, M; De Rosa, R J; Macintosh, B; Song, I; Doyon, R; Zuckerman, B; Lafrenière, D; Barman, T

2012-01-01

217

Direct imaging of extra-solar planets in star forming regions. Lessons learned from a false positive around IM Lupi  

NASA Astrophysics Data System (ADS)

Context. Most exoplanet imagers consist of ground-based adaptive optics coronagraphic cameras which are currently limited in contrast, sensitivity and astrometric precision, but advantageously observe in the near-infrared window (1-5 ?m). Because of these practical limitations, our current observational aim at detecting and characterizing planets puts heavy constraints on target selection, observing strategies, data reduction, and follow-up. Most surveys so far have thus targeted young systems (1-100 Myr) to catch the putative remnant thermal radiation of giant planets, which peaks in the near-infrared. They also favor systems in the solar neighborhood (d < 80 pc), which eases angular resolution requirements but also ensures a good knowledge of the distance and proper motion, which are critical to secure the planet status, and enable subsequent characterization. Aims: Because of their youth, it is very tempting to target the nearby star forming regions, which are typically twice as far as the bulk of objects usually combed for planets by direct imaging. Probing these interesting reservoirs sets additional constraints that we review in this paper by presenting the planet search that we initiated in 2008 around the disk-bearing T Tauri star IM Lup, which is part of the Lupus star forming region (140-190 pc). Methods: We show and discuss why age determination, the choice of evolutionary model for both the central star and the planet, precise knowledge of the host star proper motion, relative or absolute (between different instruments) astrometric accuracy (including plate scale calibration), and patience are the key ingredients for exoplanet searches around more distant young stars. Results: Unfortunately, most of the time, precision and perseverance are not paying off: we discovered a candidate companion around IM Lup in 2008, which we report here to be an unbound background object. We nevertheless review in details the lessons learned from our endeavor, and additionally present the best detection limits ever calculated for IM Lup. We also accessorily report on the successful use of innovative data reduction techniques, such as the damped-LOCI and iterative roll subtraction. Based on the ESO observing programs 380.C-0910, 084.C-0444, 287.C-5040; and HST observing program 10177.

Mawet, D.; Absil, O.; Montagnier, G.; Riaud, P.; Surdej, J.; Ducourant, C.; Augereau, J.-C.; Röttinger, S.; Girard, J.; Krist, J.; Stapelfeldt, K.

2012-08-01

218

Determining Nearby AGN Inclinations via Gemini/NIFS IFU Spectroscopy  

NASA Astrophysics Data System (ADS)

Our team has utilized a robust technique for determining inclinations of nearby AGN by mapping the kinematics of their narrow-line regions (NLRs) using Hubble Space Telescope [O III] images and long-slit spectra from STIS to fit the observed radial velocities to a simple kinematic model. Advances in adaptive optics have made ground-based IFUs capable of achieving the resolution required for mapping these regions to model outflows and determine inclinations. Thus, we present an investigation into applying our inclination modeling technique to Near-IR [SIII] 0.9533?m NLR observations using the Near Infrared Integral Field Spectrometer (NIFS) and Gemini North.

Fischer, Travis C.; Crenshaw, D. M.; Kraemer, S. B.; Schmitt, H. R.; Storchi-Bergmann, T.; Riffel, R.

2013-01-01

219

Revision of Earth-sized Kepler Planet Candidate Properties with High Resolution Imaging by Hubble Space Telescope  

NASA Astrophysics Data System (ADS)

In this paper we present the first results of our HST GO/SNAP program GO-12893 and describe how our image analysis using STScI's DrizzlePac software combined with our own empirical point spread function definition were used to re-evaluate the habitability of some of the most interesting Kepler planet candidates. We used our high resolution imaging to calibrate Kp to the F555W and F775W filters on WFC3/UVIS, and spatially resolved the stellar multiplicity of KOI-1422, KOI-2626, and KOI-3049. We found KOI-1422 to be a tight binary star system with a projected separation of 0.217’’ 90 AU). We found KOI-2626 to be a triple star system with a projected separation of 0.201’’ 110 AU) between the primary and secondary components and 0.161’’ 90 AU) between the primary and tertiary components. We found KOI-3049 to be a binary star system with a projected separation of 0.464’’ 330 AU). Using theoretical isochrones from the Dartmouth Stellar Evolution Database, we performed hierarchical fitting using our derived photometry and the synthetic photometry from the isochrones. Revised stellar parameters for the individual components of the systems show that the stars in these systems range from early-K dwarf to early-M dwarf spectral types. We report with high confidence that all three systems are bound and co-eval based on the tight isochrone fitting and false positive analysis. Using our best-fit stellar parameters from the isochrone matches, we solved for the properties of the planets in the three systems and found that the planets range in size from ~2REarth to ~4 REarth, placing them in the Super Earth/mini-Neptune range. Some planets analyzed here are potentially habitable depending on their stellar host and greenhouse effect level.

Star, Kimberly Michelle; Gilliland, Ronald L.

2014-06-01

220

A Survey of Massive Planets by Direct Imaging with Advanced Adaptive Optics  

NASA Technical Reports Server (NTRS)

The observations are completed. The observing that has been done essentially on the Canada-France-Hawaii Telescope with the PUEO adaptive optics system, is sufficient to identify approximately 10 Jupiter masses objects around the selected targets. A small amount of data was also collected on the Gemini Telescope with the Hokupa'a adaptive optics system. For most of the stars of the sample, about 30mn of exposure time was collected per epoch, with at least 2 epochs. About 15% of the stars of the sample did not meet these requirements, due to observing difficulties listed below: (1) Guide star is too faint for the AO system; (2) The guide star is a close double (about 0.5 to 1 inch separation), which makes it unsuitable for AO guiding; (3) For a few stars, weather and observing constraints could not allow observations.

Owen, Tobias C.

2003-01-01

221

Women Astronomers at Gemini: A Success Story  

NASA Astrophysics Data System (ADS)

Gemini Observatory has been very successful at attracting, hiring and retaining female Scientists. We present data on the growth of the scientific staff since the start of the Observatory, and science fellow recruiting from 2006-2008. At Gemini 31% of the Science Staff holding PhDs are female compared with 13.9% within the United States. The Science Management is 75% female, as is 50% of the Gemini Directorate. This critical mass of female representation within the science staff and management appears to have had a positive effect on female recruitment and hiring. The science fellow recruitment during the past 3 years has attracted 21-38% female applicants and 57% of new hires during this period have been female scientists. Perhaps even more significant, the retention rate of female science staff at Gemini is 88%, compared to 64% for male science staff. There are likely many factors that contribute to this success, but the conclusion is that Gemini has earned a reputation in the scientific community as a place where female scientists are valued and can be successful.

Rodgers, Bernadette; Jorgensen, I.; Barker, N.; Edwards, M.; Trancho, G.

2010-01-01

222

USGS Map-a-Planet  

NSDL National Science Digital Library

Explore global imagery of the planets and satellites from a variety of missions in an easy to use web interface. Customize and download your own image maps of the Moon, Mars, Venus, and other planets and moons.

USGS Astrogeology

223

Which Planet Shall We Visit?  

NSDL National Science Digital Library

Learners will compare images of planets and select one planet to visit and tell the tale of their visit through a comic strip. This is activity 9 of 9 in Mars and Earth: Science Learning Activities for After School.

224

Radiation dosimetry for the Gemini program  

NASA Technical Reports Server (NTRS)

The principal source of radiation for low-earth-orbit, low inclination space flights is in the area of the South Atlantic magnetic anomaly. None of the Gemini dose measurements reported in the paper are of high enough intensity to be considered hazardous. There is a trend toward larger doses as missions are flown higher and longer. Extended orbital operations between 1400 and 4400 kilometers would encounter high interior radiation levels. Pronounced spacecraft geometry effects have been measured in manned spacecraft. Instrumentation for radiation measurements on Gemini spacecraft is described.

Richmond, R. G.

1972-01-01

225

Optical images of an exosolar planet 25 light-years from Earth.  

PubMed

Fomalhaut, a bright star 7.7 parsecs (25 light-years) from Earth, harbors a belt of cold dust with a structure consistent with gravitational sculpting by an orbiting planet. Here, we present optical observations of an exoplanet candidate, Fomalhaut b. Fomalhaut b lies about 119 astronomical units (AU) from the star and 18 AU of the dust belt, matching predictions of its location. Hubble Space Telescope observations separated by 1.73 years reveal counterclockwise orbital motion. Dynamical models of the interaction between the planet and the belt indicate that the planet's mass is at most three times that of Jupiter; a higher mass would lead to gravitational disruption of the belt, matching predictions of its location. The flux detected at 0.8 mum is also consistent with that of a planet with mass no greater than a few times that of Jupiter. The brightness at 0.6 mum and the lack of detection at longer wavelengths suggest that the detected flux may include starlight reflected off a circumplanetary disk, with dimension comparable to the orbits of the Galilean satellites. We also observe variability of unknown origin at 0.6 mum. PMID:19008414

Kalas, Paul; Graham, James R; Chiang, Eugene; Fitzgerald, Michael P; Clampin, Mark; Kite, Edwin S; Stapelfeldt, Karl; Marois, Christian; Krist, John

2008-11-28

226

Optical Images of an Exosolar Planet 25 Light Years from Earth  

SciTech Connect

Fomalhaut is a bright star 7.7 parsec (25 light years) from Earth that harbors a belt of cold dust with a structure consistent with gravitational sculpting by an orbiting planet. Here, we present optical observations of an exoplanet candidate, Fomalhaut b. In the plane of the belt, Fomalhaut b lies approximately 119 astronomical units (AU) from the star, and within 18 AU of the dust belt. We detect counterclockwise orbital motion using Hubble Space Telescope observations separated by 1.73 years. Dynamical models of the interaction between the planet and the belt indicate that the planet's mass is at most three times that of Jupiter for the belt to avoid gravitational disruption. The flux detected at 0.8 {micro}m is also consistent with that of a planet with mass no greater than a few times that of Jupiter. The brightness at 0.6 {micro}m and the lack of detection at longer wavelengths suggest that the detected flux may include starlight reflected off a circumplanetary disk, with dimension comparable to the orbits of the Galilean satellites. We also observed variability of unknown origin at 0.6 {micro}m.

Kalas, P; Graham, J R; Chiang, E; Fitzgerald, M P; Clampin, M; Kite, E S; Stapelfeldt, K; Krist, J

2008-11-12

227

Geo-Engineering through Internet Informatics (GEMINI)  

SciTech Connect

The program, for development and methodologies, was a 3-year interdisciplinary effort to develop an interactive, integrated Internet Website named GEMINI (Geo-Engineering Modeling through Internet Informatics) that would build real-time geo-engineering reservoir models for the Internet using the latest technology in Web applications.

Doveton, John H.; Watney, W. Lynn

2003-03-06

228

NIRI Imaging of Transitional Protoplanetary Disks with Submm-Resolved Inner Holes/Gaps  

NASA Astrophysics Data System (ADS)

Disks around young stars with inner holes/gaps (transitional disks) provide a crucial probe of active planet formation and/or the last phases of planet formation. We propose high-contrast Gemini/NIRI imaging of disks around four stars with inner holes/gaps: LkCa 15, MWC 758, LkHa 330, and UX Tau A. In all cases, the disks have been spatially resolved in the submm, have inner holes/gaps large enough to be resolved by NIRI, and show structural features indicative of sculpting by unseen planets. Our study will provide sensitive constraints on the presence of planet-mass objects and provide a detailed probe of the structure of disks in the process of spawning planetary systems.

Currie, Thayne; Condell, Hannah Jang; Robitaille, Thomas; Dahm, Scott; Wilner, David; Andrews, Sean; Kuchner, Marc

2011-08-01

229

The First H-band Spectrum of the Giant Planet ? Pictoris b  

NASA Astrophysics Data System (ADS)

Using the recently installed Gemini Planet Imager (GPI), we have obtained the first H-band spectrum of the planetary companion to the nearby young star ? Pictoris. GPI is designed to image and provide low-resolution spectra of Jupiter-sized, self-luminous planetary companions around young nearby stars. These observations were taken covering the H band (1.65 ?m). The spectrum has a resolving power of ~45 and demonstrates the distinctive triangular shape of a cool substellar object with low surface gravity. Using atmospheric models, we find an effective temperature of 1600-1700 K and a surface gravity of log (g) = 3.5-4.5 (cgs units). These values agree well with "hot-start" predictions from planetary evolution models for a gas giant with mass between 10 and 12 M Jup and age between 10 and 20 Myr.

Chilcote, Jeffrey; Barman, Travis; Fitzgerald, Michael P.; Graham, James R.; Larkin, James E.; Macintosh, Bruce; Bauman, Brian; Burrows, Adam S.; Cardwell, Andrew; De Rosa, Robert J.; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Gavel, Donald; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Kalas, Paul; Konopacky, Quinn; Maire, Jérôme; Marchis, Franck; Marley, Mark S.; Marois, Christian; Millar-Blanchaer, Max; Morzinski, Katie; Norton, Andrew; Oppenheimer, Rebecca; Palmer, David; Patience, Jennifer; Perrin, Marshall; Poyneer, Lisa; Pueyo, Laurent; Rantakyrö, Fredrik T.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Sivaramakrishnan, Anand; Song, Inseok; Soummer, Rémi; Thomas, Sandrine; Wallace, J. Kent; Wiktorowicz, Sloane; Wolff, Schuyler

2015-01-01

230

Blue Planet  

NSDL National Science Digital Library

This Web site is a companion to the Discovery Channel/ BBC television series Blue Planet: Seas of Life. The Web site includes images, games, and expeditions all related to oceanography and marine biology. One feature that is particularly interesting is Ocean Alert, an interactive, current events feature where users can identify the topics that most interest them. News headlines, with links to more complete stories, are organized into twelve topics; users select the topics and area of the world of interest from a rotating map. This site is fun to use and informative, and users may appreciate the options to explore only as in-depth as they choose.

2002-01-01

231

IBIS: An Interferometer-Based Imaging System for Detecting Extrasolar Planets with a Next Generation Space Telescope  

NASA Technical Reports Server (NTRS)

The direct detection of extrasolar planetary systems is a challenging observational objective. The observing system must be able to detect faint planetary signals against the background of diffracted and scattered starlight, zodiacal light, and in the IR, mirror thermal radiation. As part of a JPL study, we concluded that the best long-term approach is a 10-20 m filled-aperture telescope operating in the thermal IR (10-15 microns). At these wavelengths, the star/planet flux ratio is on the order of 10(exp 6)-10(exp 8). Our study supports the work of Angel et al., who proposed a cooled 16-m IR telescope and a special apodization mask to suppress the stellar light within a limited angular region around the star. Our scheme differs in that it is capable of stellar suppression over a much broader field-of- view, enabling more efficient planet searches. To do this, certain key optical signal-processing components are needed, including a coronagraph to apodize the stellar diffraction pattern, an infrared interferometer to provide further starlight suppression, a complementary visible-wavelength interferometer to sense figure errors in the telescope optics, and a deformable mirror to adaptively compensate for these errors. Because of the central role of interferometry we have designated this concept the Interferometer-Based Imaging System (IBIS). IBIS incorporates techniques originally suggested by Ken Knight for extrasolar planet detection at visible wavelengths. The type of telescope discussed at this workshop is well suited to implementation of the IBIS concept.

Diner, David J.

1989-01-01

232

Exploring the Planets Gallery  

NSDL National Science Digital Library

Based upon the Exploring the Planets gallery at the National Air and Space Museum in Washington, DC, this site provides information about our solar system and its exploration. The gallery begins with a Discovery Section, which explores the development of astronomical thought, beginning with the Greeks, the Renaissance, and Galileo, and ending with satellites and the discovery of new planets. A section on Exploration Tools investigates the past, present and future of earth-based exploration, telescopes, spacecraft, landers, orbiters and rovers. The Planetary Comparisons section discusses similarities and differences between planets such as their atmospheres and geography. An entire section is devoted to the planets themselves with data sets showing statistics on size, mass, orbits, satellites and more. Each planet and the asteroids have their own page with images, exploration facts and other data. There is also a section about comets discussing their discovery, history, observations, anatomy and images.

233

The software design of the Gemini 8m telescopes Stephen Wampler  

E-print Network

The software design of the Gemini 8m telescopes Stephen Wampler Gemini 8m Telescopes Project, 950 N. Cherry Ave, Tucson, AZ 85726 ABSTRACT The design of the software for the Gemini 8m Telescopes is nearly. Keywords: telescope software design, design processes, Gemini software 1. INTRODUCTION The Gemini 8m

234

Observations Of The LCROSS Impact With NIFS On The Gemini North Telescope  

NASA Astrophysics Data System (ADS)

The Lunar CRater Observation and Sensing Satellite (LCROSS) Centaur rocket impacted a permanently shadowed crater near the south pole of the Moon at 11:31 UTC 2009 October 09. Gemini, one of several telescopes in a coordinated network observing the impact, conducted observations using NIFS to obtain 3D K-band imaging spectroscopy to detect water ice in the ejected plume of material. The spectral slope of the NIFS data can constrain the grain size and height distribution as the plume evolves, measuring the total mass and the water ice concentration in the plume. These observations provided an engineering challenge for Gemini, including the need to track non-sidereal with constantly changing track rates and guide on small bright moon craters, in order to keep the impact site within the NIFS field-of-view. High quality images taken by GMOS-N, NIRI and the acquisition camera during engineering periods at specific lunar libration and illumination were also used by the LCROSS ground based observing team to supplement slit positioning and offset plans for other ground based observatories. LCROSS mission support and engineering has resulted in improved telescope functionality for non-sidereal targets, including the ability to upload and import target ephemerides directly into the TCS, starting in semester 2010B. In this poster we present the engineering results and observing improvements which will facilitate enhanced user capabilities of the Gemini telescopes arising from the intensive LCROSS support challenge. Gemini Observatory is operated by AURA, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the NSF (United States), the STFC (United Kingdom), the NRC (Canada), CONICYT (Chile), the ARC (Australia), Ministério da Ciência e Tecnologia (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). In part this research was supported by NASA through contracts to SWRI and NSF grant AST-0706980 to the U. Minnesota.

Roth, Katherine; Stephens, A. W.; Trujillo, C. A.; McDermid, R. M.; Woodward, C. E.; Walls, B. D.; Coulson, D. M.; Matulonis, A. C.; Ball, J. G.; Wooden, D. H.

2010-01-01

235

Gemini 10 prime crew during post flight press conference  

NASA Technical Reports Server (NTRS)

At podium during Gemini 10 press conference are (l-r) Dr. Robert C. Seamans, Astronauts John Young and Michael Collins and Dr. Robert R. Gilruth (39895); Wide angle view of the Manned Spacecraft Center (MSC) News Center during the Gemini 10 prime crew post flight press conference (38786); Astronaut Young draws diagram on chalk board of tethered extravehicular activity accomplished during Gemini 10 flight (39897).

1966-01-01

236

Detecting Planets Outside The Solar System  

NASA Technical Reports Server (NTRS)

Report describes proposed Astrometric Imaging Telescope, used to detect planets in orbit around distant stars. Includes executive summary and statement of scientific objectives of Astrometric Imaging Telescope program.

Pravdo, Steven H.; Terrile, Richard J.; Ftaclas, Christ; Gatewood, George

1993-01-01

237

Direct imaging of exoplanets around multiple star systems  

NASA Astrophysics Data System (ADS)

Direct imaging of extra-solar planets is now a reality, especially with the deployment and commissioning of the first generation of specialized ground-based instruments such as the Gemini Planet Imager and SPHERE. These systems will allow detection of Jupiter-like planets 10^7 times fainter than their host star. Obtaining this contrast level and beyond requires the combination of a coronagraph to suppress light coming from the host star and a wavefront control system including a deformable mirror (DM) to remove residual starlight (speckles) created by the imperfections of telescope. However, all these current and future systems focus on detecting faint planets around a single host star or unresolved binaries/multiples, while several targets or planet candidates are located around nearby binary stars such as our neighboring star Alpha Centauri.Here, we present a method to simultaneously correct aberrations and diffraction of light coming from the target star as well as its companion star in order to reveal planets orbiting the target star. This method works even if the companion star is outside the control region of the DM (beyond its half-Nyquist frequency), by taking advantage of aliasing effects.

Thomas, Sandrine

2015-01-01

238

DIRECT IMAGING OF FINE STRUCTURES IN GIANT PLANET-FORMING REGIONS OF THE PROTOPLANETARY DISK AROUND AB AURIGAE  

SciTech Connect

We report high-resolution 1.6 {mu}m polarized intensity (PI) images of the circumstellar disk around the Herbig Ae star AB Aur at a radial distance of 22 AU (0.''15) up to 554 AU (3.''85), which have been obtained by the high-contrast instrument HiCIAO with the dual-beam polarimetry. We revealed complicated and asymmetrical structures in the inner part ({approx}<140 AU) of the disk while confirming the previously reported outer (r {approx}> 200 AU) spiral structure. We have imaged a double ring structure at {approx}40 and {approx}100 AU and a ring-like gap between the two. We found a significant discrepancy of inclination angles between two rings, which may indicate that the disk of AB Aur is warped. Furthermore, we found seven dips (the typical size is {approx}45 AU or less) within two rings, as well as three prominent PI peaks at {approx}40 AU. The observed structures, including a bumpy double ring, a ring-like gap, and a warped disk in the innermost regions, provide essential information for understanding the formation mechanism of recently detected wide-orbit (r > 20 AU) planets.

Hashimoto, J.; Tamura, M.; Fukue, T.; Kokubo, E. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Muto, T. [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551 (Japan); Kudo, T. [Subaru Telescope, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Fukagawa, M. [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Goto, M.; Henning, T. [Max Planck Institute for Astronomy, Heidelberg (Germany); Grady, C. A. [Eureka Scientific and Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Hodapp, K. [Institute for Astronomy, University of Hawaii, 640 North A'ohoku Place, Hilo, HI 96720 (United States); Honda, M. [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan); Inutsuka, S. [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan); Knapp, G.; McElwain, M. W.; Turner, E. L. [Department of Astrophysical Sciences, Princeton University, NJ 08544 (United States); Momose, M.; Okamoto, Y. K. [College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512 (Japan); Ohashi, N.; Takami, M., E-mail: jun.hashimoto@nao.ac.jp, E-mail: motohide.tamura@nao.ac.jp [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)

2011-03-10

239

PET performance of the GEMINI TF PET — MR: The world's first whole body PET — MRI scanner  

Microsoft Academic Search

The GEMINI TF PET-MRI (Philips Healthcare, Cleveland, OH) is a newly released whole body hybrid imaging system with a Philips Achieva 3T system and a Philips TF (TruFlight) PET. We report the standard NEMA NU2 measurements for the scanner. Compared to PET-CT, modifications to the PET were made to avoid mutual system interference and deliver uncompromising performance which is equivalent

Navdeep Ojha; Jerome Griesmer; Zhiqiang Hu; Ling Shao; David Izquierdo; Josef Machac; Osman Ratib; Habib Zaidi; Valentin Fuster; Zahi A Fayad

2010-01-01

240

Astrometric performance of the Gemini multiconjugate adaptive optics system in crowded fields  

NASA Astrophysics Data System (ADS)

The Gemini multiconjugate adaptive optics system (GeMS) is a facility instrument for the Gemini South telescope. It delivers uniform, near-diffraction-limited image quality at near-infrared wavelengths over a 2 arcmin field of view. Together with the Gemini South Adaptive Optics Imager (GSAOI), a near-infrared wide-field camera, GeMS/GSAOI's combination of high spatial resolution and a large field of view will make it a premier facility for precision astrometry. Potential astrometric science cases cover a broad range of topics including exoplanets, star formation, stellar evolution, star clusters, nearby galaxies, black holes and neutron stars, and the Galactic Centre. In this paper, we assess the astrometric performance and limitations of GeMS/GSAOI. In particular, we analyse deep, mono-epoch images, multi-epoch data and distortion calibration. We find that for single-epoch, undithered data, an astrometric error below 0.2 mas can be achieved for exposure times exceeding 1 min, provided enough stars are available to remove high-order distortions. We show however that such performance is not reproducible for multi-epoch observations, and an additional systematic error of ˜0.4 mas is evidenced. This systematic multi-epoch error is the dominant error term in the GeMS/GSAOI astrometric error budget, and it is thought to be due to time-variable distortion induced by gravity flexure.

Neichel, Benoit; Lu, Jessica R.; Rigaut, François; Ammons, S. Mark; Carrasco, Eleazar R.; Lassalle, Emmanuel

2014-11-01

241

Ocean Planet  

NSDL National Science Digital Library

_Ocean Planet_ is a Smithsonian Institution Traveling Exhibition that now has a companion on-line exhibition. It covers varied topics associated with the ocean, such as the science of the ocean, the animals, people, and communities who use the ocean, and pollution problems currently endangering ocean resources. The exhibit features all of the text and a good portion of the images from the traveling exhibit. The curator of this exhibit has put together six special interest tours including Biodiversity, Women and the Sea, and Pollution. Users can also build their own special tour from a list of key words. The current list contains only four words, but is expected to grow in the future. Visitors can also consult a comprehensive list of educational materials and ocean resources.

242

High-contrast planet imager for Kyoto 4m segmented telescope  

NASA Astrophysics Data System (ADS)

We propose a new high contrast imager for Kyoto 4m segmented telescope called SEICA (Second-generation Exoplanet Imager with Coronagraphic Adaptive optics), aiming at detection and characterization of selfluminous gas giants within 10AU around nearby stars. SEICA is aggressively optimized for high performance at very small inner working angle, 10-6 detection contrast at 0".1 in 1-hour integration. We start the on-sky commissioning test in 2016 and the science observations in 2017. Since it is the first time to realize the highcontrast imaging on the segmented telescope, SEICA is an important step toward future high contrast sciences on Extremely Large Telescopes (ELTs). This paper presents an overall of the SEICA program and the conceptual design for ultimate performance under given atmospheric conditions.

Matsuo, Taro; Murakami, Naoshi; Kotani, Takayuki; Kawahara, Hajime; Natsume, Noriaki; Kino, Masaru; Yamamoto, Kodai; Imada, Hiroaki; Kurita, Mikio; Iribe, Masatsugu; Nishida, Hideya; Kida, Manabu; Kitou, Hirofumi; Ishikawa, Kumi; Uda, Yutaka; Tokoro, Hitoshi; Nagata, Tetsuya; Iwamuro, Fumihide; Miura, Noriaki; Oya, Shin; Itoh, Yoichi; Shibai, Hiroshi; Tamura, Motohide

2014-07-01

243

The Planet Pluto  

NSDL National Science Digital Library

This series of webpages is part of a course called Astronomy 161: The Solar System, offered by the Department of Physics and Astronomy at the University of Tennessee. This section covers the general features of Pluto, including information on whether it is the eighth or ninth planet from the Sun, and whether there are additional planets beyond Pluto. There are also subsections on the surface of Pluto and its moon, Charon, including Hubble Space Telescope images.

244

Mass-Radius Relationships for Low-Mass Planets: From Iron Planets to Water Planets  

NASA Technical Reports Server (NTRS)

Transit observations, and radial velocity measurements, have begun to populate the mass radius diagram for extrasolar planets; fubture astrometric measurements and direct images promise more mass and radius information. Clearly, the bulk density of a planet indicates something about a planet s composition--but what? I will attempt to answer this question in general for low-mass planets (planets obey a kind of universal mass-radius relationship: an expansion whose first term is M approx. R(sup 3).

Kuchner, Marc

2007-01-01

245

Extrasolar planets  

Microsoft Academic Search

The discovery of the first extra-solar planet surrounding a main-sequence star was announced in 1995, based on very precise radial velocity (Doppler) measurements. A total of 34 such planets were known by the end of March 2000, and their numbers are growing steadily. The newly discovered systems confirm some of the features predicted by standard theories of star and planet

M. A. C. Perryman

2000-01-01

246

Manned Space-Flight Experiments: Gemini V Mission  

NASA Technical Reports Server (NTRS)

This compilation of papers constitutes an interim report on the results of experiments conducted during the Gemini V manned space flight. The results of experiments conducted on Gemini III and IV manned space flights have been published previously in a similar interim report, "Manned Space Flight Experiments Symposium, Gemini Missions III and IV," which is available upon request from MSC Experiments Program Office, Houston, Texas (Code EX, Attention of R. Kinard). The Gemini V mission provided the greatest opportunity to date for conducting experiments; the increased mission duration of eight days provided this added capability. The total mission experiment complement was seventeen. Five experiments were designed to obtain basic scientific knowledge, five were medical, and seven were technological and engineering in nature. Six of the experiments had flown previously on Gemini IV, and eleven were new. The results of the experiments, including real-time modification to preflight plans made necessary by abnormal spacecraft system operation, are presented.

1966-01-01

247

Giant Planets  

NASA Astrophysics Data System (ADS)

Beyond the inner solar system's terrestrial planets, with their compact orbits and rock -metal compositions, lies the realm of the outer solar system and the giant planets. Here the distance between planets jumps by an order of magnitude relative to the spacing of the terrestrial planets, and the masses of the giants are one to two orders of magnitude greater than Venus and Earth - the largest terrestrial bodies. Composition changes as well, since the giant planets are largely gaseous, with inferred admixtures of ice, rock, and metal, while the terrestrial planets are essentially pure rock and metal. The giant planets have many more moons than do the terrestrial planets, and the range of magnetic field strengths is larger in the outer solar system. It is the giant planets that sport rings, ranging from the magnificent ones around Saturn to the variable ring arcs of Neptune. Were it not for the fact that only Earth supports abundant life (with life possibly existing, but not proved to exist, in the martian crust and liquid water regions underneath the ice of Jupiter's moon Europa), the terrestrial planets would pale in interest next to the giant planets for any extraterrestrial visitor.

Lunine, J. I.

248

870 micron Imaging of a Transitional Disk in Upper Scorpius: Holdover from the Era of Giant Planet Formation?  

E-print Network

We present 880 micron images of the transition disk around the star [PZ99] J160421.7-213028, a solar-mass star in the nearby Upper Scorpius association. With a resolution down to 0.34 arcsec, we resolve the inner hole in this disk, and via model fitting to the visibilities and spectral energy distribution we determine both the structure of the outer region and the presence of sparse dust within the cavity. The disk contains about 0.1 Jupiter masses of mm-emitting grains, with an inner disk edge of about 70 AU. The inner cavity contains a small amount of dust with a depleted surface density in a region extending from about 20-70 AU. Taking into account prior observations indicating little to no stellar accretion, the lack of a binary companion, and the presence of dust near 0.1 AU, we determine that the most likely mechanism for the formation of this inner hole is the presence of one or more giant planets.

Mathews, Geoffrey S; Menard, Francois

2012-01-01

249

Astrometric Detection of Earthlike Planets  

E-print Network

Astrometry can detect rocky planets in a broad range of masses and orbital distances and measure their masses and three-dimensional orbital parameters, including eccentricity and inclination, to provide the properties of terrestrial planets. The masses of both the new planets and the known gas giants can be measured unambiguously, allowing a direct calculation of the gravitational interactions, both past and future. Such dynamical interactions inform theories of the formation and evolution of planetary systems, including Earth-like planets. Astrometry is the only technique technologically ready to detect planets of Earth mass in the habitable zone (HZ) around solar-type stars within 20 pc. These Earth analogs are close enough for follow-up observations to characterize the planets by infrared imaging and spectroscopy with planned future missions such as the James Webb Space Telescope (JWST) and the Terrestrial Planet Finder/Darwin. Employing a demonstrated astrometric precision of 1 microarcsecond and a noise ...

Shao, Michael; Catanzarite, Joseph H; Edberg, Stephen J; Leger, Alain; Malbet, Fabien; Queloz, Didier; Muterspaugh, Matthew W; Beichman, Charles; Fischer, Debra A; Ford, Eric; Olling, Robert; Kulkarni, Shrinivas; Unwin, Stephen C; Traub, Wesley

2009-01-01

250

Self-Assembly of Gemini Surfactants  

NASA Astrophysics Data System (ADS)

The self-assembly behavior of Gemini (dimeric or twin-tail) dicarboxylate disodium surfactants is studied using molecular dynamics simulations. This gemini architecture, in which two single tailed surfactants are joined through a flexible hydrophobic linker, has been shown to exhibit concentration-dependent aqueous self-assembly into lyotropic phases including hexagonal, gyroid, and lamellar morphologies. Our simulations reproduce the experimentally observed phases at similar amphiphile concentrations in water, including the unusual ability of these surfactants to form gyroid phases over unprecedentedly large amphiphile concentration windows. We demonstrate quanitative agreement between the predicted and experimentally observed domain spacings of these nanostructured materials. Through careful conformation analyses of the surfactant molecules, we show that the gyroid phase is electrostatically stabilized related to the lamellar phase. By starting with a lamellar phase, we show that decreasing the charge on the surfactant headgroups by carboxylate protonation or use of a bulkier tetramethyl ammonium counterion in place of sodium drives the formation of a gyroid phase.

Yethiraj, Arun; Mondal, Jagannath; Mahanthappa, Mahesh

2013-03-01

251

Atmospheres of Extrasolar Giant Planets  

NASA Technical Reports Server (NTRS)

The next decade will almost certainly see the direct imaging of extrasolar giant planets around nearby stars. Unlike purely radial velocity detections, direct imaging will open the door to characterizing the atmosphere and interiors of extrasola planets and ultimately provide clues on their formation and evolution through time. This process has already begun for the transiting planets, placing new constraints on their atmospheric structure, composition, and evolution. Indeed the key to understanding giant planet detectability, interpreting spectra, and constraining effective temperature and hence evolution-is the atmosphere. I will review the universe of extrasolar giant planet models, focusing on what we have already learned from modeling and what we will likely be able to learn from the first generation of direct detection data. In addition to these theoretical considerations, I will review the observations and interpretation of the - transiting hot Jupiters. These objects provide a test of our ability to model exotic atmospheres and challenge our current understanding of giant planet evolution.

Marley, Mark

2006-01-01

252

Information extraction from digital images of the earth and the planets  

NASA Technical Reports Server (NTRS)

An overview is presented of recent developments at the JPL Image Processing Laboratory which emphasize the utilization of a digital computer to automate the process of information extraction from digital imagery. Consideration is given to: (1) the analysis of Viking Orbiter stereo imagery to determine elevation profiles of the Mars surface, (2) the use of Viking Lander stereo imagery to determine nonhazardous surface sample acquisition strategies, (3) the correlation of Landsat imagery with geographically referenced cultural data to determine land use trends, and (4) the generation of mosaics using digital computer techniques.

Green, W. B.

1978-01-01

253

Microlensing Extrasolar Planets  

E-print Network

Microlensing Searches for Extrasolar Planets Microlensing Searches for Extrasolar Planets Microlensing Searches for Extrasolar Planets, B. Scott Gaudi, IAS Scientific Frontiers in Research on Extrasolar Planets, June 19, 2002 #12;Microlensing and PlanetsMicrolensing and Planets Microlensing Searches

Gaudi, B. Scott

254

Wobbling Toward Planet Detection  

NASA Astrophysics Data System (ADS)

Several techniques have matured during the past year which enable indirect detection of planets orbiting main sequence stars. These methods include: RADIAL VELOCITIES, LONG BASELINE INTERFEROMETRY (astrometric, not imaging), LARGE TELESCOPE ASTROMETRY, TRANSITS BY TERRESTRIAL PLANETS, and GRAVITATIONAL LENSING. Current velocity precision is better than 10 m/s (at several observatories) which enables detection of jupiter-like planets within 5AU. Ground-based astrometry by Gatewood achieves a precision of 0.001arcsec, sufficient to detect jupiter-like planets orbiting >5AU from nearby stars. The above two techniques will soon benefit from larger aperture (Keck, HET, VLT) and superior seeing. Future ground-based interferometric astrometry should be able to detect planets like Uranus and Neptune. Detection of terrestrial planets are possible, in principle, with techniques of transits or lensing. I will review each of the above techniques with regard to instrumentation status and ultimate usefulness. I will report the results to date of on-going projects to detect planetary systems, especially from velocities and single-aperture astrometry. The status of the companion to 51 Pegasus and other reported planets will be described.

Marcy, G. W.

1995-12-01

255

Structure of the complex monolayer of gemini surfactant and DNA at the air/water interface.  

PubMed

The properties of the complex monolayers composed of cationic gemini surfactants, [C(18)H(37)(CH(3))(2)N(+)-(CH(2))(s)-N(+)(CH(3))(2)C(18)H(37)],2Br(-) (18-s-18 with s = 3, 4, 6, 8, 10 and 12), and ds-DNA or ss-DNA at the air/water interface were in situ studied by the surface pressure-area per molecule (?-A) isotherm measurement and the infrared reflection absorption spectroscopy (IRRAS). The corresponding Langmuir-Blodgett (LB) films were also investigated by the atomic force microscopy (AFM), the Fourier transform infrared spectroscopy (FT-IR), and the circular dichroism spectroscopy (CD). The ?-A isotherms and AFM images reveal that the spacer of gemini surfactant has a significant effect on the surface properties of the complex monolayers. As s ? 6, the gemini/ds-DNA complex monolayers can both laterally and normally aggregate to form fibril structures with heights of 2.0-7.0 nm and widths of from several tens to ~300 nm. As s > 6, they can laterally condense to form the platform structure with about 1.4 nm height. Nevertheless, FT-IR, IRRAS, and CD spectra, as well as AFM images, suggest that DNA retains its double-stranded character when complexed. This is very important and meaningful for gene therapy because it is crucial to maintain the extracellular genes undamaged to obtain a high transfection efficiency. In addition, when s ? 6, the gemini/ds-DNA complex monolayers can experience a transition of DNA molecule from the double-stranded helical structure to a typical ?-phase with a supramolecular chiral order. PMID:22260723

Chen, Qibin; Kang, Xueli; Li, Rong; Du, Xuezhong; Shang, Yazhuo; Liu, Honglai; Hu, Ying

2012-02-21

256

Management of the Gemini 8M Telescopes Project R. Kurz, M. Mountain  

E-print Network

Management of the Gemini 8­M Telescopes Project R. Kurz, M. Mountain Gemini Telescopes Project, 950 N. Cherry Ave., Tucson AZ 85719 Gemini Preprint #7 #12; Management of the Gemini 8­M Telescopes. The construction phase of the project has demanding scientific requirements, a fixed budget that is tight

257

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.

258

Validation of a Monte Carlo simulation of the Philips Allegro/GEMINI PET systems using GATE.  

PubMed

A newly developed simulation toolkit, GATE (Geant4 Application for Tomographic Emission), was used to develop a Monte Carlo simulation of a fully three-dimensional (3D) clinical PET scanner. The Philips Allegro/GEMINI PET systems were simulated in order to (a) allow a detailed study of the parameters affecting the system's performance under various imaging conditions, (b) study the optimization and quantitative accuracy of emission acquisition protocols for dynamic and static imaging, and (c) further validate the potential of GATE for the simulation of clinical PET systems. A model of the detection system and its geometry was developed. The accuracy of the developed detection model was tested through the comparison of simulated and measured results obtained with the Allegro/GEMINI systems for a number of NEMA NU2-2001 performance protocols including spatial resolution, sensitivity and scatter fraction. In addition, an approximate model of the system's dead time at the level of detected single events and coincidences was developed in an attempt to simulate the count rate related performance characteristics of the scanner. The developed dead-time model was assessed under different imaging conditions using the count rate loss and noise equivalent count rates performance protocols of standard and modified NEMA NU2-2001 (whole body imaging conditions) and NEMA NU2-1994 (brain imaging conditions) comparing simulated with experimental measurements obtained with the Allegro/GEMINI PET systems. Finally, a reconstructed image quality protocol was used to assess the overall performance of the developed model. An agreement of <3% was obtained in scatter fraction, with a difference between 4% and 10% in the true and random coincidence count rates respectively, throughout a range of activity concentrations and under various imaging conditions, resulting in <8% differences between simulated and measured noise equivalent count rates performance. Finally, the image quality validation study revealed a good agreement in signal-to-noise ratio and contrast recovery coefficients for a number of different volume spheres and two different (clinical level based) tumour-to-background ratios. In conclusion, these results support the accurate modelling of the Philips Allegro/GEMINI PET systems using GATE in combination with a dead-time model for the signal flow description, which leads to an agreement of <10% in coincidence count rates under different imaging conditions and clinically relevant activity concentration levels. PMID:16467589

Lamare, F; Turzo, A; Bizais, Y; Le Rest, C Cheze; Visvikis, D

2006-02-21

259

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. PMID:11035782

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

2000-01-01

260

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.

261

Mystery Planet  

NSDL National Science Digital Library

This activity is about the study of planetary samples. Learners will use samples of crustal material to sort, classify, and make observations about an unknown planet. From their observations, students will interpret the geologic history of their mystery planet and make inferences about past life or the potential for life on the "Mystery" planet. The lesson models scientific inquiry using the 5E instructional model and includes teacher notes and vocabulary.

262

Planet X  

NASA Astrophysics Data System (ADS)

A name given to a hypothetical tenth major planet once believed to exist in the outer solar system, beyond the orbit of Neptune. The `X', which stood for `unknown', was also appropriate as the roman numeral for `ten'. The label `Planet X' was originated by Percival Lowell. From the late nineteenth century, he and others, including William H Pickering, worked out orbits for a large tenth planet wh...

Murdin, P.

2000-11-01

263

Shallow Cavities in Multiple-planet Systems  

NASA Astrophysics Data System (ADS)

Large cavities are often observed in protoplanetary disks, which might suggest the presence of planets opening gaps in the disk. Multiple planets are necessary to produce a wide cavity in the gas. However, multiple planets may also be a burden to the carving out of very deep gaps. When additional planets are added to the system, the time-dependent perturbations from these additional satellites can stir up gas in the gap, suppressing cavity opening. In this study, we perform two-dimensional numerical hydro calculations of gap opening for single and multiple planets, showing the effect that additional planets have on the gap depths. We show that multiple planets produce much shallower cavities than single planets, so that more massive planets are needed in the multiple-planet case to produce an equivalent gap depth as in the single-planet case. To deplete a gap by a factor of 100 for the parameters chosen in this study, one only requires Mp ? 3.5 MJ in the single-planet case, but much more massive planets, Mp ? 7 MJ are required in the multiple-planet case. This requirement of high-mass planets implies that such planets may be detectable in the next generation of direct imaging projects, in gaps whose depths are constrained to be sufficiently deep by ALMA.

Duffell, Paul C.; Dong, Ruobing

2015-03-01

264

Gemini: A long-range cargo transport  

NASA Technical Reports Server (NTRS)

The proposed Gemini, a long-range cargo transport, is designed as a high capacity, dedicated cargo transporter of 8'x8'x20' inter-modal containers, and long-range design. These requirements will result in a design that is larger than any existing aircraft. Due to the size, a conventional configuration would result in an aircraft unable to operate economically at existing airports. It is necessary to design for a minimum possible empty weight, wingspan, and landing gear track. After considering both a single fuselage biplane and a double fuselage biplane configuration, the design team choose the double fuselage biplane configuration. Both of these configuration choices result in a reduced wing root bending moment and subsequently in substantial savings in the wing weight. An overall decrease in the weight of the airplane, its systems, and fuel will be a direct result of the wing weight savings.

1994-01-01

265

Geo-Engineering through Internet Informatics (GEMINI)  

SciTech Connect

GEMINI will resolve reservoir parameters that control well performance; characterize subtle reservoir properties important in understanding and modeling hydrocarbon pore volume and fluid flow; expedite recognition of bypassed, subtle, and complex oil and gas reservoirs at regional and local scale; differentiate commingled reservoirs; build integrated geologic and engineering model based on real-time, iterate solutions to evaluate reservoir management options for improved recovery; provide practical tools to assist the geoscientist, engineer, and petroleum operator in making their tasks more efficient and effective; enable evaluations to be made at different scales, ranging from individual well, through lease, field, to play and region (scalable information infrastructure); and provide training and technology transfer to evaluate capabilities of the client.

Watney, W. Lynn; Doveton, John H.; Victorine, John R.; Bohling, Goeffrey C.; Bhattacharya, Saibal; Byers, Alan P.; Carr, Timothy R.; Dubois, Martin K.; Gagnon, Glen; Guy, Willard J.; Look, Kurt; Magnuson, Mike; Moore, Melissa; Olea, Ricardo; Pakalapadi, Jayprakash; Stalder, Ken; Collins, David R.

2002-06-25

266

Geological interpretation of a Gemini photo  

USGS Publications Warehouse

Study of the Gemini V photograph of the Salt Range and Potwar Plateau, West Pakistan, indicates that small-scale orbital photographs permit recognition of the regional continuity of some geologic features, particularly faults and folds that could he easily overlooked on conventional air photographs of larger scale. Some stratigraphic relationships can also be recognized on the orbital photograph, but with only minimal previous geologic knowledge of the area, these interpretations are less conclusive or reliable than the interpretation of structure. It is suggested that improved atmospheric penetration could be achieved through the use of color infrared film. Photographic expression of topography could also be improved by deliberately photographing some areas during periods of low sun angle.

Hemphill, William R.; Danilchik, Walter

1968-01-01

267

Catalogue of Spaceborne Imaging: A Guide to NSSDC 's Planetary Image Archives  

NSDL National Science Digital Library

This image archive, supported by the NASA National Space Science Data Center (NSSDC), features photos taken during NASA space missions (Apollo, Gemini, Mariner, Voyager, and others) and the Soviet Venera probes to Venus. The photos are organized by subject: each of the planets, Earth's Moon, and other objects in the solar system such as comets and asteroids. Each subject category includes a fact sheet with information such as orbital parameters, bulk parameters, and other details about the objects photographed. Each image is accompanied by a brief description and information about location and time when the photo was taken, imaging properties, and ordering information. The photos are also indexed by mission, with links to pages of the NSSDC site describing the mission. The photos may be downloaded in high- and low-resolution versions, or ordered as hard copies (prints, transparencies, or 35 mm slides).

268

Planet Business  

NSDL National Science Digital Library

The directory Planet Business aims to provide a "great gateway between Africa, America, Asia, Europe and Oceania." Business metasites from around the world are listed in an A-Z index and by region, and the new Marketplace of Planet Business connects potential business partners among importers, exporters, traders, and distributors.

269

Extreme Planets  

NASA Technical Reports Server (NTRS)

This artist's concept depicts the pulsar planet system discovered by Aleksander Wolszczan in 1992. Wolszczan used the Arecibo radio telescope in Puerto Rico to find three planets - the first of any kind ever found outside our solar system - circling a pulsar called PSR B1257+12. Pulsars are rapidly rotating neutron stars, which are the collapsed cores of exploded massive stars. They spin and pulse with radiation, much like a lighthouse beacon. Here, the pulsar's twisted magnetic fields are highlighted by the blue glow.

All three pulsar planets are shown in this picture; the farthest two from the pulsar (closest in this view) are about the size of Earth. Radiation from charged pulsar particles would probably rain down on the planets, causing their night skies to light up with auroras similar to our Northern Lights. One such aurora is illustrated on the planet at the bottom of the picture.

Since this landmark discovery, more than 160 extrasolar planets have been observed around stars that are burning nuclear fuel. The planets spotted by Wolszczan are still the only ones around a dead star. They also might be part of a second generation of planets, the first having been destroyed when their star blew up. The Spitzer Space Telescope's discovery of a dusty disk around a pulsar might represent the beginnings of a similarly 'reborn' planetary system.

2006-01-01

270

An Analysis of the SEEDS High-Contrast Exoplanet Survey: Massive Planets or Low-Mass Brown Dwarfs?  

E-print Network

We conduct a statistical analysis of a combined sample of direct imaging data, totalling nearly 250 stars observed by HiCIAO on the Subaru Telescope, NIRI on Gemini North, and NICI on Gemini South. The stars cover a wide range of ages and spectral types, and include five detections (kap And b, two ~60 M_J brown dwarf companions in the Pleiades, PZ Tel B, and CD-35 2722 B). We conduct a uniform, Bayesian analysis of the ages of our entire sample, using both membership in a kinematic moving group and activity/rotation age indicators, to obtain posterior age distributions. We then present a new statistical method for computing the likelihood of a substellar distribution function. By performing most integrals analytically, we achieve an enormous speedup over brute-force Monte Carlo. We use this method to place upper limits on the maximum semimajor axis beyond which the distribution function for radial-velocity planets cannot extend, finding model-dependent values of ~30--100 AU. Finally, we treat our entire subst...

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

2014-01-01

271

View of Gemini 11 experiment S-13 Ultraviolet Astronomical Camera  

NASA Technical Reports Server (NTRS)

View of Gemini 11 experiment S-13 Ultraviolet Astronomical Camera before flight. Its object was to obtain data on ultraviolet radiation of hot stars and to develop and evaluate basic techniques for photography of celestial objects from manned spacecraft.

1966-01-01

272

Gemini 12 Experiment D-10 Ion-Sensing Attitude Control  

NASA Technical Reports Server (NTRS)

Gemini 12 Experiment D-10 Ion-Sensing Attitude Control to investigate feasibility of attitude control system using environmental positive ions and an electrostatic detection system to measure spacecraft pitch and yaw.

1966-01-01

273

GEMINI: A Natural Language System for Spoken-Language Understanding  

Microsoft Academic Search

Gemini is a natural language understanding system developed for spoken language applications. This paper describes the details of the system, and includes relevant measurements of size, efficiency, and performance of each of its sub-components in detail.

John Dowding; Jean Mark Gawron; Douglas E. Appelt; John Bear; Lynn Cherny; Robert C. Moore; Douglas B. Moran

1993-01-01

274

Food packages for use on the Gemini 4 flight  

NASA Technical Reports Server (NTRS)

Food packages for use on the Gemini 4 flight. Packages include beef and gravy, peaches, strawberry cereal cubes and beef sandwiches. Water gun is used to reconstitute dehydrated food. Scissors are used to open the packages.

1965-01-01

275

Ocean Planet Exhibition  

NSDL National Science Digital Library

This virtual tour of the Smithsonian Institution's Ocean Planet exhibit can be navigated by clicking on the floor plan which is pictured, or it can be searched by image, subject, or topic outline. Links to educational materials and to a special curator's tour are also included.

276

Building Planet Earth  

Microsoft Academic Search

Continental plates, moving as fast as human hair grows, collide, mountains buckle, the ocean abyss sucks in the Earth's crust, and volcanos explode. Here is a story that Hollywood wished it could option: the dynamic cycle of geological destruction and renewal that has stretched across billions of years and shaped our planet in its current image. Scene by scene, this

Peter Cattermole

2000-01-01

277

Ocean Planet: Biodiversity  

NSDL National Science Digital Library

Ocean Planet is now an archival version of the 1995 Smithsonian Institution traveling exhibition which is no longer on display. This website spotlights 32 organisms to demonstrate the incredible diversity found in the oceans, images included. Over 99 percent of living space on earth is in the ocean, but we still know only a little about it.

278

GEMINI: Integrative Exploration of Genetic Variation and Genome Annotations  

PubMed Central

Modern DNA sequencing technologies enable geneticists to rapidly identify genetic variation among many human genomes. However, isolating the minority of variants underlying disease remains an important, yet formidable challenge for medical genetics. We have developed GEMINI (GEnome MINIng), a flexible software package for exploring all forms of human genetic variation. Unlike existing tools, GEMINI integrates genetic variation with a diverse and adaptable set of genome annotations (e.g., dbSNP, ENCODE, UCSC, ClinVar, KEGG) into a unified database to facilitate interpretation and data exploration. Whereas other methods provide an inflexible set of variant filters or prioritization methods, GEMINI allows researchers to compose complex queries based on sample genotypes, inheritance patterns, and both pre-installed and custom genome annotations. GEMINI also provides methods for ad hoc queries and data exploration, a simple programming interface for custom analyses that leverage the underlying database, and both command line and graphical tools for common analyses. We demonstrate GEMINI's utility for exploring variation in personal genomes and family based genetic studies, and illustrate its ability to scale to studies involving thousands of human samples. GEMINI is designed for reproducibility and flexibility and our goal is to provide researchers with a standard framework for medical genomics. PMID:23874191

Paila, Umadevi; Chapman, Brad A.; Kirchner, Rory; Quinlan, Aaron R.

2013-01-01

279

New serine-derived gemini surfactants as gene delivery systems.  

PubMed

Gemini surfactants have been extensively used for in vitro gene delivery. Amino acid-derived gemini surfactants combine the special aggregation properties characteristic of the gemini surfactants with high biocompatibility and biodegradability. In this work, novel serine-derived gemini surfactants, differing in alkyl chain lengths and in the linker group bridging the spacer to the headgroups (amine, amide and ester), were evaluated for their ability to mediate gene delivery either per se or in combination with helper lipids. Gemini surfactant-based DNA complexes were characterized in terms of hydrodynamic diameter, surface charge, stability in aqueous buffer and ability to protect DNA. Efficient formulations, able to transfect up to 50% of the cells without causing toxicity, were found at very low surfactant/DNA charge ratios (1/1-2/1). The most efficient complexes presented sizes suitable for intravenous administration and negative surface charge, a feature known to preclude potentially adverse interactions with serum components. This work brings forward a new family of gemini surfactants with great potential as gene delivery systems. PMID:25513958

Cardoso, Ana M; Morais, Catarina M; Cruz, A Rita; Silva, Sandra G; do Vale, M Luísa; Marques, Eduardo F; de Lima, Maria C Pedroso; Jurado, Amália S

2015-01-01

280

Properties of Ellipticity Correlation with Atmospheric Structure From Gemini South  

SciTech Connect

Cosmic shear holds great promise for a precision independent measurement of {Omega}{sub m}, the mass density of the universe relative to the critical density. The signal is expected to be weak, so a thorough understanding of systematic effects is crucial. An important systematic effect is the atmosphere: shear power introduced by the atmosphere is larger than the expected signal. Algorithms exist to extract the cosmic shear from the atmospheric component, though a measure of their success applied to a range of seeing conditions is lacking. To gain insight into atmospheric shear, Gemini South imaging in conjunction with ground condition and satellite wind data were obtained. We find that under good seeing conditions Point-Spread-Function (PSF) correlations persist well beyond the separation typical of high-latitude stars. Under these conditions, ellipticity residuals based on a simple PSF interpolation can be reduced to within a factor of a few of the shot-noise induced ellipticity floor. We also find that the ellipticity residuals are highly correlated with wind direction. Finally, we correct stellar shapes using a more sophisticated procedure and generate shear statistics from stars. Under all seeing conditions in our data set the residual correlations lie everywhere below the target signal level. For good seeing we find that the systematic error attributable to atmospheric turbulence is comparable in magnitude to the statistical error (shape noise) over angular scales relevant to present lensing surveys.

Asztalos, Stephen J.; /LLNL, Livermore; de Vries, W.H.; /UC, Davis /LLNL, Livermore; Rosenberg, L.J; Treadway, T.; /LLNL, Livermore; Burke, D.; /SLAC; Claver, C.; Saha, A.; /NOAO, Tucson; Puxley, P.; /Gemini Observ., La Serena

2007-01-17

281

FIRST LIGHT LBT AO IMAGES OF HR 8799 bcde AT 1.6 AND 3.3 {mu}m: NEW DISCREPANCIES BETWEEN YOUNG PLANETS AND OLD BROWN DWARFS  

SciTech Connect

As the only directly imaged multiple planet system, HR 8799 provides a unique opportunity to study the physical properties of several planets in parallel. In this paper, we image all four of the HR 8799 planets at H band and 3.3 {mu}m with the new Large Binocular Telescope adaptive optics system, PISCES, and LBTI/LMIRCam. Our images offer an unprecedented view of the system, allowing us to obtain H and 3.3 {mu}m photometry of the innermost planet (for the first time) and put strong upper limits on the presence of a hypothetical fifth companion. We find that all four planets are unexpectedly bright at 3.3 {mu}m compared to the equilibrium chemistry models used for field brown dwarfs, which predict that planets should be faint at 3.3 {mu}m due to CH{sub 4} opacity. We attempt to model the planets with thick-cloudy, non-equilibrium chemistry atmospheres but find that removing CH{sub 4} to fit the 3.3 {mu}m photometry increases the predicted L' (3.8 {mu}m) flux enough that it is inconsistent with observations. In an effort to fit the spectral energy distribution of the HR 8799 planets, we construct mixtures of cloudy atmospheres, which are intended to represent planets covered by clouds of varying opacity. In this scenario, regions with low opacity look hot and bright, while regions with high opacity look faint, similar to the patchy cloud structures on Jupiter and L/T transition brown dwarfs. Our mixed-cloud models reproduce all of the available data, but self-consistent models are still necessary to demonstrate their viability.

Skemer, Andrew J.; Hinz, Philip M.; Rodigas, Timothy J.; Close, Laird; McCarthy, Don; Kulesa, Craig; Apai, Daniel; Bailey, Vanessa [Steward Observatory, Department of Astronomy, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States); Esposito, Simone; Arcidiacono, Carmelo; Mannucci, Filippo; Agapito, Guido; Argomedo, Javier; Briguglio, Runa [Istituto Nazionale di Astrofisica, Osservatorio Astrofisico di Arcetri, Largo E Fermi 5, 50125 Firenze (Italy); Burrows, Adam [Department of Astronomy, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 (United States); Leisenring, Jarron [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Skrutskie, Michael [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Desidera, Silvano; Mesa, Dino [Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Boutsia, Konstantina [Large Binocular Telescope Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States); and others

2012-07-01

282

Planet Pals  

NSDL National Science Digital Library

Created by designer, illustrator, and educator Judith Ann Gorgone, the Planet Pals Web site provides good material for young kids related to the health of the planet. The colorful pages contain basic information about the earth, energy, recycling, water conservation, pollution, and more. The fun and interactive Meet the Planet Pals area is especially interesting, where kids can listen to animated cartoons talk about various aspects of conservation. Even though the site is geared towards young children, they may have difficulty finding the educational specific pages by themselves; so, a parent's or teacher's assistance would most likely be helpful.

Gorgone, Judith.

283

Strange Planets Planetarium Program  

NSDL National Science Digital Library

This planetarium show is designed to engage visitors directly in activities and demonstrations, and is optimized for group sizes of 25 to 70 people. Show content includes general planet-finding techniques (Doppler, astrometric, etc.), an audience activity about the transit method of extrasolar planet discovery, NASA Kepler mission, and Johannes Kepler's work. It is 50-minutes long, but modular, so that it can be adjusted for shorter lengths (suggestions for 30-minute and 40-minute versions are provided in the script). The script, images, movies and music are available for free download at the website provided.

2012-12-06

284

Planet Slayer  

NSDL National Science Digital Library

The Australian Broadcasting Company offers a fun, interactive way to learn about environmentally responsible consumption. Visitors are invited to follow Greena, eco-chic Warrior Princess, as she navigates the world of green living. The Web site contains loads of engaging animated features, such as the Adventures of Greena, a cartoon in which Greena battles some environmental ill in each chapter. In the Planet Slayer Game, players choose to play earnestly as Greena and save the planet or ironically as a pink-swathed Barbie-like character to slay the planet. With the Greenhouse Calculator, users can figure out their toll on the planet in terms of carbon dioxide emissions -- a service you could find easily enough on the Web, but this one features exploding pigs. Lots of other great features are available, as is a set of well-selected links for more information on ethical investing, Kyoto Protocol, the 2002 Johannesburg World Summit on Sustainable Development, and more.

285

Planet Party  

NSDL National Science Digital Library

Learners and their families are encouraged to go outside on a clear evening and view the sky to see the planets for themselves. Using sky charts and other resources, and possibly in partnership with a local astronomical society, children navigate the night sky and view planets with the naked eye and binoculars or telescopes. This activity is part of Explore! Jupiter's Family Secrets, a series designed to engage children in space and planetary science in libraries and informal learning environments.

2012-08-26

286

A survey of young, nearby, and dusty stars conducted to understand the formation of wide-orbit giant planets. VLT/NaCo adaptive optics thermal and angular differential imaging  

NASA Astrophysics Data System (ADS)

Context. Over the past decade, direct imaging has confirmed the existence of substellar companions on wide orbits from their parent stars. To understand the formation and evolution mechanisms of these companions, their individual as well as the full population properties must be characterized. Aims: We aim at detecting giant planet and/or brown dwarf companions around young, nearby, and dusty stars. Our goal is also to provide statistics on the population of giant planets at wide-orbits and discuss planet formation models. Methods: We report the results of a deep survey of 59 stars, members of young stellar associations. The observations were conducted with the ground-based adaptive optics system VLT/NaCo at L'-band (3.8 ?m). We used angular differential imaging to reach the best detection performances down to the planetary mass regime. A statistical analysis of about 60% of the young and southern A-F stars closer than 65 pc allowed us to derive the fraction of giant planets on wide orbits. We used gravitational instability models and planet population synthesis models following the core-accretion scenario to discuss the occurrence of these companions. Results: We resolve and characterize new visual binaries and do not detect any new substellar companion. The survey's median detection performance reaches contrasts of 10 mag at 0.5? and 11.5 mag at 1.0?. We find the occurrence of planets to be between 10.8 and 24.8% at 68% confidence level assuming a uniform distribution of planets in the interval [1,13] MJ and [1,1000] AU. Considering the predictions of planetary formation models, we set important constraints on the occurrence of massive planets and brown dwarf companions that would have formed by gravitational instability. We show that this mechanism favors the formation of rather massive clumps (Mclump > 30 MJ) at wide (a > 40 AU) orbits, which may evolve dynamically and/or fragment. For the population of close-in giant planets that would have formed by core accretion (without considering any planet - planet scattering), our survey marginally explores physical separations (?20 AU) and cannot constrain this population. We will have to wait for the next generation of planet finders to start exploring that population, and even for the extremely large telescopes for a more complete overlap with other planet-hunting techniques. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile, ESO: runs 084.C-0396A, 085.C-0675A, 085.C-0277B, 087.C-0292A, 087.C-0450B, 088.C-0085A, 089.C-0149A.

Rameau, J.; Chauvin, G.; Lagrange, A.-M.; Klahr, H.; Bonnefoy, M.; Mordasini, C.; Bonavita, M.; Desidera, S.; Dumas, C.; Girard, J. H.

2013-05-01

287

GEO-ENGINEERING MODELING THROUGH INTERNET INFORMATICS (GEMINI)  

SciTech Connect

GEMINI (Geo-Engineering Modeling through Internet Informatics) is a public-domain web application focused on analysis and modeling of petroleum reservoirs and plays (http://www.kgs.ukans.edu/Gemini/index.html). GEMINI creates a virtual project by ''on-the-fly'' assembly and analysis of on-line data either from the Kansas Geological Survey or uploaded from the user. GEMINI's suite of geological and engineering web applications for reservoir analysis include: (1) petrofacies-based core and log modeling using an interactive relational rock catalog and log analysis modules; (2) a well profile module; (3) interactive cross sections to display ''marked'' wireline logs; (4) deterministic gridding and mapping of petrophysical data; (5) calculation and mapping of layer volumetrics; (6) material balance calculations; (7) PVT calculator; (8) DST analyst, (9) automated hydrocarbon association navigator (KHAN) for database mining, and (10) tutorial and help functions. The Kansas Hydrocarbon Association Navigator (KHAN) utilizes petrophysical databases to estimate hydrocarbon pay or other constituent at a play- or field-scale. Databases analyzed and displayed include digital logs, core analysis and photos, DST, and production data. GEMINI accommodates distant collaborations using secure password protection and authorized access. Assembled data, analyses, charts, and maps can readily be moved to other applications. GEMINI's target audience includes small independents and consultants seeking to find, quantitatively characterize, and develop subtle and bypassed pays by leveraging the growing base of digital data resources. Participating companies involved in the testing and evaluation of GEMINI included Anadarko, BP, Conoco-Phillips, Lario, Mull, Murfin, and Pioneer Resources.

W. Lynn Watney; John H. Doveton

2004-05-13

288

Extrasolar Planet Finding via Optimal Apodized and Shaped Pupil Coronagraphs  

E-print Network

Extrasolar Planet Finding via Optimal Apodized and Shaped Pupil Coronagraphs N. Jeremy Kasdin Dept examine several different apodization approaches to achieving high-contrast imaging of extrasolar planets extrasolar planets discovered to date, interest in planet finding is becom- ing intense. Both the scientific

Vanderbei, Robert J.

289

OPTIMAL OCCULTER DESIGN FOR FINDING EXTRASOLAR PLANETS Robert J. Vanderbei  

E-print Network

for finding terrestrial planets around nearby stars is to use two spacecraft: a telescope and a specially, but none have the capability to image Earth-like planets directly. Finding terrestrial planets is difficultOPTIMAL OCCULTER DESIGN FOR FINDING EXTRASOLAR PLANETS Robert J. Vanderbei Operations Research

290

Atmospheric Dynamics of Brown Dwarfs and Directly Imaged Giant Planets: Emergence of Zonal Jets and Eddies from Small-Scale Convective Perturbations  

NASA Astrophysics Data System (ADS)

A variety of observations now provide evidence for vigorous motion in the atmospheres of brown dwarfs and directly imaged giant planets; these observations include spectral evidence for clouds, disequilibrium chemistry, lightcurve variability, and maps of surface patchiness. These observations raise major questions about the nature of the atmospheric circulation on these exotic worlds, which resemble high-heat-flux, high-gravity, rapidly rotating versions of Jupiter. Although brown dwarfs and directly imaged giant planets generally lack the strong external stellar irradiation that causes the atmospheric circulation on most solar system planets, the vigorous convection in their interiors will drive a wealth of waves and perhaps a coherent large-scale circulation in their overlying stably stratified atmospheres. Here, we investigate this process using state-of-the-art, global 3D simulations of the atmospheric circulation using the MITgcm. We parameterize convective perturbations near the radiative-convective boundary using a spatially and temporally random, isotropic, small-scale thermal forcing at the bottom of the domain. Radiation is parameterized with an idealized Newtonian cooling scheme. Clouds and condensates are neglected. Our simulations show that brown dwarfs can in many cases develop large-scale atmospheric circulations comprising banded flow patterns, zonal jets, turbulence, and in some cases stable vortices. We will describe how the amplitude, length scales, and fundamental nature of the circulation -- in particular, the tendency to favor zonal jets versus quasi-isotropic turbulence -- depends on the radiative time constant, the convective forcing amplitude and timescale, gravity, and other parameters. The simulations provide a foundation for understanding observed lightcurves and surface maps of brown dwarfs, and moreover illuminate the continuum of atmospheric-dynamics processes between brown dwarfs and Jupiter itself.

Showman, Adam P.; Zhang, Xi; Tan, Xianyu; Lewis, Nikole K.

2014-11-01

291

Gemini-NIRI K-band observations of the sites of two recent radio transients in M82  

Microsoft Academic Search

We obtained a 30 minute exposure of the central region of M82, using the Near InfraRed Imager and Spectrometer (NIRI) together with the ALTAIR adaptive optics system on the Gemini North telescope. The observation was taken on June 11 2009 (54993.26 UT), using the K band filter and the f\\/14 camera (0.05 arcsec \\/ pixel, over a 51 x 51

M. Fraser; S. J. Smartt; M. Crockett; S. Mattila; A. Gal-Yam A. Stephens; K. Roth

2009-01-01

292

High Contrast Imaging: A New Frontier for Exoplanets Search and Characterization  

NASA Astrophysics Data System (ADS)

The discovery of 51 Peg in 1995 initiated the search for extrasolar planets with radial velocity. Since then, more than 330 expoplanets have been discovered with this successful technique. After a more timid start, the search for extrasolar planets with the transit method has begun to collect very promising results (55 planets discovered up till now). COROT, Kepler, TESS and ground-based surveys will provide many more candidates in a short term future. Moreover, for a selected sample of transiting exoplanets it is already possible to probe their atmospheres. Although very successful, both these methods are sensitive to planets which orbit quite close to their parent star. High contrast imaging will be the new frontier for exoplanet search and characterization. This technique will provide the opportunity to explore planets with masses down to the earth mass and/or orbiting at larger separation from their parent star, especially in the habitable zone. The possibility to couple an integral field spectrograph to a module for extreme adaptive optics and a 8m class telescope (SPHERE for VLT and GPI for South Gemini) or in the future to ELTs (EPICS), will allow to characterize the atmospheres of the observed exoplanets with low resolution spectroscopy. Here we present the advantages and limits of the high contrast imaging technique to detect and characterize exoplanets in the short and long term future, expecially compared to the RV and Transit methods.

Claudi, R. U.; Bonavita, M.; Desidera, S.; Gratton, R.; Tinetti, G.; Beuzit, J.; Kasper, M.; Mordassini, C.

2011-12-01

293

High-Contrast Imaging: A Wider View on Extrasolar Planetary Systems  

NASA Astrophysics Data System (ADS)

Although very successful (more than 350 planets discovered up to now) indirect methods for extrasolar planet detection (radial velocity, transits) are sensitive to planets quite close to their hosts. Moreover, accurate studies of planet characteristics are feasible only for a subset of object which are strongly irradiated. Standing at this point, any information about the exoplanets in wide orbits (more than 5-10 AU) is missing. High contrast imaging could be the key to open us a door to an unexplored region of star planet separation and to shed light on these unknown far away worlds. But it's not just a matter of detections. In fact coupling integral field spectrographs to extreme adaptive optic modules at the focus of 8m class telescopes (SPHERE for VLT and GPI for South Gemini), and in the future to ELTs (EPICS), would allow us to perform a first order characterization of the exoplanets themselves. Here we present the potential of the high contrast imaging technique, comparing it's capabilities with the ones of the indirect methods.

Bonavita, M.; Claudi, R. U.; Tinetti, G.; Beuzit, J.; Chauvin, G.; Desidera, S.; Gratton, R.; Kasper, M.

2011-12-01

294

Infrared and the search for extrasolar planets  

NASA Technical Reports Server (NTRS)

Search for evidence concerning the existence of extrasolar planets will involve both indirect detection as well as direct (imaging). Indirect detection may be possible using ground based instrumentation on the Keck telescope, Imaging probably will require an orbiting system. Characterizing other planets for complex molecules will require a large orbiting or lunar-based telescope or inteferometer. Cryogenic infrared techniques appear to be necessary. Planning for a NASA ground and space-based program, Toward Other Planet Systems (TOPS), is proceeding.

Meinel, Aden B.; Meinel, Marjorie P.

1991-01-01

295

LGS AO photon return simulations and laser requirements for the Gemini LGS AO program  

E-print Network

requirements 1. INTRODUCTION Gemini North and Gemini South, two IR-optimized 8-m telescopes respectively sites. Providing funding is secured a 3 W continuous wave (CW) commercial dye laser will be the first

296

Planet Jargon  

NSDL National Science Digital Library

Planet Jargon is a fun way to learn about computer jargon. Students will do research on vocabulary, parts of a computer, history of a computer, as well as interpreting the words through illustrations. Students will create a PowerPoint to show their findings. INTRODUCTION! You have landed on the Planet Jargon. The inhabitants use very strange words to communicate with each other. Some of the words are familiar computer terms to you, but others are completely alien. You will need to discover the meanings of the computer jargon in order to ...

Ms. Moeai

2007-05-07

297

Planet Formation  

NASA Astrophysics Data System (ADS)

The origin of the Sun's planetary system is a long-standing problem but one whose solution may be in sight. Recent progress has been rapid and much has changed since the first edition of this book. This article will describe a reasonably coherent story for the formation of the planets, based on what people know today, with the obvious caveat that future discoveries are bound to change some of the details. This article outlines the various aspects of planet formation according to the current paradigm, with a particular emphasis on the origin of the Sun's planetary system.

Chambers, J. E.

298

Mass Function of the Arches Cluster - Gemini meets HST  

NASA Astrophysics Data System (ADS)

We have analyzed deep, high resolution H and K' images of the Arches cluster obtained with the Gemini/Hokupa'a adaptive optics (AO) system. Arches, a young stellar cluster (YC) with an age of about 2-4 Myr, is located within a projected distance of 30 arcmin from the Galactic Center (GC). At the same time, Arches is one of the most massive YCs in the Milky Way. The total mass is estimated to be 2 × 104 Msolar Models suggest that young stellar clusters located in an environment as extreme as the GC may disrupt on timescales of about 10 Myr due to the strong Galactic tidal forces near the GC (Kim et al. 2000, ApJ, 545, 301). Thus, Arches, and also its neighbouring cluster Quintuplet, may represent an evolutionary snapshot of cluster formation in a dense environment. It has been shown earlier from HST data that the initial mass function (IMF) deviates from the standard Salpeter value (Figer et al. 1999, ApJ, 525, 750, F99). Using a 2 Myr Geneva isochrone (Lejeune & Schaerer 2001, A&A, 366, 538) to transform K'-magnitudes into masses, we obtain an IMF slope of ? = -0.77 ± 0.15, where the Salpeter (1955) slope ? = -1.35, in agreement with F99. The high spatial resolution of our AO data allows a direct comparison with the HST data. Though HST is still superior in the detection of objects in a very dense field, ground-based AO systems are capable of yielding comparable scientific results.

Stolte, Andrea; Grebel, Eva K.; Brandner, Wolfgang; Figer, Don

299

U.S.S. Intrepid alongside Gemini 3 spacecraft after landing  

NASA Technical Reports Server (NTRS)

The U.S.S. Intrepid pulls up alongside the Gemini 3 spacecraft during recovery operations following the successful Gemini-Titan 3 flight. Navy swimmers stand on the spacecraft's flotation collar waiting to hook a hoist line to the Gemini 3.

1965-01-01

300

Edinburgh Research Explorer The Giant Gemini GMOS survey of zem > 4.4  

E-print Network

Edinburgh Research Explorer The Giant Gemini GMOS survey of zem > 4.4 quasars ­ I Giant Gemini GMOS survey of zem > 4.4 quasars ­ I. Measuring the mean free path across cosmic time. 2014 #12;MNRAS 445, 1745­1760 (2014) doi:10.1093/mnras/stu1827 The Giant Gemini GMOS survey of zem > 4

Millar, Andrew J.

301

Gemini North and South Laser Guide Star Systems Requirements and Preliminary Designs  

E-print Network

Gemini North and South Laser Guide Star Systems Requirements and Preliminary Designs C. d, AZ 85945 #12;Gemini North and South Laser Guide Star Systems Requirements and Preliminary Designs. In this paper we discuss the similarities and differences between the Gemini North and South Laser Guide Star

302

Salt Effect on Microstructures in Cationic Gemini Surfactant Solutions as Studied by Dynamic Light Scattering  

E-print Network

Salt Effect on Microstructures in Cationic Gemini Surfactant Solutions as Studied by Dynamic LightVed September 12, 2007. In Final Form: NoVember 6, 2007 A cationic gemini surfactant, dodecanediyl-1,12-bis negligible scattered intensity, we attributed it to multimacroion domains. Introduction Gemini surfactants

Huang, Jianbin

303

Active Optics Performance Study of the Primary Mirror of the Gemini Telescopes Project  

E-print Network

Active Optics Performance Study of the Primary Mirror of the Gemini Telescopes Project Myung K. Cho Optical Sciences Center in the University of Arizona Tucson, AZ 85721 and Gemini Telescopes Project P. O. Box 26732 Tucson, AZ 85726­6732 Gemini Preprint #9 #12; Active optics performance study of the primary

304

Tenth Planet Discovered  

NASA Technical Reports Server (NTRS)

These time-lapse images of a newfound planet in our solar system, called 2003UB313, were taken on Oct. 21, 2003, using the Samuel Oschin Telescope at the Palomar Observatory near San Diego, Calif. The planet, circled in white, is seen moving across a field of stars. The three images were taken about 90 minutes apart.

A joint effort between JPL and the California Institute of Technology, the Palomar Observatory near San Diego houses a collection of famous telescopes, including the Hale 200-inch and Samuel Oschin 48-inch telescopes. The Palomar Adaptive Optics System, built by JPL and Caltech, corrects for the atmospheric blur of astronomical targets caused by turbulence in Earth's atmosphere. This system's camera was built by Cornell University, Ithaca, N.Y.

2005-01-01

305

Exploring the Planets: Venus  

NSDL National Science Digital Library

This site contains most of the up-to-date information known about the planet Venus, including mean distance from Sun, length of year, rotation period, mean orbital velocity, inclination of axis, average temperature (day and night), and diameter. Many discoveries about Venus have been made using Earth-based radio telescopes, however the images of Venus in this exhibit were collected by the Magellan spacecraft. Magellan used radar to produce the first high-resolution global map of Venus. Since Venus has no water erosion and little wind, volcanic eruptions are a major force reshaping the landscape. Geologic forces at work beneath the crust create mountains, rifts, and patterns of fractures, while the sluggish winds sculpt the surface in subtler ways but many mysteries remain. This site includes numerous images of the planet.

306

UNVEILING THE NEW GENERATION OF STARS IN NGC 604 WITH GEMINI-NIRI  

SciTech Connect

We present a near-infrared study focused on the detection and characterization of the youngest stellar component of the NGC 604 giant star-forming region in the Triangulum galaxy (M 33). By means of color-color diagrams derived from the photometry of JHK{sub s} images taken with the Gemini Near Infrared Imaging and Spectrometer (NIRI), we have found 68 candidate massive young stellar objects. The spatial distribution of these sources matches the areas where previous studies suggested that star formation might be taking place, and the high spatial resolution of our deep NIRI imaging allows us to pinpoint the star-forming knots. An analysis of the fraction of objects that show infrared excess suggests that the star formation is still active, supporting the presence of a second generation of stars being born, although the evidence for or against sequential star formation does not seem to be conclusive.

Farina, Cecilia; Bosch, Guillermo L. [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo de Bosque S/N (B1900FWA), La Plata (Argentina); Barba, Rodolfo H., E-mail: ceciliaf@fcaglp.unlp.edu.ar [Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE-CONICET), Av. Espana Sur 1512 (J5402DSP), San Juan (Argentina)

2012-02-15

307

Unveiling the New Generation of Stars in NGC 604 with Gemini-NIRI  

NASA Astrophysics Data System (ADS)

We present a near-infrared study focused on the detection and characterization of the youngest stellar component of the NGC 604 giant star-forming region in the Triangulum galaxy (M 33). By means of color-color diagrams derived from the photometry of JHKs images taken with the Gemini Near Infrared Imaging and Spectrometer (NIRI), we have found 68 candidate massive young stellar objects. The spatial distribution of these sources matches the areas where previous studies suggested that star formation might be taking place, and the high spatial resolution of our deep NIRI imaging allows us to pinpoint the star-forming knots. An analysis of the fraction of objects that show infrared excess suggests that the star formation is still active, supporting the presence of a second generation of stars being born, although the evidence for or against sequential star formation does not seem to be conclusive.

Fariña, Cecilia; Bosch, Guillermo L.; Barbá, Rodolfo H.

2012-02-01

308

Gemini multiconjugate adaptive optics system review - II. Commissioning, operation and overall performance  

NASA Astrophysics Data System (ADS)

The Gemini multiconjugate adaptive optics system - GeMS, a facility instrument mounted on the Gemini South telescope, delivers a uniform, near diffraction limited images at near-infrared wavelengths (0.95-2.5 ?m) over a field of view of 120 arcsec. GeMS is the first sodium layer based multilaser guide star adaptive optics system used in astronomy. It uses five laser guide stars distributed on a 60 arcsec square constellation to measure for atmospheric distortions and two deformable mirrors to compensate for it. In this paper, the second one devoted to describe the GeMS project, we present the commissioning, overall performance and operational scheme of GeMS. Performance of each subsystem is derived from the commissioning results. The typical image quality, expressed in full with at half-maximum, Strehl ratios and variations over the field delivered by the system are then described. A discussion of the main contributor to performance limitation is carried out. Finally, overheads and future system upgrades are described.

Neichel, Benoit; Rigaut, François; Vidal, Fabrice; van Dam, Marcos A.; Garrel, Vincent; Carrasco, Eleazar Rodrigo; Pessev, Peter; Winge, Claudia; Boccas, Maxime; d'Orgeville, Céline; Arriagada, Gustavo; Serio, Andrew; Fesquet, Vincent; Rambold, William N.; Lührs, Javier; Moreno, Cristian; Gausachs, Gaston; Galvez, Ramon L.; Montes, Vanessa; Vucina, Tomislav B.; Marin, Eduardo; Urrutia, Cristian; Lopez, Ariel; Diggs, Sarah J.; Marchant, Claudio; Ebbers, Angelic W.; Trujillo, Chadwick; Bec, Matthieu; Trancho, Gelys; McGregor, Peter; Young, Peter J.; Colazo, Felipe; Edwards, Michelle L.

2014-05-01

309

Planet Applet  

NSDL National Science Digital Library

This Java applet calculates three views of the bright planets (Mercury, Venus, Mars, Jupiter, Saturn) and the Moon. It displays a diagram showing rise and set times over the year, a view at local horizon, and a view of the ecliptic plane.

Juergen Giesen

310

Kids' Planet  

NSDL National Science Digital Library

Kids Planet provides wildlife games, a story about the web of life, a map based on wolf populations, a report on the status of wolves worldwide, and a wildlife defense section with endangered species fact sheets. Teacher resources include a wolf discovery curriculum, sea otter unit, and a Florida Black Bear curriculum, as well as a wildlife bibliography.

311

Planet Surfing  

NSDL National Science Digital Library

In this astronomy activity (page 6 of the PDF), learners will compare and contrast two planets in the solar system using data obtained from the internet. They will convert distances from light years to miles and vice versa. Although this activity was created as a post visit for a workshop about astronomy, it also makes an excellent stand alone activity.

COSI

2009-01-01

312

The Nine Planets: The Sun  

NSDL National Science Digital Library

This page of the Nine Planets gives detailed data about the Sun, including diameter, mass, temperature, how energy is made, mythology, composition, and recent data collected from spacecraft. Layers of the Sun are discussed, including the corona, chromosphere, and photosphere. Images and links to additional images and movies are provided, as well as questions still unanswered about the sun.

Bill Arnett

313

Binary Planets  

NASA Astrophysics Data System (ADS)

Can a bound pair of similar mass terrestrial planets exist? We are interested here in bodies with a mass ratio of ~ 3:1 or less (so Pluto/Charon or Earth/Moon do not qualify) and we do not regard the absence of any such discoveries in the Kepler data set to be significant since the tidal decay and merger of a close binary is prohibitively fast well inside of 1AU. SPH simulations of equal mass “Earths” were carried out to seek an answer to this question, assuming encounters that were only slightly more energetic than parabolic (zero energy). We were interested in whether the collision or near collision of two similar mass bodies would lead to a binary in which the two bodies remain largely intact, effectively a tidal capture hypothesis though with the tidal distortion being very large. Necessarily, the angular momentum of such an encounter will lead to bodies separated by only a few planetary radii if capture occurs. Consistent with previous work, mostly by Canup, we find that most impacts are disruptive, leading to a dominant mass body surrounded by a disk from which a secondary forms whose mass is small compared to the primary, hence not a binary planet by our adopted definition. However, larger impact parameter “kissing” collisions were found to produce binaries because the dissipation upon first encounter was sufficient to provide a bound orbit that was then rung down by tides to an end state where the planets are only a few planetary radii apart. The long computational times for these simulation make it difficult to fully map the phase space of encounters for which this outcome is likely but the indications are that the probability is not vanishingly small and since planetary encounters are a plausible part of planet formation, we expect binary planets to exist and be a non-negligible fraction of the larger orbital radius exoplanets awaiting discovery.

Ryan, Keegan; Nakajima, Miki; Stevenson, David J.

2014-11-01

314

Review article: Mars - the Red Planet  

Microsoft Academic Search

A summary of our current knowledge of Mars, and methods of observing the planet. Printing Options Send high resolution image to Level 2 Postscript Printer Send low resolution image to Level 2 Postscript Printer Send low resolution image to Level 1 Postscript Printer Get high resolution PDF image Get low resolution PDF Send 300 dpi image to PCL Printer Send

R. Baum

1983-01-01

315

Protostars and Planets VI  

NASA Astrophysics Data System (ADS)

The Protostars and Planets book and conference series has been a long-standing tradition that commenced with the first meeting led by Tom Gehrels and held in Tucson, Arizona, in 1978. The goal then, as it still is today, was to bridge the gap between the fields of star and planet formation as well as the investigation of planetary systems and planets. As Tom Gehrels stated in the preface to the first Protostars and Planets book, "Cross-fertilization of information and understanding is bound to occur when investigators who are familiar with the stellar and interstellar phases meet with those who study the early phases of solar system formation." The central goal remained the same for the subsequent editions of the books and conferences Protostars and Planets II in 1984, Protostars and Planets III in 1990, Protostars and Planets IV in 1998, and Protostars and Planets V in 2005, but has now been greatly expanded by the flood of new discoveries in the field of exoplanet science. The original concept of the Protostars and Planets series also formed the basis for the sixth conference in the series, which took place on July 15-20, 2013. It was held for the first time outside of the United States in the bustling university town of Heidelberg, Germany. The meeting attracted 852 participants from 32 countries, and was centered around 38 review talks and more than 600 posters. The review talks were expanded to form the 38 chapters of this book, written by a total of 250 contributing authors. This Protostars and Planets volume reflects the current state-of-the-art in star and planet formation, and tightly connects the fields with each other. It is structured into four sections covering key aspects of molecular cloud and star formation, disk formation and evolution, planetary systems, and astrophysical conditions for life. All poster presentations from the conference can be found at www.ppvi.org. In the eight years that have passed since the fifth conference and book in the Protostars and Planets series, the field of star and planet formation has progressed enormously. The advent of new space observatories like Spitzer and more recently Herschel have opened entirely new windows to study the interstellar medium, the birthplaces of new stars, and the properties of protoplanetary disks. Millimeter and radio observatories, in particular interferometers, allow us to investigate even the most deeply embedded and youngest protostars. Complementary to these observational achievements, novel multi-scale and multi-physics theoretical and numerical models have provided new insights into the physical and chemical processes that govern the birth of stars and their planetary systems. Sophisticated radiative transfer modeling is critical in order to better connect theories with observations. Since the last Protostars and Planets volume, more than 1000 new extrasolar planets have been identified and there are thousands more waiting to be verified. Such a large database allows for the first time a statistical assessment of the planetary properties as well as their evolution pathways. These investigations show the enormous diversity of the architecture of planetary systems and the properties of planets. High-contrast imaging at short and long wavelengths has resolved protoplanetary disks and associated planets, and transit spectroscopy is a new tool that allows us to study even the physical properties of extrasolar planetary atmospheres. The understanding of our own solar system has also progressed enormously since 2005. For instance, the sample-return Stardust mission has provided direct insight into the composition of comets and asteroids, and has demonstrated the importance of mixing processes in the early solar system. And much more is now known about the origin and role of short-lived nuclides at these stages of the solar system. For generations of astronomers, the Protostars and Planets volumes have served as an essential resource for our understanding of star and planet formation. They are used by students to dive into new topics, and

Beuther, Henrik; Klessen, Ralf S.; Dullemond, Cornelis P.; Henning, Thomas

316

Gemini photographs of the world: A complete index  

NASA Technical Reports Server (NTRS)

The most authoritative catalogs of photographs of all Gemini missions are assembled. Included for all photographs are JSC (Johnson Space Center) identification number, percent cloud cover, geographical area in sight, and miscellaneous information. In addition, details are given on cameras, filters, films, and other technical details.

Giddings, L. E.

1977-01-01

317

Michelle: a mid-infrared spectrometer for UKIRT and Gemini  

Microsoft Academic Search

Michelle is a long slit grating spectrometer which is being built at the Royal Observatory Edinburgh for the UKIRT and Gemini telescopes. It will incorporate five diffraction gratings and seven entrance slits to give spectral resolving powers ranging from a few dozen up to 3,000, with wavelength coverage from 5 to 28 mum. In addition, the same detector array can

A. C. H. Glasse; E. E. Atad-Ettedgui; I. R. Bryson; G. F. Morrison

1995-01-01

318

Northwestern Mexico as seen from the Gemini 9-A spacecraft  

NASA Technical Reports Server (NTRS)

Northwestern Mexico as seen from the Gemini 9-A spacecraft during its 32nd revolution of the earth. Large peninsula is Baja California. Body of water at lower right is Pacific Ocean. Land mass at upper left is State of Sonora. Gulf of California separates Sonora from peninsula. Nose of spacecraft is at left and at right is open hatch of spacecraft.

1966-01-01

319

Designing Scalable PGAS Communication Subsystems on Cray Gemini Interconnect  

SciTech Connect

The Cray Gemini Interconnect has been recently introduced as a next generation network architecture for building multi-petaflop supercomputers. Cray XE6 systems including LANL Cielo, NERSC Hopper, ORNL Titan and proposed NCSA BlueWaters leverage the Gemini Interconnect as their primary Interconnection network. At the same time, programming models such as the Message Passing Interface (MPI) and Partitioned Global Address Space (PGAS) models such as Unified Parallel C (UPC) and Co-Array Fortran (CAF) have become available on these systems. Global Arrays is a popular PGAS model used in a variety of application domains including hydrodynamics, chemistry and visualization. Global Arrays uses Aggregate Re- mote Memory Copy Interface (ARMCI) as the communication runtime system for Remote Memory Access communication. This paper presents a design, implementation and performance evaluation of scalable and high performance communication subsystems on Cray Gemini Interconnect using ARMCI. The design space is explored and time-space complexities of commu- nication protocols for one-sided communication primitives such as contiguous and uniformly non-contiguous datatypes, atomic memory operations (AMOs) and memory synchronization is presented. An implementation of the proposed design (referred as ARMCI-Gemini) demonstrates the efficacy on communication primitives, application kernels such as LU decomposition and full applications such as Smooth Particle Hydrodynamics (SPH) application.

Vishnu, Abhinav; Daily, Jeffrey A.; Palmer, Bruce J.

2012-12-26

320

Gemini North Laser Guide Star System: operations and maintenance review  

Microsoft Academic Search

The Gemini North telescope has been providing Laser Guide Star Adaptive Optics (LGS AO) regular science queue observations for worldwide astronomers since February 2007. In this paper we comment on the reliability of the Laser Guide Star Facility high-power solid-state laser during normal operations, and discuss progress made on various issues that will enable a \\

Richard J. Oram; Vincent Fesquet; Robert Wyman; Celine D'Orgeville

2010-01-01

321

Surface properties of Gemini surfactants with pyrrolidinium head groups.  

PubMed

Gemini surfactants C(n)-4-(n)PB (where n represents the alkyl chain length of 10, 12, 14 and 16) were synthesized and characterized. Their surface activity, thermodynamic properties, and aggregation behavior were investigated by means of surface tension, electrical conductivity, and steady-state fluorescence. It was found that the Gemini surfactants C(n)-4-(n)PB have superior surface activity to their corresponding monomer surfactants C(n)MPB as expected. Additionally, these compounds have lower cmc and surface tension in comparison with conventional cationic Gemini surfactants m-4-m. Thermodynamic parameters (?G(m)(0),?H(m)(0),T?S(m)(0)) show that the micellization is an entropy driven process with shorter hydrophobic chain lengths but instead is enthalpy driven for longer hydrophobic chain lengths. The effect of the hydrophobic alkyl chain length and the addition of inorganic salt NaBr on the surface activity and micellization are in line with the conventional cationic Gemini surfactants. PMID:22261268

Cai, Bo; Li, Xuefeng; Yang, Yi; Dong, Jinfeng

2012-03-15

322

Comparing the Planets: Water  

NSDL National Science Digital Library

This set of images summarizes what scientists currently know about the occurrence of water ice and water vapor on the terrestrial planets and satellites in our Solar System. Accompanied by a brief description, the Jpeg images show the ice cap at Mars' south pole, ice rafting on Europa, liquid water covering the surface of Earth (the famous 'Blue Marble' photo), and an impact crater on the Moon that may contain water ice. There is also a diagram showing the possible distribution of ice on Mars, as it varies with latitude.

323

Unveiling the new generation of stars in NGC 604 with Gemini-NIRI  

E-print Network

We present a near infrared study focused on the detection and characterization of the youngest stellar component of the NGC 604 giant star-forming region, in the Triangulum galaxy (M 33). By means of color-color diagrams derived from the photometry of JHKs images taken with Gemini-NIRI, we have found 68 candidate massive young stellar objects. The spatial distribution of these sources matches the areas where previous studies suggested that star formation might be taking place, and the high spatial resolution of our deep NIRI imaging allows to pinpoint the star-forming knots. An analysis of the fraction of objects that show infrared excess suggests that the star formation is still active, supporting the presence of a second generation of stars being born, although the evidence for or against sequential star formation does not seem to be conclusive.

Farina, Cecilia; Barba, Rodolfo H

2011-01-01

324

Planet Math  

NSDL National Science Digital Library

This is an activity about the different characteristics of the planets in our Solar System. Learners will use the Solar System Update program to complete a worksheet. The worksheet asks learners to identify multiple characteristics for each planetary body, and consider the relationships between certain characteristics. Required materials include the Solar System Update software and a computer with Internet access. This activity is Solar System Activity 3 in a larger resource, Space Update.

325

Planet Oobleck  

NSDL National Science Digital Library

Learners imagine a world covered in a mysterious substance called Oobleck. Learners make this substance and investigate its properties. Using an online program, they then design a spacecraft that can land on the planet, collect a sample, and return to Earth. A chart shows how their design compares to others' designs. Additionally, learners can build their spacecraft and test it. This activity presents a great engineering extension to other Oobleck-related activities posted elsewhere.

2012-06-26

326

Kid's Planet  

NSDL National Science Digital Library

A Web sitedesigned just for kids by Defenders of Wildlife, Kid's Planet has much to offer for teachers and students. Teacher's Table contains downloadable .pdf lesson plans and activities. Designed primarily for middle school students, these lesson plans and essay contests cover topics like wolves and sea otters. With electronic fact sheets on over 50 species, the section titled Get the Facts may prove useful. This editor particularly enjoyed weaving through the Web of Life with the garden spider.

327

Populating the Virgo Velocity Function with Early-Type Galaxies at Gemini  

NASA Astrophysics Data System (ADS)

We propose to sample the circular velocity function (CVF) and stellar-to-halo mass relation (SHMR) of Virgo early-type galaxies (ETGs) in the stellar mass range M* = 10^(7-10) Msol. This proposal is part of a large effort to characterize the dynamical and stellar population properties of a representative sample of Virgo ETGs for which deep near-UV/optical/near-IR imaging exists. The proposed sample will significantly augment the crucial low-mass range below M* < 10^9 Msol, where the sharp LCDM predictions for the CVF and SHMR (abundance matching) are fully unconstrained due to significant incompleteness (0-20%) of current data bases. Numerous tantalizing trends, such as bifurcations and possible bimodalities of mass relations for ETGs and LTGs, may prove transformational for galaxy structure studies and must be confirmed with a study like ours. We seek GMOS absorption spectra of 35 faint ETGs for a total of 100 hours of Canadian, US, and Chilean Gemini time. Our program exploits synergies of the Gemini and VLT observatories and will deliver a benchmark dataset of lasting legacy value, building upon our large Virgo cluster team expertise.

Ouellette, Nathalie; Courteau, Stephane; Holtzman, Jon; Puzia, Thomas; Bovill, Mia; Cappellari, Michele; Cote, Patrick; Dalcanton, Julianne; Dutton, Aaron; Eigenthaler, Paul; Emsellem, Eric; Ferrarese, Laura; McDonald, Michael; Munoz, Roberto; Roediger, Joel; Tully, Brent

2014-02-01

328

Photometry and Dynamics of the Minor Merger AM1219-430 with Gemini GMOS-S  

E-print Network

We present an observational study of the interaction effect on the dynamics and morphology of the minor merger AM1219-430. This work is based on r' and g' images and long-slit spectra obtained with the Gemini Multi-Object Spectrograph at the Gemini South Telescope. We detected a tidal tail in the main galaxy (AM1219A) and a bridge of material connecting the galaxies. In luminosity, AM1219A is about 3.8 times brighter than the secondary (AM1219B). The surface brightness profile of AM1219A was decomposed into bulge and disc components. The profile shows a light excess of ~ 53 % due to the contribution of star-forming regions, which is typical of starburst galaxies. On the other hand, the surface brightness profile of AM1219B shows a lens structure in addition to the bulge and disc. The scale lengths and central magnitudes of the disc structure of both galaxies agree with the average values derived for galaxies with no sign of ongoing interaction or disturbed morphology. The S\\'ersic index (n<2), the effectiv...

Hernandez-Jimenez, J A; Rodrigues, I; Krabbe, A C; Winge, Cláudia; Bonatto, C

2013-01-01

329

Quaternary ammonium-type gemini surfactants synthesized from oleic acid: aqueous solution properties and adsorption characteristics.  

PubMed

Cationic gemini surfactants having a quaternary ammonium headgroup have been synthesized from oleic acid. The hydrocarbon chain is covalently bound to the terminal carbonyl group of oleic acid via an amide bond, while the quaternary ammonium headgroup is introduced onto the cis double bond of oleic acid. The Krafft temperature of these surfactants drops below room temperature (ca. 25°C) when the counterion is exchanged from Br? to Cl?. The aqueous solution properties of the Cl series of surfactants have been assessed by means of pyrene fluorescence, dynamic light scattering (DLS), and static surface tension measurements. An increased hydrocarbon chain length results in a lower critical micelle concentration (cmc) and a higher adsorption efficiency at the air/aqueous solution interface. Surface tension measurements suggest the formation of premicelles at concentrations below cmc, whereas, above cmc, DLS indicates the formation of micellar aggregates whose diameter ranges from 5 to 10 nm. We, furthermore, characterized the adsorption of these surfactants to the silica/aqueous solution interface and observed their spontaneous adsorption to the solid surface by electrostatic and intermolecular hydrophobic interactions. The combination of soft-contact imaging atomic force microscopy (AFM) and force-curve data suggests bilayer formation above cmc, which is reflective of the large packing parameter of the gemini surfactants. Interestingly, we found the repulsive interaction observed during compression of the adsorbed layer to be relatively weak, as a result of the low adsorption density and/or the loose molecular packing arrangement, which arises from the asymmetric structure. PMID:23823915

Sakai, Kenichi; Saito, Yuki; Uka, Akihito; Matsuda, Wataru; Takamatsu, Yuichiro; Kitiyanan, Boonyarach; Endo, Takeshi; Sakai, Hideki; Abe, Masahiko

2013-01-01

330

Planet Under Pressure  

NSDL National Science Digital Library

Planet Under Pressure is a six-part British Broadcasting Company (BBC) News Online series looking at some of the most pressing environmental issues facing the human race today. The series takes a detailed look at six areas where most experts agree that a crisis is brewing. They include food, water, energy, climate change, biodiversity, and pollution. In addition there are special features including: an animated guide that shows how the greenhouse effect might shape our climate; before and after images of the effects of climate change; the European Union (EU) emissions trading scheme and the carbon revolution; opinions about the Kyoto Protocol; graphic climate evidence of a warming world, rising sea, and melting ice; teenagers' opinions on how they would tackle environmental damage; the results of an eco-friendly garden competition; pictures of environmental change around the world; and a link to a BBC website exploring the UN's goals for the planet in 2015.

331

Make a Planet!  

NSDL National Science Digital Library

Make your own planet on this website! You can change the color of your planet and add land, water, trees, and weather. You can then name your planet and write a short story about it. For even more fun, compare the planets in our solar system with your planet!

2010-01-01

332

FURTHER EVIDENCE OF THE PLANETARY NATURE OF HD 95086 b FROM GEMINI/NICI H-BAND DATA  

SciTech Connect

We present our analysis of the Gemini/NICI H-band data of HD 95086, following the discovery of the planet HD 95086 b in L'. The H-band data reach a contrast of 12.7 mag relative to the host star at 5? levels in the location of HD 95086 b, and no point source is found. Our non-detection and H – L' color limit rules out the possibility that the object is a foreground L/T dwarf and that, if it is bound to HD 95086, it is a genuine planetary mass object. We estimate a new pre-main-sequence isochronal age for HD 95086 of 17 ± 4 Myr, which is commensurate with previous mean age estimates for the Lower Cen-Crux subgroup. Adopting an age of 17 Myr, the color limit is inconsistent with the COND model, marginally consistent with the BT-SETTL model, and consistent with the DUSTY model.

Meshkat, T.; Kenworthy, M. [Sterrewacht Leiden, P.O. Box 9513, Niels Bohrweg 2, 2300 RA Leiden (Netherlands)] [Sterrewacht Leiden, P.O. Box 9513, Niels Bohrweg 2, 2300 RA Leiden (Netherlands); Bailey, V.; Su, K. Y. L. [Steward Observatory, Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States)] [Steward Observatory, Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Rameau, J.; Chauvin, G.; Lagrange, A.-M. [UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France)] [UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); Bonnefoy, M. [Max Planck Institute für Astronomy, Königsthul 17, D-69117 Heidelberg (Germany)] [Max Planck Institute für Astronomy, Königsthul 17, D-69117 Heidelberg (Germany); Boccaletti, A. [LESIA, Observatoire de Paris, CNRS, University Pierre et Marie Curie Paris 6 and University Denis Diderot Paris 7, 5 place Jules Janssen, F-92195 Meudon (France)] [LESIA, Observatoire de Paris, CNRS, University Pierre et Marie Curie Paris 6 and University Denis Diderot Paris 7, 5 place Jules Janssen, F-92195 Meudon (France); Mamajek, E. E. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States)] [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Currie, T. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George St., Toronto, Ontario, M5S 1A1 (Canada)] [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George St., Toronto, Ontario, M5S 1A1 (Canada)

2013-10-01

333

Completing the follow-ups of the 300 stars International Deep Planet Survey  

NASA Astrophysics Data System (ADS)

The International Deep Planet Survey has already provided exciting results with the first detection of a four-planet system orbiting the young star HR 8799. Over the course of the IDPS we have surveyed 300 stars, using several AO systems such as ALTAIR/NIRI (Gemini North), NICI (Gemini South), NIRC2 (Keck), and NACO (VLT). The entire campaign was fully reduced and analyzed over the last year and we found a total of 250 planet candidates at less than 200AU projected separation. Using our own data as well as archive data from other programs, we have already confirmed most of the candidates as background objects. However, 48 stars having 100 Jupiter-like planet candidates orbiting at less than 200AU still remain to be followed. We need follow-up observations to distinguish between true planets and background objects using a parallax and proper motion analysis. A statistical study of the actual sample and colour measurements of some candidates let us believe that there is a high probability that a few of the remaining candidates are true planets. Assuming good weather, this is the second to last IDPS proposal. A small proposal will be submitted for 2013A to complete the follow-ups for 5 stars that are not accessible in 2012B

Galicher, Raphael; Marois, Christian; Macintosh, Bruce; Zuckerman, Ben; Barman, Travis; Doyon, Rene; Lafreniere, David; Song, Inseok; Patience, Jenny

2012-08-01

334

External Resource: Making a Model Planet  

NSDL National Science Digital Library

This PDF worksheet from NASA's I.M.A.G.E. Satellite Program challenges learners/students to work like Astronomers. Learners/students make predictions of what the interior of planets look like by carefully measuring the mass of the planet and its radius. S

1900-01-01

335

Microlensing Planets: Multiple Planet Systems as Gravitational Triple Lenses  

NASA Astrophysics Data System (ADS)

Gravitational microlensing is a superb exoplanet search technique. The merits include: mass sensitivity to all range of planets down to Mars; the detection window is partially inclusive of the habitable zones; massive moons of the exoplanets can be found; the duration of the events is typically less than two months, ~ 70 times shorter than the 12 year orbital period of Jupiter; it is largely free of selection bias because microlensing occurs by chance, and "oddities" such as circumbinary planets and multiple planets will be detected with a fair share of chance; it is the only method that can probe the Galactic and extragalactic families of planets that may orbit ordinary stars. Most of the microlensing planets will be discovered as gravitational (planetary) binary lenses. However, some of them will be discovered as higher multiple lens systems. Here, we discuss the gravitational triple lens systems which can produce up to 10 images. Discussion subjects include: classification of caustics, effect of three-body instabilities, numerical complications, and discovery perspective of multiple planet systems with GEST (Galactic Exoplanet Survey Telescope). This work has been supported in part by the NASA and the NSF.

Rhie, S.; Bennett, D.

2000-12-01

336

Gemini surfactants mediate efficient mitochondrial gene delivery and expression.  

PubMed

Gene delivery targeting mitochondria has the potential to transform the therapeutic landscape of mitochondrial genetic diseases. Taking advantage of the nonuniversal genetic code used by mitochondria, a plasmid DNA construct able to be specifically expressed in these organelles was designed by including a codon, which codes for an amino acid only if read by the mitochondrial ribosomes. In the present work, gemini surfactants were shown to successfully deliver plasmid DNA to mitochondria. Gemini surfactant-based DNA complexes were taken up by cells through a variety of routes, including endocytic pathways, and showed propensity for inducing membrane destabilization under acidic conditions, thus facilitating cytoplasmic release of DNA. Furthermore, the complexes interacted extensively with lipid membrane models mimicking the composition of the mitochondrial membrane, which predicts a favored interaction of the complexes with mitochondria in the intracellular environment. This work unravels new possibilities for gene therapy toward mitochondrial diseases. PMID:25634573

Cardoso, Ana M; Morais, Catarina M; Cruz, A Rita; Cardoso, Ana L; Silva, Sandra G; do Vale, M Luísa; Marques, Eduardo F; Pedroso de Lima, Maria C; Jurado, Amália S

2015-03-01

337

Upgrading the Gemini secondary mirror micro-controller  

NASA Astrophysics Data System (ADS)

The Gemini Observatory is continuing in the preliminary design stages of upgrading the micro-controller and related data acquisition components for the Secondary Mirror Tip/tilt System (M2TS). The Gemini North M2TS has surpassed a decade of service in the scientific community, yet the designs at both sites are nearly twenty years old and maintenance costs continue to increase. The next generation M2TS acquisition system takes a look at today's more common practices such as alternatives to VME, and the use of Industry Pack modules and high-rate data logging. An overview of the refactored software design will be described including the use of The Real-Time Executive for Multiprocessor Systems, or RTEMS, as the operating system of choice to meet the real-time performance requirements.

Rippa, Mathew J.; Soto, Jose; Sheehan, Mike; Carter, Christopher J.; Perez, Gabriel; James, Eric; Wyman, Robert; Nakayama, Cooper; Yamasaki, Chris

2010-07-01

338

Aqueous Gemini Surfactant Self-Assembly into Complex Lyotropic Phases  

NASA Astrophysics Data System (ADS)

In spite of the potentially wide-ranging applications of aqueous bicontinuous lyotropic liquid crystals (LLCs), the discovery of amphiphiles that reliably form these non-constant mean curvature morphologies over large phase windows remains largely serendipitous. Recent work has established that cationic gemini surfactants exhibit a pronounced tendency to form bicontinuous cubic (e.g. gyroid) phases as compared to their parent single-tail amphiphiles. The universality of this phenomenon in other surfactant systems remains untested. In this paper, we will report the aqueous LLC phase behavior of a new class of anionic gemini surfactants derived from long chain carboxylic acids. Our studies show that these new surfactants favor the formation of non-constant mean curvature gyroid and primitive (``Plumber's Nightmare'') structures over amphiphile concentration windows up to 20 wt% wide. Based on these observations, we will discuss insights gained into the delicate force balance governing the self-assembly of these surfactants into aqueous bicontinuous LLCs.

Mahanthappa, Mahesh; Sorenson, Gregory

2012-02-01

339

Gemini Observatory Takes its Local Communities on an Expanding Journey  

NASA Astrophysics Data System (ADS)

Currently in its 7th year (2011) Hawaii's annual Journey through the Universe (JttU) program is a flagship Gemini Observatory public education/outreach initiative involving a broad cross-section of the local Hawai'i Island astronomical community, the public, educators, businesses, local government officials, and thousands of local students. This paper describes the program, its history, planning, implementation, as well as the program's objectives and philosophy. The success of this program is documented here, as measured by continuous and expanding engagement of educators, the community, and the public, along with formal evaluation feedback and selected informal verbal testimony. The program's success also serves as justification for the planned adaptation of a version of the program in Chile in 2011 (adapted for Chilean educational and cultural differences). Finally, lessons learned are shared which have refined the program for Gemini's host communities but can also apply to any institution wishing to initiate a similar program.

Harvey, Janice; Michaud, Peter

2012-08-01

340

Giant Planets Tristan Guillot  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4.2 Uranus and Neptune . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 4 the interior structure and evolution of Jupiter, Saturn, Uranus and Neptune, and extrasolar giant planets, Jupiter, Saturn, Uranus, Neptune, planet formation 1 Introduction In our Solar System, four planets stand

Paris-Sud XI, Université de

341

Dynamical Outcomes of Planet-Planet Scattering  

E-print Network

Observations in the past decade have revealed extrasolar planets with a wide range of orbital semimajor axes and eccentricities. Based on the present understanding of planet formation via core accretion and oligarchic growth, we expect that giant planets often form in closely packed configurations. While the protoplanets are embedded in a protoplanetary gas disk, dissipation can prevent eccentricity growth and suppress instabilities from becoming manifest. However, once the disk dissipates, eccentricities can grow rapidly, leading to close encounters between planets. Strong planet--planet gravitational scattering could produce both high eccentricities and, after tidal circularization, very short-period planets, as observed in the exoplanet population. We present new results for this scenario based on extensive dynamical integrations of systems containing three giant planets, both with and without residual gas disks. We assign the initial planetary masses and orbits in a realistic manner following the core accretion model of planet formation. We show that, with realistic initial conditions, planet--planet scattering can reproduce quite well the observed eccentricity distribution. Our results also make testable predictions for the orbital inclinations of short-period giant planets formed via strong planet scattering followed by tidal circularization.

Sourav Chatterjee; Eric B. Ford; Soko Matsumura; Frederic A. Rasio

2008-05-15

342

Planet Ocean  

NASA Astrophysics Data System (ADS)

A more adequate name for Planet Earth could be Planet Ocean, seeing that ocean water covers more than seventy percent of the planet's surface and plays a fundamental role in the survival of almost all living species. Actually, oceans are aqueous solutions of extraordinary importance due to its direct implications in the current living conditions of our planet and its potential role on the continuity of life as well, as long as we know how to respect the limits of its immense but finite capacities. We may therefore state that natural aqueous solutions are excellent contexts for the approach and further understanding of many important chemical concepts, whether they be of chemical equilibrium, acid-base reactions, solubility and oxidation-reduction reactions. The topic of the 2014 edition of GIFT ('Our Changing Planet') will explore some of the recent complex changes of our environment, subjects that have been lately included in Chemistry teaching programs. This is particularly relevant on high school programs, with themes such as 'Earth Atmosphere: radiation, matter and structure', 'From Atmosphere to the Ocean: solutions on Earth and to Earth', 'Spring Waters and Public Water Supply: Water acidity and alkalinity'. These are the subjects that I want to develop on my school project with my pupils. Geographically, our school is located near the sea in a region where a stream flows into the sea. Besides that, our school water comes from a borehole which shows that the quality of the water we use is of significant importance. This project will establish and implement several procedures that, supported by physical and chemical analysis, will monitor the quality of water - not only the water used in our school, but also the surrounding waters (stream and beach water). The samples will be collected in the borehole of the school, in the stream near the school and in the beach of Carcavelos. Several physical-chemical characteristics related to the quality of the water will be taken into consideration, for instance, the value of the pH, using universal indicator paper, color, through visual evaluation and the temperature with the help of a thermometer. There will be also registered some existent chemical parameters as chloride, alkalinity, total hardness (Ca2+ and Mg2+), nitrate, nitrite, ammonia and phosphate. Two methods will be used for analysis, the titration and the kit of semi-quantitative chemical analyses. This kit is composed by biocompatible substances, which means they are not harmful for the environment and can be disposed of by domestic sewage systems. The results will be subsequently analyzed bearing in mind the maximum and recommended standards values for each one of the parameters. After this, the results achieved will be discussed. I believe this project contains characteristics that will be of interest to our students, thus enabling them to participate actively and effectively develop their knowledge and enhance their scientific curiosity.

Afonso, Isabel

2014-05-01

343

New strategy for planets serach in debris disks  

NASA Astrophysics Data System (ADS)

Based on the modern theory of planet formation, planetary systems are formed in protoplanetary disks that could surround young stellar and substellar objects. Giant planets formation process starts at first 100 thousand years as a consequence of disk gravitational instability. Rocky planets form later, through the coagulation of planetesimals. Common feature in both types planets formation scenarios is that once planet reaches stable orbit (especially if orbit is circular), planet clears a gap in the disk along the planet's orbit. By the debris disk stage the gap opened by planet becomes optically thin. There are two observational methods to study the structure of debris disks: with an image and via an excess in stellar spectral energy distribution (SED) at the infrared. The image of such disk is the best way to detect the gap opened by planet and even the planet itself. It is almost impossible to detect the planet around the star by studying SED, due to the big difference of their luminosities. But it is possible to suspect planet based on the param- eters of the gap cleaned by planet, that could be derived based on the analysis of SED profile. The aim of present work is to investigate a possibility to detect planet in debris disk via SED profile analyze and to determine planets physical parameters that can be derived with this method. I will present the results of numerical calculations for systems with low-mass stellar and substellar objects at 1 Gyr. Debris disk particles radii vary from 0.1 microns to 1 meter; disk masses vary from 10**-16 to 0.05 masses of the star (that initially doesn't account extinction due to the gap opened by the planet). Width of the gap opened by the planet is determined as a diameter of Hill sphere. Planet masses are varied from 10 Earth to 10 Jupiter masses. Distance from the planet to the central star is within all possible positions along the disk radius.

Zakhozhay, O.

2014-09-01

344

Novel Gemini vitamin D 3 analogs have potent antitumor activity  

Microsoft Academic Search

The active form of vitamin D3, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], modulates proliferation and induces differentiation of many cancer cells. A new class of analogs of vitamin D3 has been synthesized, having two side-chains attached to carbon-20 (Gemini) and deuterium substituted on one side-chain. We have examined six of these analogs for their ability to inhibit growth of myeloid leukemia (HL-60), prostate

Tsuyako Saito; Ryoko Okamoto; Talin Haritunians; James O’Kelly; Milan Uskokovic; Hubert Maehr; Stanislaw Marczak; Pawel Jankowski; Riem Badr; H. Phillip Koeffler

2008-01-01

345

GIRMOS: an infrared multi-object spectrograph for Gemini  

Microsoft Academic Search

Gemini have funded a design study to investigate the technologies needed in a versatile multi-object spectrograph for IR astronomy. We report on our investigations into wide- field spectroscopy using multiple integral-field units (MIFUs) to match particular areas of interest to the available detector(s). Such technologies enable integral field spectroscopy of several targets over a much wider field than can be

Gillian S. Wright; Ray M. Sharples; Peter R. Hastings; Martyn Wells; Eli Atad-Ettedgui; Jeremy R. Allington-Smith; David J. Robertson; Ian R. Parry

2000-01-01

346

Northwestern Mexico as seen from the Gemini 12 spacecraft  

NASA Technical Reports Server (NTRS)

Area of northwestern Mexico as seen from the Gemini 12 spacecraft during its 16th revolution of the earth. View is looking northwest. Body of water in foreground is Gulf of California. Pacific Ocean is in background. Peninsula in center of picture is Baja California. States of Sonora (upper right) and Sinaloa (lower center) of Mexican mainland is in right foreground. City of Guaymas, Sonora, is near center of picture.

1966-01-01

347

Extrasolar planet detection  

NASA Technical Reports Server (NTRS)

This paper discusses the concept of extrasolar planet detection using a large-aperture infared imaging telescope. Coronagraphic stellar apodization techniques are less efficient at infrared wavelengths compared to the visible, as a result of practical limitations on aperture dimensions, thus necessitating additional starlight suppression to make planet detection feasible in this spectral domain. We have been investigating the use of rotational shearing interferometry to provide up to three orders of magnitude of starlight suppression over broad spectral bandwidths. We present a theoretical analysis of the system performance requirements needed to make this a viable instrument for planet detection, including specifications on the interferometer design and telescope aperture characteristics. The concept of using rotational shearing interferometry as a wavefront error detector, thus providing a signal that can be used to adaptively correct the wavefront, will be discussed. We also present the status of laboratory studies of on-axis source suppression using a recently constructed rotational shearing interferometer that currently operates in the visible.

Korechoff, R. P.; Diner, D. J.; Tubbs, E. F.; Gaiser, S. L.

1994-01-01

348

A Virtual Field Trip to the Gemini Observatory  

NASA Astrophysics Data System (ADS)

Live from Gemini (LfG) is a virtual field trip using video conferencing technology to connect primary, secondary and post-secondary students with scientists and educators at the Gemini Observatory. As a pilot project, LfG is rapidly becoming one of the observatory's most often-requested educational programs for learners of all ages. The program aligns exceptionally well with national science (and technology) standards, as well as existing school curricula. This combination makes it easy for teachers to justify participation in the program, especially as the necessary video conferencing technology becomes ever more ubiquitous in classrooms and technology learning centers around the world. In developing and testing this pilot project, a programmatic approach and philosophy evolved that includes post-field-trip educational materials, multi-disciplinary subject matter (astronomy, geology, mathematics, meteorology, engineering and even language - the program is offered in Spanish from Gemini South in Chile), and the establishment of a personal connection and rapport with students. The presenters work to create a comfortable interaction despite the perceived technological barriers. The authors’ experiences with the LfG pilot project convince us that this model is viable for almost any astronomical observatory and should be considered by any dynamic, technology- and education-oriented facility.

Fisher, R. Scott; Michaud, P. D.

2010-01-01

349

On the Shoulders of Titans: A History of Project Gemini  

NASA Technical Reports Server (NTRS)

Gemini was the intermediate manned space flight program between America's first steps into space with Mercury and the manned lunar expeditions of Apollo. Because of its position between these two other efforts, Gemini is probably less remembered. Still, it more than had its place in man's progress into this new frontier. Gemini accomplishments were manyfold. They included many firsts: first astronaut-controlled maneuvering in space; first rendezvous in space of one spacecraft with another; first docking of one spacecraft with a propulsive stage and use of that stage to transfer man to high altitude; first traverse of man into the earth's radiation belts; first extended manned flights of a week or more in duration; first extended stays of man outside his spacecraft; first controlled reentry and precision landing; and many more. These achievements were significant in ways one cannot truly evaluate even today, but two things stand out: (1) it was the time when America caught up and surpassed the Soviet Union in manned space flight, and (2) these demonstrations of capability were an absolute prerequisite to the phenomenal Apollo accomplishments then yet to come.

Hacker, B. C.

1977-01-01

350

Gemini - John W. Young in Rendezvous Docking Simulator  

NASA Technical Reports Server (NTRS)

Astronaut John Young (above) was one of 14 astronauts, 8 NASA test pilots, and 2 McDonnell test pilots who took part in simulator studies. Young piloted the simulator on November 12, 1963 Arthur Vogeley wrote: 'Many of the astronauts have flown this simulator in support of the Gemini studies and they, without exception, appreciated the realism of the visual scene. The simulator has also been used in the development of pilot techniques to handle certain jet malfunctions in order that aborts could be avoided. In these situations large attitude changes are sometimes necessary and the false motion cues that were generated due to earth gravity were somewhat objectionable; however, the pilots were readily able to overlook these false motion cues in favor of the visual realism.' Roy F. Brissenden wrote:'The basic Gemini control studies developed the necessary techniques and demonstrated the ability of human pilots to perform final space docking with the specified Gemini-Agena systems using only visual references. ... Results... showed that trained astronauts can effect the docking with direct acceleration control and even with jet malfunctions as long as good visual conditions exist.... Probably more important than data results was the early confidence that the astronauts themselves gained in their ability to perform the maneuver in the ultimate flight mission.'

1963-01-01

351

Easier Phase IIs: Recent Improvements to the Gemini User Tools  

NASA Astrophysics Data System (ADS)

During 2011 and 2012 Gemini Observatory undertook a significant project to improve the software tools used by investigators to propose for and prepare observations. The main goal was to make the definition of observation details (the Phase II process) easier and faster. The main initiatives included rewriting the observing proposal tool (Phase I Tool) and making several major improvements to the Observing Tool, including automatic settings for arc and flat exposures, automatic guide star selection for all instruments and wavefront sensors, and more complete initial template observations with capabilities for simultaneous editing of many observations. This poster explains these major changes as well as outlines future development plans. The Gemini Observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

Miller, Bryan; Nuñez, A.

2013-01-01

352

The Microlensing Planet Finder: Completing the Census of Extrasolar Planets in the Milky Way  

E-print Network

The Microlensing Planet Finder (MPF) is a proposed Discovery mission that will complete the first census of extrasolar planets with sensitivity to planets like those in our own solar system. MPF will employ a 1.1m aperture telescope, which images a 1.3 sq. deg. field-of-view in the near-IR, in order to detect extrasolar planets with the gravitational microlensing effect. MPF's sensitivity extends down to planets of 0.1 Earth masses, and MPF can detect Earth-like planets at all separations from 0.7AU to infinity. MPF's extrasolar planet census will provide critical information needed to understand the formation and frequency of extra solar planetary systems similar to our own.

D. P. Bennett; I. Bond; E. Cheng; S. Friedman; P. Garnavich; B. Gaudi; R. Gilliland; A. Gould; M. Greenhouse; K. Griest; R. Kimble; J. Lunine; J. Mather; D. Minniti; M. Niedner; B. Paczynski; S. Peale; B. Rauscher; M. Rich; K. Sahu; D. Tenerelli; A. Udalski; N. Woolf; P. Yock

2004-09-09

353

Synthesis of organic rectorite with novel Gemini surfactants for copper removal  

NASA Astrophysics Data System (ADS)

Three novel Gemini surfactants were used to prepare organic rectorite (OREC) under microwave irradiation, in comparison with single-chain surfactant ester quaternary ammonium salt (EQAS) and cetyltrimethyl ammonium bromide (CTAB). The structure and morphology of OREC were characterized by XRD, BET, FT-IR, TEM and TGA. The removal of Cu2+ on OREC from aqueous solution was performed. The results reveal that Gemini surfactants modified REC had larger interlayer distance and higher surface area than single-chain surfactants EQAS and CTAB, and the increasing amount or chain length of Gemini surfactants led to larger layer spacing and higher adsorption capacities. The adsorption behavior of Gemini surfactant modified REC can be better described by Freundlich adsorption isotherm model, with a maximum adsorption capacity of 15.16 mg g-1. The desorption and regeneration experiments indicate good reuse property of Gemini modified REC adsorbent. Therefore, this study may widen the utilization of Gemini surfactants modified layered silicates.

Han, Guocheng; Han, Yang; Wang, Xiaoying; Liu, Shijie; Sun, Runcang

2014-10-01

354

Line-by-line analysis of Neptune's near-IR spectrum observed with Gemini/NIFS and VLT/CRIRES  

NASA Astrophysics Data System (ADS)

New line data describing the absorption of CH4 and CH3D from 1.26 to 1.71 ?m (WKMC-80K, Campargue, A., Wang, L., Mondelain, D., Kassi, S., Bézard, B., Lellouch, E., Coustenis, A., de Bergh, C., Hirtzig, M., Drossart, P. [2012]. Icarus 219, 110-128) have been applied to the analysis of Gemini-N/NIFS observations of Neptune made in 2009 and VLT/CRIRES observations made in 2010. The new line data are found to greatly improve the fit to the observed spectra and present a considerable advance over previous methane datasets. The improved fits lead to an empirically derived wavelength-dependent correction to the scattering properties of the main observable cloud deck at 2-3 bars that is very similar to the correction determined for Uranus' lower cloud using the same line dataset by Irwin et al. (Irwin, P.G.J., de Bergh, C., Courtin, R., Bézard, B., Teanby, N.A., Davis, G.R., Fletcher, L.N., Orton, G.S., Calcutt, S.B., Tice, D., Hurley, J. [2012]. Icarus 220, 369-382). By varying the abundance of CH3D in our simulations, analysis of the Gemini/NIFS observations leads to a new determination of the CH3D/CH4 ratio for Neptune of 3.0-0.9+1.0×10-4, which is smaller than previous determinations, but is identical (to within error) with the CH3D/CH4 ratio of 2.9-0.5+0.9×10-4 derived by a similar analysis of Gemini/NIFS observations of Uranus made in the same year. Thus it appears that the atmospheres of Uranus and Neptune have an almost identical D/H ratio, which suggests that the icy planetisimals forming these planets came from the same source reservoir, or a reservoir that was well-mixed at the locations of ice giant formation, assuming complete mixing between the atmosphere and interior of both these planets. VLT/CRIRES observations of Neptune have also been analysed with the WKMC-80K methane line database, yielding very good fits, with little evidence for missing absorption features. The CRIRES spectra indicate that the mole fraction of CO at the 2-3 bar level must be substantially less than its estimated stratospheric value of 1 × 10-6, which suggests that the predominant source of CO in Neptune's atmosphere is external, through the influx of micrometeorites and comets, although these data cannot rule out an additional internal source.

Irwin, P. G. J.; Lellouch, E.; de Bergh, C.; Courtin, R.; Bézard, B.; Fletcher, L. N.; Orton, G. S.; Teanby, N. A.; Calcutt, S. B.; Tice, D.; Hurley, J.; Davis, G. R.

2014-01-01

355

Determining the Narrow-Line Region Geometry of Mrk 3 with Gemini/NIFS  

NASA Astrophysics Data System (ADS)

We present a study of the narrow-line region (NLR) and inner disk of the Seyfert 2 Mrk 3, based on observations from the Gemini Near-Infrared Integral Field Spectrometer (NIFS). Mrk 3 exhibits emission-line knots within the NLR that are in the shape of a backward S, which is likely due to dust/gas spirals in the galaxy's disk that have been illuminated by the AGN's ionizing bicone. With our NIFS observations, we determine the kinematics of Mrk 3 using an automated Bayesian model selection algorithm. Comparing the NLR kinematics measured with NIFS to those previously measured with the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS), we are able to test the accuracy of our previous kinematic outflow model.

Pope, Crystal L.; Fischer, Travis C.; Crenshaw, D. Michael

2015-01-01

356

Terrestrial Planet Geophysics  

NASA Astrophysics Data System (ADS)

Terrestrial planet geophysics beyond our home sphere had its start arguably in the early 1960s, with Keith Runcorn contending that the second-degree shape of the Moon is due to convection and Mariner 2 flying past Venus and detecting no planetary magnetic field. Within a decade, in situ surface geophysical measurements were carried out on the Moon with the Apollo program, portions of the lunar magnetic and gravity fields were mapped, and Jack Lorell and his colleagues at JPL were producing spherical harmonic gravity field models for Mars using tracking data from Mariner 9, the first spacecraft to orbit another planet. Moreover, Mariner 10 discovered a planetary magnetic field at Mercury, and a young Sean Solomon was using geological evidence of surface contraction to constrain the thermal evolution of the innermost planet. In situ geophysical experiments (such as seismic networks) were essentially never carried out after Apollo, although they were sometimes planned just beyond the believability horizon in planetary mission queues. Over the last three decades, the discipline of terrestrial planet geophysics has matured, making the most out of orbital magnetic and gravity field data, altimetric measurements of surface topography, and the integration of geochemical information. Powerful constraints are provided by tectonic and volcanic information gleaned from surface images, and the engagement of geologists in geophysical exercises is actually quite useful. Accompanying these endeavors, modeling techniques, largely adopted from the Earth Science community, have become increasingly sophisticated and have been greatly enhanced by the dramatic increase in computing power over the last two decades. The future looks bright with exciting new data sets emerging from the MESSENGER mission to Mercury, the promise of the GRAIL gravity mission to the Moon, and the re-emergence of Venus as a worthy target for exploration. Who knows? With the unflagging optimism and persistence of a few diehards, we may eventually have a seismic and heat flow network on Mars.

Phillips, R. J.

2008-12-01

357

The Nine Planets: Small Bodies  

NSDL National Science Digital Library

This page of Nine Planets contains links and information about asteroids and comets in our solar system. It includes information on Comet Halley and Shoemaker-Levy 9, as well as the Asteroid Belt, interplanetary matter, the Oort Cloud, and the Kuiper Belt. Also provided are links for more information, movies, and images.

Bill Arnett

358

Mission to Planet Earth  

NSDL National Science Digital Library

These four written and computer activities cover concepts of remote sensing in general and NASA's Mission to Planet Earth. The first is a written activity asking students to consider what about the earth they would want to study. The second combines a written activity on the Galileo spacecraft with a computer activity. Students will view images of the earth taken from the spacecraft. In the third activity, students receive their first introduction to image processing programs as they view two earth images and are asked to detect differences. They work with several software tools and become comfortable opening files and applying various image processing techniques. In the final section, students work with whole earth optical images and then open up their first radar image, seeing first an image of Los Angeles and then a close-up view of Elysium Park and Dodger Stadium taken at the same time, and derive an understanding of the various advantages and limitations of the remote sensing platforms.

359

Gemini 7 prime crew during suiting up procedures at Launch Complex 16  

NASA Technical Reports Server (NTRS)

Astronaut James A. Lovell Jr. (left), Gemini 7 prime crew pilot, talks with NASA space suit technician Clyde Teague during suiting up procedures at Launch Complex 16, Kennedy Space Center. Lovell wears the new lightweight space suit planned for use during the Gemini 7 mission (61756); Astronaut Frank Borman, comand pilot of the Gemini 7 space flight, undergoes suiting up operations in Launch Complex 16 during prelaunch countdown. Medical biosensors are attached to his scalp (61757).

1965-01-01

360

Hubble Observes the Planet Uranus  

NASA Technical Reports Server (NTRS)

This NASA Hubble Space Telescope image of the planet Uranus reveals the planet's rings and bright clouds and a high altitude haze above the planet's south pole.

Hubble's new view was obtained on August 14, 1994, when Uranus was 1.7 billion miles (2.8 billion kilometers) from Earth. These details, as imaged by the Wide Field Planetary Camera 2, were only previously seen by the Voyager 2 spacecraft, which flew by Uranus in 1986. Since then, none of these inner satellites has been further observed, and detailed observations of the rings have not been possible.

Though Uranus' rings were discovered indirectly in 1977 (through stellar occultation observations), they have never before been seen in visible light through a ground-based telescope.

Hubble resolves several of Uranus' rings, including the outermost Epsilon ring. The planet has a total of 11 concentric rings of dark dust. Uranus is tipped such that its rotation axis lies in the plane of its orbit, so the rings appear nearly face-on.

Three of Uranus' inner moons each appear as a string of three dots at the bottom of the picture. This is because the picture is a composite of three images, taken about six minutes apart, and then combined to show the moons' orbital motions. The satellites are, from left to right, Cressida, Juliet, and Portia. The moons move much more rapidly than our own Moon does as it moves around the Earth, so they noticeably change position over only a few minutes.

One of the four gas giant planets of our solar system, Uranus is largely featureless. HST does resolve a high altitude haze which appears as a bright 'cap' above the planet's south pole, along with clouds at southern latitudes (similar structures were observed by Voyager). Unlike Earth, Uranus' south pole points toward the Sun during part of the planet's 84-year orbit. Thanks to its high resolution and ability to make observations over many years, Hubble can follow seasonal changes in Uranus's atmosphere, which should be unusual given the planet's large tilt.

The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

1994-01-01

361

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

362

Disposable Planet  

NSDL National Science Digital Library

BBC Online presents this six-part special on sustainable development. Created in anticipation of the now concluded Johannesburg Summit, this Web site provides a valuable resource for viewers wishing to learn more about sustainable development and related issues. The Web site consists of an overview and six sections: Population, Food, Cities, Waste, Tourism, and Energy. The sections offer an in-depth look at each topic and include audio clips of related interviews and news stories. The discussion forums are now closed, but visitors may read the occasionally insightful and often times heated comments that have already been posted. View the slide show to get a quick, visceral sense of human impact on the planet -- past, present, and future. Visitors may also take a quiz to calculate their ecological footprint, or how much of the earth's resources they individually consume each year.

2002-01-01

363

Detecting companions to extrasolar planets using mutual events  

E-print Network

We investigate a new approach to the detection of companions to extrasolar planets beyond the transit method. We discuss the possibility of the existence of binary planets. We develop a method based on the imaging of a planet-companion as an unresolved system (but resolved from its parent star). It makes use of planet-companion mutual phenomena, namely mutual transits and mutual shadows. We show that companions can be detected and their radius measured down to lunar sizes.

J. Cabrera; J. Schneider

2007-03-23

364

The effect of a small heat source on PSF stability for high-contrast imaging.  

PubMed

High-contrast adaptive optics systems, such as those needed to image extrasolar planets, are known to require excellent wavefront control and diffraction suppression. The Laboratory for Adaptive Optics at UC Santa Cruz is investigating limits to high-contrast imaging in support of the Gemini Planet Imager (GPI). In this paper we examine the effect of heat sources in the testbed on point-spread-function (PSF) stability. Introducing a heat source primarily introduces image motion. The GPI error budget requires image motion to be less than 0.1 lambda /D. Systematic motion of the PSF core is typically 0.01 lambda /D rms and with a 20 watt heat source introduced near the pupil plane image motion is increased to 0.02 lambda /D rms. Therefore, even a heat source as large as 20 watts near the pupil plane causes errors below the GPI requirement, but the combination of the heat source and additional air turbulence on the system introduced by changes to the enclosure or the fan of other components can produce significantly more motion. Heat also can affect the speckle pattern in the high-contrast region, but in the final instrument other sources of error should be more significant. PMID:19582080

Evans, Julia W; Macintosh, Bruce; Norton, Andrew; Dillon, Daren; Gavel, Donald

2009-07-01

365

The properties of the planet(s) around Beta Pictoris  

NASA Astrophysics Data System (ADS)

Since the discovery of the Beta Pictoris dust system in the 80s, the detailed study of the disk and the discovery of the falling evaporating bodies phenomenon around this star provided a growing evidence that the system was hosting, at least, on gas giant planet. In 2009, Lagrange et al. identified in VLT/NaCo high resolution imaging data a candidate planet located at a projected separation of 9 AU in the disk of Beta Pictoris. Since then, follow-up images of the system obtained with various instruments from 0.98 m to 4.8 m enabled to confirm that Beta Pic b is circling the star on a low-eccentricity orbit, has a mass of ~7-13 MJup, and a hot (Teff 1700 K) dusty atmosphere. The determination of Beta Pic b's orbital motion and spectro-photometric properties, the radial velocity (RV) measurements of the star, and the detailed study of disk structures offer altogether a unique chance to characterize the chemical and physical properties of a directly imaged planet, and to understand in detail how it formed and influenced the system architecture. In this talk, I will review the past and ongoing efforts to characterize the properties of Beta Pictoris b, and to find additional planets in the system.

Bonnefoy, M.

2014-09-01

366

HUBBLE OBSERVES THE PLANET URANUS  

NASA Technical Reports Server (NTRS)

This NASA Hubble Space Telescope image of the planet Uranus reveals the planet's rings and bright clouds and a high altitude haze above the planet's south pole. Hubble's new view was obtained on August 14, 1994, when Uranus was 1.7 billion miles (2.8 billion kilometers) from Earth. These details, as imaged by the Wide Field Planetary Camera 2, were only previously seen by the Voyager 2 spacecraft, which flew by Uranus in 1986. Since then, none of these inner satellites has been further observed, and detailed observations of the rings have not been possible. Though Uranus' rings were discovered indirectly in 1977 (through stellar occultation observations), they have never before been seen in visible light through a ground-based telescope. Hubble resolves several of Uranus' rings, including the outermost Epsilon ring. The planet has a total of 11 concentric rings of dark dust. Uranus is tipped such that its rotation axis lies in the plane of its orbit, so the rings appear nearly face-on. Three of Uranus' inner moons each appear as a string of three dots at the bottom of the picture. This is because the picture is a composite of three images, taken about six minutes apart, and then combined to show the moons' orbital motions. The satellites are, from left to right, Cressida, Juliet, and Portia. The moons move much more rapidly than our own Moon does as it moves around the Earth, so they noticeably change position over only a few minutes. One of the four gas giant planets of our solar system, Uranus is largely featureless. HST does resolve a high altitude haze which appears as a bright 'cap' above the planet's south pole, along with clouds at southern latitudes (similar structures were observed by Voyager). Unlike Earth, Uranus' south pole points toward the Sun during part of the planet's 84-year orbit. Thanks to its high resolution and ability to make observations over many years, Hubble can follow seasonal changes in Uranus's atmosphere, which should be unusual given the planet's large tilt. Credit: Kenneth Seidelmann, U.S. Naval Observatory, and NASA These observations were conducted by a team led by Dr. Ken Seidelmann of the U.S. Naval Observatory as Principal Investigator. These images have been processed by Professor Douglas Currie and Mr. Dan Dowling in the Department of Physics at the University of Maryland. Other team members are Dr. Ben Zellner at Georgia Southern University, Dr. Dan Pascu and Mr. Jim Rhode at the U.S. Naval Observatory, and Dr. Ed Wells, Mr. Charles Kowal (Computer Science Corporation) and Dr. Alex Storrs of the Space Telescope Science Institute.

2002-01-01

367

Dance of the Planets  

ERIC Educational Resources Information Center

As students continue their monthly plotting of the planets along the ecliptic they should start to notice differences between inner and outer planet orbital motions, and their relative position or separation from the Sun. Both inner and outer planets have direct eastward motion, as well as retrograde motion. Inner planets Mercury and Venus,…

Riddle, Bob

2005-01-01

368

Further seasonal changes in Uranus’ cloud structure observed by Gemini-North and UKIRT  

NASA Astrophysics Data System (ADS)

Near-infrared observations of Uranus were made in October/November 2010 with the Gemini-North telescope in Hawaii, using NIFS, an integral field spectrograph, and the NIRI instrument in imaging mode. Observations were acquired using adaptive optics and have a spatial resolution of approximately 0.1-0.2?. The observed spectra along Uranus’ central meridian were analysed using a multiple-scattering retrieval algorithm to infer the vertical/latitudinal variation in cloud optical depth, which we compare with previous observations made by Gemini-North/NIFS in 2009 and UKIRT/UIST observations made between 2006 and 2008. Assuming a continuous distribution of small particles (r ? 1 ?m, and refractive index of 1.4 + 0i) with the single scattering albedo set to 0.75 and using a Henyey-Greenstein phase function with asymmetry parameter set to 0.7 at all wavelengths and latitudes, the retrieved cloud density profiles show that the north polar zone at 45°N has continued to steadily brighten while the south polar zone at 45°S has continued to fade. As with our previous analyses we find that, assuming that the methane vertical profile is the same at all latitudes, the clouds forming these polar zones at 45°N and 45°S lie at slightly lower pressures than the clouds at more equatorial latitudes. However, we also find that the Gemini data can be reproduced by assuming that the main cloud remains fixed at ?2 bar at all latitudes and adjusting the relative humidity of methane instead. In this case we find that the deep cloud is still more opaque at the equator and at the zones at 45°N and 45°S and shows the same seasonal trends as when the methane humidity remain fixed. However, with this approach the relative humidity of methane is seen to rise sharply from approximately 20% at polar latitudes to values closer to 80% for latitudes equatorward of 45°S and 45°N, consistent with the analysis of 2002 HST observations by Karkoschka and Tomasko (Karkoschka, E., Tomasko, M. [2009]. Icarus 202, 287-302), with a possible indication of seasonal variability. Overall, Uranus appeared to be less convectively active in 2010 than in the previous 4 years, supporting the conclusion that now the northern spring equinox (which occurred in 2007) has passed, the atmosphere is settling back into the more quiescent state seen by Voyager 2 in 1986.

Irwin, P. G. J.; Teanby, N. A.; Davis, G. R.; Fletcher, L. N.; Orton, G. S.; Calcutt, S. B.; Tice, D. S.; Hurley, J.

2012-03-01

369

Diamond turned high precision PIAA optics and four mirror PIAA system for high contrast imaging of exo-planets  

NASA Astrophysics Data System (ADS)

Off-axis, high-sag PIAA optics for high contrast imaging present challenges in manufacturing and testing. With smaller form factors and consequently smaller surface deformations (< 80 microns), diamond turned fabrication of these mirrors becomes feasible. Though such a design reduces the system throughput, it still provides 2?/D inner working angle. We report on the design, fabrication, measurements, and initial assessment of the novel PIAA optics in a coronagraph testbed. We also describe, for the first time, a four mirror PIAA coronagraph that relaxes apodizer requirements and significantly improves throughput while preserving the low-cost benefits.

Balasubramanian, Kunjithapatham; Cady, Eric; Pueyo, Laurent; An, Xin; Shaklan, Stuart; Guyon, Olivier; Belikov, Ruslan

2011-10-01

370

Characterizing K2 Planet Discoveries  

NASA Astrophysics Data System (ADS)

We present an effort to confirm the first planet discovered by the two-wheeled Kepler mission. We analyzed K2 photometry, correcting for nonuniform detector response as a function of the spacecraft's pointing, and detected a transiting planet candidate. We describe our multi-telescope followup observing campaign, consisting of photometric, spectroscopic, and high resolution imaging observations, including over 40 HARPS-N radial velocity measurements. The new planet is a super-Earth orbiting a bright star amenable to followup observations. HARPS-N was funded by the Swiss Space Office, the Harvard Origin of Life Initiative, the Scottish Universities Physics Alliance, the University of Geneva, the Smithsonian Astrophysical Observatory, the Italian National Astrophysical Institute, the University of St. Andrews, Queens University Belfast, and the University of Edinburgh.

Vanderburg, Andrew; Montet, Benjamin; Johnson, John; Buchhave, Lars A.; Zeng, Li; Bieryla, Allyson; Latham, David W.; Charbonneau, David; Harps-N Collaboration, The Robo-Ao Team

2015-01-01

371

Disk-Planet Interactions During Planet Formation  

E-print Network

The discovery of close orbiting extrasolar giant planets led to extensive studies of disk planet interactions and the forms of migration that can result as a means of accounting for their location. Early work established the type I and type II migration regimes for low mass embedded planets and high mass gap forming planets respectively. While providing an attractive means of accounting for close orbiting planets intially formed at several AU, inward migration times for objects in the earth mass range were found to be disturbingly short, making the survival of giant planet cores an issue. Recent progress in this area has come from the application of modern numerical techniques which make use of up to date supercomputer resources. These have enabled higher resolution studies of the regions close to the planet and the initiation of studies of planets interacting with disks undergoing MHD turbulence. This work has led to indications of how the inward migration of low to intermediate mass planets could be slowed down or reversed. In addition, the possibility of a new very fast type III migration regime, that can be directed inwards or outwards, that is relevant to partial gap forming planets in massive disks has been investigated.

J. C. B. Papaloizou; R. P. Nelson; W. Kley; F. S. Masset; P. Artymowicz

2006-03-08

372

Characterizing Transiting Exoplanet Atmospheres with Gemini/GMOS: First Results  

NASA Astrophysics Data System (ADS)

We present the first results from a 4-year ground-based survey of nine transiting exoplanet atmospheres. The program uses the Multi-Object Spectrograph (GMOS) on both Gemini north and south to repetitively measure transit lightcurves of individual exoplanets at high spectrophotometric precision. I will present the first results from this program. We attain photometric precisions per spectral bin of 200-600 ppm. Such precision enables us to construct transmission spectra of hot Jupiters. These transmission spectra reveal the dominant upper-atmosphere absorbers in the optical bandpass. Our overarching goal is to understand the prevalence and formation of high altitude clouds and hazes, and other important atmospheric constituents.

Huitson, Catherine; Desert, Jean-Michel; Bean, Jacob; Fortney, Jonathan J.; Stevenson, Kevin B.; Bergmann, Marcel

2015-01-01

373

Eastern Mediterranean as seen from Gemini 7 spacecraft  

NASA Technical Reports Server (NTRS)

The eastern Mediterranean area is photographed by Astronaut Frank Borman and James A. Lovell during the Gemini 7 mission. The Nile Delta in Egypt is at bottom. The Suez Canal, Gulf of Suez, and Red Sea are in center of photograph. Sinai Peninsula is in upper right corner of photograph. Body of water at top edge of photograph is Gulf of Aqaba. The Dead Sea can be seen in top center of picture. Israel, Palestine, Jordan and Syria are also at top center. The Island of Cyprus is at extreme left.

1965-01-01

374

Giant Micelles of Organoplatinum(II) Gemini Amphiphiles  

PubMed Central

Organoplatinum(II) gemini amphiphiles with two different chain lengths are synthesized and characterized. Self-assembly at the air-water interface is investigated as a function of chain length and reduction in surface area by using Langmuir-trough techniques. The Langmuir-trough experiments lead to a conjecture that surface aggregates may be the adsorbing units. Atomic force microscopy on the transferred Langmuir-Schaefer films reveals spontaneous formation of wormlike micellar aggregates. A shear-induced transition and alignment are proposed for the observed effects. PMID:18439034

Maran, Umamageswaran; Conley, Hiram; Frank, Markus; Arif, Atta M.; Orendt, Anita M.; Britt, David; Hlady, Vladimir; Davis, Robert; Stang, Peter J.

2008-01-01

375

A curvature-based laser guide star adaptive optics system for Gemini-South  

E-print Network

A curvature-based laser guide star adaptive optics system for Gemini-South M. Chun, C. d;1 A curvature-based laser guide star adaptive optics system for Gemini-South Mark Chuna , Céline d adaptive optics systems are limited by the requirement of a bright near-by reference source

376

Network Infrastructure Improvements at Gemini James R. Wright, Tod Fujioka and Jim Kennedy  

E-print Network

two grants for use in improving the network infrastructures in Hawaii and in Chile. 2. THE PARTNERSHIPNetwork Infrastructure Improvements at Gemini James R. Wright, Tod Fujioka and Jim Kennedy Gemini NSF grants to be used for enhancing the network connectivity in Hawaii and in Chile. We discuss our

377

Effect of Hydrotropic Salt on the Assembly Transitions and Rheological Responses of Cationic Gemini Surfactant Solutions  

E-print Network

Surfactant Solutions Ting Lu, Jianbin Huang,*, Zihui Li, Shikai Jia, and Honglan Fu Beijing National ReceiVed: August 17, 2007; In Final Form: NoVember 18, 2007 Cationic gemini surfactant dimethylene-1 of sodium salicylate (NaSal) on the assembly formation and transition of this cationic gemini surfactant

Huang, Jianbin

378

Design considerations of the AO module for the Gemini South multi-conjugate adaptive optics system  

E-print Network

Design considerations of the AO module for the Gemini South multi-conjugate adaptive optics system Observatory, 670 N. A'ohoku Place, Hilo, HI 96720 B. Optical Design Service, 8 S. Bella Vista Drive, Tucson optics system E. Jamesa , C. Boyera , R. A. Buchroederb , B.L. Ellerbroeka , M. Huntena a Gemini

379

Characterization of a photon counting EMCCD for space-based high contrast imaging spectroscopy of extrasolar planets  

E-print Network

We present the progress of characterization of a low-noise, photon counting Electron Multiplying Charged Coupled Device (EMCCD) operating in optical wavelengths and demonstrate possible solutions to the problems of Clock-Induced Charge (CIC) and other trapped charge through sub-bandgap illumination. Such a detector will be vital to the feasibility of future space-based direct imaging and spectroscopy missions for exoplanet characterization, and is scheduled to fly on-board the AFTA-WFIRST mission. The 512$\\times$512 EMCCD is an e2v detector housed and clocked by a N\\"uv\\"u Cameras controller. Through a multiplication gain register, this detector produces as many as 5000 electrons for a single, incident-photon-induced photoelectron produced in the detector, enabling single photon counting operation with read noise and dark current orders of magnitude below that of standard CCDs. With the extremely high contrasts (Earth-to-Sun flux ratio is $\\sim$ 10$^{-10}$) and extremely faint targets (an Earth analog would m...

Wilkins, Ashlee N; Norton, Timothy J; Rauscher, Bernard J; Rothe, Johannes F; Malatesta, Michael; Hilton, George M; Bubeck, James R; Grady, Carol A; Lindler, Don J

2014-01-01

380

Masses, Radii, and Orbits of Small Kepler Planets: The Transition from Gaseous to Rocky Planets  

NASA Astrophysics Data System (ADS)

We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm-3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than ~2 R ?. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O). Based in part on observations obtained at the W. M. Keck Observatory, which is operated by the University of California and the California Institute of Technology.

Marcy, Geoffrey W.; Isaacson, Howard; Howard, Andrew W.; Rowe, Jason F.; Jenkins, Jon M.; Bryson, Stephen T.; Latham, David W.; Howell, Steve B.; Gautier, Thomas N., III; Batalha, Natalie M.; Rogers, Leslie; Ciardi, David; Fischer, Debra A.; Gilliland, Ronald L.; Kjeldsen, Hans; Christensen-Dalsgaard, Jørgen; Huber, Daniel; Chaplin, William J.; Basu, Sarbani; Buchhave, Lars A.; Quinn, Samuel N.; Borucki, William J.; Koch, David G.; Hunter, Roger; Caldwell, Douglas A.; Van Cleve, Jeffrey; Kolbl, Rea; Weiss, Lauren M.; Petigura, Erik; Seager, Sara; Morton, Timothy; Johnson, John Asher; Ballard, Sarah; Burke, Chris; Cochran, William D.; Endl, Michael; MacQueen, Phillip; Everett, Mark E.; Lissauer, Jack J.; Ford, Eric B.; Torres, Guillermo; Fressin, Francois; Brown, Timothy M.; Steffen, Jason H.; Charbonneau, David; Basri, Gibor S.; Sasselov, Dimitar D.; Winn, Joshua; Sanchis-Ojeda, Roberto; Christiansen, Jessie; Adams, Elisabeth; Henze, Christopher; Dupree, Andrea; Fabrycky, Daniel C.; Fortney, Jonathan J.; Tarter, Jill; Holman, Matthew J.; Tenenbaum, Peter; Shporer, Avi; Lucas, Philip W.; Welsh, William F.; Orosz, Jerome A.; Bedding, T. R.; Campante, T. L.; Davies, G. R.; Elsworth, Y.; Handberg, R.; Hekker, S.; Karoff, C.; Kawaler, S. D.; Lund, M. N.; Lundkvist, M.; Metcalfe, T. S.; Miglio, A.; Silva Aguirre, V.; Stello, D.; White, T. R.; Boss, Alan; Devore, Edna; Gould, Alan; Prsa, Andrej; Agol, Eric; Barclay, Thomas; Coughlin, Jeff; Brugamyer, Erik; Mullally, Fergal; Quintana, Elisa V.; Still, Martin; Thompson, Susan E.; Morrison, David; Twicken, Joseph D.; Désert, Jean-Michel; Carter, Josh; Crepp, Justin R.; Hébrard, Guillaume; Santerne, Alexandre; Moutou, Claire; Sobeck, Charlie; Hudgins, Douglas; Haas, Michael R.; Robertson, Paul; Lillo-Box, Jorge; Barrado, David

2014-02-01

381

Create Your Own Planet  

NSDL National Science Digital Library

In this project you will be the creator of a new planet in our solar system. You will be free to decide all of the characteristics of your planet. Look at the different websites below to find out more about the planets in our solar system and then decide what characteristics your planet will have. PLANET PICTURES AND FACTS I I I I I V Mercury Facts Venus Facts Earth Facts Mars Facts Jupiter Facts Saturn Facts Uranus Facts Neptune Facts PROJECT REQUIREMENTS: Your planet must have one moon or more. You must decide how long it takes your planet to rotate (length of a day on your planet). You must decide how long it takes your planet to ...

Mr. Larsen

2008-11-25

382

Extrasolar Carbon Planets  

E-print Network

We suggest that some extrasolar planets 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 enhancement of the protoplanetary disk's C/O ratio above solar, a condition that pileups of carbonaceous grains may create in ordinary protoplanetary disks. Hot, Neptune-mass carbon planets should show a significant paucity of water vapor in their spectra compared to hot planets with solar abundances. Cooler, less massive carbon planets may show hydrocarbon-rich spectra and tar-covered surfaces. The high sublimation temperatures of diamond, SiC, and other carbon compounds could protect these planets from carbon depletion at high temperatures.

Marc J. Kuchner; S. Seager

2005-05-02

383

The Photodimerization of a Cinnamoyl Moiety Derivative in Dilute Solution Based on the Intramolecular Chain Interaction of Gemini Surfactant  

E-print Network

on the Intramolecular Chain Interaction of Gemini Surfactant Haiming Fan, Xiaoming Zhu, Lining Gao, Zichen Li 8, 2008 A Gemini surfactant, sodium N,N-di(4-n-butyloxy cinnamoly)-L-cystine, containing a cinnamoyl. The incorporation of a cinnamoyl moiety into the alkyl chains of Gemini surfactant makes it easy to probe

Huang, Jianbin

384

Optical contamination evidence from Skylab and Gemini flights  

NASA Technical Reports Server (NTRS)

Final results from a part of the T027 experiment performed on the first Skylab mission are presented. The sample array system containing 248 optical surfaces and exposed outside the orbital workshop did not collect any significant contaminants. Unfortunate performance compromises and the relative cleanliness of the assembly on the antisolar side placed the amount of available surface contaminants at or below the limiting sensitivity of the ground measuring instruments. Significant contamination was seen near the extravehicular hatch quadrant on the solar side of the orbiting assembly, and some results from returned samples are presented. Optical windows and mirrors exposed on the Gemini 12 mission showed degradation up to 35% in the UV wavelength region and solar absorptance increases up to 1.8 times the clean values. An expression for the attenuation coefficient vs wavelength is presented. The contaminant, a silicone base material, varied in thickness from 22 nm to 88 nm. The postflight scattered luminance of a contaminated Gemini 12 left-hand spacecraft hatch window was used to obtain threshold stellar visibility curves as a function of scattered and incident sunlight angles.

Muscari, J. A.; Westcott, P.

1975-01-01

385

OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. IV. OBSERVATIONS OF KEPLER, CoRoT, AND HIPPARCOS STARS FROM THE GEMINI NORTH TELESCOPE  

SciTech Connect

We present the results of 71 speckle observations of binary and unresolved stars, most of which were observed with the DSSI speckle camera at the Gemini North Telescope in 2012 July. The main purpose of the run was to obtain diffraction-limited images of high-priority targets for the Kepler and CoRoT missions, but in addition, we observed a number of close binary stars where the resolution limit of Gemini was used to better determine orbital parameters and/or confirm results obtained at or below the diffraction limit of smaller telescopes. Five new binaries and one triple system were discovered, and first orbits are calculated for other two systems. Several systems are discussed in detail.

Horch, Elliott P. [Department of Physics, Southern Connecticut State University, 501 Crescent Street, New Haven, CT 06515 (United States); Howell, Steve B. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Everett, Mark E. [National Optical Astronomy Observatory, 950 N. Cherry Ave, Tucson, AZ 85719 (United States); Ciardi, David R., E-mail: horche2@southernct.edu, E-mail: steve.b.howell@nasa.gov, E-mail: everett@noao.edu, E-mail: ciardi@ipac.caltech.edu [NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Avenue, Mail Code 100-22, Pasadena, CA 91125 (United States)

2012-12-01

386

Radial velocities of stars with multiple co-orbital planets  

NASA Astrophysics Data System (ADS)

To date, well over a thousand planets have been discovered orbiting other stars, hundreds of them in multi-planet systems. Most of these exoplanets have been detected by either the transit method or the radial velocity method, rather than by other methods such as astrometry or direct imaging. Both the radial velocity and astrometric methods rely upon the reflex motion of the parent star induced by the gravitational attraction of its planets. However, this reflex motion is subject to misinterpretation when a star has two or more planets with the same orbital period. Such co-orbital planets may effectively "hide" from detection by current algorithms.

Dobrovolskis, Anthony R.

2015-04-01

387

Characterizing Transiting Planet Atmospheres through 2025  

NASA Astrophysics Data System (ADS)

The discovery of planets around other stars is revolutionizing our notions of planet formation and is poised to do the same for planetary climate. Studying transiting planets is complementary to eventual studies of directly imaged planets: (1) we can readily measure the mass and radius of transiting planets, linking atmospheric properties to bulk composition and formation, (2) many transiting planets are strongly irradiated and exhibit novel atmospheric physics, and (3) the most common temperate terrestrial planets orbit close to red dwarf stars and are difficult to image directly. We have only been able to comprehensively characterize the atmospheres of a handful of transiting planets, because most orbit faint stars. The Transiting Exoplanet Survey Satellite (TESS) will discover transiting planets orbiting the brightest stars, enabling, in principle, an atmospheric survey of 102-103 bright hot Jupiters and warm sub-Neptunes. Uniform observations of such a statistically significant sample would provide leverage to understand - and learn from - the diversity of short-period planets, and would identify the minority of truly special planets worthy of more intensive follow-up. We argue that the best way to maximize the scientific returns of TESS is to adopt a triage approach. A space mission consisting of a ˜1 m telescope with an optical-NIR spectrograph could measure molecular absorption for nonterrestrial planets discovered by TESS, as well as eclipses and phase variations for the hottest jovians. Such a mission could observe up to 103 transits per year, thus enabling it to survey a large fraction of the bright (J < 11) hot-Jupiters and warm sub-Neptunes TESS is expected to find. The James Webb Space Telescope (JWST) could be used to perform detailed atmospheric characterization of the most interesting transiting targets (transit, eclipse, and - when possible - phase-resolved spectroscopy). TESS is also expected to discover a few temperate terrestrial planets transiting nearby M-Dwarfs. Characterizing these worlds will be time-intensive: JWST will need months to provide tantalizing constraints on the presence of an atmosphere, planetary rotational state, clouds, and greenhouse gases. Future flagship missions should be designed to provide better constraints on the habitability of M-Dwarf temperate terrestrial planets.

Cowan, N. B.; Greene, T.; Angerhausen, D.; Batalha, N. E.; Clampin, M.; Colón, K.; Crossfield, I. J. M.; Fortney, J. J.; Gaudi, B. S.; Harrington, J.; Iro, N.; Lillie, C. F.; Linsky, J. L.; Lopez-Morales, M.; Mandell, A. M.; Stevenson, K. B.; ExoPAG SAG-10

2015-03-01

388

Watching How Planets Form  

NASA Astrophysics Data System (ADS)

Anatomy of a Planet-Forming Disc around a Star More Massive than the Sun With the VISIR instrument on ESO's Very Large Telescope, astronomers have mapped the disc around a star more massive than the Sun. The very extended and flared disc most likely contains enough gas and dust to spawn planets. It appears as a precursor of debris discs such as the one around Vega-like stars and thus provides the rare opportunity to witness the conditions prevailing prior to or during planet formation. "Planets form in massive, gaseous and dusty proto-planetary discs that surround nascent stars. This process must be rather ubiquitous as more than 200 planets have now been found around stars other than the Sun," said Pierre-Olivier Lagage, from CEA Saclay (France) and leader of the team that carried out the observations. "However, very little is known about these discs, especially those around stars more massive than the Sun. Such stars are much more luminous and could have a large influence on their disc, possibly quickly destroying the inner part." The astronomers used the VISIR instrument [1] on ESO's Very Large Telescope to map in the infrared the disc surrounding the young star HD 97048. With an age of a few million years [2], HD 97048 belongs to the Chameleon I dark cloud, a stellar nursery 600 light-years away. The star is 40 times more luminous than our Sun and is 2.5 times as massive. The astronomers could only have achieved such a detailed view due to the high angular resolution offered by an 8-metre size telescope in the infrared, reaching a resolution of 0.33 arcsecond. They discovered a very large disc, at least 12 times more extended than the orbit of the farthest planet in the Solar System, Neptune. The observations suggest the disc to be flared. "This is the first time such a structure, predicted by some theoretical models, is imaged around a massive star," said Lagage. ESO PR Photo 36/06 ESO PR Photo 36/06 A Flared Proto-Planetary Disc Such a geometry can only be explained if the disc contains a large amount of gas, in this case, at least as much as 10 times the mass of Jupiter. It should also contain more than 50 Earth masses in dust. The dust mass derived here is more than thousand times larger than what is observed in debris discs and Kuiper belt-like structures found around older, 'Vega-like' stars, such as Beta Pictoris, Vega, Fomalhaut and HR 4796. The dust around these stars is thought to be produced by collisions of larger bodies. The dust mass observed around HD 97048 is similar to the mass invoked for the (undetected) parent bodies in the more evolved systems. HD 97048's disc is thus most likely a precursor of debris discs observed around older stars. "From the structure of the disc, we infer that planetary embryos may be present in the inner part of the disc," said Lagage. "We are planning follow-up observations at higher angular resolution with ESO's VLT interferometer in order to probe these regions." A video, made by the CEA, is also available. More Information The scientists report their discovery in the 28 September issue of Science Express, the rapid online publication service of the journal Science: "Anatomy of a flaring proto-planetary disc around a young intermediate-mass star", by P.-O. Lagage et al. The team is composed of Pierre-Olivier Lagage, Coralie Doucet, and Eric Pantin, (CEA Saclay, France), Sébastien Charnoz (Paris 7 Denis Diderot University), Emilie Habart (Institut d'Astrophysique Spatiale, Orsay, France), Gaspard Duchêne, François Ménard, and Christophe Pinte (Laboratoire d'Astrophysique de Grenoble, France), and Jan-Willem Pel (Groningen University, The Netherlands).

2006-09-01

389

Exploring the Planets: Mars  

NSDL National Science Digital Library

Students will learn that Mars, and each planet in the solar system, is unique due to the materials from which it is made and the processes that shaped it. Images and information from Mars exploration voyages, including the Viking Mission in 1975, the Pathfinder Landing in 1997, the Mars Global Surveyor project, the Mars Odyssey and Mars Express spacecrafts, the Mars Exploration Rovers, and the Reconnaissance Orbiter are presented. Students will learn about Mars mean distance from Sun, length of year, rotation period, mean orbital velocity, inclination of axis, average temperature (day and night), diameter, inclination to ecliptic, and number of observed satellites. The seasons, volcanoes, canyons and plains, craters, water, wind patterns, and two moons of Mars are also discussed.

390

Create Your Own Planet  

NSDL National Science Digital Library

This activity can be used to evaluate students understanding of the characteristics of inner and outer planets. This activity allows the students to create their own planet with the appropriate characteristics. A rubric is attached.

Wendy Duroseau

2012-04-30

391

A Complete Image of the LkCa 15 Disk Gap  

NASA Astrophysics Data System (ADS)

One of the greatest open questions in present-day astrophysics is how planetary systems like ours form. In the quest for answers, transitional disks like the one surrounding the star LkCa 15 are of paramount importance. These protoplanetary disks featuring wide gaps in their central regions are thought to represent snapshots of a brief but critical stage in the formation of a planetary system in which the disk material is rapidly dissipated. Although a wealth of information can be gleaned from the spectral energy distribution of such a system, degeneracies remain that can only be broken by obtaining a direct image of the disk gap. Our observations of LkCa 15 with ground-based adaptive optics resulted in the first resolved imaging of a transitional disk. We propose a sequence of deep Gemini NIRI K-band observations sampling both short and long timescales to establish decisive, high-confidence images of the LkCa 15 disk gap, looking for temporal variability of disk features, attempting direct detection of planets, and measuring the reliability of our imaging technique. This would provide an improved understanding of this exciting system, and an important observational contribution to the field of planet formation.

Thalmann, Christian; Hodapp, Klaus; Carson, Joseph; Janson, Markus; Fukagawa, Misato; Goto, Miwa; Grady, Carol; Hashimoto, Jun; Henning, Thomas; Honda, Mitsuhiko; McElwain, Michael W.; Min, Michiel; Mulders, Gijs; Tamura, Motohide; Wisniewski, John

2011-08-01

392

Barnard’s Star: Planets or Pretense  

NASA Astrophysics Data System (ADS)

Barnard’s Star remains popular with planet hunters because it is not only an extremely near, high proper motion star, but also the object of early planet-detection claims. In 1963, van de Kamp explained perturbations in its proper motion by the presence of a planet. In 1969, he produced another single-planet solution and a two-planet solution to the astrometric wobbles detected. At least 19 studies have failed to confirm his results using a range of techniques, including radial velocity, direct imaging, and speckle interferometry. However, most of them lacked the sensitivity to detect the planets he described, including astrometric studies at the McCormick and Naval Observatories. However, radial-velocity monitoring of Barnard’s Star at Lick and Keck Observatories from 1987 through 2012 appears to have ruled out such planets. Based upon observations made at the Sproul Observatory between 1916 and 1962, van de Kamp claimed that Barnard’s Star had a planet with about 1.6 times the mass of Jupiter and an orbital period of 24 years. After accounting for instrumentation effects that might have been partially responsible for his initial results, he continued to assert that this red dwarf had two planets. In his 1982 analysis of ~20,000 exposures collected between 1938 and 1981, he calculated that two planets with 0.7- and 0.5-Jupiter masses in 12- and 20-year orbits, respectively, orbited the second-closest stellar system to our own. Starting in 1995, the dramatic successes of radial velocity searches for extrasolar planets drove van de Kamp’s unsubstantiated claims from popular consciousness. Although many low-mass stellar companions were discovered through astrometry, the technique has been less successful for planets: “The Extrasolar Planets Encyclopaedia” identifies one such discovery out of the 997 planets listed on 2013 September 23. Although Barnard’s Star has lost its pretensions to hosting the first extrasolar planets known, its intrinsic properties will keep it under observation. NSF grant AST 98-20711, Litton Marine Systems, Levinson Fund, University of Virginia, Hampden-Sydney College, and US Naval Observatory supported this research.

Bartlett, Jennifer L.; Ianna, P. A.

2014-01-01

393

Dunking the Planets  

NSDL National Science Digital Library

In this demonstration, learners compare the relative sizes and masses of scale models of the planets as represented by fruits and other foods. Learners dunk the "planets" in water to highlight the fact that even a large, massive planet — such as Saturn — can have low density. They discuss how a planet's density is related to whether it is mainly made up of rock or gas. This activity is part of a sequence of activities focused on Jupiter's immense size.

2014-07-11

394

Planet Designer: Kelvin Climb  

NSDL National Science Digital Library

This is an activity about the way distance, albedo, and atmosphere affect the temperature of a planet. Learners will create a planet using a computer game and change features of the planet to increase or decrease the planet's temperature. They will then discuss their results in terms of greenhouse strength and the presence of liquid water. This lesson is part of Project Spectra, a science and engineering education program focusing on how light is used to explore the Solar System.

395

Resolved Imaging of the HD191089 Debris Disc  

E-print Network

Two thirds of the F star members of the 12 Myr old Beta Pictoris Moving Group (BPMG) show significant excess emission in the mid-infrared, several million years after the expected dispersal of the protoplanetary disc. Theoretical models of planet formation suggest that this peak in the mid-infrared emission could be due to the formation of Pluto-sized bodies in the disc, which ignite the collisional cascade and enhance the production of small dust. Here we present resolved mid-infrared imaging of the disc of HD191089 (F5V in the BPMG) and consider its implications for the state of planet formation in this system. HD191089 was observed at 18.3 microns using T-ReCS on Gemini South and the images were compared to models of the disc to constrain the radial distribution of the dust. The emission observed at $18.3\\umu m$ is shown to be significantly extended beyond the PSF at a position angle of 80 degrees. This is the first time dust emission has been resolved around HD191089. Modelling indicates that the emission...

Churcher, Laura J; Smith, Rachel

2010-01-01

396

Terrestrial Planets: Comparative Planetology  

NASA Technical Reports Server (NTRS)

Papers were presented at the 47th Annual Meteoritical Society Meeting on the Comparative planetology of Terrestrial Planets. Subject matter explored concerning terrestrial planets includes: interrelationships among planets; plaentary evolution; planetary structure; planetary composition; planetary Atmospheres; noble gases in meteorites; and planetary magnetic fields.

1985-01-01

397

The Dwarf Planets  

NSDL National Science Digital Library

This website, by California Institute of Technology astronomer Mike Brown, describes dwarf planets and the issues in their classification. A diagram show the "new" solar system, including the approximately 50 dwarf planets in the Kuiper Belt. A table shows the size and distance of each dwarf planet.

Brown, Mike

398

Microlensing Searches for Extrasolar Planets  

E-print Network

Microlensing Searches for Extrasolar Planets Microlensing Searches for Extrasolar Planets I for Extrasolar Planets, B. Scott Gaudi, IAS #12;The Search for Extrasolar PlanetsThe Search for Extrasolar Planets Why Search for Extrasolar Planets ? Frequency of Life Clues to Star Formation Low End

Gaudi, B. Scott

399

Terrestrial Planet Finding with a Visible Light Coronagraph  

E-print Network

Directly imaging extrasolar planets using a monolithic optical telescope avoids many pitfalls of space interferometry and opens up the prospect of visible light studies of extrasolar planetary systems. Future astronomical missions may require interferometry for high spatial resolution, but given that the first direct imaging missions will probably fit into a single launch vehicle, the astrophysics of planet finding calls for a visible light coronagraph as the first space mission to search for extrasolar terrestrial planets. New coronagraphic techniques place the necessary dynamic range within reach for detecting planets in reflected starlight.

M. J. Kuchner; D. N. Spergel

2003-05-28

400

Three Lyman-alpha Emitters at z approx 6: Early GMOS/Gemini Data from the GLARE Project  

E-print Network

We report spectroscopic detection of three z~6 Lyman-alpha emitting galaxies, in the vicinity of the Hubble Ultra Deep Field, from the early data of the Gemini Lyman-$\\alpha$ at Reionisation Era (GLARE) project. Two objects, GLARE#3001 (z =5.79) and GLARE#3011 (z =5.94), are new detections and are fainter in $z'$ (z'_{AB} =26.37 and 27.15) than any Lyman break galaxy previously detected in Lyman-alpha. A third object, GLARE#1042 (z =5.83) has previously been detected in line emission from the ground; we report here a new spectroscopic continuum detection. Gemini/GMOS-S spectra of these objects, obtained using nod & shuffle, are presented together with a discussion of their photometric properties. All three objects were selected for spectroscopy via the i-drop Lyman Break technique, the two new detections from the GOODS v1.0 imaging data. The red i'-z' colors and high equivalent widths of these objects suggest a high-confidence z>5 Lyman-alpha identification of the emission lines. This brings the total number of known z>5 galaxies within 9 arcmin of the Hubble Ultra Deep Field to four, of which three are at the same redshift (z=5.8 within 2000 km/s suggesting the existence of a large-scale structure at this redshift.

Elizabeth R. Stanway; Karl Glazebrook; Andrew J. Bunker; Roberto G. Abraham; Isobel Hook; James Rhoads; Patrick J. McCarthy; Brian Boyle; Matthew Colless; David Crampton; Warrick Couch; Inger Jørgensen; Sangeeta Malhotra; Rick Murowinski; Kathy Roth; Sandra Savaglio; Zlatan Tsvetanov

2004-03-05

401

A two deformable-mirror concept to improve the laser efficiency of Gemini South MCAO (GeMS)  

NASA Astrophysics Data System (ADS)

Gem's is the first laser-based multi-conjugate adaptive optics offeredto the astronomical community. Its asterism of 5 laser guide stars hasrecently proved to provide very uniform turbulence correction over the85''x85'' observation field, opening the new era of wide-field highangular resolution studies from the ground. Good AO performance requireshowever good wavefront sensing measurements from the laser guide stars,which directly depends on the quality of the laser spot image. Theoptimization of the lasers launched out of the telescope requires tofollow frequent and constraining calibrations and alignments procedures(quasi-static aberrations), in order to guarantee satisfying amplitudeand phase of the beam. These complex and time-consuming procedures willstrongly penalize the availability of Gem's.A laser beam shaping concept has been recently suggested to overcomesuch issues. It consists in applying, in the beam transfer optics, afield-conjugation thanks to 2 deformable mirrors. We review thisconcept. In particular, we discuss the criterion to be optimized and thedesired amplitude and phase shapes at the output of the Gemini beamtransfer optics. We deduce the control to be applied to the mirrors fromthe optimization of the signal-to-noise ratio of the wavefront sensingin Gem's. An iterative algorithm is used to estimate the phases, with aweighted least-squares unwrapper to avoid branch points. This algorithmefficiency is demonstrated with adequate beam shaping simulations.Discussion is made about how to implement such concept at Gemini.

Béchet, Clémentine; Guesalaga, Andrés; Neichel, Benoit; Fesquet, Vincent; Guzman, Dani

2013-12-01

402

High gene delivery efficiency of alkylated low-molecular-weight polyethylenimine through gemini surfactant-like effect  

PubMed Central

To our knowledge, the mechanism underlying the high transfection efficiency of alkylated low-molecular-weight polyethylenimine (PEI) is not yet well understood. In this work, we grafted branched PEI (molecular weight of 1,800 Da; bPEI1800) with lauryl chains (C12), and found that bPEI1800-C12 was structurally similar to gemini surfactant and could similarly assemble into micelle-like particles. Stability, cellular uptake, and lysosome escape ability of bPEI1800-C12/DNA polyplexes were all greatly enhanced after C12 grafting. bPEI1800-C12/DNA polyplexes exhibited significantly higher transfection efficiency than Lipofectamine™ 2000 in the presence of serum. Bioluminescence imaging showed that systemic injection of bPEI1800-C12/DNA polyplexes resulted in intensive luciferase expression in vivo and bioluminescence signals that could be detected even in the head. Altogether, the high transfection efficacy of bPEI1800-C12 was because bPEI1800-C12, being an analog of gemini surfactant, facilitated lysosome escape and induced the coil–globule transition of DNA to assemble into a highly organized micelle-like structure that showed high stability. PMID:25114526

Liu, Shan; Huang, Wei; Jin, Ming-Ji; Wang, Qi-Ming; Zhang, Gan-Lin; Wang, Xiao-Min; Shao, Shuai; Gao, Zhong-Gao

2014-01-01

403