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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

Wavefront control for the Gemini Planet Imager  

Microsoft Academic Search

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 × 32 MEMS device. Detailed analytic models and algorithms for Shack-Hartmann wavefront sensor alignment and calibration are presented.

Lisa A. Poyneer; Jean-Pierre Véran; Daren Dillon; Scott Severson; Bruce A. Macintosh

2006-01-01

3

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

4

Gemini planet imager one button approach  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is an "extreme" adaptive optics coronagraph system that is now on the Gemini South telescope in Chile. This instrument is composed of three different systems that historically have been separate instruments. These systems are the extreme Adaptive Optics system, with deformable mirrors, including a high-order 64x64 element MEMS system; the Science Instrument, which is a near-infrared integral field spectrograph; and the Calibration system, a precision IR wavefront sensor that also holds key coronagraph components. Each system coordinates actions that require precise timing. The observatory is responsible for starting these actions and has typically done this asynchronously across independent systems. Despite this complexity we strived to provide an interface that is as close to a onebutton approach as possible. This paper will describe the sequencing of these systems both internally and externally through the observatory.

Dunn, Jennifer; Kerley, Dan; Saddlemyer, Leslie; Smith, Malcolm; Wooff, Robert; Savransky, Dmitry; Palmer, David; Macintosh, Bruce; Weiss, Jason; Quiroz, Carlos; Rantakyrö, Fredrik T.; Goodsell, Stephen J.

2014-07-01

5

First light of 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. During first light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-sigma 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-second exposure with minimal post-processing. Beta Pictoris b is observed at a separation of $434 \\pm 6$ milli-arcseconds and position angle $211.8 \\pm 0.5$ deg. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of three improvement in most parameters over previous solutions. The planet orbits at a semi-major axis of $9.0^{+0.8}_{-0.4}$ 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% posterior probability of a transit of the planet in late 2017.

Macintosh, B.; Graham, J. R.; Ingraham, P.; Konopacky, Q.; Marois, C.; Perrin, M.; Poyneer, L.; Bauman, B.; Barman, T.; Burrows, A. S.; Cardwell, A.; Chilcote, J.; De Rosa, R. J.; Dillon, D.; Doyon, R.; Dunn, J.; Erikson, D.; Fitzgerald, M. P.; Gavel, D.; Goodsell, S.; Hartung, M.; Hibon, P.; Kalas, P.; Larkin, J.; Maire, J.; Marchis, F.; Marley, M. S.; McBride, J.; Millar-Blanchaer, M.; Morzinski, K.; Norton, A.; Oppenheimer, B. R.; Palmer, D.; Patience, J.; Pueyo, L.; Rantakyro, F.; Sadakuni, N.; Saddlemyer, L.; Savransky, D.; Serio, A.; Soummer, R.; Sivaramakrishnan, A.; Song, I.; Thomas, S.; Wallace, J. K.; Wiktorowicz, S.; Wolff, S.

2014-09-01

6

Wavefront control for the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

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 × 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, Lisa A.; Véran, Jean-Pierre; Dillon, Daren; Severson, Scott; Macintosh, Bruce A.

2006-06-01

7

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

8

The Gemini Planet Imager: From Science to Design to Construction  

SciTech Connect

The Gemini Planet Imager (GPI) is a facility instrument under construction for the 8-m Gemini South telescope. It combines a 1500 subaperture AO system using a MEMS deformable mirror, an apodized-pupil Lyot coronagraph, a high-accuracy IR interferometer calibration system, and a near-infrared integral field spectrograph to allow detection and characterization of self-luminous extrasolar planets at planet/star contrast ratios of 10{sup -7}. I will discuss the evolution from science requirements through modeling to the final detailed design, provide an overview of the subsystems and show models of the instrument's predicted performance.

Macintosh, B; Graham, J R; Palmer, D; Doyon, R; Dunn, J; Gavel, D; Larkin, J; Oppenheimer, B; Saddlemyer, L; Sivaramakrishnan, A; Wallace, J K; Bauman, B; Erickson, D; Marois, C; Poyneer, L; Soummer, R

2008-07-01

9

Gemini planet imager observational calibrations VII: on-sky polarimetric performance of the Gemini planet imager  

NASA Astrophysics Data System (ADS)

We present on-sky polarimetric observations with the Gemini Planet Imager (GPI) obtained at straight Cassegrain focus on the Gemini South 8-m telescope. Observations of polarimetric calibrator stars, ranging from nearly un- polarized to strongly polarized, enable determination of the combined telescope and instrumental polarization. We find the conversion of Stokes I to linear and circular instrumental polarization in the instrument frame to be I --> (QIP, UIP, PIP, VIP) = (-0.037 +/- 0.010%, +0.4338 +/- 0.0075%, 0.4354 +/- 0.0075%, -6.64 +/- 0.56%). Such precise measurement of instrumental polarization enables ~0.1% absolute accuracy in measurements of linear polarization, which together with GPI's high contrast will allow GPI to explore scattered light from circumstellar disk in unprecedented detail, conduct observations of a range of other astronomical bodies, and potentially even study polarized thermal emission from young exoplanets. Observations of unpolarized standard stars also let us quantify how well GPI's differential polarimetry mode can suppress the stellar PSF halo. We show that GPI polarimetry achieves cancellation of unpolarized starlight by factors of 100-200, reaching the photon noise limit for sensitivity to circumstellar scattered light for all but the smallest separations at which the calibration for instrumental polarization currently sets the limit.

Wiktorowicz, Sloane J.; Millar-Blanchaer, Max; Perrin, Marshall D.; Graham, James R.; Fitzgerald, Michael P.; Maire, Jérôme; Ingraham, Patrick; Savransky, Dmitry; Macintosh, Bruce A.; Thomas, Sandrine J.; Chilcote, Jeffrey K.; Draper, Zachary H.; Song, Inseok; Cardwell, Andrew; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Rantakyrö, Fredrik; Sadakuni, Naru

2014-07-01

10

First Semester Science Operations with the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) has now gone through its first six months of operations at Gemini South, starting in August 1st, 2014 and finishing in January 31st, 2015. We present here the experiences in integrating and operating the instrument in mixed queue and classical modes. A total of 72 hours of observations was accepted out of a total of proposed 266 hours, out of a total of 2469 hours for all instruments at Gemini South. The 72 hours were distributed over 12 programs from almost all partner countries. In addition to the standard classical and queue time 140 hours was assigned to the GPIES campaign.

Tord Rantakyro, Fredrik; Hibon, Pascale; Cardwell, Andrew; Sadakuni, Naru; Quiroz, Carlos; Rutten, Rene; Gausachs, Gaston; Galvez, Ramon; Gpi Commissioning Team, Gpies Team

2015-01-01

11

Observations of Beta Pictoris b with the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

Using the recently installed Gemini Planet Imager (GPI), we present measurements of the planetary companion to the nearby young star beta Pic. GPI is a facility class instrument located at Gemini South designed to image and provide low-resolution spectra of Jupiter sized, self-luminous planetary companions around young nearby stars. We present the current imaged spectrum and atmospheric models of the planet based upon GPI's R ˜50 integral field spectrograph. Further, we present a joint analysis of the GPI and NACO astrometry, and the Snellen et al. (2014) radial velocity measurement of beta Pic b that provides the first constraint on the argument of periastron, providing a causal link to the infalling, evaporating bodies.

Chilcote, J.; Graham, J.; Barman, T.; Fitzgerald, M.; Larkin, J.; Macintosh, B.; Bauman, B.; Burrows, A.; Cardwell, A.; De Rosa, R.; Dillon, D.; Doyon, R.; Dunn, J.; Erikson, D.; Gavel, D.; Goodsell, S.; Hartung, M.; Hibon, P.; Ingraham, P.; Kalas, P.; Konopacky, Q.; Maire, J.; Marchis, F.; Marley, M.; Mcbride, J.; Millar-Blanchaer, M.; Morzinski, K.; Norton, A.; Oppenheimer, B.; Palmer, D.; Patience, J.; Pueyo, L.; Rantakyro, F.; Sadakuni, N.; Saddlemyer, L.; Savransky, D.; Serio, A.; Soummer, R.; Sivaramakrishnan, A.; Song, I.; Thomas, S.; Wallace, K.; Wiktorowicz, S.; Wolff, S.

2014-09-01

12

Gemini Planet Imager Observational Calibrations II: Detector Performance and Calibration  

E-print Network

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; Sadakuni, Naru; Ruffio, Jean-Baptiste; Maire, Jerome; Chilcote, Jeff; Larkin, James; Marchis, Franck; Galicher, Raphael; Weiss, Jason

2014-01-01

13

Test results for the Gemini Planet Imager data reduction pipeline  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a new facility instrument for the Gemini Observatory designed to detect and characterize planets and debris disks orbiting nearby stars; its science camera is a near infrared integral field spectrograph. We have developed a data pipeline for this instrument, which will be made publicly available to the community. The GPI data reduction pipeline (DRP) incorporates all necessary image reduction and calibration steps for high contrast imaging in both the spectral and polarimetric modes, including datacube generation, wavelength solution, astrometric and photometric calibrations, and speckle suppression via ADI and SSDI algorithms. It is implemented in IDL as a flexible modular system, and includes both command line and graphical interface tools including a customized viewer for GPI datacubes. This GPI data reduction pipeline is currently working very well, and is in use daily processing data during the instrument’s ongoing integration and test period at UC Santa Cruz. Here we summarize the results from recent pipeline tests, and present reductions of instrument test data taken with GPI. We will continue to refine and improve these tools throughout the rest of GPI’s testing and commissioning, and they will be released to the community, including both IDL source code and compiled versions that can be used without an IDL license.

Maire, Jérôme; Perrin, Marshall D.; Doyon, René; Chilcote, Jeffrey; Larkin, James E.; Weiss, Jason L.; Marois, Christian; Konopacky, Quinn M.; Millar-Blanchaer, Maxwell; Graham, James R.; Dunn, Jennifer; Galicher, Raphael; Marchis, Franck; Wiktorowicz, Sloane J.; Labrie, Kathleen; Thomas, Sandrine J.; Goodsell, Stephen J.; Rantakyro, Fredrik T.; Palmer, David W.; Macintosh, Bruce A.

2012-09-01

14

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

15

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

16

Gemini planet imager observational calibrations V: astrometry and distortion  

NASA Astrophysics Data System (ADS)

We present the results of both laboratory and on sky astrometric characterization of the Gemini Planet Imager (GPI). This characterization includes measurement of the pixel scale* of the integral field spectrograph (IFS), the position of the detector with respect to north, and optical distortion. Two of these three quantities (pixel scale and distortion) were measured in the laboratory using two transparent grids of spots, one with a square pattern and the other with a random pattern. The pixel scale in the laboratory was also estimate using small movements of the artificial star unit (ASU) in the GPI adaptive optics system. On sky, the pixel scale and the north angle are determined using a number of known binary or multiple systems and Solar System objects, a subsample of which had concurrent measurements at Keck Observatory. Our current estimate of the GPI pixel scale is 14.14 +/- 0.01 millarcseconds/pixel, and the north angle is -1.00 +/- 0.03°. Distortion is shown to be small, with an average positional residual of 0.26 pixels over the field of view, and is corrected using a 5th order polynomial. We also present results from Monte Carlo simulations of the GPI Exoplanet Survey (GPIES) assuming GPI achieves ~1 milliarcsecond relative astrometric precision. We find that with this precision, we will be able to constrain the eccentricities of all detected planets, and possibly determine the underlying eccentricity distribution of widely separated Jovians.

Konopacky, Quinn M.; Thomas, Sandrine J.; Macintosh, Bruce A.; Dillon, Daren; Sadakuni, Naru; Maire, Jérôme; Fitzgerald, Michael; Hinkley, Sasha; Kalas, Paul; Esposito, Thomas; Marois, Christian; Ingraham, Patrick J.; Marchis, Franck; Perrin, Marshall D.; Graham, James R.; Wang, Jason J.; De Rosa, Robert J.; Morzinski, Katie; Pueyo, Laurent; Chilcote, Jeffrey K.; Larkin, James E.; Fabrycky, Daniel; Goodsell, Stephen J.; Oppenheimer, Ben R.; Patience, Jenny; Saddlemyer, Leslie; Sivaramakrishnan, Anand

2014-07-01

17

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

18

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

19

Gemini Planet Imager Observational Calibrations V: Astrometry and Distortion  

E-print Network

We present the results of both laboratory and on sky astrometric characterization of the Gemini Planet Imager (GPI). This characterization includes measurement of the pixel scale of the integral field spectrograph (IFS), the position of the detector with respect to north, and optical distortion. Two of these three quantities (pixel scale and distortion) were measured in the laboratory using two transparent grids of spots, one with a square pattern and the other with a random pattern. The pixel scale in the laboratory was also estimate using small movements of the artificial star unit (ASU) in the GPI adaptive optics system. On sky, the pixel scale and the north angle are determined using a number of known binary or multiple systems and Solar System objects, a subsample of which had concurrent measurements at Keck Observatory. Our current estimate of the GPI pixel scale is 14.14 $\\pm$ 0.01 millarcseconds/pixel, and the north angle is -1.00 $\\pm$ 0.03$\\deg$. Distortion is shown to be small, with an average posi...

Konopacky, Quinn M; Macintosh, Bruce A; Dillon, Daren; Sadakuni, Naru; Maire, Jérôme; Fitzgerald, Michael; Hinkley, Sasha; Kalas, Paul; Esposito, Thomas; Marois, Christian; Ingraham, Patrick J; Marchis, Franck; Perrin, Marshall D; Graham, James R; Wang, Jason J; De Rosa, Robert J; Morzinski, Katie; Pueyo, Laurent; Chilcote, Jeffrey K; Larkin, James E; Fabrycky, Daniel; Goodsell, Stephen J; Oppenheimer, B R; Patience, Jenny; Saddlemyer, Leslie; Sivaramakrishnan, Anand

2014-01-01

20

Adaptive Optics for Direct Detection of Extrasolar Planets: The Gemini Planet Imager  

SciTech Connect

The direct detection of photons emitted or reflected by extrasolar planets, spatially resolved from their parent star, is a major frontier in the study of other solar systems. Direct detection will provide statistical information on planets in 5-50 AU orbits, inaccessible to current Doppler searches, and allow spectral characterization of radius, temperature, surface gravity, and perhaps composition. Achieving this will require new dedicated high-contrast instruments. One such system under construction is the Gemini Planet Imager (GPI.) This combines a high-order/high-speed adaptive optics system to control wavefront errors from the Earth's atmosphere, an advanced coronagraph to block diffraction, ultrasmooth optics, a precision infrared interferometer to measure and correct systematic errors, and a integral field spectrograph/polarimeter to image and characterize target planetary systems. We predict that GPI will be able to detect planets with brightness less than 10{sup -7} of their parent star, sufficient to observe warm self-luminous planets around a large population of targets.

Macintosh, B; Graham, J; Palmer, D; Doyon, R; Gavel, D; Larkin, J; Oppenheimer, B; Saddlemyer, L; Wallace, J K; Bauman, B; Erikson, D; Poyneer, L; Sivaramakrishnan, A; Soummer, R; Veran, J

2007-04-24

21

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

22

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 Drive, Rochester, NY 14620 USA f Precision Optical Imaging, 7466 West Henrietta Rd., Rush, NY 14543 g are comparable to the wavelength of the light, surface plasmon effects can complicate the optical density (OD) vs

23

Gemini Planet Imager coronagraph testbed results Anand Sivaramakrishnana,b, Remi Soummerc, Ben R. Oppenheimera,  

E-print Network

Light Source, adaptive optics, corona- graph, coronagraphic astometry, coronagraphic photometry, high of comparative planetary science. Recent advances in adaptive optics (or AO, which corrects atmospheric The Gemini Planet Imager (GPI) is an extreme AO coronagraphic integral field unit YJHK spectrograph destined

24

The optical alignment of the Gemini planet imager adaptive optics bench  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a facility instrument under construction for the 8-m Gemini South telescope. This paper describes the methods used for optical alignment of the adaptive optics (AO) bench. The optical alignment of the off-axis paraboloid mirrors was done using a pre-alignment method utilizing a HeNe laser and alignment telescopes followed by a fine-tuning using a Shack-Hartmann wavefront sensor and a shear plate. A FARO arm measuring system was used to place the fiducials for the alignment. Using these methods the AO bench was aligned to 13nm RMS of wavefront error.

Pazder, John; Bauman, Brian; Dillon, Daren; Fletcher, Murray; Lacoursière, Jean; Reshetov, Vlad

2012-09-01

25

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

26

Test Results for the Integral Field Spectrograph for the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

We present the status of the construction, testing and characterization of the Integral Field Spectrograph (IFS) for the Gemini Planet Imager (GPI). GPI is a facility class instrument for the Gemini Observatory led by Bruce Macintosh at LLNL and involving eight institutions. The UCLA Infrared Lab is currently involved with the construction and testing of the IFS. The IFS design is similar to the OSIRIS instrument at Keck and utilizes an infrared transmissive lenslet array to sample a rectangular field of view. The IFS uses a Hawaii-2RG detector to produce a field of view greater than 2.8 x 2.8 arcseconds, with a spectral resolution in H band of R?45. A cryogenic Wollaston prism can be inserted into the reimaging optic path to produce two images of orthogonal polarization states. We present the most current results from in-lab system tests of performance and characterization.

Chilcote, J.; Larkin, J.; Perrin, M.

2010-10-01

27

Status of the Integral Field Spectrograph for the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

We present the status of the construction, testing and characterization of the Integral Field Spectrograph (IFS) for the Gemini Planet Imager (GPI). GPI is a facility class instrument for the Gemini Observatory led by Bruce Macintosh at LLNL and involving eight institutions. The UCLA Infrared Lab is currently involved with the construction and testing of the IFS. The IFS design is similar to the OSIRIS instrument at Keck and utilizes an infrared transmissive lenslet array to sample a rectangular field of view. The IFS uses a Hawaii-2RG detector to produce a field of view greater than 2.8 x 2.8 arcseconds, with a spectral resolution in H band of R 45. A cryogenic Wollaston prism can be inserted into the reimaging optic path to produce two images of orthogonal polarization states. We present the most current results from in-lab system tests of performance and characterization.

Chilcote, Jeffrey K.; Larkin, J. E.; Doyon, R.; Fitzgerald, M. P.; Graham, J. R.; Macintosh, B. A.; Palmer, D. W.; Perrin, M. D.; Saddlemyer, L.

2011-09-01

28

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

29

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

30

Probing the AU Microscopii Debris Disk at Close Separations with the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

We present Gemini Planet Imager (GPI) observations of AU Microscopii, a 10-20 Myr old star with a previously imaged debris disk. The data was taken during the commissioning of GPI using both integral field spectroscopy and broadband imaging polarimetry. Using our integral field spectroscopy data, we present constraints on the mass of possible planets around AU Microscopii. In our broadband imaging polarimetry observations, we detect the disk only in total intensity at separations between ~0.2" to ~2" (~2-20 AU) from the star. We find that the southeast side of the disk is more diffuse and has a larger scale height than the northwest side of the disk at these separations and discuss possible explainations for this. Lastly, we present our upper limits on the polarization fraction of the disk and compare with models.

Wang, Jason; Graham, James R.; Pueyo, Laurent; Nielsen, Eric L.; Duchene, Gaspard; Millar-Blanchaer, Max; Kalas, Paul; Chen, Christine; Matthews, Brenda C.; Gemini Planet Imager team

2015-01-01

31

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

32

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

33

Near-infrared Scattered Light Imaging of the Protoplanetary Disk Around V4046 Sgr with the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

V4046 Sgr is a nearby (d ~73 pc), young (~23 Myr-old) spectroscopic binary that is still surrounded by, and is actively accreting from, a gaseous and dusty protoplanetary disk. Previous submm studies have revealed the presence of an inner 'hole' devoid of mm-sized dust grains, suggesting that gas giant planets may be forming in the inner disk. Here, we present near-infrared scattered light imaging of the disk around V4046 Sgr obtained with the Gemini Planet Imager. These images allow us to probe the planet forming region of the disk, down to r = 7 au from the central binary, and search for direct evidence of past or ongoing planet formation.

Rapson, Valerie; Kastner, Joel; Andrews, Sean M.; Hines, Dean C.; Macintosh, Bruce; Millar-Blanchaer, Max; Tamura, Motohide

2015-01-01

34

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

35

Status of the Integral Field Spectrograph for the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

We present the status of construction and testing of the Integral Field Spectrograph (IFS) for the Gemini Planet Imager (GPI). The IFS is being constructed in the UCLA Infrared Laboratory as the science instrument. GPI is a facility class instrument for the Gemini Observatory being led by Bruce Macintosh at LLNL and involving eight institutions. The goals of GPI are to detect and characterize young, Jovian-mass planetary companions by distinguishing them from PSF speckle noise, to detect and measure debris disks through polarization, and to record low-resolution spectra from 0.98-2.4 microns. The IFS design is similar to the OSIRIS instrument at Keck and utilizes an infrared transmissive lenslet array to sample a rectangular field of view behind the "extreme” adaptive optics system. The IFS uses a Hawaii-2RG detector to produce a field of view greater than 2.8 x 2.8 arcseconds, with a spectral resolution in H band of R 45. The all transmissive powered optics of the IFS uses a prism instead of a grating. A cryogenic Wollaston prism can be inserted into the reimaging optic path to produce two images of orthogonal polarization states. The IFS is currently scheduled to be integrated into GPI in mid 2010, with first light expected in 2011. We will present the current status of the IFS and early test results.

Chilcote, Jeffrey K.; Larkin, J. E.; Aliado, T.; Brims, G.; Canfield, J.; Corlies, L.; Fox, G.; Johnson, C.; Kress, E.; Magnone, K.; Mclean, I. S.; Perrin, M. D.; Konopacky, Q.; Wang, E.; Weiss, J.; Doyon, R.; Thibault, S.; Vallée, P.; Poyneer, L.; Marois, C.; Macintosh, B. A.; Graham, J. R.; Saddlemyer, L.; Palmer, D. W.

2010-01-01

36

Gemini planet imager observational calibrations IV: wavelength calibration and flexure correction for the integral field spectograph  

NASA Astrophysics Data System (ADS)

We present the wavelength calibration for the lenslet-based Integral Field Spectrograph (IFS) that serves as the science instrument for the Gemini Planet Imager (GPI). The GPI IFS features a 2.7" x 2.7" field of view and a 190 x 190 lenslet array (14.3 mas/lenslet) operating in Y, J, H, and K bands with spectral resolving power ranging from R ~ 35 to 78. Due to variations across the field of view, a unique wavelength solution is determined for each lenslet characterized by a two-dimensional position, the spectral dispersion, and the rotation of the spectrum with respect to the detector axes. The four free parameters are fit using a constrained Levenberg-Marquardt least-squares minimization algorithm, which compares an individual lenslet's arc lamp spectrum to a simulated arc lamp spectrum. This method enables measurement of spectral positions to better than 1/10th of a pixel on the GPI IFS detector using Gemini's facility calibration lamp unit GCAL, improving spectral extraction accuracy compared to earlier approaches. Using such wavelength calibrations we have measured how internal flexure of the spectrograph with changing zenith angle shifts spectra on the detector. We describe the methods used to compensate for these shifts when assembling datacubes from on-sky observations using GPI.

Wolff, Schuyler G.; Perrin, Marshall D.; Maire, Jérôme; Ingraham, Patrick J.; Rantakyrö, Fredrik T.; Hibon, Pascale

2014-08-01

37

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

38

Gemini planet imager observational calibrations X: non-redundant masking on GPI  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) Extreme Adaptive Optics Coronograph contains an interferometric mode: a 10-hole non-redundant mask (NRM) in its pupil wheel. GPI operates at Y, J, H, and K bands, using an integral field unit spectrograph (IFS) to obtain spectral data at every image pixel. NRM on GPI is capable of imaging with a half resolution element inner working angle at moderate contrast, probing the region behind the coronagraphic spot. The fine features of the NRM PSF can provide a reliable check on the plate scale, while also acting as an attenuator for spectral standard calibrators that would otherwise saturate the full pupil. NRM commissioning data provides details about wavefront error in the optics as well as operations of adaptive optics control without pointing control from the calibration system. We compare lab and on-sky results to evaluate systematic instrument properties and examine the stability data in consecutive exposures. We discuss early on-sky performance, comparing images from integration and tests with the first on-sky images, and demonstrate resolving a known binary. We discuss the status of NRM and implications for future science with this mode.

Greenbaum, Alexandra Z.; Cheetham, Anthony; Sivaramakrishnan, Anand; Tuthill, Peter; Norris, Barnaby; Pueyo, Laurent; Sadakuni, Naru; Rantakyrö, Fredrik; Hibon, Pascale; Goodsell, Stephen; Hartung, Markus; Serio, Andrew; Cardwell, Andrew; Poyneer, Lisa; Macintosh, Bruce; Savransky, Dmitry; Perrin, Marshall D.; Wolff, Schuyler; Ingraham, Patrick; Thomas, Sandrine

2014-08-01

39

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

40

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

41

The Gemini NICI Planet-Finding Campaign  

NASA Astrophysics Data System (ADS)

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 state-of-the-art AO observing methods and data processing, NICI typically achieves ~2 magnitudes better contrast compared to previous ground-based or space-based planet-finding efforts, at separations inside of ~2". In preparation for the Campaign, we carried out efforts to identify previously unrecognized young stars as targets, to develop a rigorous quantitative method for constructing our observing strategy, and to optimize the combination of angular differential imaging and spectral differential imaging. The Planet-Finding Campaign is in its second year, with first-epoch imaging of 174 stars already obtained out of a total sample of 300 stars. We describe the Campaign's goals, design, target selection, implementation, on-sky performance, and preliminary results. The NICI Planet-Finding Campaign represents the largest and most sensitive imaging survey to date for massive (>~ 1 MJup) planets around other stars. Upon completion, the Campaign will establish the best measurements to date on the properties of young gas-giant planets at -> 5-10 AU separations. Finally, Campaign discoveries will be well-suited to long-term orbital monitoring and detailed spectrophotometric followup with next-generation planet-finding instruments.

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

2010-07-01

42

The Gemini NICI Planet-Finding Campaign  

NASA Astrophysics Data System (ADS)

Our team is currently carrying out a major two-year, 50-night observing program to directly image and characterize young (< 1 Gyr) 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 start for high-contrast imaging, comprising a high-performance adaptive optics (AO) system with a simultaneous dual-channel coronagraphic imager. In combination with state-of-the-art AO observing and data analysis methods, NICI currently achieves better contrast than any previous ground-based or space-based instrument at separations inside of 2 arcseconds. The Campaign Team has also carried out significant preparatory efforts to identify previously unrecognized young stars as targets and to develop a rigorous quantitative methodology for constructing the observing strategy. The Planet-Finding Campaign began in December 2008 and is in full operation, with deep imaging of several dozen stars already obtained. We describe the Campaign's goals, design, target selection, on-sky performance to date, and early science results. The NICI Planet-Finding Campaign represents the largest and most sensitive imaging survey to date for massive ( 1 Mjup) planets around other stars.

Liu, Michael C.; Wahhaj, Z.; Biller, B.; Chun, M.; Close, L.; Ftaclas, C.; Hartung, M.; Hayward, T.; Nielsen, E.; Toomey, D.; Shkolnik, E.; Reid, I.; NICI Planet-Finding Campaign Team

2010-01-01

43

The Gemini NICI Planet-Finding Campaign  

NASA Astrophysics Data System (ADS)

Our team is currently carrying out a major two-year, 50-night observing program to directly image and characterize young (< 1 Gyr) 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 start for high-contrast imaging, comprising a high-performance adaptive optics (AO) system with a simultaneous dual-channel coronagraphic imager. In combination with state-of-the-art AO observing and data analysis methods, NICI currently achieves about an order of magnitude better contrast than any previous ground-based or space-based instrument at separations inside of 2 arcseconds. The Campaign Team has also carried out significant preparatory efforts to identify previously unrecognized young stars as targets and to develop a rigorous quantitative methodology for constructing the observing strategy. The Planet-Finding Campaign began in December 2008 and is in full operation, with deep imaging of several dozen stars already obtained. We describe the Campaign's goals, design, target selection, on-sky performance to date, and early science results. The NICI Planet-Finding Campaign represents the largest and most sensitive imaging survey to date for massive ( 1 Mjup) planets around other stars.

Liu, Michael C.

2009-05-01

44

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

45

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

46

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

47

A Combined VLT and Gemini Study of the Atmosphere of the Directly-Imaged Planet, beta Pictoris b  

E-print Network

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 mimick that 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. $\\kappa$ And b and 1RXJ 1609B -- match $\\beta$ Pic b's $JHK_{s}L^\\prime$ photometry, and its 3.1 $\\mu m$ and 5 $\\mu m$ photometry are particularly difficult to reproduce. Atmosphere models adopting cloud prescriptions and large ($\\sim$ 60 $\\mu m$) dust grains fail to reproduce the $\\beta$ 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 uncertainties. Assuming solar abundance models...

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

2013-01-01

48

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

49

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

50

Final A&T Stages of the Gemini Planet Finder  

E-print Network

The Gemini Planet Imager (GPI) is currently in its final Acceptance & Testing stages. GPI is an XAO system based on a tweeter & woofer architecture (43 & 9 actuators respectively 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 testing started in February 2013 at the University of California, Santa Cruz. A conclusive acceptance review was held in July 2013 and the instrument was found ready for shipment to the Gemini South telescope on Cerro Pachon, Chile. Commissioning at the telescope will take place by the end of 2013, matching the summer window of the southern hemisphere. According to current estimates the 3 year planet finding campaign (890 allocated hours) might discover, image, and spectroscopically analyze 20 to 40 new exo-planets. Final acceptance testing of the integrated instrument can always bring up surprises when using cold chamber and flexure rig installations. ...

Hartung, M; Poyneer, L; Savransky, D; Gavel, D; Palmer, D; Thomas, S; Dillon, D; Chilcote, J; Ingraham, P; Sadakuni, N; Wallace, K; Perin, M D; Marois, C; Maire, J; Rantakyro, F; Hibon, P; Saddlemyer, L; Goodsell, S

2013-01-01

51

Polarized Light Imaging of the HD 142527 Transition Disk with the Gemini Planet Imager: Dust around the Close-in Companion  

NASA Astrophysics Data System (ADS)

When giant planets form, they grow by accreting gas and dust. HD 142527 is a young star that offers a scaled-up view of this process. It has a broad, asymmetric ring of gas and dust beyond ~100 AU and a wide inner gap. Within the gap, a low-mass stellar companion orbits the primary star at just ~12 AU, and both the primary and secondary are accreting gas. In an attempt to directly detect the dusty counterpart to this accreted gas, we have observed HD 142527 with the Gemini Planet Imager in polarized light at Y band (0.95-1.14 ?m). We clearly detect the companion in total intensity and show that its position and photometry are generally consistent with the expected values. We also detect a point source in polarized light that may be spatially separated by ~ a few AU from the location of the companion in total intensity. This suggests that dust is likely falling onto or orbiting the companion. Given the possible contribution of scattered light from this dust to previously reported photometry of the companion, the current mass limits should be viewed as upper limits only. If the dust near the companion is eventually confirmed to be spatially separated, this system would resemble a scaled-up version of the young planetary system inside the gap of the transition disk around LkCa 15. 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 National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministrio da Cincia, Tecnologia e Inovao (Brazil), and Ministerio de Ciencia, Tecnologa e Innovacin Productiva (Argentina).

Rodigas, Timothy J.; Follette, Katherine B.; Weinberger, Alycia; Close, Laird; Hines, Dean C.

2014-08-01

52

Calibrating IR optical densities for the Gemini Planet Imager extreme adaptive optics coronagraph apodizers  

Microsoft Academic Search

High contrast imaging sometimes uses apodized masks in coronagraphs to suppress diffracted starlight from a bright source in order to observe its environs. Continuously graded opacity material and metallic half-tone dots are two possible apodizers fabrication techniques. In the latter approach if dot sizes are comparable to the wavelength of the light, surface plasmon effects can complicate the optical density

Anand Sivaramakrishnan; Rémi Soummer; G. Lawrence Carr; Christophe Dorrer; Allen Bolognesi; Neil Zimmerman; Ben R. Oppenheimer; Robin Roberts; Alexandra Greenbaum

2009-01-01

53

Astrometric Calibration of the Gemini NICI Planet-Finding Campaign  

E-print Network

We describe the astrometric calibration of the Gemini NICI Planet-Finding Campaign. The Campaign requires a relative astrometric accuracy of $\\approx$ 20 mas across multi-year 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 $\\lesssim 7$ 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; Liu, Michael C; Nielsen, Eric L; Wahhaj, Zahed; Chun, Mark; Ftaclas, Christ; Hartung, Markus; Toomey, Douglas W

2014-01-01

54

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

55

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

56

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

57

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

58

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

59

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

E-print Network

We present new astrometry for the young (12-21 Myr) exoplanet beta Pictoris b taken with the Gemini/NICI, Magellan/MagAO+Clio2, and Magellan/MagAO+VisAO instruments between 2009 and 2012. The high dynamic range of our observations allows us to measure the relative position of beta 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 9.2 [+8.3, -0.5] AU and orbital eccentricity Pic system (primary star, planet, and disk) obtained thanks to NICI's semi-transparent focal plane...

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

2014-01-01

60

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

61

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

62

The Gemini NICI Planet-Finding Campaign: Discovery of a Multiple System Orbiting the Young A Star HD 1160  

NASA Astrophysics Data System (ADS)

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+50 - 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+0.03 - 0.04 M ?, while NIR photometry of HD 1160 B suggests a brown dwarf with a mass of 33+12 - 9 M 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; Biller, Beth A.; Hayward, Thomas L.; Boss, Alan; Bowler, Brendan; Kraus, Adam; Shkolnik, Evgenya L.; Tecza, Matthias; Chun, Mark; Clarke, Fraser; Close, Laird M.; Ftaclas, Christ; Hartung, Markus; Males, Jared R.; Reid, I. Neill; Skemer, Andrew J.; Alencar, Silvia H. P.; Burrows, Adam; de Gouveia Dal Pino, Elisabethe; Gregorio-Hetem, Jane; Kuchner, Marc; Thatte, Niranjan; Toomey, Douglas W.

2012-05-01

63

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

64

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

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

Extreme Adaptive Optics Planet Imager  

Microsoft Academic Search

Direct detection of photons emitted or reflected by extrasolar planets is the next major step in extrasolar planet studies. Current adaptive optics (AO) systems, with <300 subapertures and Strehl ratio 0.4-0.7, can achieve contrast levels of 106 at 2\\

B. Macintosh; J. R. Graham; A. Ghez; P. Kalas; J. Lloyd; R. Makidon; S. Olivier; J. Patience; M. Perrin; L. Poyneer; S. Severson; A. Sheinis; A. Sivaramakrishnan; M. Troy; J. Wallace; J. Wilhelmsen

2002-01-01

67

Extreme adaptive optics planet imager: XAOPI  

Microsoft Academic Search

Ground based adaptive optics is a potentially powerful technique for direct imaging detection of extrasolar planets. Turbulence in the Earth's atmosphere imposes some fundamental limits, but the large size of ground-based telescopes compared to spacecraft can work to mitigate this. We are carrying out a design study for a dedicated ultra-high-contrast system, the eXtreme Adaptive Optics Planet Imager (XAOPI), which

Bruce A. Macintosh; James Graham; Lisa Poyneer; Gary Sommargren; Julia Wilhelmsen; Don Gavel; Steve Jones; Paul Kalas; James P. Lloyd; Russ Makidon; Scot Olivier; Dave Palmer; Jennifer Patience; Marshall Perrin; Scott Severson; Andrew Sheinis; Anand Sivaramakrishnan; Mitch Troy; J. K. Wallace

2003-01-01

68

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

69

Gemini multiobject spectrographs  

Microsoft Academic Search

As the only two optical instruments appearing in its first fleet of instrumentation, the GEMINI MultiObject Spectrograph (GMOS) are indeed being developed as workhorse instruments. One GMOS will be located at each of the GEMINI telescopes to perform: (1) exquisite direct imaging, (2) 5.5 arcminute longslit spectroscopy, (3) up to 600 object multislit spectroscopy, and (4) about 2000 element integral

Richard G. Murowinski; Tim Bond; David Crampton; Timothy J. Davidge; J. M. Fletcher; Brian Leckie; Christopher L. Morbey; Scott Roberts; Leslie Saddlemyer; Jerry Sebesta; James R. Stilburn; Kei Szeto; Jeremy R. Allington-Smith; Roger L. Davies; G. N. Dodsworth; Roger Haynes; David J. Robinson; David J. Robertson; J. Webster; David Lee; Steven M. Beard; Colin G. Dickson; Dennis Kelly; R. Bennet; Maureen A. Ellis; Peter R. Hastings; Phil R. Williams

1998-01-01

70

Imaging of the outer planets and satellites.  

NASA Technical Reports Server (NTRS)

Imaging is the most widely applicable single means of exploring the outer planets and their satellites and also complements other planet-oriented instruments. Photography of Jupiter from terrestrial telescopes has revealed features which were neither predictable or predicted. Close-up imaging from fly-bys and orbiters affords the opportunity for discovery of atmospheric phenomena on the outer planets forever beyond the reach of terrestrial laboratories and intuition. On the other hand, a large number of specific applications of close-up imaging to study the giant planets are suggested by experience in photography from Earth and Mars orbit, and by ground-based telescopic studies of Jupiter and Saturn. The satellites of the outer planets actually constitute three distinct classes: lunar-sized objects, asteroidal-sized objects, and particulate rings. Imaging promises to be the primary observational tool for each category with results that could impact scientific thinking in the late 70's and 80's as significantly as has close-up photography of Mars and the Moon in the last 10 yr.

Murray, B. C.

1973-01-01

71

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

72

HST image of Pluto - the 'Double Planet'  

NASA Technical Reports Server (NTRS)

European Space Agency (ESA) Faint Object Camera (FOC) image was taken by the Hubble Space Telescope (HST) of Pluto - the 'Double Planet'. This FOC image, the first long duration HST exposure of a moving target, appears in the upper right hand frame and shows Pluto (bright object at the center of the frame) and Charon (fainter object in the lower left). Charon's orbit around Pluto is indicated in the diagram at the bottom and the best ground-based image of Pluto and Charon taken from the Canada-France-Hawaii telescope in Hawaii appears in the upper left hand frame. Image was released 10-04-90.

1990-01-01

73

Direct imaging of habitable planets with ELTs  

NASA Astrophysics Data System (ADS)

ELTs will offer unprecedented angular resolution and collecting area, two of the essential ingredients for direct imaging and characterization of habitable exoplanets. If equipped with high performance AO system and coronagraph, ELTs will therefore be very powerful instruments for high contrast imaging of the immediate surroundings of nearby stars. An analysis of the expected performance of such a system, both from fundamental principles and extrapolations using current technologies developed for 10-m class telescopes, reveals that it will be able to image a large number of extrasolar planets. One of the most interesting finding of this analysis is that ELTs should be able to directly image potentially habitable planets in reflected light, and that reflected light imaging in the near-IR is easier than thermal emission imaging with an ELT (in part thanks to the ability to chose the most nearby stars as targets, as opposed to more distant young stars). While an Earth analog at 10pc would be at the very limit of detection even with a nearly optimal system (using a high sensitivity and high speed ExAO system), adopting a slightly broader definition of habitable planets including Super-Earths around late-type stars shows that detection and spectroscopic characterization of habitable planets will be within reach. For such targets, the reflected light contrast is more favorable and the planet is intrinsically brighter (since late type stars are more numerous, and can therefore be selected at small distance). The key to enable these detections is angular resolution, since the habitable zone around late type stars is very close to the star. An ExAO system for ELT should therefore use techniques optimal for high contrast imaging at a few diffraction limits from the central star. Such techniques are currently being developed in laboratories, and some of them are being deployed on existing telescopes: small inner working coronagraphs can now deliver full sensitivity images down to ˜1 ?/D, and new wavefront sensing techniques fully utilizing coherence over the entire pupil allow more than 10000x gain in sensitivity over conventional seeing-limited wavefront sensors. This science goal is complementary to direct imaging and characterization of habitable exoplanets from space, which favors F-G-K type stars at larger angular separation. Since no such space mission is planned for the near future (and will therefore likely not fly before ˜2025-2030), ground-based ELTs may in fact offer the first opportunity for detailed characterization of nearby habitable worlds.

Guyon, Olivier

2011-09-01

74

Extreme Adaptive Optics Planet Imager: XAOPI  

SciTech Connect

Ground based adaptive optics is a potentially powerful technique for direct imaging detection of extrasolar planets. Turbulence in the Earth's atmosphere imposes some fundamental limits, but the large size of ground-based telescopes compared to spacecraft can work to mitigate this. We are carrying out a design study for a dedicated ultra-high-contrast system, the eXtreme Adaptive Optics Planet Imager (XAOPI), which could be deployed on an 8-10m telescope in 2007. With a 4096-actuator MEMS deformable mirror it should achieve Strehl >0.9 in the near-IR. Using an innovative spatially filtered wavefront sensor, the system will be optimized to control scattered light over a large radius and suppress artifacts caused by static errors. We predict that it will achieve contrast levels of 10{sup 7}-10{sup 8} at angular separations of 0.2-0.8 inches around a large sample of stars (R<7-10), sufficient to detect Jupiter-like planets through their near-IR emission over a wide range of ages and masses. We are constructing a high-contrast AO testbed to verify key concepts of our system, and present preliminary results here, showing an RMS wavefront error of <1.3 nm with a flat mirror.

Macintosh, B A; Graham, J; Poyneer, L; Sommargren, G; Wilhelmsen, J; Gavel, D; Jones, S; Kalas, P; Lloyd, J; Makidon, R; Olivier, S; Palmer, D; Patience, J; Perrin, M; Severson, S; Sheinis, A; Sivaramakrishnan, A; Troy, M; Wallace, K

2003-09-17

75

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

76

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

77

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

78

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

79

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

80

eXtreme Adaptive Optics Planet Imager: overview and status  

Microsoft Academic Search

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 \\

Bruce A. Macintosh; Brian Bauman; Julia Wilhelmsen Evans; James R. Graham; Christopher Lockwood; Lisa Poyneer; Daren Dillon; Don T. Gavel; Joseph J. Green; James P. Lloyd; Russell B. Makidon; Scot Olivier; Dave Palmer; Marshall D. Perrin; Scott Severson; Andrew I. Sheinis; Anand Sivaramakrishnan; Gary Sommargren; Remi Soummer; Mitchell Troy; J. Kent Wallace; Edward Wishnow

2004-01-01

81

A bright future for direct imaging of extrasolar planets  

E-print Network

1 A bright future for direct imaging of extrasolar planets Olivier Guyon (guyon@naoj.org) http, Rock, Water, Atmosphere) Atmosphere composition & structure Rotation period Habitability Orbit Asteroid albedo (VIS) ? Eff. temp (IR) ? impact frequency surface temperature, pressure & composition ? tidal

Guyon, Olivier

82

Gemini multiobject spectrographs  

NASA Astrophysics Data System (ADS)

As the only two optical instruments appearing in its first fleet of instrumentation, the GEMINI MultiObject Spectrograph (GMOS) are indeed being developed as workhorse instruments. One GMOS will be located at each of the GEMINI telescopes to perform: (1) exquisite direct imaging, (2) 5.5 arcminute longslit spectroscopy, (3) up to 600 object multislit spectroscopy, and (4) about 2000 element integral field spectroscopy. The GMOSs are the only GEMINI instrumentation duplicated at both telescopes. The UK and Canadian GMOS team successfully completed their critical design review in February 1997. They are now well into the fabrication phase, and will soon approach integration of the first instrument. The first GMOS is scheduled to be delivered to Mauna Kea in the fall of '99 and the second to Cerro Pachon one year later. In this paper, we will look at how a few of the more interesting details of the final GMOS design help meet its demanding scientific requirements. These include its transmissive optical design and mask handling mechanisms. We will also discuss our plans for the mask handling process in GEMINI's queue scheduled environment, from the taking of direct images through to the use of masks on the telescope. Finally, we present the status of fabrication and integration work to date.

Murowinski, Richard G.; Bond, Tim; Crampton, David; Davidge, Timothy J.; Fletcher, J. M.; Leckie, Brian; Morbey, Christopher L.; Roberts, Scott; Saddlemyer, Leslie; Sebesta, Jerry; Stilburn, James R.; Szeto, Kei; Allington-Smith, Jeremy R.; Content, Robert; Davies, Roger L.; Dodsworth, G. N.; Haynes, Roger; Robinson, David J.; Robertson, David J.; Webster, J.; Lee, David; Beard, Steven M.; Dickson, Colin G.; Kelly, Dennis; Bennet, R.; Ellis, Maureen A.; Hastings, Peter R.; Williams, Phil R.

1998-07-01

83

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

84

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

85

The International Deep Planet Survey  

NASA Astrophysics Data System (ADS)

After completing the Gemini Deep Planet Survey (GDPS), an 86 young Sun-like/late-type star direct adaptive optics ADI imaging campaign, the International Deep Planet Survey was designed to complement the GDPS young late-type star sample by focusing mainly on early-type stars. The main idea behind the IDPS is that more early-type stars, being more massive, could harbor more massive and extended planetary disks, possibly forming more massive planets at wide separations -- partially compensating for their less favorable observing conditions (on average brighter, older and further away than late-type targets). I will present the overall IDPS survey (currently ongoing at Keck, Gemini North/South and VLT) and current statistics. I will also go over several software upgrades (data archive and ADI/SSDI data reduction tools) that are being implemented to prepare for the upcoming next generation order-of-magnitude larger campaigns that will be carried out with the Gemini Planet Imager.

Marois, C.

2010-10-01

86

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

87

Planet formation imager (PFI): introduction and technical considerations  

NASA Astrophysics Data System (ADS)

Complex non-linear and dynamic processes lie at the heart of the planet formation process. Through numerical simulation and basic observational constraints, the basics of planet formation are now coming into focus. High resolution imaging at a range of wavelengths will give us a glimpse into the past of our own solar system and enable a robust theoretical framework for predicting planetary system architectures around a range of stars surrounded by disks with a diversity of initial conditions. Only long-baseline interferometry can provide the needed angular resolution and wavelength coverage to reach these goals and from here we launch our planning efforts. The aim of the Planet Formation Imager" (PFI) project is to develop the roadmap for the construction of a new near-/mid-infrared interferometric facility that will be optimized to unmask all the major stages of planet formation, from initial dust coagulation, gap formation, evolution of transition disks, mass accretion onto planetary embryos, and eventual disk dispersal. PFI will be able to detect the emission of the cooling, newlyformed planets themselves over the first 100 Myrs, opening up both spectral investigations and also providing a vibrant look into the early dynamical histories of planetary architectures. Here we introduce the Planet Formation Imager (PFI) Project (www.planetformationimager.org) and give initial thoughts on possible facility architectures and technical advances that will be needed to meet the challenging top-level science requirements.

Monnier, John D.; Kraus, Stefan; Buscher, David; Berger, J.-P.; Haniff, Christopher; Ireland, Michael; Labadie, Lucas; Lacour, Sylvestre; Le Coroller, Herve; Petrov, Romain G.; Pott, JoÌrg-Uwe; Ridgway, Stephen; Surdej, Jean; ten Brummelaar, Theo; Tuthill, Peter; van Belle, Gerard

2014-07-01

88

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

89

The lowest mass giant planet ever imaged around a star  

NASA Astrophysics Data System (ADS)

Understanding planetary systems formation and evolution has become one of the challenges in astronomy, since the discovery of the first exoplanet around the solar-type star 51 Peg in the 90's. While more than 800 planets (mostly giants) closer than a few AU have been identified with radial velocity and transit techniques, very few have been imaged and definitely confirmed around stars, at separations below a hundred of astronomical units. Direct imaging detection of exoplanet is indeed a major frontier in planetary astrophysics. It surveys a region of semi-major axes (> 5 AU) that is almost inaccessible to other methods. Moreover, the planets imaged so far orbit young stars; indeed the young planets are still hot and the planetstar contrasts are compatible with the detection limits currently achievable, in contrast with similar planets in older systems. Noticeably, the stars are of early-types, and surrounded by debris disks, i.e. disks populated at least by small grains with lifetimes so short that they must be permanently produced, probably by destruction (evaporation, collisions) of larger solid bodies. Consequently, every single discovery has a tremendous impact on the understanding of the formation, the dynamical evolution, and the physics of giant planets. In this context, I will present our recent discovery of one faint companion to a nearby, dusty, and young A-type star (at 56 AU projected separation). Background contaminants are rejected with high confidence level based on both astrometry and photometry with three dataset at more than a yeartime-laps and two different wavelength regimes. From the system age (10 to 17 Myr) and from model-dependent luminosity estimates, we derive mass of 4 to 5 Jupiter mass. This planet is therefore the one with the lowest mass ever imaged around a star. Given its orbital and physical properties, I will discuss the implication on its atmosphere with respect to other imaged companions but also on its formation which is not straightforward assuming standard mechanisms. This planet will be of great interest for future planets imagers to search for additional close-in and lower mass companions but also for spectral characterization.

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

2013-09-01

90

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.

91

Geometric processing of digital images of the planets  

NASA Technical Reports Server (NTRS)

New procedures and software have been developed for geometric transformation of images to support digital cartography of the planets. The procedures involve the correction of spacecraft camera orientation of each image with the use of ground control and the transformation of each image to a Sinusoidal Equal-Area map projection with an algorithm which allows the number of transformation calculations to vary as the distortion varies within the image. When the distortion is low in an area of an image, few transformation computations are required, and most pixels can be interpolated. When distortion is extreme, the location of each pixel is computed. Mosaics are made of these images and stored as digital databases. Completed Sinusoidal databases may be used for digital analysis and registration with other spatial data. They may also be reproduced as published image maps by digitally transforming them to appropriate map projections.

Edwards, Kathleen

1987-01-01

92

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

93

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

94

Advanced image slicers for integral field spectroscopy with UKIRT and GEMINI  

NASA Astrophysics Data System (ADS)

The new design of image slicer developed at Durham University for 2D area spectroscopy is described. The unit acts as a coupler between the telescope and a spectrograph to reformat a square or rectangular field into a long slit. Its advantages over previous designs of image slicers and other methods using fibers, lenses or narrow-band filtering are discussed, mainly: large field, high spatial resolution, large number of spectral resolution elements, high transmission, and the small size of the instrument. The system is also easy to cool and is then well suited for IR spectroscopy. The proposed design is a new type of image slicer in which the original 2D image is sliced into narrow sub-images that are re-imaged side by side to form a long 1D image at the spectrograph input. The flexibility of the concept at the base of this new design is highlighted through the description of 5 different slicer designs. Three of these are for future instruments now at the design phase: the CGS4 slicer, the UIST slicer and the GNIRS slicer; the two others are studies for possible future slicers on GMOS and NGST. These designs show how easily our slicer can be added to an existing instrument, how it can be incorporated to the slit wheel of future instruments, and how multi-slit reformatting permits a much larger field of view.

Content, Robert

1998-08-01

95

A probable giant planet imaged in the Beta Pictoris disk  

E-print Network

Since the discovery of its dusty disk in 1984, Beta Pictoris has become the prototype of young early-type planetary systems, and there are now various indications that a massive Jovian planet is orbiting the star at ~ 10 AU. However, no planets have been detected around this star so far. Our goal was to investigate the close environment of Beta Pic, searching for planetary companion(s). Deep adaptive-optics L'-band images of Beta Pic were recorded using the NaCo instrument at the Very Large Telescope. A faint point-like signal is detected at a projected distance of ~ 8 AU from the star, within the North-East side of the dust disk. Various tests were made to rule out with a good confidence level possible instrumental or atmospheric artifacts. The probability of a foreground or background contaminant is extremely low, based in addition on the analysis of previous deep Hubble Space Telescope images. The object L'=11.2 apparent magnitude would indicate a typical temperature of ~1500 K and a mass of ~ 8 Jovian masses. If confirmed, it could explain the main morphological and dynamical peculiarities of the Beta Pic system. The present detection is unique among A-stars by the proximity of the resolved planet to its parent star. Its closeness and location inside the Beta Pic disk suggest a formation process by core accretion or disk instabilities rather than a binary-like formation process.

A. -M. Lagrange; D. Gratadour; G. Chauvin; T. Fusco; D. Ehrenreich; D. Mouillet; G. Rousset; D. Rouan; F. Allard; E. Gendron; J. Charton; L. Mugnier; P. Rabou; J. Montri; F. Lacombe

2008-11-21

96

High-contrast imaging using adaptive optics for extrasolar planet detection  

Microsoft Academic Search

Direct imaging of extrasolar planets is an important, but challenging in planetary science. Most planets identified to elate have been detected indirectly---not by emitted or reflected light but through the effect of the planet on the parent star. Indirect techniques only probe about 15% of the orbital parameter space of our solar system. Direct methods would probe new parameter space,

Julia Wilhelmsen Evans

2006-01-01

97

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

E-print Network

#12; -- 2 -- 1. Introduction The detection of a large number of extrasolar planets and planetary­like planets will be carried out at low spectral resolution. This maximizes the number of photons fromAccepted for publication in ApJ, October 2002 Imaging Spectroscopy for Extrasolar Planet Detection

98

Predictions for Shepherding Planets in Scattered Light Images of Debris Disks  

NASA Astrophysics Data System (ADS)

Planets can affect debris disk structure by creating gaps, sharp edges, warps, and other potentially observable signatures. However, there is currently no simple way for observers to deduce a disk-shepherding planet's properties from the observed features of the disk. Here we present a single equation that relates a shepherding planet's maximum mass to the debris ring's observed width in scattered light, along with a procedure to estimate the planet's eccentricity and minimum semimajor axis. We accomplish this by performing dynamical N-body simulations of model systems containing a star, a single planet, and an exterior disk of parent bodies and dust grains to determine the resulting debris disk properties over a wide range of input parameters. We find that the relationship between planet mass and debris disk width is linear, with increasing planet mass producing broader debris rings. We apply our methods to five imaged debris rings to constrain the putative planet masses and orbits in each system. Observers can use our empirically derived equation as a guide for future direct imaging searches for planets in debris disk systems. In the fortuitous case of an imaged planet orbiting interior to an imaged disk, the planet's maximum mass can be estimated independent of atmospheric models.

Rodigas, Timothy J.; Malhotra, Renu; Hinz, Philip M.

2014-01-01

99

A probable giant planet imaged in the Beta Pictoris disk  

E-print Network

Since the discovery of its dusty disk in 1984, Beta Pictoris has become the prototype of young early-type planetary systems, and there are now various indications that a massive Jovian planet is orbiting the star at ~ 10 AU. However, no planets have been detected around this star so far. Our goal was to investigate the close environment of Beta Pic, searching for planetary companion(s). Deep adaptive-optics L'-band images of Beta Pic were recorded using the NaCo instrument at the Very Large Telescope. A faint point-like signal is detected at a projected distance of ~ 8 AU from the star, within the North-East side of the dust disk. Various tests were made to rule out with a good confidence level possible instrumental or atmospheric artifacts. The probability of a foreground or background contaminant is extremely low, based in addition on the analysis of previous deep Hubble Space Telescope images. The object L'=11.2 apparent magnitude would indicate a typical temperature of ~1500 K and a mass of ~ 8 Jovian mas...

Lagrange, A -M; Chauvin, G; Fusco, T; Ehrenreich, D; Mouillet, D; Rousset, G; Rouan, D; Allard, F; Gendron, E; Charton, J; Mugnier, L; Rabou, P; Montri, J; Lacombe, F

2008-01-01

100

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

101

Study of spin-scan imaging for outer planets missions. [imaging techniques for Jupiter orbiter missions  

NASA Technical Reports Server (NTRS)

The constraints that are imposed on the Outer Planet Missions (OPM) imager design are of critical importance. Imager system modeling analyses define important parameters and systematic means for trade-offs applied to specific Jupiter orbiter missions. Possible image sequence plans for Jupiter missions are discussed in detail. Considered is a series of orbits that allow repeated near encounters with three of the Jovian satellites. The data handling involved in the image processing is discussed, and it is shown that only minimal processing is required for the majority of images for a Jupiter orbiter mission.

Russell, E. E.; Chandos, R. A.; Kodak, J. C.; Pellicori, S. F.; Tomasko, M. G.

1974-01-01

102

Direct detection of extrasolar planets with the eXtreme Adaptive Optics Planet Imager  

Microsoft Academic Search

Current radial-velocity searches for extrasolar planets, though powerful, are fundamentally constrained in the range of orbits they can access by the need for a near-complete orbital period: the largest detectable semi-major axis only grows with time to the 2\\/3 power. In the next several decades, radial velocity detection will barely reach planets with orbits comparable to Saturn. However, planets in

B. A. Macintosh; J. R. Graham; G. Duchene; S. Jones; P. Kalas; J. Lloyd; R. B. Makidon; S. Olivier; D. Palmer; M. Perrin; L. Poyneer; A. Sheinis; A. Sivaramakrishnan; S. Severson; G. Sommargren; M. Troy; J. K. Wallace

2003-01-01

103

Grand Tour outer planet missions definition phase. Part 1: Quantitative imaging of the outer planets and their satellites  

NASA Technical Reports Server (NTRS)

A recommended imaging system is outlined for use aboard the Outer Planet Grand Tour Explorer. The system features the high angular resolution capacity necessary to accommodate large encounter distances, and to satisfy the demand for a reasonable amount of time coverage. Specifications for all components within the system are provided in detail.

Belton, M. J. S.; Aksnes, K.; Davies, M. E.; Hartmann, W. K.; Millis, R. L.; Owen, T. C.; Reilly, T. H.; Sagan, C.; Suomi, V. E.; Collins, S. A., Jr.

1972-01-01

104

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

105

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

106

Communications challenge for the Gemini 8-m Telescopes James R. Wright  

E-print Network

the nightly calibrations of the telescope pointing and image quality the system operator for Mauna Kea startsCommunications challenge for the Gemini 8-m Telescopes James R. Wright Gemini 8-m Telescopes and design of the communications system for the Gemini 8-meter Telescopes Project . This system is unique

107

Communications challenge for the Gemini 8m Telescopes James R. Wright  

E-print Network

the nightly calibrations of the telescope pointing and image quality the system operator for Mauna Kea startsCommunications challenge for the Gemini 8­m Telescopes James R. Wright Gemini 8­m Telescopes and design of the communications system for the Gemini 8­meter Telescopes Project \\Lambda . This system

108

Imaging planets around nearby white dwarfs M. R. Burleigh,1P  

E-print Network

.g. Nakajima et al. 1995). The end state of main-sequence stars with M # 8 M(, white dwarfs, are typically 103 in the brightness contrast between a planet and a white dwarf when compared to a main-sequence star, assumingImaging planets around nearby white dwarfs M. R. Burleigh,1P F. J. Clarke2P and S. T. Hodgkin2P 1

Burleigh, Matt

109

Resolved imaging of extra-solar planets with future 10-100km optical interferometric arrays  

E-print Network

In the recent years, interferometric arrays of optical telescopes have reached sizes of the order of 100m, but they have yet to produce high-resolution images. The analysis of image formation now shows that such images are obtainable directly in the recombined focal plane, if there are enough telescopes. Resolved images of extra-solar planets are in principle obtainable with 10km ground-based arrays.

Antoine Labeyrie

1996-02-19

110

Computer vision applications for coronagraphic optical alignment and image processing  

E-print Network

Modern coronagraphic systems require very precise alignment between optical components and can benefit greatly from automated image processing. We discuss three techniques commonly employed in the fields of computer vision and image analysis as applied to the Gemini Planet Imager, a new facility instrument for the Gemini South Observatory. We describe how feature extraction and clustering methods can be used to aid in automated system alignment tasks, and also present a search algorithm for finding regular features in science images used for calibration and data processing. Along with discussions of each technique, we present our specific implementation and show results of each one in operation.

Savransky, Dmitry; Poyneer, Lisa A; Macintosh, Bruce A; 10.1364/AO.52.003394

2013-01-01

111

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

112

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

113

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

114

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

115

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

116

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

117

EPICS: direct imaging of exoplanets with the E-ELT  

Microsoft Academic Search

Presently, dedicated instruments at large telescopes (SPHERE for the VLT, GPI for Gemini) are about to discover and explore self-luminous giant planets by direct imaging and spectroscopy. The next generation of 30m-40m ground-based telescopes, the Extremely Large Telescopes (ELTs), have the potential to dramatically enlarge the discovery space towards older giant planets seen in reflected light and ultimately even a

Markus Kasper; Jean-Luc Beuzit; Christophe Verinaud; Raffaele G. Gratton; Florian Kerber; Natalia Yaitskova; Anthony Boccaletti; Niranjan Thatte; Hans Martin Schmid; Christoph Keller; Pierre Baudoz; Lyu Abe; Emmanuel Aller-Carpentier; Jacopo Antichi; Mariangela Bonavita; Kjetil Dohlen; Enrico Fedrigo; Hiddo Hanenburg; Norbert Hubin; Rieks Jager; Visa Korkiakoski; Patrice Martinez; Dino Mesa; Olivier Preis; Patrick Rabou; Ronald Roelfsema; Graeme Salter; Mathias Tecza; Lars Venema

2010-01-01

118

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

119

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.

SEEDS Survey Team

2015-01-01

120

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

121

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.

122

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

123

Resolved Image of Surface of the Planet Mercury in Longitude Sector 210^O to 290^OW  

NASA Astrophysics Data System (ADS)

Results of observations of the unknown portion of Mercury are presented. The observations were made by the millisecond exposure method. The planet's disk subtended, on average, 7 arcsec. Geocentric distance of Mercury was 0.87 AU. The observations were carried out in a near IR-range. For the instrument with diameter D=1.25 m, on wavelength ? = 600 nanometer the ratio 1.22 ?/D = 0.15 arc sec, limiting resolution on surface of the planet should make exactly 100 km. Under good atmospheric conditions a sufficient number of initial electronic images were obtained that when stacked increased the signal to noise ratio and gave rise to resolution that dramatically shows unprecedented detail of the surface albedo and physical features. By processing a great number of electronic images, a sufficiently distinct synthesized image of the planet's surface was obtained. The most prominent formation in the sector 210° to 290°W longitude, a region not imaged by Mariner 10 is a giant basin centered at about 8N, 280W. The inner portion of this double rimmed basin extends 1000 km across. The total dimension of the outer eroded rim is slightly more than 2000 km. This basin includes and extends west and north of the dark albedo feature known as Solitudo Criophori. Many well defined impact craters have also been imaged. Some regions within the basin area have circular rims that apparently lack rayed structure or evidence of ejecta material. An attempt has been made to restore information about relief of the 210° to 290°W (70° to 150°E) longitude sector. In addition, regions on the order of 10° of latitude and 10° of longitude have been examined and reveal rayed craters in comparable detail to the Aericebo radar imaging and, at the same location of craters where radar backscatter indicates infilling by volatiles or some other highly coherent backscattering material. Implications of the huge basin for the geophysics of Mercury are discussed.

Ksanfomality, L. V.

2006-08-01

124

Gemini 9 spacecraft recovery operations  

NASA Technical Reports Server (NTRS)

The Gemini 9-A spacecraft, with Astronauts Thomas Stafford and Eugene Cernan still inside, in water as the aircraft carrier U.S.S. Wasp, the recovery ship, comes alongside to recover the astronauts and their spaceship.

1966-01-01

125

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

126

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

127

Gemini-north multiobject spectrograph integration, test, and commissioning  

NASA Astrophysics Data System (ADS)

The first of two Gemini Multi Object Spectrographs (GMOS) has recently begun operation at the Gemini-North 8m telescope. In this presentation we give an overview of the instrument and describe the overall performance of GMOS-North both in the laboratory during integration, and at the telescope during commissioning. We describe the development process which led to meeting the demanding reliability and performance requirements on flexure, throughput and image quality. We then show examples of GMOS data and performance on the telescope in its imaging, long-slit and MOS modes. We also briefly highlight novel features in GMOS that are described in more detail in separate presentations, particularly the flexure compensation system and the on-instrument wavefront sensor. Finally we give an update of the current status of GMOS on Gemini-North and future plans.

Hook, Isobel; Allington-Smith, Jeremy R.; Beard, Steven M.; Crampton, David; Davies, Roger L.; Dickson, Colin G.; Ebbers, Angelic W.; Fletcher, J. Murray; Jorgensen, Inger; Jean, I.; Juneau, S.; Murowinski, Richard G.; Nolan, Robert; Laidlaw, Ken; Leckie, Brian; Marshall, G. E.; Purkins, Terry; Richardson, Ian M.; Roberts, Scott C.; Simons, Douglas A.; Smith, Malcolm J.; Stilburn, James R.; Szeto, Kei; Tierney, Chris; Wolff, Richard J.; Wooff, Robert

2003-03-01

128

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

129

The Gemini Observatory Virtual Tour  

NASA Astrophysics Data System (ADS)

Because of their remoteness and the resultant difficulty of visiting the Gemini telescopes on Mauna Kea and Cerro Pachon, a virtual tour of the Gemini Observatory was instigated. This has been developed over the years and has received wide acclaim. This talk illustrates where we are now with the Virtual Tour and gives some examples of topics that have worked well and some idea of the costs involved in such an enterprise.

Michaud, P.

2005-12-01

130

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

131

The Planets Around Low-Mass Stars (PALMS) Direct Imaging Survey  

NASA Astrophysics Data System (ADS)

Direct imaging is the only method to study the outer architecture (>10 AU) of extrasolar planetary systems in a targeted fashion. Previous imaging surveys have primarily focused on intermediate- and high-mass stars because of the relative dearth of known nearby young M dwarfs. As a result, even though M dwarfs make up 70% of stars in our galaxy, there are few constraints on the population of giant planets at moderate separations (10-100 AU) in this stellar mass regime. We present results from an ongoing high-contrast adaptive optics imaging survey targeting newly identified nearby (<35 pc) young (<300 Myr) M dwarfs with Keck-2/NIRC2 and Subaru/HiCIAO. We have already discovered four young brown dwarf companions with masses between 30-70 Mjup; two of these are members of the ~120 Myr AB Dor moving group, and another one will yield a dynamical mass in the near future. Follow-up optical and near-infrared spectroscopy of these companions reveal spectral types of late-M to early-L and spectroscopic indicators of youth such as angular H-band morphologies, weak J-band alkali lines, and Li absorption and Halpha emission in one target. Altogether our survey is sensitive to planet masses a few times that of Jupiter at separations down to ~10 AU. With a sample size of roughly 80 single M dwarfs, this program represents the deepest and most extensive imaging search for planets around young low-mass stars to date.

Bowler, Brendan P.; Liu, M. C.; Shkolnik, E.; Mann, A.; Tamura, M.

2013-01-01

132

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

133

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).

ACEND team; ACESat team

2015-01-01

134

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

135

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).

2001-01-01

136

The Nine Planets: Pluto  

NSDL National Science Digital Library

This page of Nine Planets contains details about the planet Pluto. 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 information about Pluto's moon, Charon. Unanswered questions are discussed, and links to more images, movies, and facts are provided.

Arnett, Bill

137

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.

Arnett, Bill

138

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

139

Recovery of Gemini 4 spacecraft and astronauts  

NASA Technical Reports Server (NTRS)

Recovery of Gemini 4 spacecraft and astronauts. Views include Astronaut James A. McDivitt, command pilot of the Gemini 4 space flight, sitting in life raft awaiting pickup by helicopter from the recovery ship, the aircraft carrier U.S.S. Wasp (33490); Navy frogmen stand on the flotation collar of the Gemini 4 spacecraft during recovery operations (33491).

1965-01-01

140

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

141

Developing for Gemini's Extensible Pipeline Environment  

NASA Astrophysics Data System (ADS)

Gemini is developing a near real-time data quality assurance pipeline. The final product will support all facility instruments and all of their observing modes. Rather than developing separate pipelines for each instrument and mode, the choice was made early on to design an extensible pipeline environment where configuration plugins are added to a core infrastructure. The iterative deployment of this extensible pipeline environment at Gemini has recently begun. The first deployment includes the core infrastructure support for the processing and image quality assessment of optical imaging GMOS data. Support for an instrument and mode is added to the pipeline through a collection of configurations that must include data type definitions, data descriptors, and implementations for applicable processing steps, and that must respect interface control rules. The configurations provide the data abstraction necessary to the pipeline infrastructure, and the interface definitions allows for one simple, reusable lexicon describing the data and the processing of those data. The key benefits from a development point of view is maximum code reuse, with top-level recipes and many processing algorithms being completely instrument agnostic.

Labrie, K.; Allen, C.; Hirst, P.

2012-09-01

142

Gemini analogs of vitamin d.  

PubMed

The Gemini analogs are the last significant contribution to the family of vitamin D derivatives in medicine, for the treatment of cancer. The first Gemini analog was characterized by two symmetric side chains at C-20. Following numerous modifications, the most active analog bears a C-23-triple bond, C-26, 27- hexafluoro substituents on one side chain and a terminal trideuteromethylhydroxy group on the other side chain. This progression was possible due to improvements in the synthetic methods for the preparation of these derivatives, which allowed for increasing molecular complexity and complete diastereoselective control at C-20 and the substituted sidechains. PMID:25486935

Pazos, Gonzalo; Rivadulla, Marcos L; Perez-García, Xenxo; Gandara, Zoila; Perez, Manuel

2014-01-01

143

Hole-y Debris Disks, Batman! Where are the planets?  

NASA Astrophysics Data System (ADS)

Giant planets at wide separations are rare and direct imaging surveys are resource-intensive, so a cheaper marker for the presence of giant planets is desirable. One intriguing possibility is to use the effect of planets on their host stars' debris disks. Theoretical studies indicate giant planets can gravitationally carve sharp boundaries and gaps in their disks; this has been seen for HR 8799, ? Pic, and tentatively for HD 95086 (Su et al. 2009, Lagrange et al. 2010, Moor et al. 2013). If more broadly demonstrated, this link could help guide target selection for next generation direct imaging surveys. Using Spitzer MIPS/IRS spectral energy distributions (SEDs), we identify several dozen systems with two-component and/or large inner cavity disks (aka Hole-y Debris Disks). With LBT/LBTI, VLT/NaCo, GeminiS/NICI, MMT/Clio and Magellan/Clio, we survey a subset these SEDselected targets (~20). In contrast to previous disk-selected planet surveys (e.g.: Janson et al. 2013, Wahhaj et al. 2013) we image primarily in the thermal IR (L'-band), where planet-to-star contrast is more favorable and background contaminants less numerous. Thus far, two of our survey targets host planet-mass companions, both of which were discovered in L'-band after they were unrecognized or undetectable in H-band. For each system in our sample set, we will investigate whether the known companions and/or companions below our detection threshold could be responsible for the disk architecture. Ultimately, we will increase our effective sample size by incorporating detection limits from surveys that have independently targeted some of our systems of interest. In this way we will refine the conditions under which disk SED-based target selection is likely to be useful and valid.

Bailey, V.; Meshkat, T.; Hinz, P.; Kenworthy, M.; Su, K. Y. L.

2014-03-01

144

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

145

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

146

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.

Arnett, Bill

147

Gemini Multi-Object Spectrograph Upgrades: Hamamatsu CCDs and AO  

NASA Astrophysics Data System (ADS)

The Gemini Multi-Object Spectrographs (GMOS) at both Gemini North and South have provided crucial access to longslit, MOS and IFU moderate resolution optical spectroscopy for the Gemini international partnership for over a decade. The interim installment of e2v deep depletion CCDs at GMOS-N in November 2011, providing enhanced red sensitivity, was the first major upgrade for either GMOS since the implementation of the Nod&Shuffle mode in 2002. We present plans to replace the original EEV detectors in GMOS-S with new Hamamatsu CCDs, extending wavelength coverage out beyond 1.03 microns. GMOS-N upgrade to Hamamatsu CCDs will follow the successful deployment on GMOS-S. With the extension of GMOS sensitivity further to long wavelengths it becomes even more attractive to extend the number of observing modes to include adaptive optics imaging and spectroscopy. As has already been demonstrated with GEMS/GMOS-S imaging, adaptive optics in the 0.8-1 micron wavelength regime on Gemini can effectively transform IQ70 conditions to IQ20 and more than double the spatial resolution over the natural seeing. We present plans to move forward with plans to enable GMOS + adaptive optics as a regular user mode at both sites.

Roth, Katherine; Gimeno, G.; Murowinski, R.; Kleinman, S.; Trujillo, C. A.; Lai, O.

2014-01-01

148

Astrometry and photometry in high contrast imaging  

NASA Astrophysics Data System (ADS)

The direct exoplanet imaging field will strongly benefit from the larger aperture and the higher angular resolution achieved by next generation 30+m telescopes. To fully take advantage of these new facilities, one of the biggest challenges that ground-based adaptive optics imaging must overcome is to be able to derive accurate astrometry and photometry with realistic estimate of residual errors. The planet photometry and its astrometry are used to compare with atmospheric models and to fit orbits. If erroneous numbers are found, or if errors are underestimated, spurious fits can lead to unphysical planet characteristics or wrong/unstable orbits. Overestimating the errors also needs to be avoided as it degrades the value of the data. In the high-contrast planet imaging context, we will present various photometry/astrometry biases induced by several noise sources (anisoplanatism, non-Gaussian noise, etc.) or processing techniques (ADI/SSDI/LOCI) that we have uncovered during our ongoing direct exoplanet imaging campaign at Gemini, VLT and Keck. We will describe the procedures that we have implemented to properly estimate those biases. These solutions will be implemented in the Gemini Planet Imager campaign data pipeline and we expect that they will also play a crucial role in any future 30+m survey.

Galicher, Raphael; Marois, Christian

2011-09-01

149

High-contrast imaging testbed for the Terrestrial Planet Finder coronagraph  

NASA Astrophysics Data System (ADS)

The Terrestrial Planet Finder (TPF) mission is planning to launch a visible coronagraphic space telescope in 2014. To achieve TPF science goals, the coronagraph must have extreme levels of wavefront correction (less than 1 Å rms over controllable spatial frequencies) and stability to get the necessary suppression of diffracted starlight (~1E-10 contrast at an angular separation ~4 lambda/D). TPF Coronagraph"s primary platform for experimentation is the High Contrast Imaging Testbed, which will provide laboratory validation of key technologies as well as demonstration of a flight-traceable approach to implementation. Precision wavefront control in the testbed is provided by a high actuator density deformable mirror. Diffracted light control is achieved through use of occulting or apodizing masks and stops. Contrast measurements will establish the technical feasibility of TPF requirements, while model and error budget validation will demonstrate implementation viability. This paper describes the current testbed design, development approach, and recent experimental results.

Lowman, Andrew E.; Trauger, John T.; Gordon, Brian; Green, Joseph J.; Moody, Dwight; Niessner, Albert F.; Shi, Fang

2004-10-01

150

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

151

AO operations at Gemini South  

NASA Astrophysics Data System (ADS)

The 8m Gemini South telescope is entering an exciting new era of AO operations, which put it at the forefront of astronomical AO in terms of both wide field AO, and extreme-AO systems. Major milestones achieved were the successful commissioning of GeMS, in 2012, and GPI, in late 2013 and early 2014. Currently we are operating two of the worlds most advanced astronomical AO systems. Gemini, running primarily in queue, must balance the promise of AO with the demands of the community to use non-AO instruments. We discuss the current state of the two AO systems, and their operational models. The preparations that go into planning each AO run, the difficulties in scheduling around non-AO instruments, and the differences between scheduling LGS AO and non-LGS AO are discussed.

Marin, Eduardo; Cardwell, Andrew; Pessev, Peter

2014-08-01

152

Gemini-North Multiobject Spectrograph Stability Performance  

NASA Astrophysics Data System (ADS)

Of the Gemini Multi-Object Spectrograph's (GMOS) scientific requirements, one which led to technically interesting areas was the ability to measure velocities to an accuracy of 2km/s over the entire 5.5 arcminute square field. GMOS's design to meet this requirement includes a mechanical design for stiffness and without hysteresis or image rotation, and an open loop flexure control system which translates the detector position to compensate for flexure. The model used to predict the flexure is an empirical one developed from measured flexure results. In this paper we present the analysis of factors which enable meeting the 2km/s requirement, and the observing strategies needed to make those observations. We look in particular detail at the development and test of that flexure compensation system, including both lab results and on-telescope results.

Murowinski, Richard G.; Allington-Smith, Jeremy R.; Beard, Steven M.; Crampton, David; Davies, Roger L.; Dickson, Colin G.; Hook, Isobel; Jorgensen, Inger; Juneau, S.; Marshall, G. E.; Szeto, Kei; Tierney, Chris

2003-03-01

153

Gemini astronauts in full pressure suits  

NASA Technical Reports Server (NTRS)

Prime crew for the Gemini 3 mission are photographed in full length portraits in their space suits. Viril I. Grissom (left) and John Young are seen with the portable suit air conditioners connected and their helmets on (19431); Four Gemini astronauts are photographed in full pressure suits. From left to right are John Young and Virgil I. Grissom, the prime crew for Gemini 3; as well as Walter M. Schirra and Thomas P. Stafford, their backup crew (19432).

1964-01-01

154

Careers and interactive technologies at Gemini Observatory  

NASA Astrophysics Data System (ADS)

Gemini feels it is important to let the public know that there is a wide range of astronomy related careers that most people are not aware of. We hope to accomplish this by providing a video that profiles the different job opportunities available at Gemini. The video will be included on our next CD-ROM/internet-based Virtual Tour and will also eventually be available over Gemini's website.

Harvey, J.

2008-06-01

155

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.

1995-01-01

156

Dwarf planet Ceres: Ellipsoid dimensions and rotational pole from Keck and VLT adaptive optics images  

NASA Astrophysics Data System (ADS)

The dwarf planet (1) Ceres, the largest object between Mars and Jupiter, is the target of the NASA Dawn mission, and we seek a comprehensive description of the spin-axis orientation and dimensions of Ceres in order to support the early science operations at the rendezvous in 2015. We have obtained high-angular resolution images using adaptive optics cameras at the W.M. Keck Observatory and the ESO VLT over ten dates between 2001 and 2010, confirming that the shape of Ceres is well described by an oblate spheroid. We derive equatorial and polar diameters of 967 ± 10 km and 892 ± 10 km, respectively, for a model that includes fading of brightness towards the terminator, presumably linked to limb darkening. These dimensions lie between values derived from a previous analysis of a subset of these images obtained at Keck by Carry et al. (Carry et al. [2008]. Astron. Astrophys. 478 (4), 235-244) and a study of Hubble Space Telescope observations (Thomas et al. [2005]. Nature 437, 224-226). Although the dimensions are 1-2% smaller than those found from the HST, the oblateness is similar. We find the spin-vector coordinates of Ceres to lie at (287°, +64°) in equatorial EQJ2000 reference frame (346°, +82° in ecliptic ECJ2000 coordinates), yielding a small obliquity of 3°. While this is in agreement with the aforementioned studies, we have improved the accuracy of the pole determination, which we set at a 3° radius.

Drummond, J. D.; Carry, B.; Merline, W. J.; Dumas, C.; Hammel, H.; Erard, S.; Conrad, A.; Tamblyn, P.; Chapman, C. R.

2014-07-01

157

Obtaining coincident image observations for Mission to Planet Earth science data return  

NASA Technical Reports Server (NTRS)

One objective of the Mission to Planet Earth (MTPE) program involves comparing data from various instruments on multiple spacecraft to obtain a total picture of the Earth's systems. To correlate image data from instruments on different spacecraft, these spacecraft must be able to image the same location on the Earth at approximately the same time. Depending on the orbits of the spacecraft involved, complicated operational details must be considered to obtain such observations. If the spacecraft are in similar orbits, close formation flying or synchronization techniques may be used to assure coincident observations. If the orbits are dissimilar, the launch time of the second satellite may need to be restricted in order to align its orbit with that of the first satellite launched. This paper examines strategies for obtaining coincident observations for spacecraft in both similar and dissimilar orbits. Although these calculations may be performed easily for coplanar spacecraft, the non-coplanar case involves additional considerations which are incorporated into the algorithms presented herein.

Newman, Lauri Kraft; Folta, David C.; Farrell, James P.

1994-01-01

158

Experimental design for the eXtreme Adaptive Optics Planet Imager (XAOPI)  

Microsoft Academic Search

Direct detection of the light emitted by extra-solar planets represents the next major hurdle in the study of extra-solar planets. The NSF Center for Adaptive Optics is carrying out a design study for a dedicated ultra-high-contrast \\

J. R. Graham; B. Macintosh; A. Ghez; P. Kalas; J. Lloyd; R. Makidon; S. Olivier; J. Patience; M. Perrin; L. Poyneer; S. Severson; A. Sheinis; A. Sivaramakrishnan; M. Troy; J. Wallace; J. Wilhelmsen

2002-01-01

159

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

160

A probable giant planet imaged in the beta Pictoris disk. VLT\\/NaCo deep L'-band imaging  

Microsoft Academic Search

Context: Since the discovery of its dusty disk in 1984, beta Pictoris has become the prototype of young early-type planetary systems, and there are now various indications that a massive Jovian planet is orbiting the star at ~10 AU. However, no planets have been detected around this star so far. Aims: Our goal was to investigate the close environment of

A.-M. Lagrange; D. Gratadour; G. Chauvin; T. Fusco; D. Ehrenreich; D. Mouillet; G. Rousset; D. Rouan; F. Allard; É. Gendron; J. Charton; L. Mugnier; P. Rabou; J. Montri; F. Lacombe

2009-01-01

161

A probable giant planet imaged in the? Pictoris disk? VLT\\/NACO Deep L-band imaging  

Microsoft Academic Search

Context. Since the discovery of its dusty disk in 1984,? Pictoris has become the prototype of young early-type planetary systems, and there are now various indications that a massive Jovian planet is orbiting th e star at? 10au. However, no planets have been detected around this star so far. Aims. Our goal was to investigate the close environement of? Pic,

A.-M. Lagrange; D. Gratadour; G. Chauvin; T. Fusco; D. Ehrenreich; D. Mouillet; G. Rousset; D. Rouan; F. Allard; E. Gendron; J. Charton; L. Mugnier; P. Rabou; J. Montri; F. Lacombe

162

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

NASA Astrophysics Data System (ADS)

Over the past 14 years, Doppler spectroscopy has been very successful in detecting and characterizing extrasolar planets, providing us with a wealth of information on these distant worlds (e.g., Marcy et al. 2005a; Udry and Santos 2007b; Udry et al. 2007a). One important and considerably unexpected fact these new data have taught us is that diversity is the rule in the planetary world. Diversity is found not only in the characteristics and orbital properties of the ˜ 340 planets detected thus far,1 but also in the types of environments in which they reside and are able to form. This observation has prompted a serious revision of the theories of planet formation (e.g., Lissauer and Stevenson 2007; Durisen et al. 2007; Nagasawa et al. 2007), leading to the idea that planet formation may be a richer and more robust process than originally thought.

Eggenberger, Anne; Udry, Stéphane

163

Gemini  

NASA Astrophysics Data System (ADS)

(the Twins; abbrev. Gem, gen. Geminorum; area 514 sq. deg.) A northern zodiacal constellation which lies between Auriga and Canis Minor, and culminates at midnight in early January. It represents Castor and Pollux, the twin sons of Leda, Queen of Sparta, in Greek mythology, whose brotherly love was rewarded by a place among the stars. Its brightest stars were cataloged by Ptolemy (c. AD 100-175) ...

Murdin, P.

2000-11-01

164

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

NASA Astrophysics Data System (ADS)

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 laser safety protocol for the outdoor use of lasers and assessment of the risks considered as part of outdoor laser propagation. We will show the results of Gemini's Aircraft Spotter program, and its continuous development over the past 5 years. As part of a continuous improvement activity Gemini in conjunction with the other laser equipped MK Observatories, Keck and Subaru, is currently testing the use of an all sky camera (ASCAM) to monitor the night sky and shutter the laser for air traffic over the Mauna Kea summit, HI. Use of the ASCAM is expected to increase the efficiency and accuracy of the aircraft spotting program. Gemini not only complies with, but strives to exceed the strict FAA rules for aircraft avoidance for outdoor laser propagation. The creation and implementation of the ASCAM is reviewed in this paper.

Archambeau, Jon; Oram, Richard; Sheehan, Michael

2010-07-01

165

Scientific and technical performance of GMOS: the Gemini Multi-Object Spectrograph  

Microsoft Academic Search

GMOS is the first telescope - spectrograph combination that acts as a complete system to deliver enhanced image quality and stability while simultaneously exploiting the large aperture of an 8m telescope. The entire system (optics, mechanics, software, detectors) was designed to take advantage of the best images that the Gemini telescopes produce while being extremely reliable and efficient. The built-in

David Crampton; Richard Murowinski

2004-01-01

166

Current and Future Facility Instruments at the Gemini Observatory Douglas A. Simons, Joseph B. Jensen, Peter Gray, Manuel Lazo, Rolando Rogers, John White  

E-print Network

directions Gemini's development program will go in the next 5-10 years, as our Community embarks upon a new, the Observatory has embarked upon the development of a bold new set of instruments through the so-called "Aspen , and Simons et al.4 ). Details of Gemini's Near Infrared Imager (NIRI5 ), Multi-object Spectrometer (GMOS6

167

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

168

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

169

Schirra, Stafford and Gemini on Deck  

NASA Technical Reports Server (NTRS)

Astronaut Walter H. Schirra Jr. (on right), Command pilot, climbs from his Gemini VI spacecraft as he and Astronaut Thomas P. Stafford (not in view) arrive aboard the aircraft carrier U.S.S. Wasp. They are assisted by various McDonell Douglas technicians. The Gemini VI spacecraft splashed down in the western Atlantic recover area at 10:29 a.m. (EST) December 16, 1965, after a successful 25 hr. 52 minute mission in space.

1965-01-01

170

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

171

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

172

The medical legacy of Gemini.  

PubMed

The Mercury and Gemini space flights have provided approximately 2,000 manhours of weightless exposure which can be used in comparing flight results with the predicted effects of manned space flight. In general the environmental hazards and the effects upon man appear to be of less magnitude than originally anticipated. The effects noted on the various body systems are summarized. The principal physiologic changes noted were orthostatism for some 50 hours post-flight, reduced red cell mass, and reduced X-ray density in the os calcis and the small finger. Much was learned about man's ability to work in a pressurized suit in the extravehicular condition. Early biochemical findings have pointed the way to future investigations. All of these findings are of importance in relation to the planning for future long duration missions. Although much remains to be learned, it does appear from an overview of this medical legacy that if man is properly supported and evaluated his limitations will not be a barrier to the exploration of the universe. PMID:11982022

Berry, C A

1968-01-01

173

Gemini primary mirror cell design  

NASA Astrophysics Data System (ADS)

To minimize the wind buffeting effect on the primary mirror figure, the Gemini primary mirror cell is designed to provide additional mirror stiffness by coupling the mirror to the cell structure through a six-zone hydraulic support system. Therefore the cell structure is designed as though it were a light weight mirror for minimum top surface distortion. This paper describes the design requirements, the design features, and the detail predicted performance of this cell structure, particularly the effects on the primary mirror figure. As the cell structure supports the primary mirror with a six-zone hydraulic system, the mirror is coupled to the cell structure with three degree of freedom overconstraints. These overconstraints induce the possible distortion on the mirror figure due to the cell deformation. This paper presents a solution to eliminate this effect by supporting the mirror cell on the telescope structure through four bipods. The locations of the bipods are so arranged that the cell deformation will not distort the mirror figure as the telescope rotates from zenith to horizon pointing.

Huang, Eugene W.

1997-03-01

174

Point spread function reconstruction on the Gemini Canopus bench  

NASA Astrophysics Data System (ADS)

This paper discusses an open loop, single-conjugate, point spread function reconstruction experiment performed with a bright calibration source and synthetic turbulence injected on the ground-level deformable mirror of the Multi Conjugate Adaptive Optics Canopus bench at Gemini South. Time histories of high-order Shack-Hartmann wavefront sensor slopes were recorded on the telemetry circular buffer, and time histories of short exposure K-band point spread functions with and without turbulence injected were recorded with the Gemini South Adaptive Optics Imager. We discuss the processing of the data and show that the long exposure background- and tip/tilt-removed turbulence image can be reconstructed at a percent level accuracy from the tip/tilt-removed de-noised wavefront sensor slope covariance matrix and from the long exposure background- and tip/tilt-removed static image. Future experiments are planned with multiple calibration sources at infinite and finite range and turbulence injected on 2 deformable mirrors, aiming at validating the recently published point spread function reconstruction algorithm [Gilles et. al. Appl. Opt. 51, 7443 (2012)] for closed loop laser guide star multi-conjugate adaptive optics.

Gilles, Luc; Neichel, Benoit; Veran, Jean-Pierre; Ellerbroek, Brent

2013-12-01

175

Studying Extrasolar Planets with WFIRST  

NASA Astrophysics Data System (ADS)

The WFIRST mission will be a powerful tool for studying extrasolar planets. Through observations of gravitational microlensing, the mission will probe the demographics of extrasolar planetary systems. Its coronagraph will enable imaging and spectroscopic study of nearby planets. It will also be able to complement GAIA's astrometric measurements of masses and orbits of nearby planets.

Spergel, David N.

2014-06-01

176

Spatially resolved images of dust belt(s) around the planet-hosting subgiant ? CrB  

NASA Astrophysics Data System (ADS)

We present Herschel spatially resolved images of the debris disc orbiting the subgiant ? Coronae Borealis (? CrB). Not only are these the first resolved images of a debris disc orbiting a subgiant, but ? CrB is a rare example of an intermediate mass star where a detailed study of the structure of the planetary system can be made, including both planets and planetesimal belt(s). The only way to discover planets using the radial velocity technique around such stars is to observe `retired' A stars, which are cooler and slower rotators compared to their main-sequence counterparts. A planetary companion has already been detected orbiting the subgiant ? CrB, with revised parameters of msin i = 2.1 MJ and apl = 2.8 au (Johnson et al. 2008). We present additional Keck I HIRES (High Resolution Echelle Spectrometer) radial velocity measurements that provide evidence for a second planetary companion, alongside Keck II adaptive optics imaging that places an upper limit on the mass of this companion. Modelling of our Herschel images shows that the dust is broadly distributed, but cannot distinguish between a single wide belt (from 20 to 220 au) or two narrow dust belts (at around 40 and 165 au). Given the existence of a second planetary companion beyond ˜3 au it is possible that the absence of dust within ˜20 au is caused by dynamical depletion, although the observations are not inconsistent with depletion of these regions by collisional erosion, which occurs at higher rates closer to the star.

Bonsor, Amy; Kennedy, Grant M.; Crepp, Justin R.; Johnson, John A.; Wyatt, Mark C.; Sibthorpe, Bruce; Su, Kate Y. L.

2013-06-01

177

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

178

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.

179

Extrasolar Planets  

Microsoft Academic Search

None of the roughly one hundred hundred extrasolar planets found to date closely resembles the Solar System. Unlike the Solar System, most extrasolar planets are in eccentric orbits. The giant planets in the Solar System all orbit beyond 5 AU, while the known extrasolar planets (with one exception) all orbit within 4 AU, with several in extraordinarily small orbits with

P. Butler

2003-01-01

180

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

181

The Gemini Instrument Feasibilities Studies project  

NASA Astrophysics Data System (ADS)

The Gemini Instrument Feasibilities Studies (GIFS) project is part of a program that will provide a number of community-created science-driven instrumentation design study reports and presentations to the observatory, conforming to a number of desired principles.By the time of the AAS, Gemini will have received a number of proposals and will be evaluating them shortly afterwards with the expectation of placing 3 or more feasibility study contracts based on a facility instrument costing between USD 8,000,000 and USD 12,000,000. These instrument studies will provide synergies with new capabilities coming online (e.g. LSST, JWST, ALMA, etc)Following the project, Gemini together with the Gemini Science and Technical Advisory Committee (STAC) and input from the wider community will decide on the top-level instrument requirements for the next facility instrument (Gen4#3) and launch a targeted Request for Proposals to design, build, test and deliver a suitable instrument. Gemini expects to release an RfP for Gen4#3 in Q4 2015.Each feasibility study will include fully developed science case(s), optical, mechanical, electronic and software design elements at the conceptual level as needed to demonstrate the technical viability. In particular, each design study will thoroughly identify and mitigate key risks.Each study team will present a status summary presentation at the 2015 Meeting on the Science and Future of Gemini held in Toronto in June 2015. The final GIFS reports and presentations are expected in Sept 2015.We will discuss the status of GIFS and the currently plans for Gen4#3.

Hibon, Pascale; Goodsell, Stephen J.; Hardie, Kayla

2015-01-01

182

Remote monitoring: An implementation on the Gemini System  

SciTech Connect

The Gemini System consists of a sophisticated, digital surveillance unit and a high performance review system. Due to the open architectural design of the Gemini System, it provides an excellent hardware and software platform to support remote monitoring. The present Gemini System provides the user with the following Remote Monitoring features, via a modem interface and powerful support software: state-of-health reporting, alarm reporting, and remote user interface. Future enhancements will contribute significantly to the Gemini`s ability to provide a broader spectrum of network interfaces and remote review.

Sheridan, R.; Ondrik, M.; Kadner, S.; Resnik, W. [Aquila Technologies Group, Inc., Albuquerque, NM (United States); Chitumbo, K. [International Atomic Energy Agency, Vienna (Austria); Corbell, B. [Sandia National Labs., Albuquerque, NM (United States)

1996-12-31

183

A First-look Atmospheric Modeling Study of the Young Directly Imaged Planet-mass Companion, ROXs 42Bb  

NASA Astrophysics Data System (ADS)

We present and analyze JKsL' photometry and our previously published H-band photometry and K-band spectroscopy for ROXs 42Bb, an object Currie et al. first reported as a young directly imaged planet-mass companion. ROXs 42Bb exhibits IR colors redder than field L dwarfs but consistent with other planet-mass companions. From the H2O-2 spectral index, we estimate a spectral type of L0 ± 1; weak detections/non-detections of the CO bandheads, Na I, and Ca I support evidence for a young, low surface gravity object primarily derived from the H2(K) index. ROXs 42Bb's photometry/K-band spectrum are inconsistent with limiting cases of dust-free atmospheres (COND) and marginally inconsistent with the AMES/DUSTY models and the BT-SETTL models. However, ROXS 42Bb data are simultaneously fit by atmosphere models incorporating several micron-sized dust grains entrained in thick clouds, although further modifications are needed to better reproduce the K-band spectral shape. ROXs 42Bb's best-estimated temperature is T eff ~ 1950-2000 K, near the low end of the empirically derived range in Currie et al. For an age of ~1-3 Myr and considering the lifetime of the protostar phase, ROXs 42Bb's luminosity of log(L/L ?) ~ -3.07 ± 0.07 implies a mass of 9^{+3}_{-3} MJ , making it one of the lightest planetary-mass objects yet imaged.

Currie, Thayne; Burrows, Adam; Daemgen, Sebastian

2014-06-01

184

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

185

First Light LBT AO Images of HR 8799 bcde at 1.6 and 3.3 ?m: New Discrepancies between Young Planets and Old Brown Dwarfs  

NASA Astrophysics Data System (ADS)

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 ?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 ?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 ?m compared to the equilibrium chemistry models used for field brown dwarfs, which predict that planets should be faint at 3.3 ?m due to CH4 opacity. We attempt to model the planets with thick-cloudy, non-equilibrium chemistry atmospheres but find that removing CH4 to fit the 3.3 ?m photometry increases the predicted L' (3.8 ?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. The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are as follows: The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di AstroÞsica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

Skemer, Andrew J.; Hinz, Philip M.; Esposito, Simone; Burrows, Adam; Leisenring, Jarron; Skrutskie, Michael; Desidera, Silvano; Mesa, Dino; Arcidiacono, Carmelo; Mannucci, Filippo; Rodigas, Timothy J.; Close, Laird; McCarthy, Don; Kulesa, Craig; Agapito, Guido; Apai, Daniel; Argomedo, Javier; Bailey, Vanessa; Boutsia, Konstantina; Briguglio, Runa; Brusa, Guido; Busoni, Lorenzo; Claudi, Riccardo; Eisner, Joshua; Fini, Luca; Follette, Katherine B.; Garnavich, Peter; Gratton, Raffaele; Guerra, Juan Carlos; Hill, John M.; Hoffmann, William F.; Jones, Terry; Krejny, Megan; Males, Jared; Masciadri, Elena; Meyer, Michael R.; Miller, Douglas L.; Morzinski, Katie; Nelson, Matthew; Pinna, Enrico; Puglisi, Alfio; Quanz, Sascha P.; Quiros-Pacheco, Fernando; Riccardi, Armando; Stefanini, Paolo; Vaitheeswaran, Vidhya; Wilson, John C.; Xompero, Marco

2012-07-01

186

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

187

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.

188

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.

2007-04-14

189

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

190

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

191

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.

192

Ultraviolet stellar spectroscopy on gemini 11.  

PubMed

Objective-prism and objective-grating spectrograms were obtained in six star fields during the Gemini 11 mission. The grating spectra show absorption lines in the 2000 to 3000 angstrom wavelength region of Canopus and Sirius and provide ultraviolet-energy distribution data for approximately 50 stars. Many prism spectra show the Balmer discontinuity due to hydrogen and two absorption features probably due to ultraviolet iron multiplets. PMID:17839611

Henize, K G; Wackerling, L R; O'callaghan, F G

1967-03-17

193

Multiconjugate adaptive optics for Gemini-South  

Microsoft Academic Search

The multi-conjugate adaptive optics (MCAO) system design for the Gemini-South 8-meter telescope will provide near-diffraction-limited, highly uniform atmospheric turbulence compensation at near-infrared wavelengths over a 2 arc minute diameter field-of-view. The design includes three deformable mirrors optically conjugate to ranges of 0, 4.5, and 9.0 kilometers with 349, 468, and 208 actuators, five 10-Watt-class sodium laser guide stars (LGSs) projected

Brent L. Ellerbroek; François J. Rigaut; Brian J. Bauman; Corinne Boyer; Stephen L. Browne; Richard A. Buchroeder; James W. Catone; Paul Clark; Céline d'Orgeville; Donald T. Gavel; Glen Herriot; Mark R. Hunten; Eric James; Edward J. Kibblewhite; Iain T. McKinnie; James T. Murray; Didier Rabaud; Leslie K. Saddlemyer; Jacques Sebag; James Stillburn; John M. Telle; Jean-Pierre Veran

2003-01-01

194

Cryostat design and fabrication for the Gemini NIRI instrument  

NASA Astrophysics Data System (ADS)

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 are stress relieved to maintain dimensional stability and good optical alignment. The thermal insulation includes floating shields and cold shields. Two closed-cycle coolers are mounted opposite to each other and electronically synchronized in order to cancel the vibration caused by the oscillating expansion valve. Several different fabrication methods and stress relief methods are discussed.

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

1998-08-01

195

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

196

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

NASA Astrophysics Data System (ADS)

We present 880 ?m 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 0farcs34, 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 ~0.1 M Jup of millimeter-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 to 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. Based on observations carried out with the Submillimeter Array and the IRAM Plateau de Bure Interferometer. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).

Mathews, Geoffrey S.; Williams, Jonathan P.; Ménard, Francois

2012-07-01

197

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

198

Planet hop  

NSDL National Science Digital Library

In this interactive game, students find the coordinates of four planets shown on the grid or locate the planets when given the coordinates. Finally, they must find the slope and y-intercept of the line connecting the planets in order to write its equation. Players select one of three levels of difficulty. Tips for students are available as well as a full explanation of the key instructional ideas underlying the game.

2007-12-12

199

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

200

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.

201

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.

202

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.

203

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

204

VizieR Online Data Catalog: Kepler planet host candidates imaging (Lillo-Box+, 2014)  

NASA Astrophysics Data System (ADS)

We applied the lucky imaging technique to the selected targets to achieve diffraction-limited resolution. We used the AstraLux North instrument located at the 2.2m telescope at the Calar Alto Observatory (Almeria, Spain). The targets were observed along three visibility windows of the Kepler field during 2011, 2012, and 2013. The results regarding the non-isolated KOIs of observations on 2011 were published in Lillo-Box et al. (2012A&A...546A..10L, Cat. J/A+A/546/A10). In the present work, we report the results concerning the isolated candidates observed in 2011 and the new results for the 2012-2013 observing runs. (5 data files).

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

2014-09-01

205

FFREE: a Fresnel-FRee Experiment for EPICS, the EELT planets imager  

E-print Network

The purpose of FFREE - the new optical bench devoted to experiments on high-contrast imaging at LAOG - consists in the validation of algorithms based on off-line calibration techniques and adaptive optics (AO) respectively for the wavefront measurement and its compensation. The aim is the rejection of the static speckles pattern arising in a focal plane after a diffraction suppression system (based on apodization or coronagraphy) by wavefront pre-compensation. To this aim, FFREE has been optimized to minimize Fresnel propagation over a large near infrared (NIR) bandwidth in a way allowing efficient rejection up to the AO control radius, it stands then as a demonstrator for the future implementation of the optics that will be common to the scientific instrumentation installed on EPICS.

Antichi, Jacopo; Preis, Olivier; Delboulbé, Alain; Zins, Gérard; Rabou, Patrick; Beuzit, Jean-Luc; Dandy, Sarah; Sauvage, Jean-François; Fusco, Thierry; Aller-Carpentier, Emmanuel; Kasper, Markus; Hubin, Norbert

2010-01-01

206

ASSOCIATION OF UNIVERSITIES FOR RESEARCH IN ASTRONOMY, INC. AURA OVERSIGHT COUNCIL FOR GEMINI / GEMINI SCIENCE COMMITTEE  

E-print Network

] · Current Status · Future Plans 12h30 Lunch Begin User's Meeting 13h30 Science operations overview and NGO, October 24-26, 2005, 3 of 4 14h00 June 2007 Users Meeting, Gemini/NGO staff meeting and NGO User Issues [V

Crowther, Paul

207

The Gemini MCAO bench: system overview and lab integration  

Microsoft Academic Search

We present Canopus, the AO bench for Gemini's Multi Conjugate Adaptive Optics System (GEMS), a unique facility for the Gemini South telescope located at Cerro Pachon in Chile. The MCAO system uses five laser beacons in conjunction with different natural guide stars configurations. A deployable fold mirror located in the telescope Acquisition and Guiding Unit (A&G) sends the telescope beam

Matthieu Bec; Francois J. Rigaut; Ramon Galvez; Gustavo Arriagada; Maxime Boccas; Gaston Gausachs; Damien Gratadour; Eric James; Roberto Rojas; Rolando Rogers; Michael P. Sheehan; Gelys Trancho; Tomislav Vucina

2008-01-01

208

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.

209

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

210

Piercing the Glare: A Direct Imaging Search for Planets in the Sirius System  

NASA Astrophysics Data System (ADS)

Astrometric monitoring of the Sirius binary system over the past century has yielded several predictions for an unseen third system component, the most recent one suggesting a lsim50 M Jup object in a ~6.3 year orbit around Sirius A. Here we present two epochs of high-contrast imaging observations performed with Subaru IRCS and AO188 in the 4.05 ?m narrowband Br ? filter. These data surpass previous observations by an order of magnitude in detectable companion mass, allowing us to probe the relevant separation range down to the planetary-mass regime (6-12 M Jup at 1'', 2-4 M Jup at 2'', and 1.6 M Jup beyond 4''). We complement these data with one epoch of M-band observations from MMT/AO Clio, which reach comparable performance. No data set reveals any companion candidates above the 5? level, allowing us to refute the existence of Sirius C as suggested by the previous astrometric analysis. Furthermore, our Br ? photometry of Sirius B confirms the lack of an infrared excess beyond the white dwarf's blackbody spectrum. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan, and at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution.

Thalmann, C.; Usuda, T.; Kenworthy, M.; Janson, M.; Mamajek, E. E.; Brandner, W.; Dominik, C.; Goto, M.; Hayano, Y.; Henning, T.; Hinz, P. M.; Minowa, Y.; Tamura, M.

2011-05-01

211

PIERCING THE GLARE: A DIRECT IMAGING SEARCH FOR PLANETS IN THE SIRIUS SYSTEM  

SciTech Connect

Astrometric monitoring of the Sirius binary system over the past century has yielded several predictions for an unseen third system component, the most recent one suggesting a {approx}<50 M{sub Jup} object in a {approx}6.3 year orbit around Sirius A. Here we present two epochs of high-contrast imaging observations performed with Subaru IRCS and AO188 in the 4.05 {mu}m narrowband Br {alpha} filter. These data surpass previous observations by an order of magnitude in detectable companion mass, allowing us to probe the relevant separation range down to the planetary-mass regime (6-12 M{sub Jup} at 1'', 2-4 M{sub Jup} at 2'', and 1.6 M{sub Jup} beyond 4''). We complement these data with one epoch of M-band observations from MMT/AO Clio, which reach comparable performance. No data set reveals any companion candidates above the 5{sigma} level, allowing us to refute the existence of Sirius C as suggested by the previous astrometric analysis. Furthermore, our Br {alpha} photometry of Sirius B confirms the lack of an infrared excess beyond the white dwarf's blackbody spectrum.

Thalmann, C.; Dominik, C. [Anton Pannekoek Astronomical Institute, University of Amsterdam (Netherlands); Usuda, T.; Hayano, Y.; Minowa, Y. [Subaru Telescope, Hilo, Hawai'i (United States); Kenworthy, M. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Janson, M. [Department of Astronomy and Astrophysics, University of Toronto, Toronto (Canada); Mamajek, E. E. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Brandner, W.; Goto, M.; Henning, T. [Max Planck Institute for Astronomy, Heidelberg (Germany); Hinz, P. M. [Steward Observatory, University of Arizona, Tucson, AZ (United States); Tamura, M., E-mail: thalmann@uva.nl [National Astronomical Observatory of Japan, Tokyo (Japan)

2011-05-10

212

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

213

Searching For Planets in "Holey Debris Disks"  

NASA Astrophysics Data System (ADS)

Directly imaging planets provides a unique opportunity to study young planets in the context of their formation and evolution. It examines the underlying semi-major axis exoplanet distribution and enables the characterization of the planet itself with spectroscopic examination of its emergent flux. However, only a handful of planets have been directly imaged, and thus the stars best suited for planet imaging are still a subject of debate. The "Holey Debris Disk" project was created in order to help determine if debris disks with gaps are signposts for planets. These gaps may be dynamically caused by planets accreting the debris material as they form. We present the results from our survey with VLT/NACO and the apodized phase plate coronagraph. We demonstrate that these disks with holes are good targets for directly detecting planets with the discovery of a planet around two of our targets, HD 95086 and HD 106906, at L’-band. Our non-detection of HD 95086 b in H-band demonstrates the importance of thermal infrared observations. The detected planets shepherd the outer cool debris belt. The relatively dust-free gap in these disks implies the presence of one or more closer-in planets. We discuss our new constraints on planets around other targets in our survey as well as disk properties of these targets and describe how future instruments will find the inner planets.

Meshkat, Tiffany; Bailey, Vanessa P.; Su, Kate Y. L.; Kenworthy, Matthew A.; Mamajek, Eric E.; Hinz, Philip; Smith, Paul S.

2015-01-01

214

EXCEDE: The Exoplanetary Circumstellar Environment And Disk Explorer Utilizing A Phase Induced Amplitude Apodized Coronagraphic Telescope For High Contrast Imaging Of Circumstellar Planet-forming Environments  

NASA Astrophysics Data System (ADS)

We describe the Exoplanetary Circumstellar Environment and Disk Explorer (EXCEDE) SMEX mission to directly image starlight-scattering circumstellar material in the planet-forming regions of stars exhibiting thermal infrared emission above their stellar photospheric levels (a signpost of planetary systems in formation). EXCEDE will provide contrast-limited scattered-light detection sensitivities 100 to 1000 times more sensitive than the HST and JWST coronagraphs at a smaller inner working angle, enabling the exploration and characterization of exoplanetary circumstellar disk systems in currently inaccessible observational domains. Utilizing a laboratory-demonstrated high-performance Phase Induced Amplitude Apodized Coronagraph (PIAA-C), integrated with a small (0.5 meter diameter) unobscured aperture visible-light telescope, EXCEDE will provide unrivaled disk-to-star imaging contrast ratios of < 1:10,000,000 at a 1 lambda/d inner working angle of 0.2" with 200 mas spatial resolution at 0.4 microns. Such unprecedented spatially-resolved circumstellar disk images will enable determinations of disk characteristics (mass, geometry, surface brightness, grain properties) for stars over a wide range of stellar mass and age, providing a unique and comprehensive dataset to understand the formation and evolution of extrasolar planetary systems. Concomitantly, EXCEDE will provide unparalleled imagery of those rare debris disks previously resolved with inferior capabilities. These "Rosetta stones" are the basis of our current understanding of planetary disk systems and EXCEDE/PIAA-C observations will overcome current limitations that thus-far have resulted in significant model degeneracies. EXCEDE will also directly image and characterize extrasolar giant planets with orbital distances as small as 1.5 AU and disk sub-structures influenced by co-orbiting planets - for the first time within the terrestrial planet zone (< 5 AU) around the nearest targets. EXCEDE is a science-driven technology pathfinder and demonstrator for subsequent planet-finding and characterization missions that will also provide future missions (e.g., JWST/MIRI & TPF-C) well-honed targets sets for follow-on and multi-wavelength investigations.

Greene, Thomas P.; Schneider, G.; Science, EXCEDE; Mission Team

2007-12-01

215

Gravity and Topography of Moon and Planets  

Microsoft Academic Search

Planetology serves the understanding on the one hand of the solar system and on the other hand, for investigating similarities and differences, of our own planet. While observational evidence about the outer planets is very limited, substantial datasets exist for the terrestrial planets. Radar and optical images and detailed models of gravity and topography give an impressive insight into the

R. Rummel

2004-01-01

216

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.

217

Tumbling and spaceflight: the Gemini VIII experience.  

PubMed

A malfunctioning orbital flight attitude thruster during the flight of Gemini VIII led to acceleration forces on astronauts Neil Armstrong (commander) and David Scott (pilot) that created the potential for derogation of oculo-vestibular and eye-hand coordination effects. The spacecraft attained an axial tumbling rotation of 50 rpm and would have exceeded this had not the commander accurately diagnosed the problem and taken immediate corrective action. By the time counter-measure controls were applied, both astronauts were experiencing vertigo and the physiological effects of the tumbling acceleration. Data from the recorders reveal that one astronaut experienced -Gy of 0.92 G-units, and the other +Gy of 0.92 for approximately 46 s. Both received a -Gz of 0.89 G-units from the waist up with a +Gz of 0.05 from the waist down. A substantial increase of time and/or an increase in rpm would ultimately have produced incapacitation of both astronauts. NASA corrected the Gemini thruster problem by changing the ignition system wiring. Future space-craft undertaking long-term missions could be equipped with unambiguous thruster fault displays and could have computer-controlled automatic cutoffs to control excessive thruster burns. PMID:2302130

Mohler, S R; Nicogossian, A E; McCormack, P D; Mohler, S R

1990-01-01

218

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

219

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.

1991-01-01

220

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

221

Deep Thermal Infrared Imaging of HR 8799 bcde: New Atmospheric Constraints and Limits on a Fifth Planet  

E-print Network

We present new $L^\\prime$ (3.8 $\\mu m$) and Br-$\\alpha$ (4.05 $\\mu m$) data and reprocessed archival $L^\\prime$ data for the young, planet-hosting star HR 8799 obtained with Keck/NIRC2, VLT/NaCo and Subaru/IRCS. We detect all four HR 8799 planets in each dataset at a moderate to high signal-to-noise (SNR $\\gtrsim$ 6-15). We fail to identify a fifth planet, "HR 8799 f", at $r$ $planet cooling models, we rule out an HR 8799 f with mass of 5 $M_{J}$ (7 $M_{J}$), 7 $M_{J}$ (10 $M_{J}$), and 12 $M_{J}$ (13 $M_{J}$) at $r_{proj}$ $\\sim$ 12 $AU$, 9 $AU$, and 5 $AU$, respectively. All four HR 8799 planets have red early T dwarf-like $L^\\prime$ - [4.05] colors, suggesting that their SEDs peak in between the $L^\\prime$ and $M^\\prime$ broadband filters. We find no statistically significant difference in HR 8799 ...

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

2014-01-01

222

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.

223

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).

224

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.

225

Irregular Satellites of the Planets  

NASA Technical Reports Server (NTRS)

This proposal is directed towards the observational exploration of the irregular satellite systems of the planets. Primarily we use large-format CCD cameras on the world's largest telescopes, on Mauna Kea, to discover new irregular satellites and then to monitor their positions in order to ascertain their orbital characteristics. Separate observations are taken to determine the physical properties of the irregular satellites. The big picture science objective is to determine how these satellites were captures, and to use the properties of the satellites and their orbits to place constraints on early solar system (including formation) processes. Work in the first year has focussed on a major investigation of the Saturn irregular satellite system. We secured observing time on the Subaru and Gemini 8-m diameter telescopes in December 2004, January, February and March 2005 for the conduct of a deep, wide-area survey. This has resulted in the detection and orbit determination for 12 new satellites to be announced in the next week or two. Additional satellites were lost, temporarily, due to unusually poor weather conditions on Mauna Kea. These objects will be recovered and their orbits published next year. A separate survey of the Uranus irregular satellites was published (Sheppard, Jewitt and Kleyna 2005). Away from the telescope, we have discovered the amazing result that the four giant planets possess similar numbers of irregular satellites. This flies in the face of the standard gas-drag model for satellite capture, since only two of the giant planets are gas giants and the others (Uranus and Neptune) formed by a different process and in the absence of much gas. The constancy of the satellite number (each giant holds approximately 100 irregular satellites measured down to the kilometer scale) is either a coincidence, with different capture mechanisms at different planets giving by chance the same total numbers of irregular satellites, or indicates that the satellites were captured by a completely different process. We favor the latter (Jewitt and Sheppard 2005).

Jewitt, David

2005-01-01

226

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

227

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

228

Gemini multiobject spectrograph: a flexure critical design  

NASA Astrophysics Data System (ADS)

Each of the two Gemini telescopes will be instrumented with the Gemini Multi-Object Spectrograph (GMOS), a general purpose optical spectrograph mounted at one of the Cassegrain foci. Two GMOS are currently being designed and built by a team of scientists and engineers in Canada and in the UK. A stringent flexure specification is imposed on these instruments by the scientific requirement to measure velocity to high precision, 2 km/s at R equals 5,000 with 0.5 arcsec slits. This implies a basic stability specification of 3.125 micrometer/hour at the detector focal plane. The GMOS design has met this specification by using a combination of stiff structure (where flexure is minimized); Serrurier trusses (where the flexure is controlled); precision mechanisms (where mechanical hysteresis and error are minimized) and, finally, an open-loop active correction system at the detector focal plane (where the CCD is translated to counteract any residual flexure). Once the GMOS design was conceptualized and its component groups were identified, the design team divided the basic stability specification into allowable contribution from each group. The final division was weighted according to the degree of design difficulty, based on inputs from the engineers. An error budget was developed and maintained to ensure that GMOS would meet its overall flexure specification by controlling the contribution from each component. The error budget approach will be described and discussed in the paper. We will also look at examples from the GMOS design with reference to calculations, analyses, FEA and actual measurements from prototype components.

Szeto, Kei; Murowinski, Richard G.; Roberts, Scott; Saddlemyer, Leslie; Bennett, Richard; Dickson, Colin G.; Hastings, Peter

1998-07-01

229

Food packets for use on the Gemini 3 flight  

NASA Technical Reports Server (NTRS)

Food packets for use on the Gemini 3 flight including dehydrated beef pot roast, bacon and egg bites, toasted bread cubes, orange juice and a wet wipe. Water is being inserted into the pouch of dehydrated food.

1965-01-01

230

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

231

GEMINI: integrative exploration of genetic variation and genome annotations.  

PubMed

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

232

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

233

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 ...

Moeai, Ms.

2007-05-07

234

Giant Planets  

E-print Network

We review the interior structure and evolution of Jupiter, Saturn, Uranus and Neptune, and giant exoplanets with particular emphasis on constraining their global composition. Compared to the first edition of this review, we provide a new discussion of the atmospheric compositions of the solar system giant planets, we discuss the discovery of oscillations of Jupiter and Saturn, the significant improvements in our understanding of the behavior of material at high pressures and the consequences for interior and evolution models. We place the giant planets in our Solar System in context with the trends seen for exoplanets.

Guillot, Tristan

2014-01-01

235

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

236

Properties of Ellipticity Correlation with Atmospheric Structure from Gemini South  

E-print Network

Cosmic shear holds great promise for a precision independent measurement of $\\Omega\\rm_m$, 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.

S. Asztalos; W. H. de Vries; L. J Rosenberg; T. Treadway; D. Burke; C. Claver; A. Saha; P. Puxley

2007-01-06

237

A New Family of Planets ? "Ocean Planets"  

E-print Network

A new family of planets is considered which is between rochy terrestrial planets and gaseous giant ones: "Ocean-Planets". We present the possible formation, composition and internal models of these putative planets, including that of their ocean, as well as their possible Exobiology interest. These planets should be detectable by planet detection missions such as Eddington and Kepler, and possibly COROT (lauch scheduled in 2006). They would be ideal targets for spectroscopic missions such as Darwin/TPF.

A. Leger; F. Selsis; C. Sotin; T. Guillot; D. Despois; H. Lammer; M. Ollivier; F. Brachet; A. Labeque; C. Valette

2003-08-19

238

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.

239

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.

Giesen, Juergen

240

Building Planet Earth  

NASA Astrophysics Data System (ADS)

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 action-packed blockbuster can be experienced in Building Planet Earth. Peter Cattermole begins the story by describing a cloud of matter that surrounds a primitive Sun. Out of this the Earth was formed through compaction and internal heating to the point at which it became a stable, layered structure with a core, mantle, and crust. Using eye-catching images, artwork, and diagrams, Building Planet Earth presents this geological development and goes on to discuss what is happening to our planet now and what we can expect in the future. Cattermole covers in fascinating detail the impact of mass extinctions, global-warming, and ozone holes. The book features 241 illustrations--128 in full-color--and a number of useful appendices. For anyone who has ever wondered how this miraculous planet continues to thrive and surprise, this elegantly-written book will be an essential read. Peter Cattermole is a principal investigator with NASA's Planetary Geology and Geophysics Program. He has written several books on geology and astronomy as well as numerous articles for both scholarly and popular media, including Atlas of Venus (Cambridge University Press, 1997) and The Story of the Earth (Cambridge University Press, 1985).

Cattermole, Peter

2000-03-01

241

Survival and Detectability of Long Period Planets Beyond 100 AU  

Microsoft Academic Search

Direct imaging searches have begun to detect planetary and brown dwarf companions and to place constraints on the presence of giant planets at large separations from their host star. This work helps to motivate such planet searches by predicting a population of young giant planets that could be detectable by direct imaging campaigns. Both the classical core accretion and the

D. Veras; J. R. Crepp; E. B. Ford

2010-01-01

242

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

243

Spinning Stardust into Planets  

NASA Technical Reports Server (NTRS)

A computerized animation simulates the formation of a stellar disk and planets. Ten images from the Hubble Space Telescope (HST) show young stellar disks (taken with the Near-Infrared Camera Multi-Object Spectrometer (NICMOS)) and stellar disks around young stars (taken with the Wide-Field Planetary Camera 2 (WFPC2)). Dr. Deborah Padgett describes what astronomers see in the images of young stellar disks and Dr. Karl Stapelfeldt explains HST's role in helping astronomers to examine young stars in order to understand how solar systems like our own may form.

2001-01-01

244

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.

245

Lonely Planet  

NSDL National Science Digital Library

"Don't worry about whether your trip will work out. Just go!" This is the travel philosophy of Lonely Planet, one of the most respected publishers of off-the-beaten-path travel guidebooks worldwide. Whether you already know where you're going, or are looking for suggestions for your next trip, Lonely Planet's site is packed with information that you can actually use to plan your trip. Search or browse the section "DestiNATIONS" to find maps, facts and figures, and information on local history, culture, and transportation for 8 world regions, over 80 countries, and 20 different cities. Much of the health information found in LP's print guides is also now available here. In addition, there are links to destination-related newsgroups, tips on travel photography, and "Postcards," a forum in which travelers share experiences and give advice.

246

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.

Science, Lawrence H.

2011-01-01

247

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.

2002-01-01

248

Planet Size Comparison  

NSDL National Science Digital Library

This interactive feature lets students compare the sizes of the planets in our solar system. Users can select two solar system bodies (planets, Sun, Earth's moon) and view side-by-side images at the same scale, along with their diameters in kilometers or miles, and a ratio. Science NetLinks is part of MarcoPolo, a partnership between the Verizon Foundation and eight premier educational organizations. The MarcoPolo partnership provides free, Internet-based content across academic disciplines. Science NetLinks is managed by the American Association for the Advancement of Science (AAAS) and its role is to provide a wealth of standards-based resources for K-12 science educators, including lesson plans, interactives and reviewed Internet resources.

249

Planet Size Comparison  

NSDL National Science Digital Library

This interactive feature lets students compare the sizes of the planets in our solar system. Users can select two solar system bodies (planets, Sun, Earth's moon) and view side-by-side images at the same scale, along with their diameters in kilometers or miles, and a ratio. Science NetLinks is part of MarcoPolo, a partnership between the Verizon Foundation and eight premier educational organizations. The MarcoPolo partnership provides free, Internet-based content across academic disciplines. Science NetLinks is managed by the American Association for the Advancement of Science (AAAS) and its role is to provide a wealth of standards-based resources for K-12 science educators, including lesson plans, interactives and reviewed Internet resources.

2010-11-19

250

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.

251

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

E-print Network

like Gemini North and Gemini South require minimum laser output power in the 10 W range. Since each optimized parameters in the case of continuous wave lasers and high repetition rate pulsed lasers. LaserLGS AO photon return simulations and laser requirements for the Gemini LGS AO program C. d

252

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.

253

Simulating Planet-Hunting in a Lab  

NASA Technical Reports Server (NTRS)

Three simulated planets -- one as bright as Jupiter, one half as bright as Jupiter and one as faint as Earth -- stand out plainly in this image created from a sequence of 480 images captured by the High Contrast Imaging Testbed at JPL. A roll-subtraction technique, borrowed from space astronomy, was used to distinguish planets from background light. The asterisk marks the location of the system's simulated star.

2007-01-01

254

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

255

Terrestrial Planets  

NASA Astrophysics Data System (ADS)

The four terrestrial planets (Mercury, Venus, Earth, and Mars) and Earth's Moon display similar compositions, interior structures, and geologic histories. The terrestrial planets formed by accretion ˜ 4.5 Ga ago out of the solar nebula, whereas the Moon formed through accretion of material ejected off Earth during a giant impact event shortly after Earth formed. Geophysical investigations (gravity anomalies, seismic analysis, heat flow measurements, and magnetic field studies) reveal that all five bodies have differentiated into a low-density silicate crust, an intermediate density silicate mantle, and an iron-rich core. Seismic and heat flow measurements are only available for Earth and its Moon, and only Earth and Mercury currently exhibit actively produced magnetic fields (although Mars and the Moon retain remanent fields). Surface evolutions of all five bodies have been influenced by impact cratering, volcanism, tectonism, and mass wasting. Aeolian activity only occurs on bodies with a substantial atmosphere (Venus, Earth, and Mars) and only Earth and Mars display evidence of fluvial and glacial processes. Earth's volcanic and tectonic activity is largely driven by plate tectonics, whereas those processes on Venus result from vertical motions associated with hotspots and mantle upwellings. Mercury displays a unique tectonic regime of global contraction caused by gradual solidification of its large iron core. Early large impact events stripped away much of Mercury's crust and mantle, produced Venus' slow retrograde rotation, ejected material off Earth that became the Moon, and may have created the Martian hemispheric dichotomy. The similarities and differences between the interiors and surfaces of these five bodies provide scientists with a better understanding of terrestrial planet evolutionary paths.

Barlow, Nadine G.

256

Gemini 4 astronauts relax aboard Navy helicopter after recovery  

NASA Technical Reports Server (NTRS)

Gemini 4 astronauts, James A. McDivitt (right), command pilot, and Edward H. White II, (left), pilot, relax aboard a U.S. Navy helicopter on their way to the aircraft carrier U.S.S. Wasp after recovery from the Gemini 4 spacecraft. They had been picked up out of the Atlantic Ocean following a successful splashdown (33532); White (left) and McDivitt listen to the voice of President Lyndon B. Johnson as he congratulated them by telephone on the successful mission. They are shown aboard the carrier U.S.S. Wasp just after their recovery (33533).

1965-01-01

257

The Software Distribution for Gemini Observatory's Science Operations Group  

NASA Astrophysics Data System (ADS)

Gemini Observatory consists of two telescopes in different hemispheres. It also operates mostly on a queue observing model, meaning observations are performed by staff working shifts as opposed to PIs. For these two reasons alone, maintaining and distributing a diverse software suite is not a trivial matter. We present a way to make the appropriate tools available to staff at Gemini North and South, whether they are working on the summit or from our base facility offices in Hilo, Hawai'i and La Serena, Chile.

Hoenig, M. D.; Clarke, M.; Pohlen, M.; Hirst, P.

2014-05-01

258

Thermal emissivity analysis of a GEMINI 8-meter telescopes design  

NASA Technical Reports Server (NTRS)

The GEMINI 8-meter Telescopes Project is designing twin 8-meter telescopes to be located in Hawaii and Chile. The GEMINI telescopes will have interchangeable secondary mirrors for use in the visible and IR. The APART/PADE program is being used to evaluate the effective IR emissivity of the IR configuration plus enclosure as a function of mirror contamination at three IR wavelengths. The goal is to design a telescope whose effective IR emissivity is no more than 2 percent when the mirrors are clean.

St. Clair Dinger, Ann

1993-01-01

259

Planet Earth  

NSDL National Science Digital Library

How does the Earth work? What is its relationship to the other planets? These are but a few important questions answered by this creative instructional series created by WQED in Pittsburgh, in association with the National Academy of Sciences. The series was designed to present information about "our solar system and Earth's oceans, climate, and mineral and energy sources." The Annenberg Media group has placed this entire series online, and visitors can view all seven installments here. The programs include "The Climate Puzzle", "Gifts from the Earth", and "The Solar Sea". Teachers will note that the site also contains links to other educational resources, reviews, and related resources from the Annenberg Media organization.

1986-01-01

260

Studying the Sky/Planets Can Drown You in Images: Machine Learning Solutions at JPL/Caltech  

NASA Technical Reports Server (NTRS)

JPL is working to develop a domain-independent system capable of small-scale object recognition in large image databases for science analysis. Two applications discussed are the cataloging of three billion sky objects in the Sky Image Cataloging and Analysis Tool (SKICAT) and the detection of possibly one million small volcanoes visible in the Magellan synthetic aperture radar images of Venus (JPL Adaptive Recognition Tool, JARTool).

Fayyad, U. M.

1995-01-01

261

Quick-MESS: A Fast Statistical Tool for Exoplanet Imaging Surveys  

NASA Astrophysics Data System (ADS)

Several tools have been developed in the past few years for the statistical analysis of the exoplanet search surveys, mostly using a combination of Monte Carlo simulations or a Bayesian approach. Here we present Quick-MESS, a grid-based, non-Monte Carlo tool aimed to perform statistical analyses on results from direct imaging surveys, as well as help with the planning of these surveys. Quick-MESS uses the (expected) contrast curves for direct imaging surveys to assess for each target the probability that a planet of a given mass and semimajor axis can be detected. By using a grid-based approach, Quick-MESS is typically more than an order of magnitude faster than tools based on Monte Carlo sampling of the planet distribution. In addition, Quick-MESS is extremely flexible, enabling the study of a large range of parameter space for the mass and semimajor axes distributions without the need of resimulating the planet distribution. In order to show examples of the capabilities of Quick-MESS, we present the analysis of the Gemini Deep Planet Survey and the predictions for upcoming surveys with extreme-AO instruments.

Bonavita, M.; de Mooij, E. J. W.; Jayawardhana, R.

2013-07-01

262

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

263

Merging the CEM2k and LAQGSM Codes with GEMINI  

SciTech Connect

An improved version of the Cascade-Exciton Model (CEM) of nuclear reactions contained in the code CEM2k and the Los Alamos version of the Quark-Gluon String Model (LAQGSM) are merged with the well-known sequential-binary-decay model GEMINI by Charity. We present some results on proton-induced fragmentation, fission-product yields and on particle spectra predicted by these extended versions of CEM2k and LAQGSM. We show that merging CEM2k and LAQGSM with GEMINI allows us to describe many fission and fragmentation reactions in addition to the spallation and evaporation reactions which are already described well by these codes. Nevertheless, the current version of GEMINI merged with CEM2k and LAQGSM does not provide a completely satisfactory description of some complex-particle spectra, fragment emission, and spallation yields for some reactions, and is not yet a universal tool for applications. Our results show that GEMINI contains a powerful model to describe evaporation/fission/fragmentation reactions and often provides better results when compared to other models, especially for emission of heavy fragments from reactions on medium-heavy nuclei (where most other models simply fail), but it must be further extended and improved in order to properly describe arbitrary reactions.

Baznat, M.I.; Gudima, K.K. [Institute of Applied Physics, Academy of Science of Moldova, Chisinau, MD-2028 (Moldova, Republic of); Mashnik, S.G.; Prael, R.E. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2005-05-24

264

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

265

Gemini 12 crew arrives aboard U.S.S. Wasp  

NASA Technical Reports Server (NTRS)

A happy Gemini 12 prime crew arrives aboard the aircraft carrier, U.S.S. Wasp. Astronauts James A. Lovell Jr. (left), command pilot, and Edwin E. Aldrin Jr., pilot, had just been picked up from the splashdown area by helicopter.

1966-01-01

266

Young family together after the Gemini 3 mission  

NASA Technical Reports Server (NTRS)

Gemini-Titan 3 Astronaut John W. Young is shown with his wife and children after his return to Cape Kennedy, March 25, from the recovery ship, U.S.S. Intrepid. Shown (left to right) are Young's daughter, Sandra; his son, John; and his wife Barbara.

1965-01-01

267

Exceptional Swift and Fermi GRBs: Gemini North Targets of Opportunity  

Microsoft Academic Search

Swift and Fermi have led a renaissance in the study of GRBs, discovering an unprecedented number of events and promptly alerting the community to accurate localizations. However, it is in the follow-up, particularly at optical\\/infrared (OIR) wavebands, where the full scientific potential of these missions is realized. We propose to use the OIR instrument suite on both Gemini telescopes in

Bethany Cobb; Joshua Bloom; Brad Cenko; Daniel Perley; Hsiao-Wen Chen; Jason X. Prochaska; Karl Glazebrook; Chris Matzner; Sebastian Lopez; Max Pettini; Andrew Bunker; Adam Morgan; Maryam Modjaz; Dovi Poznanski; Charles Bailyn; Enrico Ramirez-Ruiz; Nat Butler; Adam Miller

2010-01-01

268

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

269

Three Ly? Emitters at z ~ 6: Early GMOS/Gemini Data from the GLARE Project  

NASA Astrophysics Data System (ADS)

We report spectroscopic detection of three z~6 Ly?-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 Ly?. 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-South spectra of these objects, obtained using nod and 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 version 1.0 imaging data. The red i'-z' colors and high equivalent widths of these objects suggest a high-confidence z>5 Ly? identification of the emission lines. This brings the total number of known z>5 galaxies within 9' of the Hubble Ultra Deep Field to four, of which three are at the same redshift (z=5.8 within 2000 km s-1), suggesting the existence of a large-scale structure at this redshift.

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

2004-03-01

270

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

271

A bright future for direct planets & disks  

E-print Network

A bright future for direct imaging of extrasolar planets & disks Olivier Guyon University) Atmosphere composition & structure Rotation period Habitability Orbit Asteroid belt Spectra / colors models albedo ? impact frequency surface temperature, pressure & composition ? tidal forces Measurements

Guyon, Olivier

272

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

273

A lopsided planet Photolibrary  

E-print Network

planet, about the size of Pluto. An asteroid that large can leave a serious dent in a planet>> A lopsided planet Photolibrary Where was the biggest impact in the Solar System? Rick Lovett by an asteroid. Nothing surprising in that: one look at the Red Planet's crater- pocked surface is enough

Nimmo, Francis

274

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

275

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

276

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

277

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

278

Interaction of bovine serum albumin with gemini surfactants.  

PubMed

The interactions between bovine serum albumin and cationic gemini surfactants were investigated as a function of concentration, under different pH conditions. The investigation deals with dielectric relaxation, dynamic light scattering, zeta-potential, circular dichroism, and UV spectroscopy. The interactive behavior of the anionic form is quite different from the cationic species. It indicates that protein-surfactant interactions are mostly electrostatic in nature and depend on the state of charge of bovine serum albumin. The results indicate the presence of both hydrophobic and electrostatic contributions in the interactions of gemini with bovine serum albumin. Comparison of dynamic light scattering, dielectric relaxation, electrophoretic mobility, and optical circular dichroism allows drawing some preliminary hypotheses on the different contributions to surfactant binding and supports former studies on the formation of complexes between the bovine serum albumin and the above species. PMID:20362296

Tardioli, Silvia; Bonincontro, Adalberto; La Mesa, Camillo; Muzzalupo, Rita

2010-07-01

279

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

280

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

281

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

282

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

283

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

284

Synthesis and Properties of Novel Alkyl Sulfonate Gemini Surfactants  

Microsoft Academic Search

A series of novel dialkyl disulfonate gemini surfactants (2Cn-SCT where n is the carbon number of the hydrophobic chain) were synthesized from cyanuric chloride, aliphatic amine and taurine.\\u000a The chemical structures of the prepared compounds were confirmed by 1H NMR, 13C NMR, IR spectra, and ESI–MS. Their critical micelle concentrations (CMC) in the aqueous solutions at 25 °C were determined\\u000a by

Xin Li; Zhiyong Hu; Hailin Zhu; Sufen Zhao; Duanlin Cao

2010-01-01

285

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

286

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

287

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

288

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

NASA Astrophysics Data System (ADS)

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

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

2005-08-01

289

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

290

The complex morphologies of Ti-MCM-41 templated by Gemini surfactant  

SciTech Connect

The ordered hexagonal mesoporous materials of Ti-MCM-41 have been synthesized by using the Gemini surfactant bis(hexadecyldimethylammonium bromide)hexane (GEM16-6-16) as template. The X-ray diffraction (XRD) and FTIR results provide the evidence that we can adjust the pore size by varying the Ti/Si ratio. However, there is a limit of Ti/Si ratio favoring the formation of specific structures; the ordered structures will be destructed at higher Ti/Si ratio. The scanning electron micrograph (SEM) and transmission electron micrograph (TEM) images reveal that the Ti-MCM-41 materials exhibit diverse morphologies, including ordered rods, threads and bundles, hexagonal flakes, tubes, discoid rings and helix tubes. We tentatively elucidate that the formation of the complex morphologies can be attributed to the crystal growth mechanism and the defect theory.

Hu Jun [Department of Chemistry and Laboratory for Advanced Materials, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Zhou Lihui [Department of Chemistry and Laboratory for Advanced Materials, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Han Xia [Department of Chemistry and Laboratory for Advanced Materials, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Liu Honglai [Department of Chemistry and Laboratory for Advanced Materials, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)]. E-mail: hlliu@ecust.edu.cn; Hu Ying [Department of Chemistry and Laboratory for Advanced Materials, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)

2007-01-18

291

Gemini 9-A spacecraft touches down in the Atlantic at end of mission  

NASA Technical Reports Server (NTRS)

Gemini 9-A space flight is concluded as the Gemini 9 spacecraft touches down in the Atlantic. In this view its parachute is still deployed as the spacecraft hits the water (34117); Astronauts Thomas Stafford (right) and Eugene Cernan wave to the crowd aboard the aircraft carrier U.S.S. Wasp as they emerge from their Gemini 9 capsule. John C. Stonesifer (far right), with the Manned Spacecraft Center's Landing and Recovery Division, was on board to greet the astronauts (34118).

1966-01-01

292

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

293

Observations of Rosetta Target (21) Lutetia with Keck and Gemini Adaptive Optics  

NASA Astrophysics Data System (ADS)

In support of the NASA/ESA Rosetta mission’s plans to observe asteroid (21) Lutetia during a 2010 July flyby, and in conjunction with a larger ground-based plus HST campaign to support this mission, we observed Lutetia from Keck and Gemini-North during several nights spanning 2008 Oct through 2009 Jan. Observations were made using adaptive optics in the near-IR, primarily at K-band (2.1 micron), and were timed to coincide with the asteroid's most recent opposition at a distance of about 1.4 AU. From these data, we determined Lutetia’s triaxial size and shape to be 132 x 101 x 76 km, with maximum expected uncertainties of 4 x 3 x 31 km. The spin pole is found to be at (RA, Dec) = (48, +9) deg or ecliptic (long, lat) = (49,-8) deg, with a formal uncertainty radius (not including systematics) of 3 deg. We have calibrated our technique of deriving dimensions of asteroids from AO images against Pluto and 4 satellites of Saturn with accurate diameters, and we expect that our systematics (included in the size uncertainties above) are no more than 3%. We also searched for satellites and our preliminary results indicate no detection of a satellite larger than about 1 km over a significant fraction of the Hill sphere (10-240 asteroid radii). Improved limits are expected from a more refined analysis. We are grateful for telescope time made available to us by S. Kulkarni and M. Busch (Cal Tech) for a portion of this dataset. We also thank our collaborators on Team Keck, the Keck science staff, for making possible some of these observations and for observing time granted at Gemini under NOAO time allocation. Plane-of-sky short and long axes of (21) Lutetia taken from Keck AO images on 2008 Dec 2.

Conrad, A. R.; Merline, W. J.; Drummond, J.; Carry, B.; Tamblyn, P. M.; Chapman, C. R.; Dumas, C.; Weaver, H. A.

2009-12-01

294

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

295

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

296

PLANET EARTH STRANGE NEWS  

E-print Network

& Spy Tech // Global Warming // 3D Printing // OurAmazingPlanet // Best Fitness Trackers // Human Follow TECH HEALTH PLANET EARTH SPACE STRANGE NEWS ANIMALS HISTORY HUMAN NATURE SHOP TRENDING: Military

Wenseleers, Tom

297

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.

298

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.

299

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

300

A Definition of Planet  

Microsoft Academic Search

It had proposed some definitions about what a planet is. It seems clear that the planet's mass superior limit should be lower than the threshold for deuterium thermonuclear fusion. However the inferior limit is more elusive. It had proposed either Pluto's mass or the minimum mass to produce a spherical form. The Working Group on Extrasolar Planets (WGESP) of the

H. J. Durand-Manterola

2005-01-01

301

The planet Pluto  

Microsoft Academic Search

The search for a planet exterior to Neptune and the discovery of Pluto are discussed, and current knowledge of the planet Pluto is reviewed. Following a review of the discovery of the outer planets Uranus and Neptune, the 80-year search for a body which would account for the observed residuals in the motions of Uranus and Neptune is considered, with

A. J. Whyte

1980-01-01

302

Planets X and Pluto  

Microsoft Academic Search

It is pointed out that man has discovered some fundamental truths about the universe through mathematics. The 'X' in the title of the reported study refers to the trans-Neptunian planet postulated by Percival Lowell. Attention is given to Uranus and the asteroids, Neptune, the first search for planet X, the second search for planet X, the consideration of a trans-Neptunian

W. G. Hoyt

1980-01-01

303

Eddington's planet finding capabilities  

Microsoft Academic Search

The capabilities of Eddington for the detection and analysis of extrasolar planets are outlined. The primary goal of the PF (Planet finding) part of the mission is the detection of planets that are Earth like - which limits their size to less then 3 Earth radii - and which are potentially habitable - which limits their temperature or their orbital

H. J. Deeg; K. Horne

2002-01-01

304

Journey to Planet Seven.  

ERIC Educational Resources Information Center

An imaginary journey to Planet Seven is used to introduce the concept of number systems not based on ten. Activities include making a base 7 chart, performing base 7 addition and subtraction, designing Planet Seven currency, and developing other base systems for other planets. (MT)

Gow, Ellen

1987-01-01

305

Evaporation of extrasolar planets  

E-print Network

Atomic hydrogen escaping from the extrasolar giant planet HD209458b provides the largest observational signature ever detected for an extrasolar planet atmosphere. In fact, the upper atmosphere of this planet is evaporating. Observational evidences and interpretations coming from various models are reviewed. Implications for exoplanetology are discussed.

David Ehrenreich

2008-07-11

306

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

307

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

2009-12-10

308

FORMATION, SURVIVAL, AND DETECTABILITY OF PLANETS BEYOND 100 AU  

SciTech Connect

Direct imaging searches have begun to detect planetary and brown dwarf companions and to place constraints on the presence of giant planets at large separations from their host star. This work helps to motivate such planet searches by predicting a population of young giant planets that could be detectable by direct imaging campaigns. Both the classical core accretion and the gravitational instability model for planet formation are hard pressed to form long-period planets in situ. Here, we show that dynamical instabilities among planetary systems that originally formed multiple giant planets much closer to the host star could produce a population of giant planets at large ({approx} 10{sup 2}-10{sup 5} AU) separations. We estimate the limits within which these planets may survive, quantify the efficiency of gravitational scattering into both stable and unstable wide orbits, and demonstrate that population analyses must take into account the age of the system. We predict that planet scattering creates detectable giant planets on wide orbits that decreases in number on timescales of {approx} 10 Myr. We demonstrate that several members of such populations should be detectable with current technology, quantify the prospects for future instruments, and suggest how they could place interesting constraints on planet formation models.

Veras, Dimitri; Crepp, Justin R.; Ford, Eric B. [Astronomy Department, University of Florida, 211 Bryant Space Sciences Center, Gainesville, FL 32111 (United States)], E-mail: veras@astro.ufl.edu

2009-05-10

309

A Strange New Planet  

NSDL National Science Digital Library

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

310

A Strange New Planet  

NSDL National Science Digital Library

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

2011-05-05

311

Update on the Gemini High-Resolution Optical SpecTrograph (GHOST)  

NASA Astrophysics Data System (ADS)

The Gemini High-Resolution Opitcal SpecTrograph (GHOST) is under development for the Gemini telescopes in collaboration with the Austrailian Astronomical Observatory (AAO), the NRC-Herzberg in Canada, and the Australian National University (ANU). The latest design and project plan will be presented and the scientific role of the instrument will be discussed.

Margheim, Steven J.; Ghost Instrument Team

2015-01-01

312

Exo-planet Direct Imaging with On-Axis and/or Segmented Apertures in Space: Adaptive Compensation of Aperture Discontinuities  

NASA Astrophysics Data System (ADS)

Capitalizing on a recent breakthrough in wavefront control theory for obscured apertures made by our group, we propose to demonstrate a method to achieve high contrast exoplanet imaging with on-axis obscured apertures. Our new algorithm, which we named Adaptive Compensation of Aperture Discontinuities (ACAD), provides the ability to compensate for aperture discontinuities (segment gaps and/or secondary mirror supports) by controlling deformable mirrors in a nonlinear wavefront control regime not utilized before but conceptually similar to the beam reshaping used in PIAA coronagraphy. We propose here an in-air demonstration at 1E- 7 contrast, enabled by adding a second deformable mirror to our current test-bed. This expansion of the scope of our current efforts in exoplanet imaging technologies will enabling us to demonstrate an integrated solution for wavefront control and starlight suppression on complex aperture geometries. It is directly applicable at scales from moderate-cost exoplanet probe missions to the 2.4 m AFTA telescopes to future flagship UVOIR observatories with apertures potentially 16-20 m. Searching for nearby habitable worlds with direct imaging is one of the top scientific priorities established by the Astro2010 Decadal Survey. Achieving this ambitious goal will require 1e-10 contrast on a telescope large enough to provide angular resolution and sensitivity to planets around a significant sample of nearby stars. Such a mission must of course also be realized at an achievable cost. Lightweight segmented mirror technology allows larger diameter optics to fit in any given launch vehicle as compared to monolithic mirrors, and lowers total life-cycle costs from construction through integration & test, making it a compelling option for future large space telescopes. At smaller scales, on-axis designs with secondary obscurations and supports are less challenging to fabricate and thus more affordable than the off-axis unobscured primary mirror designs envisioned in many past mission concept studies. But until recently, it was believed that internal coronagraphs were incapable of yielding very high contrast on segmented or obscured telescopes. Recent developments now show that there is in fact a clear path to high contrast coronagraphy on such apertures. For the past several years we have been pursuing high contrast imaging development for segmented telescopes, supported in part by APRA (award NNX12AG05G, ROSES 2011). The ACAD algorithm, developed in the course of our current APRA, in principle appears to enable high contrast coronagraphy on obscured apertures as we set out to achieve. The practical laboratory demonstration of this new algorithm now requires additional resources not foreseen at the time of our prior proposal. Chief of these is the need for a second Boston Micromachines deformable mirror. The ACAD algorithm relies on the conversion of phase to amplitude as light propagates between two deformable mirrors at differing optical conjugates; a second DM is absolutely essential to its laboratory demonstration and validation. We propose now to demonstrate the ACAD algorithm in air at a contrast of ~1e-7 in narrow spectral bands, and extend that performance through development of broad band ~ 20%) optimization methods. Note that this proposal is a proper subset of an alternative proposal submitted to SAT-TDEM by our team that would also include additional higher TRL demonstrations.

Soummer, Remi

313

Planets Around Massive Subgiants  

E-print Network

Compared to planets around Sun-like stars, relatively little is known about the occurrence rate and orbital properties of planets around stars more massive than 1.3 Msun. The apparent deficit of planets around massive stars is due to a strong selection bias against early-type dwarfs in Doppler-based planet searches. One method to circumvent the difficulties inherent to massive main-sequence stars is to instead observe them after they have evolved onto the subgiant branch. We show how the cooler atmospheres and slower rotation velocities of subgiants make them ideal proxies for F- and A-type stars. We present the early results from our planet search that reveal a paucity of planets orbiting within 1 AU of stars more massive than 1.5 Msun, and evidence of a rising trend in giant planet occurrence with stellar mass.

John A. Johnson

2007-10-16

314

Journey to a Star Rich with Planets  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Click on the image for movie of Journey to a Star Rich with Planets

This artist's animation takes us on a journey to 55 Cancri, a star with a family of five known planets - the most planets discovered so far around a star besides our own.

The animation begins on Earth, with a view of the night sky and 55 Cancri (flashing dot), located 41 light-years away in the constellation Cancer. It then zooms through our solar system, passing our asteroids and planets, until finally arriving at the outskirts of 55 Cancri.

The first planet to appear is the farthest out from the star -- a giant planet, probably made of gas, with a mass four times that of Jupiter. This planet orbits its star every 14 years, similar to Jupiter's 11.9-year orbit.

As the movie continues, the three inner planets are shown, the closest of which is about 10 to 13 times the mass of Earth with an orbital period of less than three days.

Zooming out, the animation highlights the newest member of the 55 Cancri family - a massive planet, likely made of gas, water and rock, about 45 times the mass of Earth and orbiting the star every 260 days. This planet is the fourth out from the star, and lies in the system's habitable zone (green). A habitable zone is the place around a star where liquid water would persist. Though the newest planet probably has a thick gaseous envelope, astronomers speculate that it could have one or more moons. In our own solar system, moons are common, so it seems likely that they also orbit planets in other solar systems. If such moons do exist, and if they are as large as Mars or Earth, astronomers speculate that they would retain atmospheres and surface liquid water that might make interesting environments for the development of life.

The animation ends with a comparison between 55 Cancri and our solar system.

The colors of the illustrated planets were chosen to resemble those of our own solar system. Astronomers do not know what the planets look like.

2007-01-01

315

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

316

Extragalactic Integral Field Spectroscopy on the Gemini Telescopes  

E-print Network

We have been undertaking a programme on the Gemini 8-m telescopes to demonstrate the power of integral field spectroscopy, using the optical GMOS spectrograph, and the new CIRPASS instrument in the near-infrared. Here we present some preliminary results from 3D spectroscopy of extra-galactic objects, mapping the emission lines in a 3CR radio galaxy and in a gravitationally lensed arc, exploring dark matter sub-structure through observations of an Einstein Cross gravitational lens, and the star formation time-scales of young massive clusters in the starburst galaxy NGC 1140.

Andrew Bunker; Joanna Smith; Ian Parry; Rob Sharp; Andrew Dean; Gerry Gilmore; Richard Bower; Mark Swinbank; Roger Davies; R. Ben Metcalf; Richard de Grijs

2004-01-03

317

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

318

A giant planet around HD95086 ?  

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

319

Mechanism of gemini disulfide detergent mediated oxidative refolding of lysozyme in a new artificial chaperone system.  

PubMed

Gemini surfactants are a new class of surfactants that consist of two hydrophilic head groups and two hydrophobic tails separated by a spacer group. As the properties of geminis are different to their monomeric counterparts, a large number of applications have been investigated. Here we report on the use of a new class of gemini detergents containing a disulfide bond in the spacer (Det-SS-Det) for protein refolding. Using lysozyme as a model protein we could demonstrate that the disulfide gemini detergents allow oxidative refolding of the protein in the absence of any external redox system in an "artificial chaperone system". Refolding kinetics using gemini disulfide detergents differing in their hydrophobicity were analysed to determine the folding and aggregation rate constants. The results point to an important role of the transiently formed mixed disulfides between the protein and the detergent (Prot-SS-Det) in the oxidative refolding process of lysozyme. PMID:20857183

Potempa, Marc; Hafner, Mathias; Frech, Christian

2010-10-01

320

Photo-switched self-assembly of a gemini ?-helical peptide into supramolecular architectures  

NASA Astrophysics Data System (ADS)

An azobenzene-linked symmetrical gemini ?-helical peptide was designed and prepared to realize the light-switched self-assembly. With the reversible molecular structure transition between Z- and U-structures, the morphology of the self-assembled gemini ?-helical peptide can reversibly change between nanofibers and nanospheres in acidic medium, and between nanospheres and vesicles in basic medium.An azobenzene-linked symmetrical gemini ?-helical peptide was designed and prepared to realize the light-switched self-assembly. With the reversible molecular structure transition between Z- and U-structures, the morphology of the self-assembled gemini ?-helical peptide can reversibly change between nanofibers and nanospheres in acidic medium, and between nanospheres and vesicles in basic medium. Electronic supplementary information (ESI) available: Experimental details and characterizations of a gemini ?-helical peptide. See DOI: 10.1039/c3nr01967e

Chen, Chang-Sheng; Xu, Xiao-Ding; Li, Shi-Ying; Zhuo, Ren-Xi; Zhang, Xian-Zheng

2013-06-01

321

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

322

Extrasolar Planets and Prospects for Terrestrial Planets  

Microsoft Academic Search

Examination of ˜2000 sun--like stars has revealed 97 planets (as of 2002 Nov), all residing within our Milky Way Galaxy and within ˜200 light years of our Solar System. They have masses between 0.1 and 10 times that of Jupiter, and orbital sizes of 0.05--5 AU. Thus planets occupy the entire detectable domain of mass and orbits. News &summaries about

Geoffrey W. Marcy; R. Paul Butler; Steven S. Vogt; Debra A. Fischer

2004-01-01

323

Which Ringed Planet...!?  

NASA Astrophysics Data System (ADS)

Don't worry - you are not the only one who thought this was a nice amateur photo of planet Saturn, Lord of the Rings in our Solar System! But then the relative brightness and positions of the moons may appear somewhat unfamiliar... and the ring system does look unusually bright when compared to the planetary disk...?? Well, it is not Saturn, but Uranus , the next giant planet further out, located at a distance of about 3,000 million km, or 20 times the distance between the Sun and the Earth. The photo shows Uranus surrounded by its rings and some of the moons, as they appear on a near-infrared image that was obtained in the K s -band (at wavelength 2.2 µm) with the ISAAC multi-mode instrument on the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory (Chile) . The exposure was made on November 19, 2002 (03:00 hrs UT) during a planetary research programme. The observing conditions were excellent (seeing 0.5 arcsec) and the exposure lasted 5 min. The angular diameter of Uranus is about 3.5 arcsec. The observers at ISAAC were Emmanuel Lellouch and Thérése Encrenaz of the Observatoire de Paris (France) and Jean-Gabriel Cuby and Andreas Jaunsen (both ESO-Chile). The rings The rings of Uranus were discovered in 1977, from observations during a stellar occultation event by astronomer teams at the Kuiper Airborne Observatory (KAO) and the Perth Observatory (Australia). Just before and after the planet moved in front of the (occulted) star, the surrounding rings caused the starlight to dim for short intervals of time. Photos obtained from the Voyager-2 spacecraft in 1986 showed a multitude of very tenuous rings. These rings are almost undetectable from the Earth in visible light. However, on the present VLT near-infrared picture, the contrast between the rings and the planet is strongly enhanced. At the particular wavelength at which this observation was made, the infalling sunlight is almost completely absorbed by gaseous methane present in the planetary atmosphere and the disk of Uranus therefore appears unsually dark. At the same time, the icy material in the rings reflects the sunlight and appears comparatively bright. Uranus is unique among the planets of the solar system in having a tilted rotation axis that is close to the main solar system plane in which most planets move (the "Ecliptic"). At the time of the Voyager-2 encounter (1986), the southern pole was oriented toward the Earth. Now, sixteen years later (corresponding to about one-fifth of Uranus' 84-year period of revolution), we observe the Uranian ring system at an angle that is comparable to the one under which we see Saturn when its ring system is most "open". The moons ESO PR Photo 31b/02 ESO PR Photo 31b/02 [Preview - JPEG: 400 x 526 pix - 76k] [Full-Res - JPEG: 1460 x 1919 pix - 1.1M] Caption : PR Photo 31b/02 provides identifications of the Uranian moons present in PR Photo 31a/02 . The unidentified, round object to the left is a background star. The image scale in indicated by the bar. Seven of the moons of Uranus have been identified in PR Photo 31b/02 [1]. Of these, Titania and Oberon are the brightest (visual magnitude about 14). They were first seen in 1787 by the discoverer of Uranus, William Herschel (1738-1822), working at Bath in England. Ariel and Umbriel were found in 1851 by William Lassell (1799-1880) at Liverpool in the same country. Miranda was discovered in 1948 by Gerard Kuiper (1905-1973) at the 5-m Palomar telescope in California (USA). The much smaller and fainter Puck and Portia (visual magnitude about 21 and barely visible in the photo) were first found in 1985-86 by Stephen P. Synnott of the Jet Propulsion Laboratory (USA), during a study of Voyager-2 photos obtained soon before this NASA spacecraft flew by Uranus in January 1986. Other VLT images If you now want to see a fine VLT photo of Saturn, please look at PR Photo 04a/02 , obtained in late 2001. It was made with the NAOS-CONICA (NACO) Adaptive Optics facility and is therefore much less influenced by atmospheric turbulence and hence correspondingly shar

2002-12-01

324

The Gemini MCAO bench: system overview and lab integration  

NASA Astrophysics Data System (ADS)

We present Canopus, the AO bench for Gemini's Multi Conjugate Adaptive Optics System (GEMS), a unique facility for the Gemini South telescope located at Cerro Pachon in Chile. The MCAO system uses five laser beacons in conjunction with different natural guide stars configurations. A deployable fold mirror located in the telescope Acquisition and Guiding Unit (A&G) sends the telescope beam to the entrance of the bench. The beam is split within Canopus into three main components: two sensing paths and the output corrected science beam. Light from the laser constellation (589nm) is directed to five Shack-Hartman wave front sensors (E2V-39 CCDs read at 800Hz). Visible light from natural guide stars is sent to three independent sensors arrays (SCPM AQ4C Avalanche Photodiodes modules in quad cell arrangement) via optical fibers mounted on independent stages and a slow focus sensor (E2V-57 back-illuminated CCD). The infrared corrected beam exits Canopus and goes to instrumentation for science. The Real Time Controller (RTC) analyses wavefront signals and correct distortions using a fast tip-tilt mirror and three deformable mirrors conjugated at different altitudes. The RTC also adjusts positioning of the laser beacon (Beam Transfer Optics fast steering array), and handles miscellaneous offloads (M1 figure, M2 tip/tilt, LGS zoom and magnification corrections, NGS probes adjustments etc.). Background optimizations run on a separate dedicated server to feed new parameters into the RTC.

Bec, Matthieu; Rigaut, Francois J.; Galvez, Ramon; Arriagada, Gustavo; Boccas, Maxime; Gausachs, Gaston; Gratadour, Damien; James, Eric; Rojas, Roberto; Rogers, Rolando; Sheehan, Michael P.; Trancho, Gelys; Vucina, Tomislav

2008-07-01

325

The Radiometric Bode's Law and Extrasolar Planets  

E-print Network

We predict the radio flux densities of the extrasolar planets in the current census, making use of an empirical relation--the radiometric Bode's Law--determined from the five ``magnetic'' planets in the solar system (Earth and the four gas giants). Radio emission from these planets results from solar-wind powered electron currents depositing energy in the magnetic polar regions. We find that most of the known extrasolar planets should emit in the frequency range 10--1000 MHz and, under favorable circumstances, have typical flux densities as large as 1 mJy. We also describe an initial, systematic effort to search for radio emission in low radio frequency images acquired with the Very Large Array. The limits set by the VLA images (~ 300 mJy) are consistent with, but do not provide strong constraints on, the predictions of the model. Future radio telescopes, such as the Low Frequency Array (LOFAR) and the Square Kilometer Array (SKA), should be able to detect the known extrasolar planets or place austere limits on their radio emission. Planets with masses much lower than those in the current census will probably radiate below 10 MHz and will require a space-based array.

Joseph Lazio; W. M. Farrell; Jill Dietrick; Elizabeth Greenlees; Emily Hogan; Christopher Jones; L. A. Hennig

2004-05-18

326

Effects of differential wavefront sensor bias drifts on high contrast imaging  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a new facility, extreme adaptive optics (AO), coronagraphic instrument, currently being integrated onto the 8-meter Gemini South telescope, with the ultimate goal of directly imaging extrasolar planets. To achieve the contrast required for the desired science, it is necessary to quantify and mitigate wavefront error (WFE). A large source of potential static WFE arises from the primary AO wavefront sensor (WFS) detector's use of multiple readout segments with independent signal chains including on-chip preamplifiers and external amplifiers. Temperature changes within GPI's electronics cause drifts in readout segments' bias levels, inducing an RMS WFE of 1.1 nm and 41.9 nm over 4.44 degrees Celsius, for magnitude 4 and 11 stars, respectively. With a goal of <2 nm of static WFE, these are significant enough to require remedial action. Simulations imply a requirement to take fresh WFS darks every 2 degrees Celsius of temperature change, for a magnitude 6 star; similarly, for a magnitude 7 star, every 1 degree Celsius of temperature change. For sufficiently dim stars, bias drifts exceed the signal, causing a large initial WFE, and the former periodic requirement practically becomes an instantaneous/continuous one, making the goal of <2 nm of static WFE very difficult for stars of magnitude 9 or fainter. In extreme cases, this can cause the AO loops to destabilize due to perceived nonphysical wavefronts, as some of the WFS's Shack-Hartmann quadcells are split between multiple readout segments. Presented here is GPI's AO WFS geometry, along with detailed steps in the simulation used to quantify bias drift related WFE, followed by laboratory and on sky results, and concluded with possible methods of remediation.

Sadakuni, Naru; Macintosh, Bruce A.; Palmer, David W.; Poyneer, Lisa A.; Max, Claire E.; Savransky, Dmitry; Thomas, Sandrine J.; Cardwell, Andrew; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Rantakyrö, Fredrik; Serio, Andrew

2014-08-01

327

Seismology of Giant Planets  

E-print Network

Seismology applied to giant planets could drastically change our understanding of their deep interiors, as it has happened with the Earth, the Sun, and many main-sequence and evolved stars. The study of giant planets' composition is important for understanding both the mechanisms enabling their formation and the origins of planetary systems, in particular our own. Unfortunately, its determination is complicated by the fact that their interior is thought not to be homogeneous, so that spectroscopic determinations of atmospheric abundances are probably not representative of the planet as a whole. Instead, the determination of their composition and structure must rely on indirect measurements and interior models. Giant planets are mostly fluid and convective, which makes their seismology much closer to that of solar-like stars than that of terrestrial planets. Hence, helioseismology techniques naturally transfer to giant planets. In addition, two alternative methods can be used: photometry of the solar light ref...

Gaulme, Patrick; Schmider, Francois-Xavier; Guillot, Tristan

2014-01-01

328

New Planets / SETI  

NSDL National Science Digital Library

New Planets / SETI (Search for Extra-Terrestrial Intelligence) is a 48 minute radio broadcast that discusses three new planets discovered orbiting distant stars; how best to communicate with ET intelligence; and the progress of the radio-based search for ET intelligence. The new planet finds are smaller than previous extrasolar planet discoveries, on par with the planet Neptune in our solar system. There is discussion of the odds of finding life elsewhere in the universe, and if it is possible to find Earth-like planets in distant solar systems. The show also discusses: a paper published in the journal, Nature, that argues that for sending lots of data over long distances, it is hard to beat sending a physical artifact engraved with data; ways to communicate lots of information over long distances; and what SETI is listening for, and what they have heard.

329

The Amazing Red Planet  

NSDL National Science Digital Library

The purpose of this lesson is to introduce students to the planet Mars. This lesson will begin by discussing the location and size of Mars relative to Earth, as well as introduce many interesting facts about this red planet. Next, the history of Martian exploration is reviewed and students discover why scientists are so interested in studying this mysterious planet. The lesson concludes with students learning about future plans to visit Mars.

Integrated Teaching And Learning Program

330

Observations of minor planets. V  

Microsoft Academic Search

A summary is given about the minor planet survey performed in 1984 on Tautenburg Schmidt plates. The authors discovered 84 planets and calculated 205 positions for them. There are 17 numbered planets among them, 16 already earlier observed and 51 new planets with provisional designations. Tautenburg observations could give a tribute to seven planets numbered in the period of this

F. Boerngen; K. Kirsch

1986-01-01

331

A new family of planets?  

Microsoft Academic Search

A new family of planets is considered which is in between rocky terrestrial planets and gaseous giant ones, Ocean-Planets. We envision that these planets would have formed in an ice-rich environment and migrated closer to their star, in the Habitable Zone. We present hereafter preliminary internal models of these putative planets. We assume that their mass is between 1 and

A. Léger; F. Selsis; C. Sotin; T. Guillot; D. Despois; H. Lammer; M. Ollivier; F. Brachet

2003-01-01

332

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

333

Upgrade and standardization of real-time software for telescope systems at the Gemini telescopes  

NASA Astrophysics Data System (ADS)

The real-time control systems for the Gemini Telescopes were designed and built in the 1990s using state-of-the-art software tools and operating systems of that time. Since these systems are in use every night they have not been kept upto- date and are now obsolete and very labor intensive to support. Gemini is currently engaged in a major upgrade of its telescope control systems. This paper reviews the studies performed to select and develop a new standard operating environment for Gemini real-time systems and the work performed so far in implementing it.

Rambold, William N.; Gigoux, Pedro; Urrutia, Cristian; Ebbers, Angelic; Taylor, Philip; Rippa, Mathew J.; Rojas, Roberto; Cumming, Tom

2014-07-01

334

Advanced Adaptive Optics for Detection of Extrasolar Planets  

Microsoft Academic Search

The next major frontier in the study of extrasolar planets is direct imaging detection of the planets themselves. To achieve this with ground-based telescopes will require advanced adaptive optics systems capable of achieving Strehl ratio > 0.9 on 8-m telescopes, combined with coronagraphy to control diffraction and ultraprecise control of systematic wavefront errors at the nanometer level. Such direct detection

B. Macintosh

2007-01-01

335

Outer planet satellites  

NASA Technical Reports Server (NTRS)

Recent findings on the outer-planet satellites are presented, with special consideration given to data on the rheologic properties of ice on icy satellites, the satellite surfaces and exogenic processes, cratering on dead cratered satellites, volcanism, and the interiors of outer-planet satellites. Particular attention is given to the state of Titan's surface and the properties of Triton, Pluto, and Charon.

Schenk, Paul M.

1991-01-01

336

Outer Planet Icy Satellites  

NASA Technical Reports Server (NTRS)

An outer planet icy satellite is any one of the celestial bodies in orbit around Jupiter, Saturn, Uranus, Neptune, or Pluto. They range from large, planet-like geologically active worlds with significant atmospheres to tiny irregular objects tens of kilometers in diameter. These bodies are all believed to have some type of frozen volatile, existing alone or in combination with other volatiles.

Buratti, B.

1994-01-01

337

Pluto: Planet or  

Microsoft Academic Search

In August 2006 during the XXVI General Assembly of the International Astronomical Union (IAU), taken place in Prague, Czech Republic, new parameters to define a planet were established. According to this new definition Pluto will be no more the ninth planet of the Solar System but it will be changed to be a \\

M. R. Voelzke; M. S. T. de Araújo

2010-01-01

338

The Eight Planets  

NSDL National Science Digital Library

This website, by Caltech astronomer Mike Brown, is an article that recounts the reclassification of Pluto as a dwarf planet. The article explains the issues, tells how they were resolved, and answers related questions. At the bottom of the page is a link to a similar website about the dwarf planet Xena.

339

Planet -Star Plasma Interactions  

E-print Network

Planet - Star Plasma Interactions Philippe Zarka LESIA, Observatoire de Paris/CNRS, Meudon philippe.zarka@obspm.fr References : · Zarka, P., Plasma interactions of exoplanets with their parent star and associated radio emissions, Planet. Space Sci., 55, 598-617, 2007. · Griessmeier, J.-M., P. Zarka and H. Spreeuw, Predicting

Demoulin, Pascal

340

What is a Planet?  

NSDL National Science Digital Library

This is a lesson about the characteristics of planets, comets, asteroids, and trans-Neptunian objects. Learners will classify objects and then apply what they have learned by participating in a formal debate about a solar system object discovered by the New Horizons spacecraft and by defining the term planet.

341

Name That Planet!  

ERIC Educational Resources Information Center

Presents an activity in which students in groups explore one planet in the solar system and present their findings to the whole class. Focuses on the planet's location in the solar system, geological features, rate of revolutions, and calendar year. (YDS)

Beck, Judy; Rust, Cindy

2002-01-01

342

Five New Extrasolar Planets  

Microsoft Academic Search

We report multiple Doppler measurements of five nearby FGK main sequence stars and subgiants obtained during the past 4-6 years at the Keck observa- tory. These stars, namely, HD 183263, HD 117207, HD 188015, HD 45350, and HD 99492 all exhibit coherent variations in their Doppler shifts consistent with a planet in Keplerian motion. The five new planets occupy known

Geoffrey W. Marcy; R. Paul Butler; Steven S. Vogt; Debra A. Fischer; Gregory W. Henry; Greg Laughlin; Jason T. Wright; John A. Johnson

2005-01-01

343

Five New Extrasolar Planets  

Microsoft Academic Search

We report multiple Doppler measurements of five nearby FGK main-sequence stars and subgiants obtained during the past 4-6 yr at the Keck Observatory. These stars, namely, HD 183263, HD 117207, HD 188015, HD 45350, and HD 99492, all exhibit coherent variations in their Doppler shifts consistent with a planet in Keplerian motion. The five new planets occupy known realms of

Geoffrey W. Marcy; R. Paul Butler; Steven S. Vogt; Debra A. Fischer; Gregory W. Henry; Greg Laughlin; Jason T. Wright; John A. Johnson

2005-01-01

344

The New Planet  

Microsoft Academic Search

I SEE that, in the notice which appeared in NATURE announcing the discovery of the new planet, it was suggested that the object might represent the outermost member of the family of planets formed from a portion of the sun drawn out by the attraction of the star the approach of which caused the catastrophic formation of the planetary system;

G. F. Daniell

1930-01-01

345

Astronomy 150: The Planets  

NSDL National Science Digital Library

This website contains lab activities on planetary astronomy and the solar system. The labs cover: the earth-moon system, atmospheric escape, craters, meteorites, comets, lunar mapping, Mars, volcanoes on Io, Europa, Neptune, satellites of giant planets, and extra-solar planets.

Palen, Stacy

2004-07-16

346

Vibration characterization and mitigation at the Gemini-South telescope  

NASA Astrophysics Data System (ADS)

This paper describes a vibration analysis carried out at the Gemini South telescope for several observation instruments, namely: Canopus, NICI, GSAOI and P2 (a peripherical WFS used for telescope guiding). The aim is to find the origins of these disturbances and possible ways to mitigate them. The analysis has shown that common vibration patterns can be identified; however they differ in terms of spike broadness, direction and modes affected. Based on these data, two types of controllers (Kalman and infinity) were designed with a particular emphasis on stability and robustness, especially under uncertainty in some of the loop components. From an analysis of the real open-loop data obtained from the instruments, we demonstrate that these controllers would provide a substantial improvement compared to standard integrator controllers in terms of vibration rejection and Strehl ratio. We recently implemented a Kalman controller for the Canopus Tip/Tilt loop. The first results obtained with this controller will be presented as well.

Rodriguez, Ignacio; Neichel, Benoit; Hartung, Markus; Haywards, Thomas; Christou, Julian; Rigaut, Francois; Guzman, Dani; Guesalaga, Andres

2011-09-01

347

Fan-In Communications On A Cray Gemini Interconnect  

SciTech Connect

Using the Cray Gemini interconnect as our platform, we present a study of an important class of communication operations the fan-in communication pattern. By its nature, fan-in communications form hot spots that present significant challenges for any interconnect fabric and communication software stack. Yet despite the inherent challenges, these communication patterns are common in both applications (which often perform reductions and other collective operations that include fan-in communication such as barriers) and system software (where they assume an important role within parallel file systems and other components requiring high-bandwidth or low-latency I/O). Our study determines the effectiveness of differing clientserver fan-in strategies. We describe fan-in performance in terms of aggregate bandwidth in the presence of varying degrees of congestion, as well as several other key attributes. Comparison numbers are presented for the Cray Aries interconnect. Finally, we provide recommended communication strategies based on our findings.

Jones, Terry R [ORNL] [ORNL; Settlemyer, Bradley W [ORNL] [ORNL

2014-01-01

348

Visit to an Ocean Planet  

NSDL National Science Digital Library

Visit to an Ocean Planet is an innovative CD-ROM that has been transferred to the web. Visit to an Ocean Planet is for grades 5-12 that makes science, ocean, climate and life education fun and interactive. There are three sections, expedition, mission and guide. The expedition section engages students in exploring the 1997 El Nino, a look at oceanographers and their work, and an ocean science research cruise planning exercise. In the mission section, students discover many details about the TOPEX/Poseidon mission and learn about previous and future missions. They also learn how to measure ocean topography. The guide section contains lessons and classroom activities in climate, oceanography, and life in our oceans. The climate activities cover properties of fresh water and sea water, Earth's hydrologic cycle, coastal versus inland temperatures ocean currents and coastal temperatures, metric measurements, solar energy and distance, salinity, deep ocean circulations and greenhouse gases. The oceanography activities cover density of water, evaporation, mixing, sound in water, wind-driven currents, tides, upwelling and the Cartesian diver. The life in our oceans activities cover plankton, bioluminescence, oil spils and plastics in the ocean. Classroom activities can be downloaded directly from the website as .pdf files. The guide section also contains movies, images, and background materials. If you are an educator or home schooler, you can obtain a copy of the "Visit to an Ocean Planet" CD-ROM free of charge from the JPL Physical Oceanography DAAC: http://podaac.jpl.nasa.gov/edu.

1998-01-01

349

Commission 53: Extrasolar Planets  

NASA Astrophysics Data System (ADS)

Commission 53 on Extrasolar Planets was created at the 2006 Prague General Assembly of the IAU, in recognition of the outburst of astronomical progress in the field of extrasolar planet discovery, characterization, and theoretical work that has occurred since the discovery of the pulsar planets in 1992 and the discovery of the first planet in orbit around a solar-type star in 1995. Commission 53 is the logical successor to the IAU Working Group on Extrasolar Planets WG-ESP, which ended its six years of existence in August 2006. The founding president of Commission 53 is Michael Mayor, in honor of his seminal contributions to this new field of astronomy. The vice-president is Alan Boss, the former chair of the WG-ESP, and the members of the Commission 53 Organizing Committee are the other former members of the WG-ESP.

Mayor, Michel; Boss, Alan P.; Butler, Paul R.; Hubbard, William B.; Ianna, Philip A.; Kürster, Martin; Lissauer, Jack J.; Meech, Karen J.; Mignard, François; Penny, Alan J.; Quirrenbach, Andreas; Tarter, Jill C.; Vidal-Madjar, Alfred

350

Find That Planet!  

NSDL National Science Digital Library

This activity has students use internet resources to learn about celestial coordinates, and how to use an emphemeris to locate planets on a horizon sky map. The sky maps are then used for outdoor observing. A more advanced application has students draw maps in celestial coordinates. They first learn about the celestial coordinate system astronomers use and then they generate a position, or ephemeris, for a planet at a certain time on a certain night and plot that position on an appropriate sky map. While engaged in this activity, students will learn to use star maps for finding a planet, plot a planet path on star maps with coordinate grids, and be able to find out when a planet is visible.

351

Extreme Planet Makeover  

NSDL National Science Digital Library

You may have heard of elaborate makeover television shows where some individual wishes to have various body enhancements performed or a new house is built in seven days. This fascinating extreme makeover website, from NASA and the Jet Propulsion Laboratory at the California Institute of Technology, is much more edifying. Here, visitors will have the opportunity to make their own planet via a series of customizable bells and whistles. Visitors can use the controls on the site to adjust key planetary attributes such as distance from a star, planet size, and planet age. After making these adjustments, visitors can learn about the planet they have created, and also compare it with other existing planets and outer-space bodies.

352

Identifying wide, cold planets within 8pc  

NASA Astrophysics Data System (ADS)

Direct imaging exoplanet studies have recently unveiled a previously-unexpected population of massive planets (up to 15 M_Jup) in wide orbits (>100AU). Although most of these discoveries have been around younger stars and have been of similar temperatures to field brown dwarfs, one object (WD 0806-661B), is the coldest planet known outside our solar system. We propose a survey of all stars and brown dwarfs within 8pc to identify massive planetary companions in the 150-1500AU separation range. We will 1) Measure the fraction of wide planetary mass companions to stars in the Solar neighbourhood. 2) Identify all planets within 8 parsecs with masses above 8 Jupiter masses in our chosen projected separation range with lower mass limits for closer and younger stars. 3) Identify approximately 8 planets, four of which will have temperatures below 300K making them ideal targets to study water clouds in cold atmospheres with both JWST and the next generation of ground-based extremely large telescopes. Our survey will be the most complete survey for wide planets to-date and will provide both a measurement of the wide planet population and a legacy of cold, well constrained targets for future observatories.

Deacon, Niall; Kraus, Adam; Crossfield, Ian

2014-12-01

353

SN 1987A after 18 Years: Mid-Infrared GEMINI and SPITZER Observations of the Remnant  

NASA Technical Reports Server (NTRS)

We present high resolution 11.7 and 18.3 micron mid-IR images of SN 1987A obtained on day 6526 since the explosion with the Thermal-Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8m telescope. The 11.7 micron flux has increased significantly since our last observations on day 6067. The images clearly show that all the emission arises from the equatorial ring (ER). Nearly contemporaneous spectra obtained on day 6184 with the MIPS at 24 micron, on day 6130 with the IRAC in 3.6- 8 micron region, and on day 6190 with the IRS in the 12-37 micron instruments on board the Spitzer Space Telescope's show that the emission consists of thermal emission from silicate dust that condensed out in the red giant wind of the progenitor star. The dust temperature is 1662(sup +18) (sub -12) K, and the emitting dust mass is (2.6(sup +2.0 (sub -1.4)) x 10 (exp -6) M(solar). Lines of [Ne II] 12.82 micron and [Ne III] 15.56 pm are clearly present in the Spitzer spectrum, as well as a weak [Si II] 3 34.8 micron line. We also detect two lines near 26 micron which we tentatively ascribe to [Fe II] 25.99 pm and [0 IV] 25.91 micron. Comparison of the mid-IR Gemini 11.7 micron image with X-ray images obtained by Chandra, UV-optical images obtained by HST, and radio synchrotron images obtained by the ATCA show generally good correlation of the images across all wavelengths. Because of the limited resolution of the mid-IR images we cannot uniquely determine the location. or heating mechanism of the dust giving rise to the emission. The dust could be collisionally heated by the X-ray emitting plasma, providing a unique diagnostic of plasma conditions. Alternatively, the dust could be radiatively heated in the dense UV-optical knots that are overrun by the advancing supernova blast wave. In either case the dust-to-gas mass ratio in the circumstellar medium around the supernova is significantly lower than that in the general interstellar medium of the LMC, suggesting either a low condensation efficiency in the wind of the progenitor star, or the efficient destruction of the dust by the SN blast wave. Overall, we are witnessing the interaction of the SN blast wave with its surrounding medium, creating an environment that is rapidly evolving at all wavelengths. Continuous multiwavelength observations of SN 1987A such as these provide unique snapshots of the very early evolution of supernova remnants.

Bouchet, Patrice; Dwek, Eli; Danziger, John; Arendt, Richard G.; DeBuizer, James M.; Park, Sangwook; Suntzeff, Nicholas B.; Kirshner, Robert P.; Challis, Peter

2007-01-01

354

Formation of Planets Around the Sun and Other Stars.  

SciTech Connect

Formation of Planets around the Sun and other stars. The quest to understand the formation of planets and planetary systems has entered an era of renaissance. Driven by observational discoveries in solar system exploration, protostellar disks, and extra solar planets, we have established a rich data bank which contains not only relic clues around mature stars, including the Sun, but also direct image of ongoing processes around young stars. For the first time in this scientific endeavor, we have adequate information to construct quantitative models to account for the ubiquity of planets and diversity of planetary systems. Some of the most intriguing theoretical questions facing us today include: a) how did the planets in the solar system form with their present-day mass, composition, and orbital elements, b) is planet formation a deterministic or chaotic process, and c) what are the observable signatures of planet formation and evolution around nearby young and mature stars? I will present a comprehensive scenario which suggests a) gas giant planets formed through coagulation of planetsimals and gas accretion onto earth-like cores; b) the final assemblage of the terrestrial planets in the solar system occurred through the propagation of Jupiter's secular resonance 4-30 Myrs after the emergence of the gas giant; and c) although they are yet to be discovered, Earth-like planets are expected to be common around nearby stars.

Professor Doug Lin

2005-11-14

355

Synthesis and crystal structures of gold nanowires with gemini surfactants as directing agents.  

PubMed

The preparation of crystalline gold nanowires (NWs) by using gemini surfactants as directing agents through a three-step seed-mediated method is reported. Unlike the nanorods with relatively low aspect ratios (typically below 20) obtained by using cetyltrimethylammonium bromide as a directing agent, the NWs obtained in this investigation can reach up to 4.4 ?m, and the largest aspect ratio is calculated to be 210. For this, each of seven different gemini surfactants are utilized as directing agents, and the length and/or aspect ratio of the NWs can be tuned by varying the hydrocarbon chain lengths of the gemini surfactants. Both single and twinned crystalline structures are elucidated by selected-area electron diffraction and high-resolution transmission electron microscopy studies. The use of gemini surfactants not only advances the synthesis of gold nanostructures, but improves the understanding of the growth mechanism for seed-mediated growth. PMID:25257473

Xu, Feng; Hou, Hao; Gao, Zhinong

2014-12-15

356

Gemini 12 crew receive Official welcome aboard U.S.S. Wasp  

NASA Technical Reports Server (NTRS)

Astronauts James A. Lovell Jr. (left), command pilot, and Edwin E. Aldrin Jr., pilot, receive Official welcome as they arrive aboard the aircraft carrier U.S.S. Wasp after their splashdown at the end of the Gemini 12 mission.

1966-01-01

357

The Near-Earth Encounter of 2005 YU55: Thermal Infrared Observations from Gemini North  

NASA Technical Reports Server (NTRS)

As part of a multi-observatory campaign to observe 2005 YU55 during its November 2011 encounter with the Earth, thermal infrared photometry and spectroscopy (7.9- 14 and 18-22 micron) were conducted using the Michelle instrument at Gemini North. Reduction of the 8.8 flm photometry and the spectroscopy from UT Nov-IO as well as of all the Gemini data from UT Nov-9 is in progress. Results will be discussed.

Lim, Lucy F.; Emery, Joshua P.; Moskovitz, Nicholas A.; Granvik, Mikael

2012-01-01

358

Orbital Evolution and Migration of Giant Planets: Modeling Extrasolar Planets  

Microsoft Academic Search

Giant planets in circumstellar disks can migrate inward from their initial (formation) positions. Radial migration is caused by inward torques between the planet and the disk, by outward torques between the planet and the spinning star, and by outward torques due to Roche lobe overflow and consequent mass loss from the planet. We present self-consistent numerical considerations of the problem

D. E. Trilling; W. Benz; T. Guillot; J. I. Lunine; W. B. Hubbard; A. Burrows

1998-01-01

359

The discovery of Eris, the largest known dwarf planet  

NSDL National Science Digital Library

A webpage about the discovery of Eris, the first known dwarf planet larger than Pluto. The discovery of Eris prompted the demotion of Pluto by the IAU, and the page includes images and information about the object.

Michael Brown

360

Gemini VRI data of counterparts associated to X-ray sources in CMa R1  

NASA Astrophysics Data System (ADS)

The molecular cloud Canis Major R1 (CMa R1) contains several embedded stellar clusters associated to a ring of nebular emission, which is an expanding shell suggested to be a supernova remnant (SNR) inducing the star formation in this region (Herbst & Assousa 1977, Comerón et al. 1998). However, there are alternatives to the SNR hypothesis, since the shell-like structure could be produced by strong stellar winds or an evolving HII region, as suggested by Reynolds & Ogden (1978), Blitz (1980), and Pyatunina & Taraskin (1986), for example. Two main challenges have motivated us to investigate this interesting region: (i) to conduct a stellar population study, from 7 to 0.4 solar masses, and (ii) to verify the evolutionary status of embedded cluster members. This contribution is dedicated to report VRI data obtained with Gemini South telescope in the direction of X-ray sources for which no counterpart had been previously identified. The Gemini imaging was performed for six fields revealing several faint candidates that are probably multiple counterparts of X-ray emitters detected by ROSAT as single sources (Gregorio-Hetem, Montmerle & Marciotto 2003). These fields have not been observed in more recent X-ray surveys. The V-R and R-I colours were estimated for the objects associated with the position of the X-ray emission, aiming to distinguish between field stars and members of the cloud. The 2MASS catalogue was inspected searching for near-infrared (NIR) counterparts related to the optical candidates. Each ROSAT source has 6 to 16 possible optical counterparts, 67% to 86% of them being NIR sources. Colour-colour and colour-magnitude diagrams have been constructed to evaluate the evolutionary status of the stellar groups. Investigating the evolutionary scenario of the embedded stellar clusters associated to X-ray emitters, which are probably very young, is a unique opportunity to better understand the star formation process in CMa R1 and to test SNR models, verifying the hypothesis of induced star formation in this region.

Gregorio-Hetem, J.; Rodrigues, C. V.; Montmerle, T.

361

Exploring the Planets: Mercury  

NSDL National Science Digital Library

This site contains most of the up-to-date information known about the planet Mercury. Facts about the planet include: mean distance from Sun, length of year, rotation period, mean orbital velocity, inclination of axis, average temperature (day and night), and diameter. The site explains why earth-based views of Mercury are so poor and describes the surface of the planet on the basis of probe photographs. The photographs do not prove whether the material on the surface is impact ejecta or volcanic. However, a colored digital mosaic of Mercury taken by Mariner 10 suggests that at least some of the mercurian smooth plains are the products of volcanism.

362

Is Pluto a Planet? And what is a planet, anyways?  

E-print Network

Is Pluto a Planet? And what is a planet, anyways? N = N* fs fGHZ fp nH #12;What is a star? A star The real issue is that we need to know precisely what we mean when we use the word planet. Is Pluto a Planet? #12;Is Pluto a Planet? A body that: ·Orbits a star ·Is large enough for its gravity to make

Walter, Frederick M.

363

Is Pluto a Planet? And what is a planet, anyways?  

E-print Network

Is Pluto a Planet? And what is a planet, anyways? N = N* fs fp AST 248 #12;What is a star? A star The real issue is that we need to know precisely what we mean when we use the word planet. Is Pluto a Planet? #12;Is Pluto a Planet? A body that: ·Orbits a star ·Is large enough for its gravity to make

Walter, Frederick M.

364

Planet Designer: What's Trending Hot?  

NSDL National Science Digital Library

This is an activity about the way distance, reflectivity, 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. This lesson is part of Project Spectra, a science and engineering education program focusing on how light is used to explore the Solar System.

365

Exploring Planetary System Evolution Through High-Contrast Imaging  

NASA Astrophysics Data System (ADS)

Direct imaging of circumstellar disks provides unique information about planetary system construction and evolution. Several hundred nearby main-sequence stars are known to host debris disks, which are produced by mutual collisions of orbiting planetesimals during a phase thought to coincide with terrestrial planet formation. Therefore, detection of the dust in such systems through scattered near-infrared starlight offers a view of the circumstellar environment during the epoch of planet assembly. We have used ground-based coronagraphic angular differential imaging (ADI) with Keck NIRC2 and Gemini Planet Imager (GPI) to investigate disk structures that may act as signposts of planets. ADI and its associated image processing algorithms (e.g., LOCI) are powerful tools for suppressing the stellar PSF and quasistatic speckles that can contaminate disk signal. However, ADI PSF-subtraction also attenuates disk surface brightness in a spatially- and parameter-dependent manner, thereby biasing photometry and compromising inferences regarding the physical processes responsible for the dust distribution. To account for this disk "self-subtraction," we developed a novel technique to forward model the disk structure and compute a self-subtraction map for a given ADI-processed image. Applying this method to NIRC2 near-IR imaging of the HD 32297 debris disk, we combined the high signal-to-noise ratio (S/N) of ADI data with unbiased photometry to measure midplane curvature in the edge-on disk and a break in the disk's radial brightness profile. Such a break may indicate the location of a planetesimal ring that is a source of the light-scattering micron-sized grains. For the HD 61005 debris disk, we examined similar data together with GPI 1.6-micron polarization data and detected the dust ring's swept-back morphology, brightness asymmetry, stellocentric offset, and inner clearing. To study the physical mechanism behind these features, we explored how eccentricity and mutual inclination affect disk morphology by constructing self-subtracted scattered-light models (using our forward-modeling technique) and comparing them with complementary NIRC2 (several-arcsecond scales) and GPI (high S/N close to the star) observations.

Esposito, Thomas; Fitzgerald, Michael P.; Kalas, Paul; Graham, James R.; Millar-Blanchaer, Max; Gpies Team

2015-01-01

366

Magnetic Mystery Planets  

NASA Astrophysics Data System (ADS)

The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and they can even give us clues to the atmospheric history of these planets. This paper highlights a classroom presentation and accompanying activity that focuses on the differences between the magnetic fields of Venus, Earth, and Mars, what these differences mean, and how we measure these differences. During the activity, students make magnetic field measurements and draw magnetic field lines of “mystery planets” using orbiting “spacecraft” (small compasses). Based on their observations, the students then determine whether they are orbiting Venus-like, Earth-like, or Mars-like planets. This activity is targeted to middle and high school audiences. However, we have also used a scaled-down version with elementary school audiences.

Fillingim, M.; Brain, D.; Peticolas, L.; Yan, D.; Fricke, K.; Thrall, L.

2014-07-01

367

Terrestrial Planet Finder  

NASA Technical Reports Server (NTRS)

Integrating and testing the proposed Terrestrial Planet Finder imposes constraints on the design. Some of these will be discussed including the dimensions of existing test facilities, the effects of gravity, ambient vibrations and the size of GSE optics.

Smith, Andrew

2004-01-01

368

The Antarctic Planet Interferometer  

NASA Technical Reports Server (NTRS)

The Antarctic Planet Interferometer is an instrument concept designed to detect and characterize extrasolar planets by exploiting the unique potential of the best accessible site on earth for thermal infrared interferometry. High-precision interferometric techniques under development for extrasolar planet detection and characterization (differential phase, nulling and astrometry) all benefit substantially from the slow, low-altitude turbulence, low water vapor content, and low temperature found on the Antarctic plateau. At the best of these locations, such as the Concordia base being developed at Dome C, an interferometer with two-meter diameter class apertures has the potential to deliver unique science for a variety of topics, including extrasolar planets, active galactic nuclei, young stellar objects, and protoplanetary disks.

Swain, Mark R.; Walker, Christopher K.; Traub, Wesley A.; Storey, John W.; CoudeduForesto, Vincent; Fossat, Eric; Vakili, Farrok; Stark, Anthony A.; Lloyd, James P.; Lawson, Peter R.; Burrows, Adam S.; Ireland, Michael; Millan-Gabet, Rafael; vanBelle, Gerard T.; Lane, Benjamin; Vasisht, Gautam; Travouillon, Tony

2004-01-01

369

Transit of Extrasolar Planets  

NASA Technical Reports Server (NTRS)

During the past five years we have pursued the detection of extrasolar planets by the photometric transit method, i.e. the detection of a planet by watching for a drop in the brightness of the light as it crosses in front of a star. The planetary orbit must cross the line-of-sight and so most systems will not be lined up for such a transit to ever occur. However, we have looked at eclipsing binary systems which are already edge-on. Such systems must be very small in size as this makes the differential light change due to a transit much greater for a given planet size (the brightness difference will be proportional to the area of the transiting planet to the disc area of the star). Also, the planet forming region should be closer to the star as small stars are generally less luminous (that is, if the same thermal regime for planet formation applies as in the solar system). This led to studies of the habitable zone around other stars, as well. Finally, we discovered that our data could be used to detect giant planets without transits as we had been carefully timing the eclipses of the stars (using a GPS antenna for time) and this will drift by being offset by any giant planets orbiting around the system, as well. The best summary of our work may be to just summarize the 21 refereed papers produced during the time of this grant. This will be done is chronological order and in each section separately.

Doyle, Laurance R.

1998-01-01

370

Planet/Moon Trivia  

NSDL National Science Digital Library

This is an activity about defining characteristics or features of the planets and their moons. Learners will use the Solar System Update software to complete a worksheet asking them to find the planet and/or moon that matches each listed description. This activity requires the use of a computer with Internet access, and is Solar System Activity 1 in a larger resource, Space Update.

371

The Terrestrial Planet Finder  

NASA Technical Reports Server (NTRS)

The Terrestrial Planet Finder (TPF) missions has as its goal the detection and characterization of earth-like planets around nearby stars. NASA is currently funding a number of small studies to look at the trade-offs in the design of TPF. The possible trade-offs include orbit location (1 to 5 AU), aperture size (6 to 1.5m), physically connected baselines or separated spacecraft flying in close formation.

Beichman, Charles

1997-01-01

372

Planets' magnetic environments  

SciTech Connect

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

Lanzerotti, L.J.; Uberoi, C.

1989-02-01

373

The planet Saturn (1970)  

NASA Technical Reports Server (NTRS)

The present-day knowledge on Saturn and its environment are described for designers of spacecraft which are to encounter and investigate the planet. The discussion includes physical properties of the planet, gravitational field, magnetic and electric fields, electromagnetic radiation, satellites and meteoroids, the ring system, charged particles, atmospheric composition and structure, and clouds and atmospheric motions. The environmental factors which have pertinence to spacecraft design criteria are also discussed.

1972-01-01

374

Outer planet satellites  

SciTech Connect

Recent findings on the outer-planet satellites are presented, with special consideration given to data on the rheologic properties of ice on icy satellites, the satellite surfaces and exogenic processes, cratering on dead cratered satellites, volcanism, and the interiors of outer-planet satellites. Particular attention is given to the state of Titan's surface and the properties of Triton, Pluto, and Charon. 210 refs.

Schenk, P.M. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

375

Classifying Planets: Nature vs. Nurture  

NASA Astrophysics Data System (ADS)

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

Beichman, Charles A.

2009-05-01

376

Mapping the Red Planet  

NASA Technical Reports Server (NTRS)

Since September 1997 the Mars Global Surveyor spacecraft has been orbiting the planet Mars and acquiring new data about the red planet that is changing our view of its present state and past history. Except for a few weeks in October 1997 and a few months in the Spring/Summer of 1998 when special science operations were conducted the spacecraft spent the first 18 months if its time at Mars getting to the right orbital geometry for the mapping mission. But on March 1, 1999 the MGS spacecraft trained its instruments onto the planet to begin a full Mars year (684 Earth days) of continuous systematic mapping and observation of the planet. The camera began wide angle and high resolution mapping, the thermal emission spectrometer began sensing the atmosphere and the material properties of the surface, the magnetometer searched out regions of abnormally high magnetism, the altimeter began determining the precise shape of the planet, and the radio science experiment began determining atmospheric pressures, temperatures and mapping the planet's gravity field. In a matter of a month more data was acquired about

Smith, David E.; Smith, David E.

2001-01-01

377

Novel Cationic Gemini Lipids, Click Chemistry Based Adducts And Amphiphile-Capped Silver Nanostructures : Synthesis, Aggregation And Biological Properties.  

E-print Network

??The thesis entitled “Novel Cationic Gemini Lipids, Click Chemistry Based Adducts and Amphiphile-Capped Silver Nanostructures: Synthesis, Aggregation and Biological Properties” elucidates the design, synthesis, aggregation… (more)

Biswas, Joydeep

2010-01-01

378

Formation of Planets Around the Sun and Other Stars  

SciTech Connect

The quest to understand the formation of planets and planetary systems has entered an era of renaissance. Driven by observational discoveries in solar system exploration, protostellar disks, and extra solar planets, we have established a rich data bank which contains not only relic clues around mature stars, including the Sun, but also direct image of ongoing processes around young stars. For the first time in this scientific endeavor, we have adequate information to construct quantitative models to account for the ubiquity of planets and diversity of planetary systems. Some of the most intriguing theoretical questions facing us today include: (a) how did the planets in the solar system form with their present-day mass, composition, and orbital elements, (b) is planet formation a deterministic or chaotic process, and (c) what are the observable signatures of planet formation and evolution around nearby young and mature stars? I will present a comprehensive scenario which suggests (a) gas giant planets formed through coagulation of planetsimals and gas accretion onto earth-like cores; (b) the final assemblage of the terrestrial planets in the solar system occurred through the propagation of Jupiter's secular resonance 4-30 Myrs after the emergence of the gas giant; and (c) although they are yet to be discovered, Earth-like planets are expected to be common around nearby stars.

Lin, Doug

2005-11-14

379

Why 400 Years to Discover Countless Planets?  

NASA Astrophysics Data System (ADS)

In 1584, Dominican monk Giordano Bruno envisioned the stars as "countless suns with countless earths, all rotating around their suns." Searching for intellectual freedom, he fled his native Italy to Protestant Switzerland and Germany, but in 1600 the Roman Inquisition condemned him for heresy. He was burned at the stake. Fast-forwarding to 1995, the Swiss astronomers Michel Mayor and Didier Queloz announced the discovery of a planet orbiting a star similar to our sun (51 Pegasi). In 2010, 500 planets had been found orbiting 421 stars. On Feb 2, 2011, NASA announced 1200 planet candidates. It took 400 years for telescope technology to advance and for Copernicus, Galileo, Newton, Bradley, and Foucault to make major contributions, culminating in today's astrophysics with digital imaging and processing. Contrasting with Bruno, in 2010 Dominican Francisco Ayala, who had been president of the Sigma Xi and AAAS, won the 1.6M Templeton Prize for affirming life's spiritual dimension.

Carr, Paul H.

2011-04-01

380

Tools for discovering and characterizing extrasolar planets  

NASA Astrophysics Data System (ADS)

Among the group of extrasolar planets, transiting planets provide a great opportunity to obtain direct measurements for the basic physical properties, such as mass and radius of these objects. These planets are therefore highly important in the understanding of the evolution and formation of planetary systems: from the observations of photometric transits, the interior structure of the planet and atmospheric properties can also be constrained. The most efficient way to search for transiting extrasolar planets is based on wide-field surveys by hunting for short and shallow periodic dips in light curves covering quite long time intervals. These surveys monitor fields with several degrees in diameter and tens or hundreds of thousands of objects simultaneously. In the practice of astronomical observations, surveys of large field-of-view are rather new and therefore require special methods for photometric data reduction that have not been used before. Since 2004, I participate in the HATNet project, one of the leading initiatives in the competitive search for transiting planets. Due to the lack of software solution which is capable to handle and properly reduce the yield of such a wide-field survey, I have started to develop a new package designed to perform the related data processing and analysis. After several years of improvement, the software package became suffi ciently robust and played a key role in the discovery of several transiting planets. In addition, various new algorithms for data reduction had to be developed, implemented and tested which were relevant during the reduction and the interpretation of data. In this PhD thesis, I summarize my efforts related to the development of a complete software solution for high precision photometric reduction of astronomical images. I also demonstrate the role of this newly developed package and the related algorithms in the case of particular discoveries of the HATNet project.

Pál, András

2009-06-01

381

Design and analysis of the Gemini chain system in dual clutch transmission of automobile  

NASA Astrophysics Data System (ADS)

Chain drive system is widely used in the conditions of high-speed, overload, variable speed and load. Many studies are focused on the meshing theory and wear characteristics of chain drive system, but system design, analysis, and noise characteristics of the chain drive system are weak. System design and noise characteristic are studied for a new type Gemini chain of dual-clutch automatic transmission. Based on the meshing theory of silent chain, the design parameters of the Gemini chain system are calculated and the mathematical models and dynamic analysis models of the Gemini chain system are established. Dynamic characteristics of the Gemini chain system is simulated and the contact force of plate and pin, plate and sprockets, the chain tension forces, the transmission error and the stress of plates and pins are analyzed. According to the simulation results of the Gemini chain system, the noise experiment about system is carried out. The noise values are tested at different speed and load and spectral characteristics are analyzed. The results of simulation and experimental show that the contact forces of plate and pin, plate and sprockets are smaller than the allowable stress values, the chain tension force is less than ultimate tension and transmission error is limited in 1.2%. The noise values can meet the requirements of industrial design, and it is proved that the design and analysis method of the Gemini chain system is scientific and feasible. The design and test system is built from analysis to test of Gemini chain system. This research presented will provide a corresponding theoretical guidance for the design and dynamic characteristics and noise characteristics of chain drive system.

Cheng, Yabing; Guo, Haitao; Fu, Zhenming; Wan, Nen; Li, Lei; Wang, Yang

2014-10-01

382

Joint inversion of marine MT and CSEM data over Gemini prospect, Gulf of Mexico  

NASA Astrophysics Data System (ADS)

In 2003 we tested a prototype marine controlled-source electromagnetic (CSEM) transmitter over the Gemini salt body in the Gulf of Mexico, collecting one line of data over 15 seafloor receiver instruments using the Cox waveform with a 0.25 Hz fundamental, yielding 3 usable frequencies. Transmission current was 95 amps on a 150 m antenna. We had previously collected 16 sites of marine magnetotelluric (MT) data along this line during the development of broadband marine MT as a tool for mapping salt geometry. Recently we commissioned a finite element code capable of joint CSEM and MT 2D inversion incorporating bathymetry and anisotropy, and this heritage data set provided an opportunity to explore such inversions with real data. We reprocessed the CSEM data to obtain objective error estimates and inverted single frequency CSEM, multi-frequency CSEM, MT, and joint MT and CSEM data sets for a variety of target misfits, using the Occam regularized inversion algorithm. As expected, MT-only inversions produce a smoothed image of the salt and a resistive basement at 9 km depth. The CSEM data image a conductive cap over the salt body and have little sensitivity to the salt or structure at depths beyond about 1500 m below seafloor. However, the joint inversion yields more than the sum of the parts - the outline of the salt body is much sharper and there is much more structural detail even at depths beyond the resolution of the CSEM data. As usual, model complexity greatly depends on target misfit, and even with well-estimated errors the choice of misfit becomes a somewhat subjective decision. Our conclusion is a familiar one; more data are always good.

Constable, S.; Orange, A. S.; Key, K.

2013-12-01

383

The Las Campanas Observatory/Gemini-South campaign for Deep Impact target comet 9P/Tempel 1: Overview and Highlights  

NASA Astrophysics Data System (ADS)

We present initial results of a combined LCO/Gemini observational programme to characterize the Deep Impact target 9P/Tempel 1 before, during and after the expected excavation of a new impact crater on 04 July 2005. Our programme combines a suite of optical, near-IR and thermal-IR instruments at the Las Campanas Observatory and Gemini South in Chile to establish a baseline and then observe the consequences when the Deep Impact Mission fires a 370kg copper projectile to penetrate the mantle of comet 9P/Tempel 1. Observations are scheduled between 20 June and 20 July, 2005. We are employing T-ReCS on Gemini South to obtain thermal infrared imaging and spectroscopy of the comet simultaneously with narrowband optical continuum and near infrared imaging from the two Magellan 6.5 meter telescopes using MagIC and PANIC. Taken together these high spatial resolution data will allow us to model the physical and chemical characteristics of the subsurface material freshly excavated by the Deep Impact projectile. We will determine or constrain the composition, albedo, size distribution, and production rate, for the dust and water ice particles in the coma prior to the mission impact (8 cometary rotations pre-impact) and then compare these same properties at three epochs following the excavation of the impact crater (immediately following the impact within the first cometary rotation, after another 4 cometary rotations and again 8 rotations after impact). To compliment the T-ReCS spectroscopy obtained within the first cometary rotation following impact, we will also have simultaneous 5-30 micron spectra obtained with the IRS instrument on the Spitzer spacecraft at UT 01:54 and 23:13 on 05 July. In addition to these simultaneous Magellan/Gemini observations, wide-field narrowband imaging will be carried out at the duPont 2.5m telescope at LCO between 27 June and 09 July, 2005. Together, these investigations will provide a detailed characterization of pristine cometary material dating back to the origins of our solar system.

Osip, D. J.; De Buizer, J.; Thomas-Osip, J. E.; Lederer, S. M.; Lisse, C.

2005-08-01

384

LONG RANGE OUTWARD MIGRATION OF GIANT PLANETS, WITH APPLICATION TO FOMALHAUT b  

SciTech Connect

Recent observations of exoplanets by direct imaging reveal that giant planets orbit at a few dozens to more than a hundred AU from their central star. The question of the origin of these planets challenges the standard theories of planet formation. We propose a new way of obtaining such far planets, by outward migration of a pair of planets formed in the 10 AU region. Two giant planets in mean motion resonance in a common gap in the protoplanetary disk migrate outward, if the inner one is significantly more massive than the outer one. Using hydrodynamical simulations, we show that their semimajor axes can increase by almost 1 order of magnitude. In a flared disk, the pair of planets should reach an asymptotic radius. This mechanism could account for the presence of Fomalhaut b; then, a second, more massive planet, should be orbiting Fomalhaut at about 75 AU.

Crida, Aurelien [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Masset, Frederic [Laboratoire AIM-UMR 7158, CEA/CNRS/Universite Paris Diderot, IRFU/Service d'Astrophysique, CEA/Saclay, 91191 Gif-sur-Yvette Cedex (France); Morbidelli, Alessandro, E-mail: A.Crida@damtp.cam.ac.u [Laboratoire Cassiopee UMR 6202, Universite de Nice Sophia-antipolis/Observatoire de la Cote d'Azur/CNRS, B.P. 4229, 06304 Nice Cedex 4 (France)

2009-11-10

385

Self-assembly, DNA binding and cytotoxicity trends of ether functionalized gemini pyridinium amphiphiles.  

PubMed

Six new ether functionalized gemini pyridinium amphiphiles have been synthesized having dodecyl, tetradecyl alkyl chain lengths and three different spacers (i.e. -(CH2)n-, where n is 4, 5 and 6) and investigated for their self-assembling behavior by state of the art techniques such as tensiometry, conductivity and spectrofluorometry. These new pyridinium gemini surfactants exhibit lower cmc values as compared to other gemini surfactants reported in literature. These amphiphiles form stable complexes with DNA as established by agarose gel electrophoresis and ethidium bromide exclusion experiments. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was carried out in vitro on C6 glioma cell line for cytotoxicity assessment of new pyridinium geminis. The dynamic light scattering (DLS) and transmission electron microscopy (TEM) have been used to measure the micellar size of gemini surfactants. Further, thermal stability of these amphiphiles has been evaluated by thermogravimetric analysis (TGA). The dependence of self-assembly behavior and other properties on spacer as well as alkyl chain length has been established. PMID:24407701

Chauhan, Vinay; Singh, Sukhprit; Kamboj, Raman; Mishra, Rachana; Kaur, Gurcharan

2014-03-01

386

Planet Detection: The Kepler Mission  

NASA Astrophysics Data System (ADS)

The search for exoplanets is one of the hottest topics in astronomy and astrophysics in the twenty-first century, capturing the public's attention as well as that of the astronomical community. This nascent field was conceived in 1989 with the discovery of a candidate planetary companion to HD114762 [35] and was born in 1995 with the discovery of the first extrasolar planet 51 Peg-b [37] orbiting a main sequence star. As of March, 2011, over 500 exoplanets have been discovered* and 106 are known to transit or cross their host star, as viewed from Earth. Of these transiting planets, 15 have been announced by the Kepler Mission, which was launched into an Earth-trailing, heliocentric orbit in March, 2009 [1,4,6,15,18,20,22,31,32,34,36,43]. In addition, over 1200 candidate transiting planets have already been detected by Kepler [5], and vigorous follow-up observations are being conducted to vet these candidates. As the false-positive rate for Kepler is expected to be quite low [39], Kepler has effectively tripled the number of known exoplanets. Moreover, Kepler will provide an unprecedented data set in terms of photometric precision, duration, contiguity, and number of stars. Kepler's primary science objective is to determine the frequency of Earth-size planets transiting their Sun-like host stars in the habitable zone, that range of orbital distances for which liquid water would pool on the surface of a terrestrial planet such as Earth, Mars, or Venus. This daunting task demands an instrument capable of measuring the light output from each of over 100,000 stars simultaneously with an unprecedented photometric precision of 20 parts per million (ppm) at 6.5-h intervals. The large number of stars is required because the probability of the geometrical alignment of planetary orbits that permit observation of transits is the ratio of the size of the star to the size of the planetary orbit. For Earth-like planets in 1-astronomical unit (AU) orbits† about sun-like stars, only ˜0.5% will exhibit transits. By observing such a large number of stars, Kepler is guaranteed to produce a robust null result in the unhappy event that no Earth-size planets are detected in or near the habitable zone. Such a result would indicate that worlds like ours are extremely rare in the Milky Way galaxy and perhaps the cosmos, and that we might be solitary sojourners in the quest to answer the age-old question: "Are we alone?" Kepler is an audacious mission that places rigorous demands on the science pipeline used to process the ever-accumulating, large amount of data and to identify and characterize the minute planetary signatures hiding in the data haystack. Kepler observes over 160,000 stars simultaneously over a field of view (FOV) of 115 square degrees with a focal plane consisting of 42 charge-coupled devices‡ (CCDs), each of which images 2.75 square degrees of sky onto 2200×1024 pixels. The photometer, which contains the CCD array, reads out each CCD every 6.54 s [10,11] and co-adds the images for 29.4 min, called a long cadence (LC) interval. Due to storage and bandwidth constraints, only the pixels of interest, those that contain images of target stars, are saved onboard the solid-state recorder (SSR), which can store 66+ days of data. An average of 32 pixels per star is allowed for up to 170,000 stellar target definitions. In addition, a total of 512 targets are sampled at 58.85-s short cadence (SC) intervals, permitting further characterization of the planet-star systems for the brighter stars with a Kepler magnitude,* Kp, brighter than 12 (Kp < 12) stars via asteroseismology [17], and more precise transit timing. In addition to the stellar images, collateral data used for calibration (CAL) are also collected and stored on the SSR. For each of the 84 CCD readout channels these data include up to 4500 background sky pixels used to estimate and remove diffuse stellar background and zodiacal light; 1100 pixels containing masked smear measurements and another 1100 pixels containing virtual smear measurements used to remove art

Jenkins, Jon M.; Smith, Jeffrey C.; Tenenbaum, Peter; Twicken, Joseph D.; Van Cleve, Jeffrey

2012-03-01

387

Commission 53: Extrasolar Planets  

NASA Astrophysics Data System (ADS)

Commission 53 was created at the 2006 Prague General Assembly (GA) of the IAU, in recognition of the outburst of astronomical progress in the field of extrasolar planet discovery, characterization, and theoretical work that has occurred since the discovery of the first planet in orbit around a solar-type star in 1995. Commission 53 is the logical successor to the IAU Working Group on Extrasolar Planets (WGESP), which ended its six years of existence in August 2006. The founding President of Commission 53 was Michael Mayor, in honor of his seminal contributions to this new field of astronomy. The current President is Alan Boss, the former chair of the WGESP. The current members of the Commission 53 (C53) Organizing Committee (OC) began their service in August 2009 at the conclusion of the Rio de Janeiro IAU GA.

Boss, Alan; Lecavelier des Etangs, Alain; Mayor, Michel; Bodenheimer, Peter; Collier-Cameron, Andrew; Kokubo, Eiichiro; Mardling, Rosemary; Minniti, Dante; Queloz, Didier

2012-04-01

388

CHARIS science: performance simulations for the Subaru Telescope's third-generation of exoplanet imaging instrumentation  

NASA Astrophysics Data System (ADS)

We describe the expected scientific capabilities of CHARIS, a high-contrast integral-field spectrograph (IFS) currently under construction for the Subaru telescope. CHARIS is part of a new generation of instruments, enabled by extreme adaptive optics (AO) systems (including SCExAO at Subaru), that promise greatly improved contrasts at small angular separation thanks to their ability to use spectral information to distinguish planets from quasistatic speckles in the stellar point-spread function (PSF). CHARIS is similar in concept to GPI and SPHERE, on Gemini South and the Very Large Telescope, respectively, but will be unique in its ability to simultaneously cover the entire near-infrared J, H, and K bands with a low-resolution mode. This extraordinarily broad wavelength coverage will enable spectral differential imaging down to angular separations of a few ?/D, corresponding to ~0".1. SCExAO will also offer contrast approaching 10-5 at similar separations, ~0".1-0".2. The discovery yield of a CHARIS survey will depend on the exoplanet distribution function at around 10 AU. If the distribution of planets discovered by radial velocity surveys extends unchanged to ~20 AU, observations of ~200 mostly young, nearby stars targeted by existing high-contrast instruments might find ~1-3 planets. Carefully optimizing the target sample could improve this yield by a factor of a few, while an upturn in frequency at a few AU could also increase the number of detections. CHARIS, with a higher spectral resolution mode of R ~ 75, will also be among the best instruments to characterize planets and brown dwarfs like HR 8799 cde and ? and b.

Brandt, Timothy D.; McElwain, Michael W.; Janson, Markus; Knapp, Gillian R.; Mede, Kyle; Limbach, Mary A.; Groff, Tyler; Burrows, Adam; Gunn, James E.; Guyon, Olivier; Hashimoto, Jun; Hayashi, Masahiko; Jovanovic, Nemanja; Kasdin, N. J.; Kuzuhara, Masayuki; Lupton, Robert H.; Martinache, Frantz; Sorahana, Satoko; Spiegel, David S.; Takato, Naruhisa; Tamura, Motohide; Turner, Edwin L.; Vanderbei, Robert; Wisniewski, John

2014-07-01

389

Location of Planet X  

SciTech Connect

Observed positions of Uranus and Neptune along with residuals in right ascension and declination are used to constrain the location of a postulated tenth planet. The residuals are converted into residuals in ecliptic longitude and latitude. The results are then combined into seasonal normal points, producing average geocentric residuals spaced slightly more than a year apart that are assumed to represent the equivalent heliocentric average residuals for the observed oppositions. Such a planet is found to most likely reside in the region of Scorpius, with considerably less likelihood that it is in Taurus. 8 references.

Harrington, R.S.

1988-10-01

390

Bing & Bong's Tiny Planet  

NSDL National Science Digital Library

The Bing & Bong's Tiny Planet website, a supplement to the educational television series, offers excellent science activities, games, and online books for small children. Users can sail around the planet to learn about wind, read an online story to discover space, take an adventure through the water cycle, and much more. Visitors can also learn the essentials of colors, shapes, and light through short videos and interactive modules. The colorful website offers a great way for children to begin learning about the fascinating world.

391

Mercury - the hollow planet  

NASA Astrophysics Data System (ADS)

Mercury is turning out to be a planet characterized by various kinds of endogenous hole (discounting impact craters), which are compared here. These include volcanic vents and collapse features on horizontal scales of tens of km, and smaller scale depressions ('hollows') associated with bright crater-floor deposits (BCFD). The BCFD hollows are tens of metres deep and kilometres or less across and are characteristically flat-floored, with steep, scalloped walls. Their form suggests that they most likely result from removal of surface material by some kind of mass-wasting process, probably associated with volume-loss caused by removal (via sublimation?) of a volatile component. These do not appear to be primarily a result of undermining. Determining the composition of the high-albedo bluish surface coating in BCFDs will be a key goal for BepiColombo instruments such as MIXS (Mercury Imaging Xray Spectrometer). In contrast, collapse features are non-circular rimless pits, typically on crater floors (pit-floor craters), whose morphology suggests collapse into void spaces left by magma withdrawal. This could be by drainage of either erupted lava (or impact melt) or of shallowly-intruded magma. Unlike the much smaller-scale BCFD hollows, these 'collapse pit' features tend to lack extensive flat floors and instead tend to be close to triangular in cross-section with inward slopes near to the critical angle of repose. The different scale and morphology of BCFD hollows and collapse pits argues for quite different modes of origin. However, BCFD hollows adjacent to and within the collapse pit inside Scarlatti crater suggest that the volatile material whose loss was responsible for the growth of the hollows may have been emplaced in association with the magma whose drainage caused the main collapse. Another kind of volcanic collapse can be seen within a 25 km-wide volcanic vent outside the southern rim of the Caloris basin (22.5° N, 146.1° E), on a 28 m/pixel MDIS NAC image from orbit. Although the vent itself may have been excavated partly by explosive volcanism, the most recent event is collapse of a 7 km wide zone in the south centre of the vent. The sharpness of features within this (unmuted either by regolith-forming processes or by fall of volcanic ejecta) suggests that this collapse considerably post-dates the rest of the vent interior. It could reflect a late-stage minor 'throat clearing' explosive eruption, but (in the absence of evidence of associated volcanic ejecta) more likely reflects collapse into a void within the volcanic conduit, itself a result of magma-drainage. A class of 'hole' that is so far conspicuous by its absence on Mercury is sinuous rilles (as opposed to much straighter tectonic grabens) or aligned skylights representing collapsed or partly-collapsed drained lava tubes. Tube-fed flows are to be expected during emplacement of volcanic plains, and it will be surprising if no examples are revealed on MESSENGER and BepiColombo high-resolution images.

Rothery, D. A.

2012-04-01

392

Gemini spectroscopy of the outer disk star cluster BH176  

NASA Astrophysics Data System (ADS)

Context. BH176 is an old metal-rich star cluster. It is spatially and kinematically consistent with belonging to the Monoceros Ring. It is larger in size and more distant from the Galactic plane than typical open clusters, and it does not belong to the Galactic bulge. Aims: Our aim is to determine the origin of this unique object by accurately determining its distance, metallicity, and age. The best way to reach this goal is to combine spectroscopic and photometric methods. Methods: We present medium-resolution observations of red clump and red giant branch stars in BH176 obtained with the Gemini South Multi-Object Spectrograph. We derive radial velocities, metallicities, effective temperatures, and surface gravities of the observed stars and use these parameters to distinguish member stars from field objects. Results: We determine the following parameters for BH176: Vh = 0 ± 15 km s-1, [Fe/H] = -0.1 ± 0.1, age 7 ± 0.5 Gyr, E(V - I) = 0.79 ± 0.03, distance 15.2 ± 0.2 kpc, ?-element abundance [?/Fe] ~ 0.25 dex (the mean of [Mg/Fe], and [Ca/Fe]). Conclusions: BH176 is a member of old Galactic open clusters that presumably belong to the thick disk. It may have originated as a massive star cluster after the encounter of the forming thin disk with a high-velocity gas cloud or as a satellite dwarf galaxy. Appendix A is available in electronic form at http://www.aanda.org

Sharina, M. E.; Donzelli, C. J.; Davoust, E.; Shimansky, V. V.; Charbonnel, C.

2014-10-01

393

Dwarf Planets as the Most Populous Class of Planet  

Microsoft Academic Search

Dwarf planets should form whenever the surface density of a protoplanetary disk is low enough, and as a transient stage during planet formation in more massive disks. In terms of physical attributes (hydrostatic shape, presence of atmospheres, internal oceans, active geology, satellites) there is no clear dividing line bewteen dwarf planets and larger, \\

W. B. McKinnon

2009-01-01

394

Early planet formation as a trigger for further planet formation  

Microsoft Academic Search

Recent discoveries of extrasolar giant planets at small orbital radii, or having significant orbital eccentricities, suggest that the planets interacted with the disks of dust and gas from which they and the central stars formed. Here we show that if a gas-giant planet reaches a mass of 4-5 jovian masses sufficiently early, when the protoplanetary disk is still massive, an

Philip J. Armitage; Brad M. S. Hansen

1999-01-01

395

From Protoplanets to Terrestrial Planets: Statistical Properties of Assembled Planets  

Microsoft Academic Search

The standard scenario of terrestrial planet formation consists of three stages: (1) dust to planetesimals, (2) planetesimals to protoplanets, and (3) protoplanets to planets. The stage (3) is known as giant impact stage where protoplanets collide one another to form the final planets. As this process is stochastic, in order to clarify it, it is necessary to investigate it statistically.

E. Kokubo; J. Kominami; S. Ida

2005-01-01

396

PHYSICS OF PLANETS: OBSERVING EXTRASOLAR GIANT PLANETS WITH Tristan Guillot  

E-print Network

for those objects with little or no atmosphere). On the other hand, extrasolar giant planets represent a new1 PHYSICS OF PLANETS: OBSERVING EXTRASOLAR GIANT PLANETS WITH DARWIN/TPF Tristan Guillot of such instruments as DARWIN or TPF represents a great opportunity to study in detail a new population

Guillot, Tristan

397

Thermodynamic investigation of the binding of dissymmetric pyrenyl-gemini surfactants to DNA.  

PubMed

Gemini surfactants have demonstrated significant potential for use in constructing non-viral transfection vectors for the delivery of genes into cells to induce protein expression. Previously, two asymmetric gemini surfactants containing pyrenyl groups in one of the alkyl tails of the surfactants were synthesized as fluorescence probes for use in mechanistic studies of the transfection process. Here we present the results of a thermodynamic investigation of the binding interaction(s) between the pyrenyl-modified surfactants and DNA. The thermodynamics of the interactions have been examined using isothermal titration calorimetry, light scattering, zeta potential, and circular dichroism measurements. Distinct differences are observed between the interaction of 12-s-12 vs. the pyrene modified py-s-12 surfactants with DNA; an intercalated binding is found for the py-s-12 surfactants that disrupts the typical interactions observed between DNA and gemini surfactants. PMID:20428564

Wettig, Shawn D; Deubry, Rubena; Akbar, Javed; Kaur, Tranum; Wang, Haitang; Sheinin, Tatiana; Joseph, Jamie W; Slavcev, Roderick A

2010-05-14

398

Adsorption and Aggregation behaviors of tetrasiloxane-tailed gemini surfactants with (EO)m spacers.  

PubMed

Adsorption and aggregation behaviors of novel tetrasiloxane-tailed gemini surfactants N,N'-ditetrasiloxane-N,N'-digluconamide oligo ethylene glycol diglycidyl (Si-m-Si, where m is the number of ethylene glycol of 1, 2, and 3) were investigasted using surface tension, bromophenol blue encapsulation, dynamic light scattering (DLS), and transmission electron microscope (TEM) methods. The static surface tension of the aqueous Si-m-Si solutions measured at the critical aggregate concentration (CAC) was observed to be lower than that of traditional hydrocarbon gemini surfactants. This suggests that these newly synthesized gemini surfactants are capable of forming a closely packed monolayer film at the air/aqueous solution interface. With a combination of DLS data, TEM measurements, and bromophenol blue entrapment studies, formations of vesicles in Si-m-Si solutions appear to occur at a concentration well above the CAC. Moreover, the size of vesicles depended on their m values. PMID:23438340

Guoyong, Wang; Wenshan, Qu; Zhiping, Du; Wanxu, Wang; Qiuxiao, Li

2013-03-21

399

Testing the correlation between low mass planets and debris disks  

NASA Astrophysics Data System (ADS)

The number of dusty debris disks has increased across all spectral types through recent infrared surveys. This has provided greater overlap with stars known to host extrasolar planets via RV surveys. New studies have therefore investigated how the different properties of host stars, exoplanets, and debris disks may be correlated, with the objective of giving empirical support to competing theories of planet formation and evolution. One such emerging correlation is that stars with only low mass planets are more likely to host prominent debris disks than stars that have at least one giant planet. If true, then M dwarfs should have abundant debris disks given that they more frequently have low mass planetary systems. However, the information needed to critically test these ideas is lacking. For most systems, the presence of an outer planet with >30 Earth masses has not been observationally tested, nor are there many M dwarf debris disks available for detailed scrutiny. Here we propose to use STIS coronagraphy to image for the first time the debris disks around three nearby stars in optical scattered light. Searching for sharp dust belt structures indirectly tests for the existence of outer planets that are otherwise undetectable by RV or adaptive optics planet searches. Moreover, two of our target stars are the most recently discovered M dwarf debris disks, both closer to the Sun than AU Mic. The scattered light observations of these two targets would present a major advance in characterizing how M dwarf debris disks co-evolve with planets under different stellar environments.

Kalas, Paul

2014-10-01

400

M2K Planet Search: Spectroscopic Screening and Transit Photometry  

NASA Astrophysics Data System (ADS)

The M2K project is a search for planets orbiting nearby early M and late K dwarf drawn from the SUPERBLINK catalog. M and K dwarfs are highly attractive targets for finding low-mass and habitable planets because (1) close-in planets are more likely to orbit within their habitable zone, (2) planets orbiting them induce a larger Doppler signal and have deeper transits than similar planets around F, G, and early K type stars, (3) planet formation models predict they hold an abundance of super-Earth sized planets, and (4) they represent the vast majority of the stars close enough for direct imaging techniques. In spite of this, only 10% of late K and early M dwarfs are being monitored by current Doppler surveys. As part of the M2K project we have obtained low-resolution spectra for more than 2000 of our sample of 10,000 M and K dwarfs. We vet our sample by screening these stars for high metallicity and low chromospheric activity. We search for transits on targets showing high RMS Doppler signal and photometry candidates provided by SuperWASP project. By using "snapshot” photometry have been able to achieve sub-millimag photometry on numerous transit targets in the same night. With further follow-up observations we will be able to detect planets smaller than 10 Earth masses.

Mann, Andrew; Gaidos, E.; Fischer, D.; Lepine, S.

2010-10-01

401

Gene Transfection in High Serum Levels: Case Studies with New Cholesterol Based Cationic Gemini Lipids  

PubMed Central

Background Six new cationic gemini lipids based on cholesterol possessing different positional combinations of hydroxyethyl (-CH2CH2OH) and oligo-oxyethylene -(CH2CH2O)n- moieties were synthesized. For comparison the corresponding monomeric lipid was also prepared. Each new cationic lipid was found to form stable, clear suspensions in aqueous media. Methodology/Principal Findings To understand the nature of the individual lipid aggregates, we have studied the aggregation properties using transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential measurements and X-ray diffraction (XRD). We studied the lipid/DNA complex (lipoplex) formation and the release of the DNA from such lipoplexes using ethidium bromide. These gemini lipids in presence of a helper lipid, 1, 2-dioleoyl phophatidyl ethanol amine (DOPE) showed significant enhancements in the gene transfection compared to several commercially available transfection agents. Cholesterol based gemini having -CH2-CH2-OH groups at the head and one oxyethylene spacer was found to be the most effective lipid, which showed transfection activity even in presence of high serum levels (50%) greater than Effectene, one of the potent commercially available transfecting agents. Most of these geminis protected plasmid DNA remarkably against DNase I in serum, although the degree of stability was found to vary with their structural features. Conclusions/Significance -OH groups present on the cationic headgroups in combination with oxyethylene linkers on cholesterol based geminis, gave an optimized combination of new genera of gemini lipids possessing high transfection efficiency even in presence of very high percentage of serum. This property makes them preferential transfection reagents for possible in vivo studies. PMID:23861884

Misra, Santosh K.; Biswas, Joydeep; Kondaiah, Paturu; Bhattacharya, Santanu

2013-01-01

402

Light Curve of Minor Planet 1026 Ingrid  

NASA Astrophysics Data System (ADS)

(Abstract only) We have imaged minor planet 1026 Ingrid over the time period of July 29, 2011, to late September 2011, using the Wheaton College 0.25m telescope at Grove Creek Observatory in Australia via internet access. This telescope is equipped with a Santa Barbara Instrument Group STL-1001E CCD Camera, used with a clear filter. Over 1,000 30-second images were obtained and imported into the MPO Canopus software package for light curve analysis. Our preliminary estimate of the rotation period of 1026 Ingrid is 5.390 ± 0.001 hours, which is consistent with the previous estimate of 5.3 ± 0.3 hours (Székely, P., et al. 2005, Planet. Space Sci., 53, 925).

Delos, S.; Ahrendts, G.; Barker, T.

2012-06-01

403

Comparison of two sensors for outer planet mission onboard navigation.  

NASA Technical Reports Server (NTRS)

Onboard instruments have been shown to be an effective aid to navigation on missions to the outer planets. The relationship of two possible candidate navigation instruments, an image tube (television) and a scanning photometer, with other systems such as data processing and attitude control is discussed. Certain key problem areas relating to the design of each sensor are considered, and the scientific uses of each sensor are examined. The navigational efficacy of both instruments is illustrated by some selected results from a navigation and guidance simulation of outer planet missions. It is concluded that both devices are viable alternatives for onboard outer planet navigation.

Malchow, H. L.; Sackett, L. L.

1972-01-01

404

Modern Gemini-Approach to Technology Development for Human Space Exploration  

NASA Technical Reports Server (NTRS)

In NASA's plan to put men on the moon, there were three sequential programs: Mercury, Gemini, and Apollo. The Gemini program was used to develop and integrate the technologies that would be necessary for the Apollo program to successfully put men on the moon. We would like to present an analogous modern approach that leverages legacy ISS hardware designs, and integrates developing new technologies into a flexible architecture This new architecture is scalable, sustainable, and can be used to establish human exploration infrastructure beyond low earth orbit and into deep space.

White, Harold

2010-01-01

405

Synthesis and self-assembly of new light-sensitive Gemini surfactants containing an azobenzene group  

Microsoft Academic Search

A homologue of dissymmetric quaternary ammonium Gemini surfactants, hexanediyl-?-(butylazobenzene dimethylammonium)-?-(alkyldimethylammonium) dibromides (referred to as a4-6-m, m=12, 14, 16), and a symmetric quaternary ammonium Gemini surfactant, hexanediyl-?,?-bis(butylazobenzene dimethylammonium bromide) (referred to as a4-6-4a), have been synthesized. The Krafft temperature at 1wt% concentration was determined to be 17–32°C for dissymmetric a4-6-m homologues depending on the length of aliphatic tail and 42.5°C for

Binglei Song; Jianxi Zhao; Beixi Wang; Rong Jiang

2009-01-01

406

What makes a planet habitable ?  

E-print Network

volcanic eruption...) #12;#12;Solar system rocky planets #12;Conclusions COMPLEX life, AS WE KNOW planets ? #12;#12;#12;#12;·Too many collisions in the first few 100 Myr ·Stellar activity decreases BUT many many "suitable" planets in our galaxy, and many many galaxies... (Drake equation) Within next

Guyon, Olivier

407

What is a Planet? Video  

NSDL National Science Digital Library

This is a video about the IAU definition of a planet. Learners will watch 3D animation designed to illustrate the history behind the discussion defining the question, what is a planet?, and to outline some of the traits that may be associated with the definition of a planet.

408

Single planet, divided world  

Microsoft Academic Search

Unlike other forms of life on planet earth, humans have contrived to flourish—or at least multiply—by splitting themselves horizontally into incommensurable units and vertically into a species above, or privileged within, the realm of nature. The human proclivity for division, exclusion, and alienation is not absolute; it is endlessly challenged and often diluted by integrating tendencies. Historically, phenomena such as

Richard Matthew

1994-01-01

409

Ocean Planet: Final Version  

NSDL National Science Digital Library

The Ocean Planet is a traveling exhibition from the Smithsonian Institution which opened in Washington DC on April 22, 1995. A part of the exhibition was a computer flyby of the Pacific Ocean developed in the SVS. This animation represents a stage in the development of that flyby.

Dave Pape

1994-04-29

410

Pluto - The distant planet  

Microsoft Academic Search

The paper discusses the history of the discovery of Pluto. It is noted that two scientists, Pickering and Lowell, worked independently in searching for Pluto. Attention is given to the peculiarities of the orbit of Pluto; its rotation, diameter, and surface structure; Pluto's moon, Charon; and the possible existence of an additional planet.

N. Vogt

1980-01-01

411

The Nine Planets: Appendices  

NSDL National Science Digital Library

This Nine Planets page offers additional information not included in any other pages of the site. It includes tables of solar system data, discovery chronology, a brief look at the origin of the solar system, planetary linguistics, explanations of astronomical names, a master picture list, and links for more information.

Bill Arnett

412

Accumulation of the planets  

NASA Technical Reports Server (NTRS)

In modeling the accumulation of planetesimals into planets, it is appropriate to distinguish between two stages: an early stage, during which approximately 10 km diameter planetesimals accumulate locally to form bodies approximate 10 to the 25th g in mass; and a later stage in which the approximately 10 to the 25th g planetesimals accumulate into the final planets. In the terrestrial planet region, an initial planetesimal swarm corresponding to the critical mass of dust layer gravitational instabilities is considered. In order to better understand the accumulation history of Mercury-sized bodies, 19 Monte-Carlo simulations of terrestrial planet growth were calculated. A Monte Carlo technique was used to investigate the orbital evolution of asteroidal collision debris produced interior to 2.6 AU. It was found that there are two regions primarily responsible for production of Earth-crossing meteoritic material and Apollo objects. The same techniques were extended to include the origin of Earth-approaching asteroidal bodies. It is found that these same two resonant mechanisms predict a steady-state number of Apollo-Amor about 1/2 that estimated based on astronomical observations.

Wetherill, G. W.

1987-01-01

413

A Planet for Goldilocks  

NASA Astrophysics Data System (ADS)

The search for life beyond Earth has inspired Solar System exploration and SETI surveys. Today, the search for life also leads to exoplanet discovery and characterization. Launched in March 2009, NASA's Kepler Mission has discovered thousands of exoplanets with diverse properties. Though each new world is interesting in its own right, Kepler aims to understand the population as a whole. Its primary objective is to determine the frequency of exoplanets of different sizes and orbital periods. Of special interest are the Earth-size planets in the “Goldilocks” (or habitable) Zone where the flux of incoming starlight is conducive to the existence of surface liquid water. Once Kepler establishes the prevalence of such planets in the Solar neighborhood, future missions can be designed to find not just a planet in the Goldilocks Zone but a planet for Goldilocks—a truly habitable environment for life as we know it. Kepler discoveries and progress will be described as well as the resources available to bring Kepler science to the public and into the classroom. The possibility of finding evidence of life beyond Earth is working its way into the public consciousness and has the potential to inspire generations. Scientific literacy is a natural consequence of awakening the spirit of exploration and discovery that led Goldilocks into the forest and leads humans into space.

Batalha, N.

2014-07-01

414

Planet Quest Observing Cards  

NSDL National Science Digital Library

The PlanetQuest Observing Cards are designed to give telescope operators and other interpreters a new way of explaining the night sky. Relating common observing objects to our search for exoplanets makes these spectacular sights more understandable. These cards are a great resource for use at observing night events, providing new stories to tell about commonly viewed celestial objects.

415

Terrestrials Dwarf Planets  

E-print Network

Terrestrials Gas Giants Ice Giants Dwarf Planets The Solar System #12;Neptune Uranus Saturn Jupiter Density: 3900 ­ 5500 kg m-3 #12;Jupiter 318 ME 5.2 AU Uranus 15 ME 19.6 AUSaturn 95 ME 9.5 AU Neptune 17 3.88 RE Uranus Neptune Uranus and Neptune are Ice Giants made mostly of ices with thin Hydrogen

Gaudi, B. Scott

416

The Outer Planets  

NSDL National Science Digital Library

Students explore the outermost planets of our solar system: Saturn, Uranus and Neptune. They also learn about characteristics of Pluto and its interactions with Neptune. Students learn a little about the history of space travel as well as the different technologies that engineers develop to make space travel and scientific discovery possible.

Integrated Teaching and Learning Program,

417

Take a Planet Walk  

ERIC Educational Resources Information Center

Physical models in the classroom "cannot be expected to represent the full-scale phenomenon with complete accuracy, not even in the limited set of characteristics being studied" (AAAS 1990). Therefore, by modifying a popular classroom activity called a "planet walk," teachers can explore upper elementary students' current understandings; create an…

Schuster, Dwight

2008-01-01

418

External Resource: Clay Planets  

NSDL National Science Digital Library

In this activity, learners/students use given amounts of clay to create models of the solar system. Learners/students use clay to represent different planets and other objects in the solar system (asteroids, moons, etc.). The learners/students can use as

1900-01-01

419

Influence of spacer of gemini on the interactions between cationic gemini surfactant and stearic acid in mixed monolayers.  

PubMed

Mixed Langmuir-Blodgett (LB) films composed of a cationic gemini surfactant, [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, 6, 8, 10 and 12), and a fatty acid of stearic acid (SA) were studied by the pi-A isotherm measurement, as well as by AFM and FT-IR. The analysis of the mean molecular area, the excess area and the excess Gibbs free energy from pi-A isotherms suggests the existence of attractive interactions between 18-s-18 and SA molecules in the mixed monolayers. The spacer group of 18-s-18 plays a very important role in the surface properties of 18-s-18/SA mixed monolayers. When s < or = 8, 18-s-18 and SA are completely miscible, while partially miscible mixed monolayers are presented when s > 8. Especially, in the latter case, when s = 12, phase separation appears in two composition regions of X(SA) = 0.4-0.75 and X(SA) = 0.75-0.85, respectively. This miscible phenomenon is confirmed by AFM observation. The result of FT-IR indicates that when X(SA) < or = 0.67, SA could ionize completely and form a "cationic-anionic surfactant" with 18-s-18 owing to the electrostatic interaction between the head groups, while when X(SA) > 0.67, SA only partially ionizes, -COO(-) and -COOH coexist in mixed monolayers. PMID:20394381

Li, Rong; Chen, Qibin; Liu, Honglai; Hu, Ying

2010-06-15

420

Influence of Stellar Multiplicity on Planet Formation. II. Planets are Less Common in Multiple-star Systems with Separations Smaller than 1500 AU  

NASA Astrophysics Data System (ADS)

Almost half of the stellar systems in the solar neighborhood are made up of multiple stars. In multiple-star systems, planet formation is under the dynamical influence of stellar companions, and the planet occurrence rate is expected to be different from that of single stars. There have been numerous studies on the planet occurrence rate of single star systems. However, to fully understand planet formation, the planet occurrence rate in multiple-star systems needs to be addressed. In this work, we infer the planet occurrence rate in multiple-star systems by measuring the stellar multiplicity rate for planet host stars. For a subsample of 56 Kepler planet host stars, we use adaptive optics (AO) imaging and the radial velocity (RV) technique to search for stellar companions. The combination of these two techniques results in high search completeness for stellar companions. We detect 59 visual stellar companions to 25 planet host stars with AO data. Three stellar companions are within 2'' and 27 within 6''. We also detect two possible stellar companions (KOI 5 and KOI 69) showing long-term RV acceleration. After correcting for a bias against planet detection in multiple-star systems due to flux contamination, we find that planet formation is suppressed in multiple-star systems with separations smaller than 1500 AU. Specifically, we find that compared to single star systems, planets in multiple-star systems occur 4.5 ± 3.2, 2.6 ± 1.0, and 1.7 ± 0.5 times less frequently when a stellar companion is present at a distance of 10, 100, and 1000 AU, respectively. This conclusion applies only to circumstellar planets; the planet occurrence rate for circumbinary planets requires further investigation.

Wang, Ji; Fischer, Debra A.; Xie, Ji-Wei; Ciardi, David R.

2014-08-01

421

A downward revision to the distance of the 1806-20 cluster and associated magnetar from Gemini Near-Infrared Spectroscopy  

NASA Astrophysics Data System (ADS)

We present H- and K-band spectroscopy of OB and Wolf-Rayet (WR) members of the Milky Way cluster 1806-20 (G10.0-0.3) to obtain a revised cluster distance, of relevance to the 2004 giant flare from the (soft gamma repeater) SGR1806-20 magnetar. From GNIRS (Gemini Near-Infrared Spectrograph) spectroscopy obtained with Gemini South, four candidate OB stars are confirmed as late O/early B supergiants, while we support previous mid-WN and late WC classifications for two WR stars. Based upon an absolute Ks-band magnitude calibration for B supergiants and WR stars, and near-infrared (IR) photometry from NIRI (Near-Infrared Imager) at Gemini North plus archival VLT/ISAAC (Very Large Telescope/Infrared Spectrometer And Array Camera) data sets, we obtain a cluster distance modulus of 14.7 +/- 0.35mag. The known stellar content of the 1806-20 cluster suggests an age of 3-5Myr, from which theoretical isochrone fits infer a distance modulus of 14.7 +/- 0.7mag. Together, our results favour a distance modulus of 14.7 +/- 0.4mag (8.7+1.8-1.5kpc) to the 1806-20 cluster, which is significantly lower than the nominal 15kpc distance to the magnetar. For our preferred distance, the peak luminosity of the 2004 December giant flare is reduced by a factor of 3 to 7 × 1046ergs-1, such that the contamination of BATSE (Burst And Transient Source Experiment) short gamma-ray bursts (GRBs) from giant flares of extragalactic magnetars is reduced to a few per cent. We infer a magnetar progenitor mass of ~48+20-8Msolar, in close agreement with that obtained recently for the magnetar in Westerlund 1.

Bibby, J. L.; Crowther, P. A.; Furness, J. P.; Clark, J. S.

2008-05-01

422

Mean motion resonances from planet-planet scattering  

E-print Network

Planet-planet scattering is the leading mechanism to explain the large eccentricities of the observed exoplanet population. However, scattering has not been considered important to the production of pairs of planets in mean motion resonances (MMRs). We present results from a large number of numerical simulations of dynamical instabilities in 3-planet systems. We show that MMRs arise naturally in about five percent of cases. The most common resonances we populate are the 2:1 and 3:1 MMRs, although a wide variety of MMRs can occur, including high-order MMRs (up to eleventh order). MMRs are generated preferentially in systems with uneven mass distributions: the smallest planet is typically ejected after a series of close encounters, leaving the remaining, more massive planets in resonance. The distribution of resonant planets is consistent with the phase-space density of resonant orbits, meaning that planets are randomly thrown into MMRs rather than being slowly pulled into them. It may be possible to distinguish between MMRs created by scattering vs. convergent migration in a gaseous disk by considering planetary mass ratios: resonant pairs of planets beyond ~1 AU with more massive outer planets are likely to have formed by scattering. In addition, scattering may be responsible for pairs of planets in high-order MMRs (3:1 and higher) that are not easily populated by migration. The frequency of MMRs from scattering is comparable to the expected survival rate of MMRs in turbulent disks. Thus, planet-planet scattering is likely to be a major contributor to the population of resonant planets.

Sean N. Raymond; Rory Barnes; Philip J. Armitage; Noel Gorelick

2008-09-19

423

Planet frequency from microlensing observations  

NASA Astrophysics Data System (ADS)

Galactic gravitational microlensing is a very efficient technique to detect brown dwarfs and extrasolar planets at large orbital distances from their stars, and down to Earth-mass planets. More than 50 planets have been discovered so far, with 31 already published. Recent statistical results on the frequency of exoplanets based on several years of microlensing observations find that planets should be the rule rather than the exception, and confirm that super-Earth are much more frequent that giant planets in the Galaxy.

Cassan, A.; Ranc, C.

2014-12-01

424

Gemini near-infrared observations of Europa's Hydrated Surface Materials  

NASA Astrophysics Data System (ADS)

Europa is a highly dynamic icy moon of Jupiter. It is thought the moon harbors a subsurface ocean, with the potential to sustain life, with Europa being a key target of ESA's forthcoming Jupiter Icy Moons Orbiter (JUICE) mission. However, much is not known concerning the chemistry of the subsurface ocean. The surface is dominated by water ice, with a hydrated non-ice material component providing the distinctive albedo contrasts seen at visible and near