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1

The Gemini Planet Imager  

SciTech Connect

The next major frontier in the study of extrasolar planets is direct imaging detection of the planets themselves. With high-order adaptive optics, careful system design, and advanced coronagraphy, it is possible for an AO system on a 8-m class telescope to achieve contrast levels of 10{sup -7} to 10{sup -8}, sufficient to detect warm self-luminous Jovian planets in the solar neighborhood. Such direct detection is sensitive to planets inaccessible to current radial-velocity surveys and allows spectral characterization of the planets, shedding light on planet formation and the structure of other solar systems. We have begun the construction of such a system for the Gemini Observatory. Dubbed the Gemini Planet Imager (GPI), this instrument should be deployed in 2010 on the Gemini South telescope. It combines a 2000-actuator MEMS-based AO system, an apodized-pupil Lyot coronagraph, a precision infrared interferometer for real-time wavefront calibration at the nanometer level, and a infrared integral field spectrograph for detection and characterization of the target planets. GPI will be able to achieve Strehl ratios > 0.9 at 1.65 microns and to observe a broad sample of science targets with I band magnitudes less than 8. In addition to planet detection, GPI will also be capable of polarimetric imaging of circumstellar dust disks, studies of evolved stars, and high-Strehl imaging spectroscopy of bright targets. We present here an overview of the GPI instrument design, an error budget highlighting key technological challenges, and models of the system performance.

Macintosh, B; al., e

2006-05-02

2

The Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a next-generation adaptive optics coronagraph designed for direct imaging and spectroscopy of extrasolar planets and polarimetry of circumstellar disks. It is the first such facility-class instrument deployed on a 8-m telescope, designed to achieve contrast levels of up to 10^7. This allows observations of warm self-luminous planets, with masses greater than a Jupiter mass and ages less than a few hundred megayears. GPI will be used for a large-scale survey of 600 nearby young stars, as well as for guest observer science. I will present first-light science results and discuss the scientific capabilities of GPI.

Macintosh, Bruce

2014-06-01

3

Gemini Planet Imager autonomous software  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is an "extreme" adaptive optics coronagraph system that will have the ability to directly detect and characterize young Jovian-mass exoplanets. The design of this instrument involves eight principal institutions geographically spread across North America, with four of those sites writing software that must run seamlessly together while maintaining autonomous behaviour. The objective of the software teams is to provide Gemini with a unified software system that not only performs well but also is easy to maintain. Issues such as autonomous behaviour in a unified environment, common memory to share status and information, examples of how this is being implemented, plans for early software integration and testing, command hierarchy, plans for common documentation and updates are explored in this paper. The project completed its preliminary design phase in 2007, and has just recently completed its critical design phase.

Dunn, Jennifer; Wooff, Robert; Smith, Malcolm; Kerley, Dan; Palmer, Dave; Jones, Steve; Weiss, Jason; Angione, John; Graham, James R.

2008-08-01

4

The Gemini Planet Imager coronagraph testbed  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a new facility instrument to be commissioned at the 8-m Gemini South telescope in early 2011. It combines of several subsystems including a 1500 subaperture Extreme Adaptive Optics system, an Apodized Pupil Lyot Coronagraph, a near-infrared high-accuracy interferometric wavefront sensor, and an Integral Field Unit Spectrograph, which serves as the science instrument. GPI's main scientific goal is to detect and characterize relatively young (<2GYr), self luminous planets with planet-star brightness ratios of <= 10-7 in the near infrared. Here we present an overview of the coronagraph subsystem, which includes a pupil apodization, a hard-edged focal plane mask and a Lyot stop. We discuss designs optimization, masks fabrication and testing. We describe a near infrared testbed, which achieved broadband contrast (H-band) below 10-6 at separations > 5?/D, without active wavefront control (no deformable mirror). We use Fresnel propagation modeling to analyze the testbed results.

Soummer, Rémi; Sivaramakrishnan, Anand; Oppenheimer, Ben R.; Roberts, Robin; Brenner, Douglas; Carlotti, Alexis; Pueyo, Laurent; Macintosh, Bruce; Bauman, Brian; Saddlemyer, Les; Palmer, David; Erickson, Darren; Dorrer, Christophe; Caputa, Kris; Marois, Christian; Wallace, Kent; Griffiths, Emily; Mey, Jacob

2009-08-01

5

Wavefront control for the Gemini Planet Imager  

SciTech Connect

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

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

2006-04-14

6

Gemini Planet Imager coronagraph testbed results  

NASA Astrophysics Data System (ADS)

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

Sivaramakrishnan, Anand; Soummer, Rémi; Oppenheimer, Ben R.; Carr, G. Lawrence; Mey, Jacob L.; Brenner, Doug; Mandeville, Charles W.; Zimmerman, Neil; Macintosh, Bruce A.; Graham, James R.; Saddlemyer, Les; Bauman, Brian; Carlotti, Alexis; Pueyo, Laurent; Tuthill, Peter G.; Dorrer, Christophe; Roberts, Robin; Greenbaum, Alexandra

2010-07-01

7

The Gemini Planet Imager: integration and status  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager is a next-generation instrument for the direct detection and characterization of young warm exoplanets, designed to be an order of magnitude more sensitive than existing facilities. It combines a 1700-actuator adaptive optics system, an apodized-pupil Lyot coronagraph, a precision interferometric infrared wavefront sensor, and a integral field spectrograph. All hardware and software subsystems are now complete and undergoing integration and test at UC Santa Cruz. We will present test results on each subsystem and the results of end-to-end testing. In laboratory testing, GPI has achieved a raw contrast (without post-processing) of 10-6 5? at 0.4", and with multiwavelength speckle suppression, 2x10-7 at the same separation.

Macintosh, Bruce A.; Anthony, Andre; Atwood, Jennifer; Barriga, Nicolas; Bauman, Brian; Caputa, Kris; Chilcote, Jeffery; Dillon, Daren; Doyon, René; Dunn, Jennifer; Gavel, Donald T.; Galvez, Ramon; Goodsell, Stephen J.; Graham, James R.; Hartung, Markus; Isaacs, Joshua; Kerley, Dan; Konopacky, Quinn; Labrie, Kathleen; Larkin, James E.; Maire, Jerome; Marois, Christian; Millar-Blanchaer, Max; Nunez, Arturo; Oppenheimer, Ben R.; Palmer, David W.; Pazder, John; Perrin, Marshall; Poyneer, Lisa A.; Quirez, Carlos; Rantakyro, Frederik; Reshtov, Vlad; Saddlemyer, Leslie; Sadakuni, Naru; Savransky, Dmitry; Sivaramakrishnan, Anand; Smith, Malcolm; Soummer, Remi; Thomas, Sandrine; Wallace, J. Kent; Weiss, Jason; Wiktorowicz, Sloane

2012-09-01

8

Gemini Planet Imager: Preliminary Design Report  

SciTech Connect

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

Macintosh, B

2007-05-10

9

The Gemini Planet Imager: from science to design to construction  

NASA Astrophysics Data System (ADS)

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 10-7. 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, Bruce A.; Graham, James R.; Palmer, David W.; Doyon, René; Dunn, Jennifer; Gavel, Donald T.; Larkin, James; Oppenheimer, Ben; Saddlemyer, Les; Sivaramakrishnan, Anand; Wallace, J. Kent; Bauman, Brian; Erickson, Darren A.; Marois, Christian; Poyneer, Lisa A.; Soummer, Remi

2008-07-01

10

Campaign Scheduling and Analysis for the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

The Gemini Planet Image (GPI) is a new, high-contrast, exoplanet-imaging, facility instrument for the Gemini South observatory, scheduled to begin science observations in 2014. The GPI Exoplanet Survey (GPIES) has been awarded 890 hours to image and spectrally and polarimetrically characterize young, giant planets within 100 parsecs of the solar system. In preparation for the survey, we have developed a framework for simulating GPI observations and generating end-to-end survey simulations. We present new extensions to this modeling effort and our latest results. We discuss systematic methods for scheduling the survey to ensure that the population of discovered planets is useful in constraining formation models and possibly distinguishing between gravitational collapse and core accretion as the primary formation mechanism.

Savransky, Dmitry; Macintosh, Bruce A.; Graham, James; Konopacky, Quinn M.

2014-01-01

11

Integration and test of the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

Exoplanet imaging is driving a race to higher contrast imaging, both from earth and from space. Next-generation instruments such as the Gemini Planet Imager (GPI) and SPHERE are designed to achieve contrast ratios of 10-6 - 10-7 this requires very good wavefront correction and coronagraphic control of diffraction. GPI is a facility instrument, now in integration and test, with first light on the 8-m Gemini South telescope expected by the middle of 2012. It combines a 1700 subaperture AO system using a MEMS deformable mirror, an apodized-pupil Lyot coronagraph, a high-accuracy IR interferometric wavefront calibration system, and a nearinfrared integral field spectrograph to allow detection and characterization of self-luminous extrasolar planets at planet/star contrast ratios of 10-7. In this paper we will discuss the status of the integration and test now taking place at the University of Santa Cruz California.

Thomas, Sandrine J.; Poyneer, Lisa; de Rosa, Rob; Macintosh, Bruce; Dillon, Daren; Wallace, James K.; Palmer, David; Gavel, Donald; Bauman, Brian; Saddlemyer, Leslie; Goodsell, Stephen

2011-09-01

12

Gemini Planet Imager: From Integration And Test To Planning Observations  

NASA Astrophysics Data System (ADS)

Achieving higher contrast is an ongoing theme in exoplanet imaging, both from earth and from space. Next-generation instruments such as the Gemini Planet Imager and SPHERE are designed to achieve contrast ratios of 106 - 107 from the ground; this requires very good static and dynamic wavefront correction as well as very good coronagraphic control of diffraction. GPI is a facility instrument, now in integration and test at the Laboratory for Adaptive Optics in Santa Cruz California. Its first light on the 8-m Gemini South telescope is expected by the end of 2012. GPI combines a high density MEMS deformable mirror (1700 subapertures), an apodized-pupil Lyot coronagraph and a high-accuracy IR interferometer calibration system. The instrument is a near-infrared integral field spectrograph (IFS) that will allow detection and characterization of self-luminous extrasolar planets at planet/star contrast ratios of 10-7. One additional feature of the IFS is a polarimetric mode to characterize scattered light from disks. We will discuss the status of the integration and test happening at the University of Santa Cruz California and discuss its scientific capabilities.

Thomas, Sandrine; Macintosh, B.; Palmer, D.; Saddlemyer, L.; Wallace, J. K.; Gavel, D.; Larkin, J.; Graham, J.; Doyon, R.; Oppenheimer, B.; GOODSell, S.; GPI Team

2012-01-01

13

Wavefront sensing and correction with the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

High-contrast imaging is a growing observational technique aimed at discovering and characterizing extrasolar planets. The Gemini Planet Imager (GPI) is designed to achieve contrast ratios of 10-6 - 10-7 and requires unprecedented wavefront correction and coronagraphic control of diffraction. G PI is a facility instrument now undergoing integration and testing and is scheduled for first light on the 8-m Gemini South telescope towards the end of 2012. In this paper, we focus on the wavefront sensing and correction aspects of the instrument. To measure the wavefront, GPI combines a Shack-Hartmann wavefront sensor and a high-accuracy infrared interferometric wavefront calibration system. The Shack-Hartmann wavefront sensor uses 1700 subapertures to precisely sample the wavefront at 1.5 kHz and features a spatial filter to prevent aliasing. The wavefront calibration system measures the slower temporal frequency errors as well as non-common path aberrations. The wavefront correction is performed using a two-stage adaptive optics system employing a 9x9 piezoelectric deformable mirror and a 43x43 actuators MEMS deformable mirror operating in a woofer-tweeter configuration. Finally, an image sharpening technique is used to further increase the contrast of the final image. In this paper, we describe the three wavefront sensing methods and how we combine their respective information to achieve the best possible contrast.

Thomas, S.; Poyneer, L.; Savransky, D.; Macintosh, B.; Hartung, M.; Dillon, D.; Gavel, D.; Dunn, Jennifer; Wallace, K.; Palmer, D.; De Rosa, Robert

2012-07-01

14

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

15

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

16

Adaptive optics for direct detection of extrasolar planets: the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

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 10-7 of their parent star, sufficient to observe warm self-luminous planets around a large population of targets. To cite this article: B. Macintosh et al., C. R. Physique 8 (2007).

Macintosh, Bruce; Graham, James; Palmer, David; Doyon, Rene; Gavel, Don; Larkin, James; Oppenheimer, Ben; Saddlemyer, Leslie; Wallace, J. Kent; Bauman, Brian; Erikson, Darren; Poyneer, Lisa; Sivaramakrishnan, Anand; Soummer, Rémi; Veran, Jean-Pierre

2007-04-01

17

Detectability of Exoplanets in the beta Pic Moving Group with the Gemini Planet Imager  

Microsoft Academic Search

We model the detectability of exoplanets around stars in the beta Pic Moving Group (BPMG) using the Gemini Planet Imager (GPI), a coronagraphic instrument designed to detect companions by imaging. Members of the BPMG are considered promising targets for exoplanet searches because of their youth (~12 Myr) and proximity (median distance ~35 pc). We wrote a modeling procedure to generate

Tiffany Kataria; Michal Simon

2010-01-01

18

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

19

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

NASA Astrophysics Data System (ADS)

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, Lisa A.; Bauman, Brian; Cornelissen, Steven; Isaacs, Joshua; Jones, Steven; Macintosh, Bruce A.; Palmer, David W.

2011-02-01

20

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

21

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

22

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

23

The Gemini Near-Infrared Imager (NIRI)  

Microsoft Academic Search

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

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

2003-01-01

24

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

25

The Gemini NICI Planet-Finding Campaign: Discovery of a Close Substellar Companion to a Young Solar Analog  

Microsoft Academic Search

We report the discovery of a tight substellar companion detected with high contrast adaptive optics imaging as part of the Gemini NICI Planet-Finding Campaign. The companion was detected at a projected separation of 0.360±0.003''. Second-epoch observations a year later demonstrate that the companion is not a background star and that it shows significant orbital motion. The near-IR colors of the

B. A. Biller; M. C. Liu; Z. Wahhaj; E. L. Nielsen; L. M. Close; T. Dupuy; T. L. Hayward; A. Burrows; M. Chun; C. Ftaclas; F. Clarke; M. Hartung; M. Tecza; N. Thatte

2010-01-01

26

High-Resolution Speckle Imaging at Gemini-North: Exoplanets and Beyond  

NASA Astrophysics Data System (ADS)

Using our state-of-the-art 2-channel speckle imaging instrument, we have recently obtained diffraction-limited optical images at the 8-m Gemini-N telescope. The primary science goal was to search for faint (delta_mag = 4-6 mag) and nearby (<0.05") stellar companions around potential planet hosting stars as part of the small small exoplanet validation for the NASA Kepler and ESA CoRoT missions. As a demonstration of the instrument capabilities on Gemini, we achieved an angular resolution of ~20 mas which yielded the highest resolution ground-based optical image of the Pluto-Charon system ever obtained. Our instrument is likely to return to Gemini-N in mid-2013 for observations by general community programs

Howell, Steve B.; Horch, E.; Everett, M. E.; Ciardi, D.

2013-01-01

27

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

Microsoft Academic Search

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

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

2010-01-01

28

Gemini Mid-Infrared Imaging of AB Auriga  

Microsoft Academic Search

We present mid-infrared images of the Herbig star AB Auriga at 11.6 and 18.5 um taken with Michelle on Gemini North. The mid-infrared emission around the star is interpreted as arising from two components. A strong hotter emission close to the star is resolved at 11.6 and 18.5 um with sizes 17 +\\/- 2 AU and 21 +\\/- 3 AU

N. Marinas; C. M. Telesco

2004-01-01

29

Direct imaging of multiple planets orbiting the star HR 8799.  

PubMed

Direct imaging of exoplanetary systems is a powerful technique that can reveal Jupiter-like planets in wide orbits, can enable detailed characterization of planetary atmospheres, and is a key step toward imaging Earth-like planets. Imaging detections are challenging because of the combined effect of small angular separation and large luminosity contrast between a planet and its host star. High-contrast observations with the Keck and Gemini telescopes have revealed three planets orbiting the star HR 8799, with projected separations of 24, 38, and 68 astronomical units. Multi-epoch data show counter clockwise orbital motion for all three imaged planets. The low luminosity of the companions and the estimated age of the system imply planetary masses between 5 and 13 times that of Jupiter. This system resembles a scaled-up version of the outer portion of our solar system. PMID:19008415

Marois, Christian; Macintosh, Bruce; Barman, Travis; Zuckerman, B; Song, Inseok; Patience, Jennifer; Lafrenière, David; Doyon, René

2008-11-28

30

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

31

Image resolution for ERTS, SKYLAB, and GEMINI/APOLLO  

USGS Publications Warehouse

Early in 1972 the first Earth Resource Technology Satellite (ERTS-A) is scheduled for launch in near-polar orbit. It will carry three return-beam-vidicon (RBV) TB cameras and a multispectral scanner (MSS). In 1973 a post-Apollo manned space flight called SKYLAB will orbit the earth at an inclination of 50° to the Equator. In addition to other sensors it will carry a battery of six multispectral cameras identified as experiment S190. This paper compares the images expected from ERTS and SKYLAB with those already obtained from GEMINI/APOLLO, all in terms of the photographic criterion of resolution. Recently provided data have led to several changes in the resolution of ERTS-A forecast a year ago (Colvocoresses, 1970).

Colvocoresses, Alden P.

1972-01-01

32

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

NASA Astrophysics Data System (ADS)

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

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

2003-03-01

33

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

34

Deep Imaging of Giant Planets  

NASA Astrophysics Data System (ADS)

With the development of high contrast imaging instruments and techniques, vast efforts have been devoted during the past decade to detect and characterize lighter, cooler and closer companions to nearby stars, and ultimately image new planetary systems. Complementary to other observing techniques (radial velocity, transit, micro-lensing, pulsar-timing and astrometry), this approach has opened a new astrophysical window to study the physical properties and the formation and evolution mechanisms of giant planets at orbits larger than a few AUs. In this review, I will briefly present the main motivations to use deep imaging to search for exoplanets and review the constant progress achieved thanks to improved performances of advanced instrumentation and data analysis techniques. I will describe the main classes of stars identified and observed so far to increase the chances of detection. I will also detail the classical strategy adopted to identify false alarms and characterize true companions. I will review the current status of the different deep imaging surveys as well as the main results that recently led to the discovery of giant planets probably formed like the ones of our solar system. Finally, I will rise the questions and uncertainties related to the formation mechanisms, the physical properties and the frequency of these planetary mass companions to conclude with the exciting and attractive perspectives offered with the future generation of deep imaging instruments.

Chauvin, G.

2010-10-01

35

Gemini Mid-Infrared Imaging of Massive Young Stellar Objects in NGC 3576  

Microsoft Academic Search

We present a mid-infrared study of NGC 3576. The high-resolution images were\\u000ataken at the Gemini South Observatory through narrow and broad band filters\\u000acentered between 7.9 micron and 18 micron. The nearly diffraction limited\\u000aimages show IRS 1 resolved into 4 sources for the first time in the 10 micron\\u000aband. The positions of the sources are coincident with

C. L. Barbosa; A. Damineli; R. D. Blum; P. S. Conti

2003-01-01

36

Beta Pictoris planet finally imaged?  

NASA Astrophysics Data System (ADS)

A team of French astronomers using ESO's Very Large Telescope have discovered an object located very close to the star Beta Pictoris, and which apparently lies inside its disc. With a projected distance from the star of only 8 times the Earth-Sun distance, this object is most likely the giant planet suspected from the peculiar shape of the disc and the previously observed infall of comets onto the star. It would then be the first image of a planet that is as close to its host star as Saturn is to the Sun. Sharpening Up Jupiter ESO PR Photo 42a/08 Beta Pictoris as seen in infrared light The hot star Beta Pictoris is one of the best-known examples of stars surrounded by a dusty 'debris' disc. Debris discs are composed of dust resulting from collisions among larger bodies like planetary embryos or asteroids. They are a bigger version of the zodiacal dust in our Solar System. Its disc was the first to be imaged -- as early as 1984 -- and remains the best-studied system. Earlier observations showed a warp of the disc, a secondary inclined disc and infalling comets onto the star. "These are indirect, but tell-tale signs that strongly suggest the presence of a massive planet lying between 5 and 10 times the mean Earth-Sun distance from its host star," says team leader Anne-Marie Lagrange. "However, probing the very inner region of the disc, so close to the glowing star, is a most challenging task." In 2003, the French team used the NAOS-CONICA instrument (or NACO [1]), mounted on one of the 8.2 m Unit Telescopes of ESO's Very Large Telescope (VLT), to benefit from both the high image quality provided by the Adaptive Optics system at infrared wavelengths and the good dynamics offered by the detector, in order to study the immediate surroundings of Beta Pictoris. Recently, a member of the team re-analysed the data in a different way to seek the trace of a companion to the star. Infrared wavelengths are indeed very well suited for such searches. "For this, the real challenge is to identify and subtract as accurately as possible the bright stellar halo," explains Lagrange. "We were able to achieve this after a precise and drastic selection of the best images recorded during our observations." The strategy proved very rewarding, as the astronomers were able to discern a feeble, point-like glow well inside the star's halo. To eliminate the possibility that this was an artefact and not a real object, a battery of tests was conducted and several members of the team, using three different methods, did the analysis independently, always with the same success. Moreover, the companion was also discovered in other data sets, further strengthening the team's conclusion: the companion is real. "Our observations point to the presence of a giant planet, about 8 times as massive as Jupiter and with a projected distance from its star of about 8 times the Earth-Sun distance, which is about the distance of Saturn in our Solar System [2]," says Lagrange. "We cannot yet rule out definitively, however, that the candidate companion could be a foreground or background object," cautions co-worker Gael Chauvin. "To eliminate this very small possibility, we will need to make new observations that confirm the nature of the discovery." The team also dug into the archives of the Hubble Space Telescope but couldn't see anything, "while most possible foreground or background objects would have been detected", remarks another team member, David Ehrenreich. The fact that the candidate companion lies in the plane of the disc also strongly implies that it is bound to the star and its proto-planetary disc. "Moreover, the candidate companion has exactly the mass and distance from its host star needed to explain all the disc's properties. This is clearly another nail in the coffin of the false alarm hypothesis," adds Lagrange. When confirmed, this candidate companion will be the closest planet from its star ever imaged. In particular, it will be located well inside the orbits of

2008-11-01

37

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

38

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

SciTech Connect

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

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

2010-10-10

39

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

NASA Technical Reports Server (NTRS)

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

Marley, Mark Scott; Sengupta, Sujan

2012-01-01

40

On the road to imaging extrasolar planets: Null results, other discoveries along the way, and signposts for the future  

NASA Astrophysics Data System (ADS)

I present my experiences designing, conducting, and analyzing the results from direct imaging surveys for extrasolar giant planets. Using the young, low-mass star AB Dor C, I show that models for low-mass stars and brown dwarfs at young ages are good representations of reality. I discuss the design of the Simultaneous Differential Imaging survey, and how Monte Carlo simulations of giant planet populations allow for the design of imaging surveys, including the choice of target list, that maximizes the expected yield of extrasolar planets. With the conclusion of the SDI survey, I examine how its null result for planets sets constraints on the allowable populations of long-period exoplanets, finding that fewer than 8% of sun-like stars can have planets more massive than 4M Jup between 20 and 100 AU, at 68% confidence. When I include null results from other direct imaging surveys, these constraints are further strengthened: at 68% confidence, fewer than 20% of sun-like stars can have planets more massive than 4M Jup , at orbital semi-major axes between 8.1 and 911 AU. Even when applying the mass scaling of Johnson et al. (2007), and the "cold start" planet luminosity models of Fortney et al. (2008), the results remain consistent: giant planets are rare at large separations around sun-like stars. I explain how these constraints and planet simulations were used to design the Gemini South NICI Planet-Finding Campaign survey and target list, in order to maximize the chance of NICI detecting a planet, and so giving the campaign the greatest ability to strongly constrain populations of extrasolar giant planets, even in the case of a null result. Finally, I discuss future directions for direct imaging planet searches, and the steps needed to move from existing surveys to a truly unified distribution of extrasolar planet populations.

Nielsen, Eric Ludwig

41

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

42

Near infrared imaging of the outer planets  

NASA Technical Reports Server (NTRS)

In the last year we have continued our program of near infrared imaging of the outer planets of the solar system. Uranus is virtually invisible at 2.3 microns, showing that the methane is an effective absorber of the incident sunlight and that there is very little aerosol content in the upper atmosphere. On the other hand, Neptune shows a haze present over the entire Northern Hemisphere at 2.3 microns. This leads to the inference that there is an aerosol layer at a high altitude. We have recovered the Neptune satellite, 1989 N1, which was first discovered in Voyager images. The satellite is exceedingly faint in the near infrared, and was detectable only because the planet itself was comparatively faint at this wavelength. Observations of this satellite, coupled with the Voyager images, permit us to substantially refine the satellite's orbit, and hence carefully probe the gravitational field of Neptune.

Matthews, K.; Soifer, B. T.

1991-01-01

43

Subaru and Gemini High Spatial Resolution Infrared 18 ?m Imaging Observations of Nearby Luminous Infrared Galaxies  

NASA Astrophysics Data System (ADS)

We present the results of a ground-based, high spatial resolution infrared 18 ?m imaging study of nearby luminous infrared galaxies (LIRGs), using the Subaru 8.2 m and Gemini-South 8.1 m telescopes. The diffraction-limited images routinely achieved with these telescopes in the Q band (17-23 ?m) allow us to investigate the detailed spatial distribution of infrared emission in these LIRGs. We then investigate whether the emission surface brightnesses are modest, as observed in starbursts, or are so high that luminous active galactic nuclei (AGNs; high emission surface brightness energy sources) are indicated. The sample consists of 18 luminous buried AGN candidates and starburst-classified LIRGs identified in earlier infrared spectroscopy. We find that the infrared 18 ?m emission from the buried AGN candidates is generally compact, and the estimated emission surface brightnesses are high, sometimes exceeding the maximum value observed in and theoretically predicted for a starburst phenomenon. The starburst-classified LIRGs usually display spatially extended 18 ?m emission and the estimated emission surface brightnesses are modest, within the range sustained by a starburst phenomenon. The general agreement between infrared spectroscopic and imaging energy diagnostic methods suggests that both are useful tools for understanding the hidden energy sources of the dusty LIRG population.

Imanishi, Masatoshi; Imase, Keisuke; Oi, Nagisa; Ichikawa, Kohei

2011-05-01

44

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

NASA Astrophysics Data System (ADS)

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

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

2008-07-01

45

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

46

Extreme adaptive optics planet imager: XAOPI  

NASA Astrophysics Data System (ADS)

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 107-108 at angular separations of 0.2-0.8" 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, Bruce A.; Graham, James; Poyneer, Lisa; Sommargren, Gary; Wilhelmsen, Julia; Gavel, Don; Jones, Steve; Kalas, Paul; Lloyd, James P.; Makidon, Russ; Olivier, Scot; Palmer, Dave; Patience, Jennifer; Perrin, Marshall; Severson, Scott; Sheinis, Andrew; Sivaramakrishnan, Anand; Troy, Mitch; Wallace, J. K.

2003-11-01

47

The Gemini/FLAMINGOS-2 Galactic Center Survey: ISPI Pre-imaging  

NASA Astrophysics Data System (ADS)

We propose to use ISPI to carry out a pre-imaging survey for the upcoming FLAMINGOS-2 Galactic Center Survey (F2GCS). The F2GCS will provide moderate-resolution (R ~ 1300) 1.5-2.4 (micron) spectra of ~ 5000 objects in the Galactic Center (GC) region using approximately 15 nights of guaranteed time observations on Gemini with FLAMINGOS-2 in 2006-2008. The survey will yield spectral identification of ~ 300 infrared counterparts to Chandra X-ray binaries in the GC, providing important constraints on the massive star formation history here and dramatically increasing the known population of such systems suitable for multi-wavelength follow-up studies. It will also provide age and luminosity class measurements of ~ 2000 red giant stars, providing the first statistically-significant constraints on the star formation history of the GC region (to one degree in Galacto- centric radius), which can in turn be used to constrain the mass evolution of the supermassive black hole in Sgr A* and thus the bulge/black-hole correlation in galaxies. In order to carry this out, we request 2 nights with ISPI on the CTIO 4-meter telescope.

Eikenberry, Stephen S.; Blum, Robert; Muno, Mike; Bandyopadhyay, Reba; Olsen, Knut; Sellgren, Kris

2005-08-01

48

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

49

Direct Imaging of Planet Transit Events  

NASA Astrophysics Data System (ADS)

Exoplanet transit events are attractive targets for the ultrahigh-resolution capabilities afforded by optical interferometers. The intersection of two developments in astronomy enable direct imaging of exoplanet transits: first, improvements in sensitivity and precision of interferometric instrumentation; and second, identification of ever-brighter host stars. Efforts are underway for the first direct high-precision detection of closure phase signatures with the CHARA Array and Navy Precision Optical Interferometer. When successful, these measurements will enable recovery of the transit position angle on the sky, along with characterization of other system parameters, such as stellar radius, planet radius, and other parameters of the transit event. This technique can directly determine the planet's radius independent of any outside observations, and appears able to improve substantially upon other determinations of that radius; it will be possible to extract wavelength dependence of that radius determination, for connection to characterization of planetary atmospheric composition & structure. Additional directly observed parameters - also not dependent on transit photometry or spectroscopy - include impact parameter, transit ingress time, and transit velocity.

van Belle, Gerard T.; von Braun, Kaspar; Boyajian, Tabetha; Schaefer, Gail

2014-04-01

50

Study of Spin-Scan Imaging for Outer Planets Missions.  

National Technical Information Service (NTIS)

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. Pos...

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

1974-01-01

51

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

52

Images of a fourth planet orbiting HR 8799.  

PubMed

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

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

2010-12-23

53

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

54

Direct Imaging of Warm Extrasolar Planets.  

National Technical Information Service (NTIS)

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 gr...

B. Macintosh

2005-01-01

55

Absolute quantification of activity content from PET images using the Philips Gemini TF PET/CT system.  

PubMed

Positron emission tomography combined with computed tomography (PET/CT) is a quantitative technique suitable for diagnostics and uptake measurements. The quantitative results can be used for the purpose of the calculating absorbed dose to patients undergoing nuclear medicine investigations. Hence, the accuracy of the quantification of the activity content in organs or tissues is of great importance. When using a planar gamma camera and single photon emission computed tomography (SPECT) images, the activity content in organs and tumours has to be determined by the user, using the number of counts in the organs and the efficiency of the camera. However, when using a Philips Gemini TF PET/CT system, the activity concentration in a region of interest (ROI) is given by the system. The reliability of activity concentration values given by the Philips Gemini TF PET/CT system was studied using a Jaszczak phantom containing hot spheres of different sizes; the influence of the ROI size and the impact of organ size, that is the partial volume effect, was investigated with three different lesion-to-background ratios in the phantom. The use of a small ROI size (40 % of the large ROI size, which covered the entire sphere) showed a 15 % improvement in the recovery of the true activity. Small lesion sizes result in large underestimations of the activity concentration values. PMID:20223853

Sydoff, M; Uusijärvi, H; Leide-Svegborn, S; Mattsson, S

2010-01-01

56

eXtreme Adaptive Optics Planet Imager: Overview and Status.  

National Technical Information Service (NTIS)

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. ...

B. A. Macintosh B. Bauman J. W. Evans J. Graham C. Lockwood

2004-01-01

57

Apodized Pupil Lyot Coronagraphs: Concepts and application to the Gemini Planet Imager  

Microsoft Academic Search

This paper summarizes the general theory and properties for Apodized Pupil Lyot Coronagraphs which consist of a classical hard-edged Lyot coronagraph with an upstream pupil apodization. The ideal apodization function can be determined from an integral eigenvalue problem which solutions are prolate spheroidal functions. Solutions exist for any geometrty, including rectangular, circular, or elliptical. Formal solutions can be extended to

Rémi Soummer; Claude Aime; André Ferrari; Anand Sivaramakrishnan; Ben R. Oppenheimer; Russell Makidon; Bruce Macintosh

2006-01-01

58

Gemini Spectroscopy and HST Imaging of the Stellar Cluster Population in Region B of M82  

NASA Astrophysics Data System (ADS)

We present new spectroscopic observations of the stellar cluster population of region B in the prototype starburst galaxy M82 obtained with the Gemini North 8.1 m telescope. By coupling the spectroscopy with UBVI photometry acquired with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST), we derive ages, extinctions, and radial velocities for seven young massive clusters (YMCs) in region B. We find the clusters to have ages between 80 and 200 Myr and velocities in the range 230-350 km s-1, while the extinctions AV vary between ~1 and 2.5 mag. We also find evidence of differential extinction across the faces of some clusters, which hinders the photometric determination of ages and extinctions in these cases. The cluster radial velocities indicate that the clusters are located at different depths within the disk and are on regular disk orbits. Our results overall contradict the findings of previous studies, in which region B was thought to be a bound region populated by intermediate-age clusters that formed in an independent, offset starburst episode that commenced 600 Myr-1 Gyr ago. Our findings instead suggest that region B is optically bright because of low-extinction patches, and that this allows us to view the cluster population of the inner M82 disk, which probably formed as a result of the last encounter with M81. This study forms part of a series of papers whose aim is to study the cluster population of M82 using deep optical spectroscopy and multiband photometry. 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), CNPq (Brazil), and CONICET (Argentina). Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 10853.

Konstantopoulos, I. S.; Bastian, N.; Smith, L. J.; Trancho, G.; Westmoquette, M. S.; Gallagher, J. S., III

2008-02-01

59

Exozodiacal Dust and Direct Imaging of Extrasolar Planets  

NASA Technical Reports Server (NTRS)

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

Kuchner, Marc

2008-01-01

60

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

61

Speckle Imaging of Kepler Exo-planet Transit Candidate Stars  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

62

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

NASA Astrophysics Data System (ADS)

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 our solar system exist at wider separations and dusty disks frequently exceed 100 AU, some with evidence for perturbing planets in wide orbits. To probe the 5-100 AU range different techniques are needed. Direct detection of photons emitted by extrasolar planets is one such technique, but requires contrast levels of 107-109 at near-infrared wavelengths. We have designed an adaptive optics (AO) system capable of reaching these contrasts. XAOPI, the eXtreme Adaptive Optics Planet Imager, is a proposed 4096-actuator adaptive optics system for an 8-10m telescope. It will achieve Strehl ratios >0.9, and is optimized to remove scattered light from 0.2-1 arcseconds, even light scattered by errors in a segmented primary mirror. Simulations predict that it will achieve contrast ratios of 107 -108 for target stars with R<7. Monte Carlo analysis of target samples shows that this allows detection of near-IR emission from warm extrasolar planets younger and/or more massive than Jupiter around a significant sample of target stars. We will examine the scientific rationale for, and capabilities of, this proposed instrument. This work has been supported by the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement No. AST - 987 Portions of this work were also performed under the auspices of the U.S. Department of Energy, National Nuclear Security Administration by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

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

2003-05-01

63

Occulter Based Missions of Different Scales for Terrestrial Planet Imaging  

Microsoft Academic Search

Free flying occulters are an attractive option as a space mission architecture for imaging exosolar planets, particular ones in the habitable zone. Their appeal is two-fold: the inner working angle is largely decoupled from telescope diameter and, because they suppress starlight before entering the telescope, there is no need for wavefront control. We present the basic operating principles of occulters

N. J. Kasdin; D. N. Spergel; R. Vanderbei; S. Shaklan; D. P. Lisman; D. Savransky; E. Cady; R. Soummer

2010-01-01

64

Direct Imaging Search for Extrasolar Planets in the Pleiades  

NASA Astrophysics Data System (ADS)

We carried out an imaging survey for extrasolar planets around stars in the Pleiades (125 Myr, 135 pc) in the H and KS bands using HiCIAO combined with adaptive optics, AO188, on the Subaru telescope. We found 13 companion candidates fainter than 14.5 mag in the H band around 9 stars. Five of these 13 were confirmed to be background stars by measurement of their proper motion. One was not found in the second epoch observation, and thus was not a background or companion object. One had multi-epoch images, but the precision of its proper motion was not sufficient to conclude whether it was a background object. Four other candidates are waiting for second-epoch observations to determine their proper motion. Finally, the remaining two were confirmed to be 60 MJ brown dwarf companions orbiting around HD 23514 (G0) and HII 1348 (K5), respectively, as had been reported in previous studies. In our observations, the average detection limit for a point source was 20.3 mag in the H band beyond 1.5' from the central star. On the basis of this detection limit, we calculated the detection efficiency to be 90% for a planet with 6 to 12 Jovian masses and a semi-major axis of 50-1000 AU. For this reason we extrapolated the distribution of the planet mass and the semi-major axis derived from radial velocity observations, and adopted the planet evolution model Baraffe et al. (2003, A&A, 402, 701). Since there was no detection of a planet, we estimated the frequency of such planets to be less than 17.9% (2 ? ) around one star of the Pleiades cluster.

Yamamoto, Kodai; Matsuo, Taro; Shibai, Hiroshi; Itoh, Yoichi; Konishi, Mihoko; Sudo, Jun; Tanii, Ryoko; Fukagawa, Misato; Sumi, Takahiro; Kudo, Tomoyuki; Hashimoto, Jun; Kusakabe, Nobuhiko; Abe, Lyu; Brandner, Wolfgang; Brandt, Timothy D.; Carson, Joseph; Currie, Thayne; Egner, Sebastian E.; Feldt, Markus; Goto, Miwa; Grady, Carol; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko; Henning, Thomas; Hodapp, Klaus; Ishii, Miki; Iye, Masanori; Janson, Markus; Kandori, Ryo; Knapp, Gillian R.; Kuzuhara, Masayuki; Kwon, Jungmi; McElwain, Mike; Miyama, Shoken; Morino, Jun-Ichi; Moro-Martin, Amaya; Nishikawa, June; Nishimura, Tetsuo; Pyo, Tae-Soo; Serabyn, Eugene; Suto, Hiroshi; Suzuki, Ryuji; Takami, Michihiro; Takato, Naruhisa; Terada, Hiroshi; Thalmann, Christian; Tomono, Daigo; Turner, Edwin L.; Wisniewski, John; Watanabe, Makoto; Yamada, Toru; Takami, Hideki; Usuda, Tomonori

2013-08-01

65

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

66

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

67

Microemulsions based on anionic gemini surfactant  

Microsoft Academic Search

Oil in water microemulsions were prepared using didodecyldiphenylether disulfonate gemini-type surfactant (C12-DADS), water, oil (toluene) and a co-solvent (short chain alcohol such as 1-propanol). The phase diagrams for microemulsions with gemini surfactants were determined and compared to those of structurally related surfactants, monododecyldiphenylether disulfonate (C12-MADS) and monododecyldiphenylether monosulfonate (C12-MAMS). Conductivity measurements and direct imaging by cryo-TEM were performed to characterize

S Magdassi; M Ben Moshe; Y Talmon; D Danino

2003-01-01

68

SPHERE: the VLT planet imager in the post FDR phase  

NASA Astrophysics Data System (ADS)

SPHERE, the ESO extra-solar planet imager for the VLT is aimed at the direct detection and spectral characterization of extra-solar planets. Its whole design is optimized towards reaching the highest contrast in a limited field of view and at short distances from the central star. SPHERE has passed its Final Design Review (FDR) in December 2008 and it is in the manufacturing and integration phase. We review the most challenging specifications and expected performance of this instrument; then we present the latest stage of the design chosen to meet the specifications, the progress in the manufacturing as well as the integration and test strategy to insure gradual verification of performances at all levels.

Wildi, Francois; Beuzit, Jean-Luc; Feldt, Markus; Mouillet, David; Dohlen, Kjetil; Puget, Pascal; Baruffolo, Andrea; Charton, Julien; Baudoz, Pierre; Boccaletti, Anthony; Abe, Lyu; Claudi, Riccardo; Feautrier, Philippe; Fusco, Thierry; Gratton, Raffaele; Hubin, Norbert; Kasper, Markus; Langlois, Maud; Lenzen, Rainer; Pavlov, Alexey; Petit, Cyril; Pragt, Johan; Rabou, Patrick; Roelfsema, Ronald; Saisse, Michel; Schmid, Hans Martin; Stadler, Eric; Moutou, Claire; Turatto, Massimo; Udry, Stephane; Waters, Rens; Henning, Thomas; Lagrange, Anne-Marie; Vakili, Farrokh

2009-08-01

69

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.

Grimwood, James

1968-06-01

70

Image Retrieval of Earth-like Planets from Light Curves  

NASA Astrophysics Data System (ADS)

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

Kawahara, Hajime; Fujii, Yuka

2014-04-01

71

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

72

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

73

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

74

Possible planet-forming regions on submillimetre images  

NASA Astrophysics Data System (ADS)

Submillimetre images of transition discs are expected to reflect the distribution of the optically thin dust. Former observation of three transition discs LkH? 330, SR 21N and HD 1353444B at submillimetre wavelengths revealed images which cannot be modelled by a simple axisymmetric disc. We show that a large-scale anticyclonic vortex that develops where the viscosity has a large gradient (e.g. at the edge of the disc dead zone), might be accountable for these large-scale asymmetries. We modelled the long-term evolution of vortices being triggered by the Rossby wave instability. We found that a horseshoe-shaped (azimuthal wavenumber m = 1) large-scale vortex forms by coalescing of smaller vortices within 5 × 104 yr, and can survive on the disc lifetime (˜5 × 106 yr), depending on the magnitude of global viscosity and the thickness of the viscosity gradient. The two-dimensional grid-based global disc simulations with local isothermal approximation and compressible-gas model have been done by the GPU version of hydrodynamic code FARGO (GFARGO). To calculate the dust continuum image at submillimetre wavelengths, we combined our hydrodynamical results with a three-dimensional radiative transfer code. By the striking similarities of the calculated and observed submillimetre images, we suggest that the three transition discs can be modelled by a disc possessing a large-scale vortex formed near the disc dead zone edge. Since the larger dust grains (larger than mm in size) are collected in these vortices, the non-axisymmetric submillimetre images of the above transition discs might be interpreted as active planet and planetesimal-forming regions situated far (?50 au) from the central stars.

Regály, Zs.; Juhász, A.; Sándor, Zs.; Dullemond, C. P.

2012-01-01

75

Occulter Based Missions of Different Scales for Terrestrial Planet Imaging  

NASA Astrophysics Data System (ADS)

Free flying occulters are an attractive option as a space mission architecture for imaging exosolar planets, particular ones in the habitable zone. Their appeal is two-fold: the inner working angle is largely decoupled from telescope diameter and, because they suppress starlight before entering the telescope, there is no need for wavefront control. We present the basic operating principles of occulters for high-contrast, including preliminary stationkeeping simulations, and a manufacturing approach being studied as part of NASA's Technology Demonstration for Exoplanet Missions. Our main focus is a comparison of mission architectures employing occulters at varying scales: large flagship observatories (THEIA, NWO), existing large aperture telescopes (JWST), small dedicated telescopes (O3), and small general purpose telescopes (such as a dark energy mission like EUCLID). THEIA, the Telescope for Habitable Exoplanets and Interstellar/Intergalactic Astronomy, is a multi-instrument space-telescope concept employing a 4-m diffraction-limited telescope operating at UV and Visible wavelengths that was developed as part of NASAs Astrophysics Strategic Mission Concept Studies in 2009 and presented to the US Academy's decadal survey review, Astro2010. By combining the telescope with a roughly 40 m occulter, operating at two different telescope-occulter separations, planets as small as Earth can be characterized over a broad band, including R>70 spectra. O3, the Occulting Ozone Observatory, is a smaller mission costing less than 1B that uses a 1 to 2 m telescope combined with a roughly 30 m occulter. O3 is capable of time-resolved photometry over 8 bands, focusing on biomarkers, such as detecting the strong ozone feature, and surface characterization. It also provides the capability for enough repeat visits to support orbit determination. We will compare the science yield and architecture and how different coronagraph and occulter approaches perform at these different mission scales.

Kasdin, N. J.; Spergel, D. N.; Vanderbei, R.; Shaklan, S.; Lisman, D. P.; Savransky, D.; Cady, E.; Soummer, R.

2010-10-01

76

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

NASA Technical Reports Server (NTRS)

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

Cady, Eric

2011-01-01

77

Gemini 7 Lunar Measurements.  

National Technical Information Service (NTIS)

Radiometric and interferometric measurements were made of the lunar surface during a penumbral eclipse from the Gemini 7 spacecraft. Data were obtained in the region from 0.25 to 2.6 microns. The bond albedo of the moon is computed for the spectral region...

T. P. Condron J. J. Lovett W. H. Barnes L. Marcotte R. Nadile

1968-01-01

78

On the Misalignment of the Directly Imaged Planet ? Pictoris b with the System's Warped Inner Disk  

NASA Astrophysics Data System (ADS)

The vertical warp in the debris disk ? Pictoris —an inclined inner disk extending into a flat outer disk— has long been interpreted as the signpost of a planet on an inclined orbit. Direct images spanning 2004-2010 have revealed ? Pictoris b, a planet with a mass and orbital distance consistent with this picture. However, it was recently reported that the orbit of planet b is aligned with the flat outer disk, not the inclined inner disk, and thus lacks the inclination to warp the disk. We explore three scenarios for reconciling the apparent misalignment of the directly imaged planet ? Pictoris b with the warped inner disk of ? Pictoris: observational uncertainty, an additional planet, and damping of planet b's inclination. We find that, at the extremes of the uncertainties, the orbit of ? Pictoris b has the inclination necessary to produce the observed warp. We also find that if planet b were aligned with the flat outer disk, it would prevent another planet from creating a warp with the observed properties; therefore planet b itself must be responsible for the warp. Finally, planet b's inclination could have been damped by dynamical friction and still produce the observed disk morphology, but the feasibility of damping depends on disk properties and the presence of other planets. More precise observations of the orbit of planet b and the position angle of the outer disk will allow us to distinguish between the first and third scenarios. R.I.D. acknowledges support by NSF Graduate Research Fellowship DGE-1144152 and D.C.F. by NASA Hubble Fellowship HF-51272.01.

Dawson, Rebekah Ilene; Murray-Clay, R. A.; Fabrycky, D. C.

2012-05-01

79

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

NASA Technical Reports Server (NTRS)

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

Kuchner, Marc

2009-01-01

80

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

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

81

Planet Formation Instrument for the Thirty Meter Telescope  

SciTech Connect

In the closing years of the 20th Century humankind began its exploration of the planetary systems in the solar neighborhood. Precision radial velocity measurements have now yielded the discovery of over 160 planets. Direct imaging of these planets, as opposed to detection of the effects of orbital motion on their parent star, is now feasible, and the first young planet in a wide orbit may have been detected using adaptive optics systems. Gemini and the VLT are building the first generation of high contrast adaptive optics systems, which deliver planet-imaging performance within few Airy rings of the host star. These systems will make the first surveys of the outer regions of solar systems by detecting the self-luminous radiation of young planets. These instruments will establish whether Jovian planets form predominantly through 'top-down' (global gravitational instability) or 'bottom-up' (core accretion) processes. The 8-m 'extreme' AO systems cannot see close enough to the host stars to image Doppler planets, and they cannot reach the relatively distant, young clusters and associations where planets are forming. The Planet Formation Instrument will use the nearly four-fold improved angular resolution of TMT to peer into the inner solar systems of Doppler-planet bearing stars to yield a unified sample of planets with known Keplerian orbital elements and atmospheric properties. In star formation regions, where T Tauri stars (young solar type stars) are found in abundance, PFI can see into the snow line, where the icy cores of planets like Jupiter must have formed. Thus, TMT will be the first facility to witness the formation of new planets.

Macintosh, B; Troy, M; Graham, J; Doyon, R

2006-02-22

82

Measuring the Orbits of Exo-Earths in Multiple-Planet Systems: The Synergy of Direct Imaging and Astrometry  

NASA Astrophysics Data System (ADS)

The holy grail of exoplanet searches is an Earth mass planet orbiting in the habitable zone around a nearby star. A single image of a planet, however, does not provide evidence that it is Earth mass or that it orbits in the habitable zone. The measurement of an orbit by direct imaging is complicated by a number of factors. One is the inner working angle (IWA). A space coronagraph or interferometer imaging an exo-Earth can separate the light from the planet from the starlight only when the star-planet separation exceeds the IWA. Secondly, a planet's apparent brightness and color depend on the phase angle. Thirdly, confusion that may arise from the presence of multiple planets. With two images of a multiple planet system, it is impossible to assign a dot to a planet based only on the photometry and color of the planet. Finally, the planet-star contrast must exceed a certain minimum value in order for the planet to be detected. The planet may be unobservable even when it is outside the IWA, as when the bright side of the planet faces away from us in a `crescent’ phase. For a coronagraphic mission, the detection of a planet and measurement of its orbit requires a moderately large number of images, compromising the ability of some types of coronagraphs from searching a large number of stars for exo-Earths. We examine the effect of confusion on imaging surveys. We investigate the synergy between astrometry and imaging, and we conclude that this synergy offers the most efficient and realistic road to detect and characterize exo-Earths in habitable zone around nearby stars. The research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Catanzarite, Joseph; Shao, M.; Pan, X.

2010-05-01

83

A high contrast survey for extrasolar giant planets with the Simultaneous Differential Imager (SDI)  

Microsoft Academic Search

We present the results of a survey of 45 young (< 250 Myr), close (< 50 pc) stars with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT for the direct detection of extrasolar planets. Our SDI devices use a double Wollaston prism and a quad filter to take images simultaneously at three wavelengths surrounding the 1.62

Beth Alison Biller

2007-01-01

84

Computer vision applications for coronagraphic optical alignment and image processing  

NASA Astrophysics Data System (ADS)

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; Thomas, Sandrine J.; Poyneer, Lisa A.; Macintosh, Bruce A.

2013-05-01

85

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

86

A Confirmed Directly Imaged Planet Orbiting a Nearby Young, Dusty Star  

NASA Astrophysics Data System (ADS)

We present new VLT/NaCo infrared (Lp/3.8 micron) high-contrast imaging observations of a nearby, young (13--21 Myr old) star known to be surrounded by a luminous Kuiper belt-like debris disk. Using multiple reduction pipelines, we unambiguously detect a faint companion located interior to the disk at a projected separation of ~55 AU in four separate data sets between 2012 and 2013. The companion’s astrometry is decisively inconsistent with that of a background object. Combining our Lp photometry with sensitive upper limits at shorter wavelengths shows that the companion has red colors characteristic of young jovian planets with an inferred mass of 3--7 Mj, making it potentially the lowest mass planet imaged thus far. This planet will be a benchmark for further physical and orbital characterization of young gas giants.

Currie, Thayne M.; Rameau, J.; Chauvin, G.; Lagrange, A.; Boccaletti, A.; Meshkat, T.; Quanz, S.; Girard, J.; Bonnefoy, M.; Kenworthy, M. A.

2014-01-01

87

An Interactive Icon Index: Images of the Outer Planets  

Microsoft Academic Search

We are interested in the exploratory analysis of large collections of complex objects. As an example, we are studying a large collection of digital images that has nearly 30,000 members. We regard each image in the collection as an individual observation. To facilitate our study we construct an index of the images in the collection. The index uses a small

William F. Eddy; Audris Mockus

1996-01-01

88

Lucky imaging of transiting planet host stars with LuckyCam  

NASA Astrophysics Data System (ADS)

We obtained high-resolution, high-contrast optical imaging in the Sloan Digital Sky Survey i' band with the LuckyCam camera mounted on the 2.56 m Nordic Optical Telescope, to search for faint stellar companions to 16 stars harbouring transiting exoplanets. The Lucky imaging technique uses very short exposures to obtain near diffraction-limited images yielding sub-arcsecond sensitivity, allowing us to search for faint stellar companions within the seeing disc of the primary planet host. Here, we report the detection of two candidate stellar companions to the planet host TrES-1 at separations <6.5 arcsec and we confirm stellar companions to CoRoT-2, CoRoT-3, TrES-2, TrES-4 and HAT-P-7 already known in the literature. We do not confirm the candidate companions to HAT-P-8 found via Lucky imaging by Bergfors et al., however, most probably because HAT-P-8 was observed in poor seeing conditions. Our detection sensitivity limits allow us to place constraints on the spectral types and masses of the putative bound companions to the planet host stars in our sample. If bound, the stellar companions identified in this work would provide stringent observational constraints to models of planet formation and evolution. In addition, these companions could affect the derived physical properties of the exoplanets in these systems.

Faedi, F.; Staley, T.; Gómez Maqueo Chew, Y.; Pollacco, D.; Dhital, S.; Barros, S. C. C.; Skillen, I.; Hebb, L.; Mackay, C.; Watson, C. A.

2013-08-01

89

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

Microsoft Academic Search

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

Olivier Guyon

2003-01-01

90

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

91

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

NASA Astrophysics Data System (ADS)

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

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

2008-09-01

92

A Moon Based Telescope To Detect and Image Extrasolar Planets  

NASA Astrophysics Data System (ADS)

A Moon-based telescope, suitably configured and equipped, can be employed as a low cost precursor to the Terrestrial Planet Finder mission. The concept is based in part on the ideas of Nisenson and Papaliolios (ApJ. Lett. 548:L201-205, 2001). The Moon is a highly stable observing platform. An advanced non-contact cryogenic bearing mechanism can provide super precise tracking and pointing. The telescope can use field rotation caused by lunar diurnal motion to sweep the optical diffraction pattern around a target star. The primary mirror is to be square, very lightweight, 1-2 meter on the side, with an off-axis shape. It must also have a highly precise optical figure and a superpolished surface. We suggest how such a mirror can be fabricated -at an affordable cost- using a process currently under development. Some preliminary laboratory test results will be presented. In addition, a variety of other advanced spacecraft technologies - propulsion, fuel saving trajectories, thermal management, low mass power systems and landers, etc. - can be combined to significantly reduce mission cost.

Kondo, Y.; Oliversen, R. J.; Lowman, P.; Chen, P. C.

2001-12-01

93

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

94

Direct Exoplanet\\/Disk Search Around Young & Nearby Early-Type Stars; The International Deep Planet Survey (IDPS)  

Microsoft Academic Search

We propose to continue a deep AO survey for exoplanets around young and close A- and F-type stars using a refined version of the very successful Angular Differential Imaging technique, which distinguishes true companions\\/disks from artifacts through sidereal rotation. Stars as massive as A- and early F-type stars have been neglected in AO searches, including the Gemini Deep Planet Survey,

Christian Marois; Bruce Macintosh; Jennifer Patience; Rene Doyon; Benjamin Zuckerman; Inseok Song; David Lafreniere; Travis Barman

2008-01-01

95

Stellar companions to exoplanet host stars: Lucky Imaging of transiting planet hosts  

NASA Astrophysics Data System (ADS)

Observed properties of stars and planets in binary/multiple star systems provide clues to planet formation and evolution. We extended our survey for visual stellar companions to the hosts of transiting exoplanets by 21 stars, using the Lucky Imaging technique with the two AstraLux instruments: AstraLux Norte at the Calar Alto 2.2-m telescope and AstraLux Sur at the European Southern Observatory 3.5-m New Technology Telescope at La Silla. Typically, a sensitivity to companions of magnitude difference ?z' ? 4 is achieved at angular separation ? = 0.5 arcsec and ?z' ? 6 for ? = 1 arcsec. We present observations of two previously unknown binary candidate companions, to the transiting planet host stars HAT-P-8 and WASP-12, and derive photometric and astrometric properties of the companion candidates. The common proper motions of the previously discovered companion candidates with the exoplanet host stars TrES-4 and WASP-2 are confirmed from follow-up observations. A Bayesian statistical analysis of 31 transiting exoplanet host stars observed with AstraLux suggests that the companion star fraction of planet hosts is not significantly different from that of solar-type field stars, but that the binary separation is on average larger for planet host stars.

Bergfors, C.; Brandner, W.; Daemgen, S.; Biller, B.; Hippler, S.; Janson, M.; Kudryavtseva, N.; Geißler, K.; Henning, T.; Köhler, R.

2013-01-01

96

Constraints on Extrasolar Planet Populations from VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations  

NASA Astrophysics Data System (ADS)

We examine the implications for the distribution of extrasolar planets based on the null results from two of the largest direct imaging surveys published to date. Combining the measured contrast curves from 22 of the stars observed with the VLT NACO adaptive optics system by Masciadri and coworkers and 48 of the stars observed with the VLT NACO SDI and MMT SDI devices by Biller and coworkers (for a total of 60 unique stars), we consider what distributions of planet masses and semimajor axes can be ruled out by these data, based on Monte Carlo simulations of planet populations. We can set the following upper limit with 95% confidence: the fraction of stars with planets with semimajor axis between 20 and 100 AU, and mass above 4 MJup, is 20% or less. Also, with a distribution of planet mass of dN/dM~M-1.16 in the range of 0.5-13 MJup, we can rule out a power-law distribution for semimajor axis (dN/da~a?) with index 0 and upper cutoff of 18 AU, and index -0.5 with an upper cutoff of 48 AU. For the distribution suggested by Cumming et al., a power-law of index -0.61, we can place an upper limit of 75 AU on the semimajor axis distribution. In general, we find that even null results from direct imaging surveys are very powerful in constraining the distributions of giant planets (0.5-13 MJup) at large separations, but more work needs to be done to close the gap between planets that can be detected by direct imaging, and those to which the radial velocity method is sensitive.

Nielsen, Eric L.; Close, Laird M.; Biller, Beth A.; Masciadri, Elena; Lenzen, Rainer

2008-02-01

97

Beyond Kepler: Direct Imaging of Earth-like Planets  

NASA Technical Reports Server (NTRS)

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

Belikov, Ruslan

2012-01-01

98

A Subaru SEEDS Imaging Search for Extrasolar Planets Around Early-Type Stars  

NASA Astrophysics Data System (ADS)

We present a status report on the Subaru SEEDS sub-program to search for extra-solar 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 high-mass star sub-program uses the Subaru 8-meter Telescope, a 188 actuator curvature AO system (AO188), and a near infrared imaging science camera (HiCIAO) to search for exoplanet signatures. We describe the early-type star target sample, science goals, observing procedures, and early results.

Carson, Joseph; Thalmann, C.; Janson, M.; Kozakis, T.; Wong, P.; Goto, M.; Henning, T.; Brandner, W.; Biller, B.; Bonnefoy, M.; Feldt, M.; McElwain, M.; Kandori, R.; Tamura, M.; SEEDS Team

2012-01-01

99

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

100

How Do Images Help Us Learn About Our Planet Earth?  

NSDL National Science Digital Library

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

101

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

NASA Astrophysics Data System (ADS)

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

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

2005-08-01

102

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

103

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

104

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.

Arnett, Bill

105

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

106

Constraints on Extrasolar Planet Populations from VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations  

NASA Astrophysics Data System (ADS)

We examine the implications for the distribution of extrasolar planets based on the null results from two of the largest direct imaging surveys published to date. Combining the measured contrast curves from Masciadri et al. (2005) and Biller et al. (2007), we consider what distributions of planet masses and semi-major axes can be ruled out by these data, based on Monte Carlo simulations of planet populations. We can set the following upper limit with 95% confidence: the fraction of stars with planets with semi-major axis between 20 and 100 AU, and mass above 4 MJup, is 20% or less. Also, with a distribution of planet mass of {dN}/{dM} ? M-1.16 in the range of 0.5-13 M Jup , we can rule out a power-law distribution for semi-major axis ({dN}/{da} ? a?) with index 0 and upper cut-off of 18 AU, and index -0.5 with an upper cut-off of 48 AU. For the distribution suggested by Cumming et al. (2008), a power-law of index -0.61, we can place an upper limit of 75 AU on the semi-major axis distribution.

Nielsen, E. L.; Close, L. M.; Biller, B. A.; Masciadri, E.; Lenzen, R.

2010-01-01

107

Multiplicity and properties of Kepler planet candidates: High spatial imaging and RV studies  

NASA Astrophysics Data System (ADS)

The Kepler space telescope is discovering thousands of new planet candidates. However, a follow up program is needed in order to reject false candidates and to fully characterize the bona-fide exoplanets. Our main aims are: 1./ Detect and analyze close companions inside the typical Kepler PSF to study if they are the responsible of the dim in the Kepler light curves, 2./ Study the change in the stellar and planetary parameters due to the presence of an unresolved object, 3./ Help to validate those Kepler Objects of Interest that do not present any object inside the Kepler PSF and 4./ Study the multiplicity rate in planet host candidates. Such a large sample of observed planet host candidates allows us to do statistics about the presence of close (visual or bounded) companions to the harboring star. We present here Lucky Imaging observations for a total amount of 98 Kepler Objects of Interest. This technique is based on the acquisition of thousands of very short exposure time images. Then, a selection and combination of a small amount of the best quality frames provides a high resolution image with objects having a 0.1 arcsec PSF. We applied this technique to carry out observations in the Sloan i and Sloan z filters of our Kepler candidates. We find blended objects inside the Kepler PSF for a significant percentage of KOIs. On one hand, only 58.2% of the hosts do not present any object within 6 arcsec. On the other hand, we have found 19 companions closer than 3 arcsec in 17 KOIs. According to their magnitudes and i - z color, 8 of them could be physically bounded to the host star. We are also collecting high-spectral resolution spectroscopuy in order to derive the planet properties. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC)

Barrado, D.; Lillo-Box, J.; Bouy, H.; Aceituno, J.; Sánchez, S.

2013-04-01

108

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

109

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

110

Adaptive Optics Images. II. 12 Kepler Objects of Interest and 15 Confirmed Transiting Planets  

NASA Astrophysics Data System (ADS)

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

Adams, E. R.; Dupree, A. K.; Kulesa, C.; McCarthy, D.

2013-07-01

111

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

112

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

113

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

114

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

115

The Nine Planets: Mercury  

NSDL National Science Digital Library

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

Arnett, Bill

116

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

117

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

118

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.

Arnett, Bill

119

Searching for Brown Dwarfs using the Gemini Science Archive  

NASA Astrophysics Data System (ADS)

The Gemini Science Archive (GSA) is a repository for all data taken on the two Gemini telescopes. After an 18 months proprietary period, these data are made available to the astronomical community. We have obtained from the GSA several high galactic latitude GMOS deep field images to search for L and T field brown dwarfs (BDs). We present analysis of two fields each imaged in two SDSS filters, i' and z'. We have used GAIA/SExtractor to identify and characterize point-like sources with i'-z'>2. These deep GSA images contain potential brown dwarfs with i'<24 magnitudes. These are sources which have a photometric errors <=10%. Future spectroscopy and J-band photometry will allow us to separate true BDs from high redshift quasars, which have similar optical colors.

Coulson, Dolores; Aspin, C.; Geballe, T. R.

2007-05-01

120

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

NASA Astrophysics Data System (ADS)

Observations of Uranus were made in September 2009 with the Gemini-North telescope in Hawaii, using both the NIFS and NIRI instruments. Observations were acquired in Adaptive Optics mode and have a spatial resolution of approximately 0.1?. NIRI images were recorded with three spectral filters to constrain the overall appearance of the planet: J, H-continuum and CH 4(long), and long slit spectroscopy measurements were also made (1.49-1.79 ?m) with the entrance slit aligned on Uranus' central meridian. To acquire spectra from other points on the planet, the NIFS instrument was used and its 3? × 3? field of view stepped across Uranus' disc. These observations were combined to yield complete images of Uranus at 2040 wavelengths between 1.476 and 1.803 ?m. The observed spectra along Uranus central meridian were analysed with the NEMESIS retrieval tool and used to infer the vertical/latitudinal variation in cloud optical depth. We find that the 2009 Gemini data perfectly complement our observations/conclusions from UKIRT/UIST observations made in 2006-2008 and show that the north polar zone at 45°N has continued to steadily brighten while that at 45°S has continued to fade. The improved spatial resolution of the Gemini observations compared with the non-AO UKIRT/UIST data removes some of the earlier ambiguities with our previous analyses and shows that the opacity of clouds deeper than the 2-bar level does indeed diminish towards the poles and also reveals a darkening of the deeper cloud deck near the equator, perhaps coinciding with a region of subduction. We find that the clouds at 45°N,S lie at slightly lower pressures than the clouds at more equatorial latitudes, which suggests that they might possibly be composed of a different condensate, presumably CH 4 ice, rather than H 2S or NH 3 ice, which is assumed for the deeper cloud. In addition, analysis of the centre-to-limb curves of both the Gemini/NIFS and earlier UKIRT/UIST IFU observations shows that the main cloud deck has a well-defined top, and also allows us to better constrain the particle scattering properties. Overall, Uranus appeared to be less convectively active in 2009 than in the previous 3 years, which suggests that now the northern spring equinox (which occurred in 2007) is passed the atmosphere is settling back into the quiescent state seen by Voyager 2 in 1986. However, a number of discrete clouds were still observed, with one at 15°N found to lie near the 500 mb level, while another at 30°N, was seen to be much higher at near the 200 mb level. Such high clouds are assumed to be composed of CH 4 ice.

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

2011-03-01

121

GAPS IN THE HD 169142 PROTOPLANETARY DISK REVEALED BY POLARIMETRIC IMAGING: SIGNS OF ONGOING PLANET FORMATION?  

SciTech Connect

We present H-band Very Large Telescope/NACO polarized light images of the Herbig Ae/Be star HD 169142 probing its protoplanetary disk as close as {approx}0.''1 to the star. Our images trace the face-on disk out to {approx}1.''7 ({approx}250 AU) and reveal distinct substructures for the first time: (1) the inner disk ({approx}<20 AU) appears to be depleted in scattering dust grains; (2) an unresolved disk rim is imaged at {approx}25 AU; (3) an annular gap extends from {approx}40 to 70 AU; (4) local brightness asymmetries are found on opposite sides of the annular gap. We discuss different explanations for the observed morphology among which ongoing planet formation is a tempting, but yet to be proven, one. Outside of {approx}85 AU the surface brightness drops off roughly {proportional_to}r {sup -3.3}, but describing the disk regions between 85-120 AU and 120-250 AU separately with power laws {proportional_to}r {sup -2.6} and {proportional_to}r {sup -3.9} provides a better fit hinting toward another discontinuity in the disk surface. The flux ratio between the disk-integrated polarized light and the central star is {approx}4.1 Multiplication-Sign 10{sup -3}. Finally, combining our results with those from the literature, {approx}40% of the scattered light in the H band appears to be polarized. Our results emphasize that HD 169142 is an interesting system for future planet formation or disk evolution studies.

Quanz, Sascha P.; Avenhaus, Henning; Garufi, Antonio; Schmid, Hans Martin [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Buenzli, Esther [Department of Astronomy and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Wolf, Sebastian, E-mail: sascha.quanz@astro.phys.ethz.ch [Institute of Theoretical Physics and Astrophysics, University of Kiel, Leibnizstrasse 15, D-24098 Kiel (Germany)

2013-03-20

122

Welcome to the Gemini Observatory  

NSDL National Science Digital Library

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

Michaud, Peter

2010-01-05

123

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

124

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

125

All Planet Sizes  

NSDL National Science Digital Library

This image, from the Lunar and Planetary Laboratory, illustrates the approximate relative sizes of the Sun and planets and their relative locations. Although distance is not to scale, viewers can see that the small rocky planets are located close to the Sun and large gaseous planets are further away.

2010-11-30

126

Target positioning and alignment on the Astra-Gemini facility  

NASA Astrophysics Data System (ADS)

The drive to ever higher intensities and the move to shorter focal length reflective optics for focussing in solid target interactions are increasingly important for studies into high intensity secondary source generation, QED and high field studies. To ensure reproducible optimum interaction conditions, presents a significant problem for accurate target positioning. Commercial optical systems exist to aid the imaging and positioning of targets. However, these are often expensive and difficult to situate within the limited space usually available inside the interaction chamber. At the Astra-Gemini system of the Central Laser Facility, the push for intensities above I = 1021 Wcm-2 with f/2 and f/1 focussing optics means positioning targets within the Rayleigh range of < few microns. Here, we present details of two systems to be implemented on the Astra-Gemini system to cheaply and accurately position targets with ? micron accuracy. These involve:- (i) a multi-wavelength interferometer to enable sub-micron accuracy in the positioning of the front surface at the interaction point within the Rayleigh range and (ii) a small, low cost near field/far field microscope with illumination at 800nm (the same as the Gemini IR beam) for imaging the rear of the target and the focal plane with high resolution. The combination of these two systems significantly improves our accuracy in target positioning and also results in a decrease in the time required to align targets between shots.

Booth, N.; Ettlinger, O.; Neely, D.; Pattathil, R.; Sellers, A.; Symes, D.

2013-09-01

127

The Nine Planets: Earth  

NSDL National Science Digital Library

This page contains details about the planet Earth. Information includes planet diameter, mass, distance from the Sun, orbit, and mythology. Also covered is planet composition, surface features, atmosphere and magnetic field data, temperature on planet, and data on its satellite: the Moon. Links are provided to more images, movies, and information about the Earth and Moon. This site discusses unanswered questions about Earth as well.

Arnett, Bill

128

Gemini surfactants from natural amino acids.  

PubMed

In this review, we report the most important contributions in the structure, synthesis, physicochemical (surface adsorption, aggregation and phase behaviour) and biological properties (toxicity, antimicrobial activity and biodegradation) of Gemini natural amino acid-based surfactants, and some potential applications, with an emphasis on the use of these surfactants as non-viral delivery system agents. Gemini surfactants derived from basic (Arg, Lys), neutral (Ser, Ala, Sar), acid (Asp) and sulphur containing amino acids (Cys) as polar head groups, and Geminis with amino acids/peptides in the spacer chain are reviewed. PMID:24238395

Pérez, Lourdes; Pinazo, Aurora; Pons, Ramon; Infante, Mrosa

2014-03-01

129

Overview of the Gemini Science Archive  

NASA Astrophysics Data System (ADS)

The Gemini Science Archive (GSA) is a new archive developed by the Canadian Astronomy Data Centre (CADC) with the aim to provide the scientific community with tools for effective on-line access to data collected by the Gemini telescopes. The first version of the GSA basic archive was released in September 2004, with subsequent releases containing advanced capabilities to follow. This paper depicts the overall architecture of the GSA basic archive, the product of a fruitful collaboration between the data provider (Gemini Observatories) and the development team (CADC).

Damian, A.; Goliath, S.; Gaudet, S.; Bohlender, D.; Hill, N.; Melnychuk, G.; Aspin, C.

2005-12-01

130

Redshift survey in the Linx Gemini region  

SciTech Connect

The study of the redshift distribution on a complete sample of galaxies brighter than 14.5 mph has been accomplished over an area encompassing about 1800 square degrees in Linx and Gemini. The main result is the discovery of a new filament of galaxies in Gemini, at a radial velocity of 4800 km/s, mainly composed of spirals. The possible connection of the cloud of galaxies around the cluster A569, the new filament in Gemini and the Linx Ursa Major supercluster with the Perseus supercluster is briefly discussed. 16 references.

Focardi, P.; Marano, B.

1984-01-01

131

Mercury Sodium Atmosphere Spectral Imager (MSASI) - taking High Resolution Interferometry to the Planets  

NASA Astrophysics Data System (ADS)

The Mercury Sodium Atmosphere Spectral Imager (MSASI) on the Mercury Magnetospheric Orbiter of the JAXA / ESA Bepi-Colombo (BC) Mission will address a range of fundamental scientific questions pertaining to Mercury's exosphere. The measurements will provide new information on regolith-exosphere-magnetosphere coupling as well as new understanding of the dynamics governing the exosphere bounded by the planetary surface, the solar wind and interplanetary space. MSASI is a high-dispersion visible spectrometer working in the spectral region near the sodium D2 emission (589 nm), a major constituent of the Mercury exosphere. A single high-resolution Fabry-Perot etalon is used in combination with a narrow-band interference filter to achieve a compact and efficient instrument design. The etalon and filter are extremely stable with respect to long-term ageing and temperature variations. Full-disk images of the planet are obtained by means of a single-axis scanning mirror in combination with the spin of the MMO spacecraft . This paper presents an overview of the MSASI and the design of the Fabry- Perot interferometer used as its spectral analyser. It is concluded that: (1) The MSASI optical design is practical and can be implemented without new or critical technology developments; (2) The thermally-stable etalon design is based on concepts, designs and materials that have a good space heritage. (3) The MSASI instrument will achieve a high SNR (˜10) in the range of 2K-10M Rayleigh.

Yoshikawa, Ichiro; Kameda, Shingo; Korablev, Oleg; Rees, David

132

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

133

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

134

Independent confirmation of ? Pictoris b imaging with NICI  

NASA Astrophysics Data System (ADS)

Context. Ever since it was identified with VLT/NaCo as a bona-fide exoplanet with a mass of about 9 times that of Jupiter at an orbital separation of 8-9 AU, ? Pictoris b has been one of the most studied objects nowadays. The link between the planet and the dusty disk is unambiguously confirmed, and this system provides an opportunity to study the disk/planet interactions and to constrain formation and evolutionary models of giant gas planets. Still, ? Pictoris b has never been confirmed with other telescopes so far. Aims: We aimed at an independent confirmation using a different instrument. Methods: We retrieved archive images from Gemini South obtained with the instrument NICI, which is designed for high-contrast imaging. The observations combine coronagraphy and angular differential imaging and were obtained at three epochs in Nov. 2008, Dec. 2009, and Dec. 2010. Results: We report the detection with NICI of the planet ? Pictoris b in Dec. 2010 images at a separation of 404 ± 10 mas and PA = 212.1 ± 0.7°. It is the first time this planet has been observed with a different telescope than the VLT. Based on data retrieved from the Gemini archive.

Boccaletti, A.; Lagrange, A.-M.; Bonnefoy, M.; Galicher, R.; Chauvin, G.

2013-03-01

135

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

136

Gemini PI Electronic Transfer and Distribution (PIETD)  

NASA Astrophysics Data System (ADS)

The Gemini Science Archive (GSA) has been developed and is operated by the Canadian Astronomy Data Centre (CADC) to provide the worldwide scientific community with tools for effective on-line access to data collected by the Gemini telescopes. In the past year, the CADC has developed tools to allow Gemini staff to automatically create and distribute Science Program data packages to Principal Investigators (PI). The tools operate in the GSA databases to create linkages between science files, calibration files, weather files, log files and science programs and assemble them upon user request. All data distribution is performed electronically via data retrieval from the CADC data stores. This automation results in significant manpower savings for Gemini relieving staff from the manual assembly of files and production of hard media. The complete version of PIETD, including the distribution of processed data products, was released in the fall of 2005.

Gaudet, S.; Bohlender, D.; Damian, A.; Goliath, S.; Hill, N.; Melnychuk, G.; Aspin, C.

2006-07-01

137

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

138

MMT/AO 5 ?m Imaging Constraints on the Existence of Giant Planets Orbiting Fomalhaut at ~13-40 AU  

NASA Astrophysics Data System (ADS)

A candidate lsim3 M Jup extrasolar planet was recently imaged by Kalas et al. using Hubble Space Telescope/Advanced Camera for Surveys and Keck II at 12farcs7 (96 AU) separation from the nearby (d = 7.7 pc) young (~200 Myr) A2V star Fomalhaut. Here, we report results from M-band (4.8 ?m) imaging of Fomalhaut on 2006 December 5 using the Clio IR imager on the 6.5 m MMT with the adaptive secondary mirror. Our images are sensitive to giant planets at orbital radii comparable to the outer solar system (~10-40 AU). Comparing our 5? M-band photometric limits to theoretical evolutionary tracks for substellar objects, our results rule out the existence of planets with masses >2 M Jup from ~13 to 40 AU and objects >13 M Jup from ~8 to 40 AU. Observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution.

Kenworthy, Matthew A.; Mamajek, Eric E.; Hinz, Philip M.; Meyer, Michael R.; Heinze, Aren N.; Miller, Douglas L.; Sivanandam, Suresh; Freed, Melanie

2009-06-01

139

An Imaging Survey for Extrasolar Planets around 45 Close, Young Stars with the Simultaneous Differential Imager at the Very Large Telescope and MMT  

Microsoft Academic Search

We present the results of a survey of 45 young (<~250 Myr), close (<~50 pc) stars with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT for the direct detection of extrasolar planets. As part of the survey, we observed 54 objects, consisting of 45 close, young stars; two more distant (<150 pc), extremely young (<=10 Myr)

Beth A. Biller; Laird M. Close; Elena Masciadri; Eric Nielsen; Rainer Lenzen; Wolfgang Brandner; Donald McCarthy; Markus Hartung; Stephan Kellner; Eric Mamajek; Thomas Henning; Douglas Miller; Matthew Kenworthy; Craig Kulesa

2007-01-01

140

Women Astronomers at Gemini: A Success Story  

NASA Astrophysics Data System (ADS)

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

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

2010-01-01

141

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

NASA Technical Reports Server (NTRS)

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

Owen, Tobias C.

2003-01-01

142

Progress in Extra-Solar Planet Detection.  

National Technical Information Service (NTIS)

Progress in extra-solar planet detection is reviewed. The following subject areas are covered: (1) the definition of a planet; (2) the weakness of planet signals; (3) direct techniques - imaging and spectral detection; and (4) indirect techniques - reflex...

R. A. Brown

1991-01-01

143

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

144

Celestial Exoplanet Survey Occulter: A Concept for Direct Imaging of Extrasolar Earth-like Planets from the Ground  

NASA Astrophysics Data System (ADS)

We present a new concept for detecting and characterizing extrasolar planets down to Earth size or smaller through direct imaging. The New Worlds Observer (NWO) occulter developed by Cash and coworkers is placed in a particular geometrical setup in which fuel requirements are small and the occulter is used in combination with ground-based telescopes, presumably leading to an extreme cost efficiency compared to other concepts with similar science goals. We investigate the various aspects of the given geometry, such as the dynamics and radiation environment of the occulter, and construct a detailed example target list to ensure that an excellent science case can be maintained despite the limited sky coverage. It is found that more than 200 systems can be observed with two to three visits per system, using only a few tons of fuel. For each system, an Earth-sized planet with an Earth-like albedo can be found in the habitable zone in less than 2 hr.

Janson, M.

2007-02-01

145

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

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

146

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

147

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

148

Antifungal activity of gemini quaternary ammonium salts.  

PubMed

A series of gemini quaternary ammonium chlorides and bromides with various alkyl chain and spacer lengths was synthesized. The most active compounds against fungi were chlorides with 10 carbon atoms within the hydrophobic chain. Among these compounds were few with no hemolytic activity at minimal inhibitory concentrations. None of the tested compounds were cytotoxic and mutagenic. Cationic gemini surfactants poorly reduced the adhesion of microorganisms to the polystyrene plate, but inhibited the filamentation of Candida albicans. One of the tested compounds eradicated C. albicans and Rodotorula mucilaginosa biofilm, what could be important in overcoming catheter-associated infections. It was also shown that gemini surfactants enhanced the sensitivity of C. albicans to azoles and polyenes, thus they might be potentially used in combined therapy against fungi. PMID:23827647

Ob??k, Ewa; Piecuch, Agata; Krasowska, Anna; Luczy?ski, Jacek

2013-12-14

149

GEO-ENGINEERING MODELING THROUGH INTERNET INFORMATICS (GEMINI)  

Microsoft Academic Search

GEMINI (Geo-Engineering Modeling through Internet Informatics) is a public-domain web application focused on analysis and modeling of petroleum reservoirs and plays (http:\\/\\/www.kgs.ukans.edu\\/Gemini\\/index.html). GEMINI creates a virtual project by ''on-the-fly'' assembly and analysis of on-line data either from the Kansas Geological Survey or uploaded from the user. GEMINI's suite of geological and engineering web applications for reservoir analysis include: (1) petrofacies-based

W. Lynn Watney; John H. Doveton

2004-01-01

150

Characterizing Extra-Solar Planets with Low Resolution Spectroscopy  

NASA Astrophysics Data System (ADS)

In the next few years, several high contrast imaging instruments equipped with integral field spectrographs will allow the direct spectral characterization of a variety of companions, from low-mass stars to Jupiter-mass extra-solar planets, at Solar System-like separations (4-40 AU). The spectra obtained by these instruments will be low resolution (R 30-60), making detailed thermo-chemical analysis difficult. Therefore, we have developed a technique that quantitatively compares observed low-resolution spectra with a set of synthetic spectra in order to obtain physical parameters, such as temperature and surface gravity, quickly and robustly. The technique requires no assumptions about age, mass, radius or metallicity of the companion or the primary. We describe this technique and demonstrate its effectiveness with simulated and observed spectra from Project 1640, the high contrast imager and integral field spectrograph on Palomar. The technique can also be used to optimize observing efficiency by determining the ideal wavelength range (for multi-filter instruments such as the Gemini Planet Imager) and signal to noise ratio for a desired precision and accuracy of inferred parameters. The current analysis uses the PHOENIX models as a basis for comparison, but the technique can be applied to any set of models and even used to quantify the differences between models created by different groups. This tool provides a necessary, fast, and comprehensive method of characterizing faint companions of stars, whether they be stellar, sub-stellar or planetary in nature.

Rice, Emily L.; Oppenheimer, B. R.; Zimmerman, N.; Roberts, L. C., Jr.; Hinkley, S.

2012-01-01

151

Active optics methods for exoplanet direct imaging. Stress polishing of supersmooth aspherics for VLT-SPHERE planet finder  

NASA Astrophysics Data System (ADS)

Context. The next generation of exoplanet hunters will be targeting hot Jupiter-like exoplanets orbiting around nearby stars through direct imaging. The high contrast needed for such planet finders requires optical surfaces free of high spatial frequency ripples that might remain in the post-coronagraphic image as quasi-static speckles. Aims: We report results on the manufacturing of three supersmooth aspherical mirrors for the ESO/VLT-SPHERE instrument. The excellent optical quality obtained will allow the future planet hunter to increase the level of achievable contrast by a strong reduction of the noise level and residual quasi-static speckles on the image plane. Methods: The stress polishing method used on these mirrors is well suited to superpolishing aspheric components for astronomy. The main advantage of this technique is the very high optical quality obtained either on the form errors or on the high spatial frequency errors. Furthermore, the roughness can be decreased to a few angstroms, thanks to the classical polishing with a large pitch tool. Results: Interferograms obtained during polishing and in the final stage show the supersmooth quality of each mirror. Errors in the high spatial frequency range are lower than 4 nm rms WF, thereby avoiding the degradation of the post-coronagraphic image. A comparison of the power spectral density (PSD) obtained by stress polishing and the PSD of the VLT-UT3 primary mirror demonstrates that the contrast capabilities will not be limited by the aspherical mirrors.

Hugot, E.; Ferrari, M.; El Hadi, K.; Costille, A.; Dohlen, K.; Rabou, P.; Puget, P.; Beuzit, J. L.

2012-02-01

152

Radiation dosimetry for the Gemini program  

NASA Technical Reports Server (NTRS)

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

Richmond, R. G.

1972-01-01

153

SN 1987A After 18 Years Mid-Infrared GEMINI and SPITZER Observations of the Remnant.  

National Technical Information Service (NTIS)

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 signi...

E. Dwek J. Danziger J. M. DeBuizer N. B. Suntzeff P. Bouchet P. Challis R. G. Arendt R. P. Kirshner S. Park

2007-01-01

154

Optical Images of an Exosolar Planet 25 Light-Years from Earth  

Microsoft Academic Search

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

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

2008-01-01

155

Optical Images of an Exosolar Planet 25 Light Years from Earth  

NASA Technical Reports Server (NTRS)

Fomalhaut is a bright star 7.7 parsecs (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 18 AU from the dust belt, matching predictions. 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 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 micron 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 micron.

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

2008-01-01

156

Optical Images of an Exosolar Planet 25 Light-Years from Earth  

NASA Technical Reports Server (NTRS)

Fomalhaut is a bright star 7.7 parsec (25 light year) 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 All 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 micron flux is also consistent with that of a planet with mass a few limes that of Jupiter. The brightness at 0.6 microns 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 microns.

Clampin, Mark

2008-01-01

157

Gemini 6 prime crew in white room atop Pad 19 during Gemini 6 countdown  

NASA Technical Reports Server (NTRS)

NASA and McDonnell technicians assist the Gemini 6 prime crew into the spacecraft in the White Room atop Pad 19 during the Gemini 6 prelaunch countdown. Astronaut Walter M. Schirra Jr., command pilot, is on left; and Astronaut Thomas P. Stafford, is on the right. Between the two is a note attached to the capsule which reads 'Good Luck from 2nd Shift'. Liftoff was at 8:37 a.m., December 15, 1965.

1965-01-01

158

Adsorption of Gemini surfactants onto clathrate hydrates.  

PubMed

This work addresses the adsorption of two Gemini surfactants at the cyclopentane (CP) hydrate-water interface. The Gemini surfactants investigated here are Dowfax C6L and Dowfax 2A1 that have two anionic head groups and one hydrophobic tail group. The adsorption of these surfactants was quantified using adsorption isotherms and the adsorption isotherms were determined using liquid-liquid titrations. Even if the Gemini surfactant adsorption isotherms show multi-layer adsorption, they possess the first Langmuir layer with the second adsorption layer only evident in the 2A1 adsorption isotherm. Zeta potentials of CP hydrate particles in the surfactant solution of various concentrations of Dowfax C6L and Dowfax 2A1 were measured to further explain their adsorption behavior at the CP hydrate-water interface. Zeta potentials of alumina particles as a model particle system in different concentrations of sodium dodecyl sulfate (SDS), Dowfax C6L and Dowfax 2A1 were also measured to confirm the configuration of all the surfactants at the interface. The determination of the isotherms and zeta-potentials provides an understanding framework for the adsorption behavior of the two Gemini surfactants at the hydrate-water interface. PMID:24144366

Salako, O; Lo, C; Couzis, A; Somasundaran, P; Lee, J W

2013-12-15

159

Radiation Dosimetry for the Gemini Program.  

National Technical Information Service (NTIS)

The principal source of radiation for low-earth-orbit, low inclination space flights is in the area of the South Atlantic magnetic anomaly. None of the Gemini dose measure ments reported in the paper are of high enough intensity to be considered hazardous...

R. G. Richmond

1972-01-01

160

The Gemini Observatory Fast-Turnaround Program  

NASA Astrophysics Data System (ADS)

Gemini's Fast-Turnaround Program is intended to greatly decrease the time from having an idea to acquiring the supporting data. The program will combine frequent proposal submission opportunities, rapid review, and fast preparation and execution of observations. We describe how the scheme will operate, and outline progress made towards its implementation.

Mason, Rachel; Adamson, A.; Crabtree, D.; Cote, S.; Kissler-Patig, M.; Levenson, N.

2014-01-01

161

Gemini alkylammonium salts as biodeterioration inhibitors.  

PubMed

To protect materials against biodeterioration, physical, biological or chemical methods can be used. Chemical inhibitors of biodeterioration are the most common and effective. A new class of chemical inhibitors-gemini alkylammonium salts-shows excellent biocidal properties and good ecological profile. These compounds can be applied as biodeterioration inhibitors in a wide variety of materials. PMID:21466039

Brycki, Bogumi?

2010-01-01

162

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

163

Geo-Engineering through Internet Informatics (GEMINI)  

Microsoft Academic Search

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

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

2002-01-01

164

Geo-Engineering through Internet Informatics (GEMINI)  

Microsoft Academic Search

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.

John H. Doveton; W. Lynn Watney

2003-01-01

165

Time exposure of Gemini 10 launch.  

NASA Technical Reports Server (NTRS)

The Gemini 10 spacecraft is launched from Complex 19 at 5:20 p.m., July 18, 1966. A time exposure creates the illusion of multiple rocker arms. Onboard are astronauts John W. Young and Michael Collins, command pilot and pilot, respectively.

1966-01-01

166

Extrasolar Planets  

NASA Astrophysics Data System (ADS)

Participants; Preface; Acknowledgements; 1. Extrasolar planet detection methods Laurance R. Doyle; 2. Statistical properties of exoplanets Stéphane Udry; 3. Characterizing extrasolar planets Timothy M. Brown; 4. From clouds to planet systems: formation and evolution of stars and planets Günther Wuchterl; 5. Abundances in stars with extrasolar planetary systems Garik Israelian; 6. Brown dwarfs: the bridge between stars and planets Rafael Rebolo; 7. The perspective: a panorama of the Solar System Agustín Sánchez-Lavega; 8. Habitable planets around the Sun and other stars James F. Kasting; 9. Biomarkers of extrasolar planets and their observability Franck Selsis, Jimmy Paillet and France Allard; Index.

Deeg, Hans; Belmonte, Juan Antonio; Aparicio, Antonio

2012-03-01

167

Extrasolar Planets  

NASA Astrophysics Data System (ADS)

Participants; Preface; Acknowledgements; 1. Extrasolar planet detection methods Laurance R. Doyle; 2. Statistical properties of exoplanets Stéphane Udry; 3. Characterizing extrasolar planets Timothy M. Brown; 4. From clouds to planet systems: formation and evolution of stars and planets Günther Wuchterl; 5. Abundances in stars with extrasolar planetary systems Garik Israelian; 6. Brown dwarfs: the bridge between stars and planets Rafael Rebolo; 7. The perspective: a panorama of the Solar System Agustín Sánchez-Lavega; 8. Habitable planets around the Sun and other stars James F. Kasting; 9. Biomarkers of extrasolar planets and their observability Franck Selsis, Jimmy Paillet and France Allard; Index.

Deeg, Hans; Belmonte, Juan Antonio; Aparicio, Antonio

2007-10-01

168

Pointing and image stability for spaceborne sensors: from comet impactors to observations of extrasolar planets  

NASA Astrophysics Data System (ADS)

From hitting a comet to long-term observations to find and characterize extrasolar planets, the spacecraft platform pointing accuracy and stability are fundamental. We describe the pointing requirements for Deep Impact, Kepler, and future extrasolar planet missions such as EPIC, and the approach to allow stable long-term measurements. The guidance, navigation, and control system consists of a suite of systems which can include star trackers, gyros, fine guidance sensors, reaction wheels, fast steering mirrors, and active and passive isolation features. One-fifth to one-twentieth of a pixel attitude determination may be needed with stabilities an order of magnitude tighter for observations that may last thousands of seconds. 1.5 milliarcsecond 3-sigma pointing stability can be achieved for the observatory enabling precision measurements by the scientific payloads.

Kendrick, Stephen E.; Stober, Jeremy; Gravseth, Ian

2006-07-01

169

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

170

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.

171

Gemini Science Archive Automatic Data Transfer  

NASA Astrophysics Data System (ADS)

The Canadian Astronomy Data Centre (CADC) has developed an automatic system for the transfer of data from the Gemini telescopes to the Gemini Science Archive (GSA). Each step in the process between the data validation at the telescope base facilities and the data becoming available to archive users is automated, including the file transfer, the ingestion of catalogue metadata, and the insertion of the file into the archive tracking system. File names, content, and metadata are checked for conformance with GSA expectations before data transfer and ingestion take place. The CADC has been using this system for transfer of GSA data since 2004 January, and has adapted it for use in the Canada-France-Hawaii Telescope Legacy Survey.

Melnychuk, G.; Damian, A.; Goliath, S.; Shao, L.; Hill, N.; Gaudet, S.; Bohlender, D.; Aspin, C.

2005-12-01

172

The Gemini Science Archive Data Dictionary  

NASA Astrophysics Data System (ADS)

The Gemini Science Archive (GSA) is a new science archive developed by the Canadian Astronomy Data Centre (CADC) to provide the scientific community with tools for effective on-line access to data collected by the Gemini telescopes. CADC has developed a MetaData Data Dictionary (MDDD) for the GSA to meet the goal of providing dependable and consistent archive data. This MDDD defines the rules that govern data manipulation on meta-data obtained from a variety of data sources. The MDDD is specified in XML, and so provides flexibility while reducing source code maintenance. The paper will discuss the rules that may be specified for the data sources and individual meta-data attributes, the role of the data dictionary in populating the GSA, verification of the consistency of the dictionary itself, and possible future improvements in the data dictionary.

Goliath, S.; Damian, A.; Gaudet, S.; Hill, N.; Bohlender, D.; Melnychuk, G.; Aspin, C.

2005-12-01

173

Welcome to the Planets  

NSDL National Science Digital Library

This collection of the best images from NASA's planetary exploration program includes descriptions of images with an audio format, planet profiles with data sets, spacecraft exploration information, and a zoom-in feature to view the image at closer range. There is also a glossary with hundreds of entries, and an explorer section to learn about past and future space missions.

174

GEMINI: A Natural Language System for Spoken-Language Understanding  

Microsoft Academic Search

Gemini is a natural language understanding system developed for spoken language applications. The paper describes the architecture of Gemini, paying particular attention to resolving the tension between robustness and overgeneration. Gemini features a broad-coverage unification-based grammar of English, fully interleaved syntactic and semantic processing in an all-paths, bottom-up parser, and an utterance-level parser to find interpretations of sentences that might

John Dowding; Jean Mark Gawron; Doug Appelt; John Bear; Lynn Cherny; Robert Moore; Douglas Moran

1994-01-01

175

The Gemini Science Archive: Current Status and Future Prospects  

NASA Astrophysics Data System (ADS)

The most recent addition to the services provided by the Canadian Astronomy Data Centre (CADC) is the Gemini Science Archive (GSA). Developed as a collaborative effort with the Gemini Observatory and released in September 2004, the GSA provides the scientific community with the tools required for effective online access to data collected by both Gemini telescopes. This paper provides a summary of the current capabilities of the GSA and discusses some of the advanced capabilities to be developed in the near future.

Bohlender, D.; Damian, A.; Gaudet, S.; Goliath, S.; Hill, N.; Melnychuk, G.; Aspin, C.

2005-12-01

176

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

177

Monochromatic imaging instrumentation for applications in aeronomy of the earth and planets  

Microsoft Academic Search

Monochromatic imaging instrumentation has been developed that uses narrow-band [12-[angstrom] full width at half maximum (FWHP)] interference filters or plane reflection gratings for 2-D imaging and imaging spectrograph applications. By changing the optics in front of the filter or grating, the field of view of the instruments can be varied from 180 deg (all sky) to 6 deg (narrow field).

Jeffrey L. Baumgardner; B. Flynn; M. Mendillo

1993-01-01

178

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

179

Study of spin-scan imaging for outer planets missions: Executive summary  

NASA Technical Reports Server (NTRS)

The development and characteristics of spin-scan imagers for interplanetary exploration are discussed. The spin-scan imaging photopolarimeter instruments of Pioneer 10 and 11 are described. In addition to the imaging function, the instruments are also used in a faint-light mode to take sky maps in both radiance and polarization. The performance of a visible-infrared spin-scan radiometer (VISSR), which operates in both visible and infrared wavelengths, is reported.

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

1974-01-01

180

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

181

Monochromatic imaging instrumentation for applications in aeronomy of the earth and planets  

NASA Technical Reports Server (NTRS)

Monochromatic imaging instrumentation has been developed that uses narrow-band (12 A FWHP) interference filters or plane reflection gratings for 2D imaging and imaging spectrograph applications. By changing the optics in front of the filter or grating, the field of view of the instruments can be varied from 180 deg to 6 deg. In the case of the 2D monochromatic imager, the 12 mm-diameter filtered image is formed at about f/1 on the input photocathode of an intensified CCD camera (380 x 488 pixels). The sensitivities of the systems are about 50-100 R s (S/N about 2). Examples of data taken with both of these instruments include detection and mapping of Jupiter's sodium magnetonebula and stable auroral red arcs in the terrestrial ionosphere.

Baumgardner, Jeffrey; Flynn, Brian; Mendillo, Michael

1992-01-01

182

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

183

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

184

Dicationic Alkylammonium Bromide Gemini Surfactants. Membrane Perturbation and Skin Irritation  

PubMed Central

Dicationic alkylammonium bromide gemini surfactants represent a class of amphiphiles potentially effective as skin permeation enhancers. However, only a limited number of studies has been dedicated to the evaluation of the respective cytotoxicity, and none directed to skin irritation endpoints. Supported on a cell viability study, the cytotoxicity of gemini surfactants of variable tail and spacer length was assessed. For this purpose, keratinocyte cells from human skin (NCTC 2544 cell line), frequently used as a model for skin irritation, were employed. The impact of the different gemini surfactants on the permeability and morphology of model vesicles was additionally investigated by measuring the leakage of calcein fluorescent dye and analyzing the NMR spectra of 31P, respectively. Detail on the interaction of gemini molecules with model membranes was also provided by a systematic differential scanning calorimetry (DSC) and molecular dynamics (MD) simulation. An irreversible impact on the viability of the NCTC 2544 cell line was observed for gemini concentrations higher than 25 mM, while no cytotoxicity was found for any of the surfactants in a concentration range up to 10 mM. A higher cytotoxicity was also found for gemini surfactants presenting longer spacer and shorter tails. The same trend was obtained in the calorimetric and permeability studies, with the gemini of longest spacer promoting the highest degree of membrane destabilization. Additional structural and dynamical characterization of the various systems, obtained by 31P NMR and MD, provide some insight on the relationship between the architecture of gemini surfactants and the respective perturbation mechanism.

Almeida, Joao A. S.; Faneca, Henrique; Carvalho, Rui A.; Marques, Eduardo F.; Pais, Alberto A. C. C.

2011-01-01

185

XML-Based Dialogue Descriptions in the GEMINI Project  

Microsoft Academic Search

GEMINI (Generic Environment for Multilingual Interactive Natural Inter- faces) is an EC funded research project. The goal of GEMINI is to provide a flexible platform for the generation of dialogue applications, able to produce multi-modal and multilingual dialogue interfaces to databases with a minimum of human effort. This platform consists of a toolset supporting all steps of application generation by

Stefan W. Hamerich; Yu-fang H. Wang; Volker Schubert; Volker Schless; Stefan Igel

2003-01-01

186

Solution properties and electrospinning of phosphonium gemini surfactants.  

PubMed

Bis(diphenylphosphino)alkanes quantitatively react with excess 1-bromododecane to prepare novel phosphonium gemini surfactants with spacer lengths ranging from 2 to 4 methylenes (12-2/3/4-12P). Dodecyltriphenylphosphonium bromide (DTPP), a monomeric surfactant analog, was readily water soluble, however, in sharp contrast, phosphonium gemini surfactants were poorly soluble in water due to two hydrophobic tails and relatively hydrophobic cationic head groups containing phenyl substituents. Isothermal titration calorimetry did not reveal a measurable critical micelle concentration for the 12-2-12P phosphonium gemini surfactant in water at 25 °C. Subsequent studies in 50/50 v/v water-methanol at 25 °C showed a CMC of 1.0 mM for 12-2-12P. All phosphonium gemini surfactants effectively complexed nucleic acids, but failed to deliver nucleic acids in vitro to HeLa cells. The solution behavior of phosphonium gemini surfactants was investigated in chloroform, which is an organic solvent where reverse micellar structures are favored. Solution rheology in chloroform explored the solution behavior of the phosphonium gemini surfactants compared to DTPP. The 12-2-12P and 12-3-12P gemini surfactants were successfully electrospun from chloroform to generate uniform fibers while 12-4-12P gemini surfactant and DTPP only electrosprayed to form droplets. PMID:24733359

Hemp, Sean T; Hudson, Amanda G; Allen, Michael H; Pole, Sandeep S; Moore, Robert B; Long, Timothy E

2014-06-14

187

Gemini 4 prime crew with NASA Officials after press conferences  

NASA Technical Reports Server (NTRS)

The Gemini 4 prime crew poses with two NASA Officials after a press conference in the Manned Spaceflight Center (MSC) auditorium. Left to right are Dr. Robert R. Gilruth, MSC Director; Dr. Robert C. Seamans Jr., Associate NASA Administrator; Astronaut James A. McDivitt, command pilot of the Gemini 4 flight; and Astronaut Edward H. White II, pilot of the mission.

1965-01-01

188

High-Contrast 3.8 Micron Imaging of the Brown Dwarf/Planet-Mass Companion to GJ 758  

NASA Technical Reports Server (NTRS)

We present L' band (3.8 Micron) MMT/Clio high-contrast imaging data for the nearby star GJ 758, which was recently reported by Thalmann et al. (2009) to have one -- possibly two-- faint comoving companions (GJ 7588 and "C", respectively). GJ 758B is detected in two distinct datasets. Additionally, we report a \\textit(possible) detection of the object identified by Thalmann et al as "GJ 758C" in our more sensitive dataset, though it is likely a residual speckle. However, if it is the same object as that reported by Thalmann et al. it cannot be a companion in a bound orbit. GJ 758B has a H-L'color redder than nearly all known L--T8 dwarfs. Based on comparisons with the COND evolutionary models, GJ 758B has Te approx. 560 K (+150 K, -90 K) and a mass ranging from approx. 10-20 Mj if it is approx. 1 Gyr old to approx. 25-40 Mj if it is 8.7 Gyr old. GJ 758B is likely in a highly eccentric orbit, e approx. 0.73 (+0.12,-0.21), with a semimajor axis of approx. 44 AU (+32 AU, -14 AU). Though GJ 758B is sometimes discussed within the context of exoplanet direct imaging, its mass is likely greater than the deuterium-burning limit and its formation may resemble that of binary stars rather than that of jovian-mass planets.

Currie, Thayne; Bailey, Vanessa; Fabrycky, Daniel; Murray-Clay, Ruth; Rodigas, Timothy; Hinz, Phil

2010-01-01

189

High-Contrast 3.8 Micron Imaging of the Brown Dwarf/Planet-Mass Companion to GJ 758  

NASA Technical Reports Server (NTRS)

We present L' band (3.8 Micron) MMT/Clio high-contrast imaging data for the nearby star GJ 758, which was recently reported by Thalmann et al. (2009) to have one - possibly two - faint comoving companions (GJ 7588 and "C", respectively). GJ 758B is detected in two distinct datasets. Additionally, we report a \\textit{possible} detection of the object identified by Thalmann et al as "GJ 758C" in our more sensitive dataset, though it is likely a residual speckle. However, if it is the same object as that reported by Thalmann et al. it cannot be a companion in a bound orbit. GJ 7588 has a H-L' color redder than nearly all known L-T8 dwarfs. 8ased on comparisons with the COND evolutionary models, GJ 7588 has Te approx. 560 K (+150 K, -90 K) and a mass ranging from approx.10-20 Mj if it is approx.1 Gyr old to approx. 25-40 Mj if it is 8.7 Gyr old. GJ 7588 is likely in a highly eccentric orbit, e approx. 0.73 (+0.12,-0.21), with a semimajor axis of approx. 44 AU (+32 AU, -14 AU). Though GJ 7588 is sometimes discussed within the context of exoplanet direct imaging, its mass is likely greater than the deuterium-burning limit and its formation may resemble that of binary stars rather than that of jovian-mass planets.

Currie, Thayne M.; Bailey, Vanessa; Fabrycky, Daniel; Murray-Clay, Ruth; Rodigas, Timothy; Hinz, Phil

2011-01-01

190

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

SciTech Connect

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

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

2011-03-10

191

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

192

Extrasolar planets  

PubMed Central

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

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

2000-01-01

193

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.

194

Planet Search  

NSDL National Science Digital Library

This is an activity about the orbits of the planets in our Solar System. Learners will utilize the Sky Tonight online program to track the movement and visibility of the planets in our night sky. They will then attempt to locate these planets outside on a clear night. This activity requires the use of a computer with Internet access and access to the clear night sky. This activity is Sky Tonight Activity 3 in a larger resource, Space Update.

195

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.

196

Self-assembled Gemini surfactant film-mediated dispersion stability.  

PubMed

The force-distance curves of 12-2-12 and 12-4-12 Gemini quaternary ammonium bromide surfactants on mica and silica surfaces obtained by atomic force microscopy (AFM) were correlated with the structure of the adsorption layer. The critical micelle concentration was measured in the presence or absence of electrolyte. The electrolyte effect (the decrease of CMC) is significantly more pronounced for Gemini than for single-chain surfactants. The maximum compressive force, F(max), of the adsorbed surfactant aggregates was determined. On the mica surface in the presence of 0.1 M NaCl, the Gemini micelles and strong repulsive barrier appear at surfactant concentrations 0.02-0.05 mM, which is significantly lower than that for the single C(12)TAB (5-10 mM). This difference between single and Gemini surfactants can be explained by a stronger adsorption energy of Gemini surfactants. The low concentration of Gemini at which this surfactant forms the strong micellar layer on the solid/solution interface proves that Gemini aggregates (micelles) potentially act as dispersing agent in processes such as chemical mechanical polishing or collector in flotation. The AFM force-distance results obtained for the Gemini surfactants were used along with turbidity measurements to determine how adsorption of Gemini surfactants affects dispersion stability. It has been shown that Gemini (or two-chain) surfactants are more effective dispersing agents, and that in the presence of electrolyte, the silica dispersion stability at pH 4.0 can also be achieved at very low surfactant concentrations ( approximately 0.02 mM). PMID:15927629

Rabinovich, Y I; Kanicky, J R; Pandey, S; Oskarsson, H; Holmberg, K; Moudgil, B M; Shah, D O

2005-08-15

197

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

198

Mercury Sodium Atmosphere Spectral Imager (MSASI) - taking High Resolution Interferometry to the Planets  

Microsoft Academic Search

The Mercury Sodium Atmosphere Spectral Imager (MSASI) on the Mercury Magnetospheric Orbiter of the JAXA \\/ ESA Bepi-Colombo (BC) Mission will address a range of fundamental scientific questions pertaining to Mercury's exosphere. The measurements will provide new information on regolith-exosphere-magnetosphere coupling as well as new understanding of the dynamics governing the exosphere bounded by the planetary surface, the solar wind

Ichiro Yoshikawa; Shingo Kameda; Oleg Korablev; David Rees

2008-01-01

199

880 {mu}m IMAGING OF A TRANSITIONAL DISK IN UPPER SCORPIUS: HOLDOVER FROM THE ERA OF GIANT PLANET FORMATION?  

SciTech Connect

We present 880 {mu}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 0.''34, 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 {approx}0.1 M{sub 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 {approx}0.1 AU, we determine that the most likely mechanism for the formation of this inner hole is the presence of one or more giant planets.

Mathews, Geoffrey S.; Williams, Jonathan P. [Institute for Astronomy (IfA), University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Menard, Francois, E-mail: gmathews@ifa.hawaii.edu [Universite Joseph-Fourier Grenoble 1/CNRS, Laboratoire d'Astrophysique de Grenoble (LAOG) UMR 5571, BP 53, F-38041 Grenoble Cedex 09 (France)

2012-07-01

200

KEOPS: Kiloparsec Explorer for Optical Planet Search, a direct-imaging optical array at Dome C of Antarctica  

NASA Astrophysics Data System (ADS)

Recent site seeing testing campaigns conducted by our team from University of Nice1 show that Dome C represents the best site on Earth for astronomical high angular resolution (HAR) observations at optical and IR wavelengths. The dramatic gain over relevant HAR parameters r0, L0, ?0 and ?0, added to very low temperatures during the polar winter nights (-70°C), the dry atmosphere and the possibility of continuous observations during several nights make Dome C the ideal site for deploying a kilometric optical interferometer before the 2015 horizon. Here we describe the concept of Kiloparsec Explorer for Optical Planet Search (KEOPS) that is studied by our group at LUAN. KEOPS is an interferometric array of 36 off-axis telescopes, each 1.5m in diameter. Its kilometric baselines open sub-mas snap-shot imaging possibilities to detect and characterize extra-solar planetary systems, especially exo-Earths out to 300 parsecs from the visible to the thermal IR. KEOPS can be considered as a DARWIN/TPF challenger but at a much lower cost.

Vakili, Farrokh; Belu, Adrian; Aristidi, Eric; Fossat, Eric; Maillard, A.; Abe, Lyu; Agabi, Karim; Vernin, Jean; Baptiste Daban, Jean; Hertmanni, Wilfried; Schmider, Francois-Xavier; Assus, Pierre; Coudé du Foresto, Vincent; Swain, Mark R.

2004-10-01

201

Information extraction from digital images of the earth and the planets  

NASA Technical Reports Server (NTRS)

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

Green, W. B.

1978-01-01

202

Maintaining the Telescope Bibliography at Gemini Observatory  

NASA Astrophysics Data System (ADS)

The library profession benefits tremendously from ever-changing web technologies. In maintaining a telescope bibliography, web-publishing revolutionized the way librarians track relevant publications. Thanks to the search abilities provided by the NASA Astrophysics Data System, arXiv, publishers, as well as Google Scholar, and other such resources, online searching for Gemini-based publications has replaced the tedious perusing of print journals. However, we should keep in mind that online searching is neither flawless nor simple — different content providers require different search strategies. Sometimes the retrievals are not as complete as one expects. Information providers should be constantly improving their searching abilities in order to make the task of electronic publication tracking more reliable and efficient.

Zhang, X.

2010-10-01

203

Gemini: A long-range cargo transport  

NASA Technical Reports Server (NTRS)

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

1994-01-01

204

Synergism in cationic gemini – additive systems  

Microsoft Academic Search

A series of dicationic gemini surfactants with the general formula C16H33(CH3)2N?(CH2)s?N(CH3)2C16H33, 2Br (where s?=?4–6), designated as 16-s-16, were synthesised. Their interaction with organic additives: n-alcohols (C3H7OH, C7H15OH, C8H17OH) and the corresponding amines (C3H7NH2, C7H15NH2, C8H17NH2) in the absence and presence of KNO3 at 30°C was studied viscometrically to observe their effect on assembly formation and micellar transition. The simultaneous presence

Umme Salma Siddiqui; Farah Khan; Iqrar Ahmad Khan

2011-01-01

205

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

206

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

207

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

NASA Astrophysics Data System (ADS)

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

Lamare, F.; Turzo, A.; Bizais, Y.; Cheze LeRest, C.; Visvikis, D.

2006-02-01

208

Debris Disks and Hidden Planets  

NASA Technical Reports Server (NTRS)

When a planet orbits inside a debris disk like the disk around Vega or Beta Pictoris, the planet may be invisible, but the patterns it creates in the disk may give it away. Observing and decoding these patterns may be the only way we can detect exo-Neptunes orbiting more than 20 AU from their stars, and the only way we can spot planets in systems undergoing the late stages of planet formation. Fortunately, every few months, a new image of a debris disk appears with curious structures begging for explanation. I'll describe some new ideas in the theory of these planet-disk interactions and provide a buyers guide to the latest models (and the planets they predict).

Kuchner, Marc

2008-01-01

209

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.

210

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

211

Gemini B Blast Shield: Mechanical Properties of Aluminum Flexcore.  

National Technical Information Service (NTIS)

The Gemini B blast shield is a sandwich construction composed of glass fabric reinforced plastic skins adhesively bonded to aluminum Flexcore. The object of this test was to determine the plate shear strength and the flatwise bare compressive strength of ...

1968-01-01

212

Indonesian Islands as seen from Gemini 11 spacecraft  

NASA Technical Reports Server (NTRS)

Indonesian Islands (partial cloud cover): Sumatra, Java, Bali, Borneo, Sumbawa, as photographed from the Gemini 11 spacecraft during its 26th revolution of the earth, at an altitude of 570 nautical miles.

1966-01-01

213

Food packages for use on the Gemini 4 flight  

NASA Technical Reports Server (NTRS)

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

1965-01-01

214

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

215

Ocean Planet Exhibition  

NSDL National Science Digital Library

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

216

Dwarf Planet Pluto  

NSDL National Science Digital Library

This page from Views of the Solar System provides access to images and animations of the binary dwarf planet composed of Pluto and Charon. Did you know that the Hubble Space Telescope discovered two additional moons in the Pluto-Charon system?

Hamilton, Calvin J.; Self-Published

217

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.

218

Planet Formation  

NASA Astrophysics Data System (ADS)

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

Klahr, Hubert; Brandner, Wolfgang

2011-02-01

219

Progress in extra-solar planet detection  

NASA Technical Reports Server (NTRS)

Progress in extra-solar planet detection is reviewed. The following subject areas are covered: (1) the definition of a planet; (2) the weakness of planet signals; (3) direct techniques - imaging and spectral detection; and (4) indirect techniques - reflex motion and occultations.

Brown, Robert A.

1991-01-01

220

The Cambridge Photographic Guide to the Planets  

Microsoft Academic Search

The Cambridge Photographic Guide to the Planets includes a broad selection of the latest images of the planets, moons, comets, and asteroids of the Earth's Solar System. Beginning with a comprehensive introduction to the planetary system, its origin and its evolution, physicist Frederick Taylor devotes each chapter to a different planet or Solar System body, with a thorough presentation of

Fredric W. Taylor

2001-01-01

221

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.

222

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

223

Optimizing Coronagraphic Surveys for Planets  

NASA Astrophysics Data System (ADS)

Recent laboratory experiments have demonstrated extremely high contrast imaging near a bright point source tep{tra07}, a pre-requisite for coronagraphic surveys for extrasolar planets with TPF and precursor telescopes. As the technology is now maturing, the question of which stars to target and how to optimize a direct imaging planet search needs to be addressed, so I discuss scaling relations and analytic estimates for how to optimize the number of planets detected (not necessarily in the habitable zone), taking into account noise from zodiacal light, exo-zodiacal light, and speckle noise, as well as the diversity among stellar and planetary systems.

Agol, E.

224

Extreme Contrast Direct Imaging of Planets and Debris disks with the Palomar P3K Adaptive Optics System and the Vector Vortex Coronagraph  

NASA Astrophysics Data System (ADS)

We present first results from using the PALM-3000 extreme adaptive optics system and imaging camera on the Hale 5m telescope. Observations using the vector vortex coronagraph have given us direct detections of the planets in the HR8799 system and the dusty debris disk around the star HD141569A. Due to the unprecedented inner working angle of the VVC, the data show a clearing within the inner ring inwards to ~20AU along the projected semi-major axis. Our observations of the disk in the K band (2.2 ?m) demonstrate the power of the next generation of adaptive optics systems coupled with phase mask coronagraphy. We also show a comparison of the data reduction techniques currently being implemented in the direct imaging field. Specifically, the Locally Optimized Combination of Images (LOCI) and the Karhunen-Loeve Image Processing (KLIP) algorithms, the latter being a more robust method for resolving debris disks.

Wahl, Matthew; Metchev, S. A.; Patel, R.; Serabyn, G.; PALM-3000 Adaptive Optics Team

2013-01-01

225

GEO-ENGINEERING MODELING THROUGH INTERNET INFORMATICS (GEMINI)  

SciTech Connect

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

W. Lynn Watney; John H. Doveton

2004-05-13

226

Polarimetry of gas planets  

NASA Astrophysics Data System (ADS)

The quest for new worlds was not only an adventure at the times of Columbus. Also nowadays mankind searches for new, undiscovered territories. But today they lie no longer only on our Earth, but also well outside the solar system. There, new planets are sought and found. One of the challenges of modern astrophysics is the direct detection of extra- solar planets. To reach this goal, the largest available telescopes and most sophisticated detection techniques are required. A promising method to "see" and analyse extra-solar planets is based on the fact, that light reflected by a planet can be polarised. For its detection, accurate polarisation measurements are needed. This is one of the methods ESO intends to make use of to find new planets outside the solar system. The Institute of Astronomy of ETH Zürich contributes ZIMPOL to this planet-finder project. ZIMPOL is a very sensitive imaging polarimeter. This thesis is situated within the ESO-planet-finder project. It deals with two problems that are crucial for a successful mission: (1) Instrumental polarisation can seriously hamper the performance of the instrument. It is therefore essential, to keep instrumental polarisation very low. (2) A knowledge of the polarisation properties of our targets would be very helpful. For this reason the polarisation properties of our solar system planets are investigated. Promising candidates for a detection with ZIMPOL are large planets with atmospheres similar to those of our giant gas planets Jupiter, Saturn, Uranus and Neptune. In the first part of the thesis the planet-finder project is presented and the role of ZIMPOL is explained. To obtain the instrumental polarisation, the polarimetric properties of mirrors and other optical components of our planet- finder instrument are analysed. The instrumental polarisation for the wavelength range of 600 to 1000 nm and for all zenith distances is calculated with Mueller matrices. Methods for reducing the instrumental polarisation are proposed and checked by the renewed application of the Mueller calculus. The correction of the instrumental polarisation is divided into two parts. First, a combination of a rotating half-wave plate and a plane mirror compensate the polarisation introduced by the Nasmyth mirror. Secondly, a rotatable and tiltable glass plate compensates the residual polarisation introduced by oblique reflections on mirrors after the Nasmyth mirror. Further, possible aging effects of the mirrors are considered and consequences for the polarisation are highlighted. An error budget for non perfect retardation of the half-wave plate is also regarded, and the effects for the polarisation are calculated. In the second part spectropolarimetric measurements of the four gas planets Jupiter, Saturn, Uranus and Neptune for the wavelength range from 530 to 930 nm are presented. Our measurements of Uranus and Neptune are the first of their kind. For Uranus and Neptune a second-order scattering effect, leading to limb polarisation, has been measured. This effect is expected in atmospheres of Rayleigh scattering type and allows conclusions on the properties of the scatterers and the stratification inside the atmosphere. The limb polarisation reaches a maximum of more than 3% on Uranus. Spectropolarimetric plots for selected regions on Uranus and polarimetric profiles parallel to the spectrographic slits are presented. An enhanced polarisation in the methane absorption bands is detected. For both planets the limb polarisation decreases with wavelength. For Jupiter and Saturn profiles parallel to the slits and polarimetric spectra for some selected regions such as the poles of Jupiter or the ring system of Saturn are presented. The poles of Jupiter exhibit a large polarisation (up to 10%) perpendicular to the limb. In the methane absorption bands at the Jovian poles the polarisation is enhanced compared to the adjacent higher albedo regions. The polarisation decreases from short wavelengths towards longer wavelengths. Disc resolved spectropolarimetry of Saturn has not yet been publi

Joos, Franco

227

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

228

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

SciTech Connect

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

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

2012-07-01

229

Resolved Silicate Emission in T Tauri Binaries: Determining the Parameters that Lead to Planet Formation  

NASA Astrophysics Data System (ADS)

The morphology of the 10 micron silicate feature in T Tauri stars can be used to infer grain-growth, which is one of the initial steps to planet formation. The properties that lead to grain growth are still unknown, in part, because the effects of stellar age are difficult to disentangle in large samples. Here we propose to use binaries, and their coeval properties to remove this degeneracy. Spatially resolved Gemini/Michelle spectra will allow us to determine how the silicate feature varies between binary components. If the spectral morphologies are similar, then stellar age might be the dominant parameter in grain-growth and planet formation. If the spectral morphologies are different, then other parameters (such as stellar mass, disk flaring geometry, accretion, binary separation and binary mass ratio) are likely more important. Our proposed data set will allow us to identify the dominant parameters which affect the silicate feature as a tracer of planet formation. Our Gemini/Michelle data will comprise spatially resolved ``low-N" spectra, and ``Si-4" and ``Qa" photometry for 7 binaries in Taurus. This will complement a similar 13 binary survey currently under way at the 6.5 meter MMT. The MMT mid-IR adaptive optics system can resolve tighter binaries than Gemini, but Gemini is much more sensitive. Together, the two data sets will provide the first large sample of spatially and spectrally resolved young binaries in the mid-infrared.

Skemer, Andrew; Close, Laird; Greene, Thomas; Hinz, Philip; Beck, Tracy

2009-08-01

230

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).

231

Operation and Service Manual for Gemini B/Laboratory Electrical Interface Substitute 58E040503.  

National Technical Information Service (NTIS)

The report discusses the operation and service of the Gemini B/Laboratory Electrical Interface Substitute, 58E040503. The report describes the cabinet, its panels and their functions and service instructions for preventive maintenance. The Gemini B/Labora...

1969-01-01

232

Astronaut James Lovell walks to elevator on Pad 19 before Gemini 7 launch  

NASA Technical Reports Server (NTRS)

Astronaut James A. Lovell Jr., pilot of the Gemini 7 space flight, walks to the elevator at Pad 19 one hour and forty minutes before launch of the spacecraft. He is dressed in the new Gemini space suit.

1965-01-01

233

Planets Beyond the Reach of Kepler - Introduction  

NASA Astrophysics Data System (ADS)

What kind of planets lie at orbit radii of 1-2 AU - beyond the reach of Kepler? In the last two decades we have explored a sample of RV-detected planets, discovered distant planets with microlensing, and several hot young planets at large radii have been detected by direct imaging, as well as the debris disks that provide clues to formation and evolution. In these 4 sessions, we explore the near future, and how we can expect to learn much more about the demographics and properties of cold outer planets. AFTA-WFIRST will open up this area, with a microlensing survey to probe the population of long-orbit planets, and coronagraphy to take images and spectra of large planets in orbits at a few AU.

Unwin, Stephen C.

2014-06-01

234

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.

235

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

Microsoft Academic Search

ABSTRACT In the near future, the Gemini Observatory will offer Laser Guide Star Adaptive Optics (LGS AO) observations on both Gemini North and South telescopes. The Gemini North AO system will use a 10W-class sodium,laser to produce one laser guide star at Mauna Kea, Hawaii, whereas the Gemini South AO System will use up to five such lasers or a

Céline d'Orgeville; Brian Bauman; Jim Catone; Brent Ellerbroek; Don Gavel; Richard Buchroeder

236

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

237

Distributed user support and the Gemini Observatory help desk  

NASA Astrophysics Data System (ADS)

The Gemini Observatory HelpDesk was activated early in 2000 to aid in the rapid and accurate resolution of queries concerning the Gemini telescopes and their capabilities. This system co- ordinates user support amongst staff within the Observatory and at National Offices in each partner country. The HelpDesk is based on a commercial product from Remedy Corporation that logs, tracks, forwards and escalates queries and self- generates a knowledgebase of previously asked questions. Timestamping of these events in the life cycle of a request and analysis of associated information provides valuable feedback on the static web content and performance of user support.

Chan, Simon; Puxley, Phil J.

2000-07-01

238

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

239

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

240

Geo-Engineering Modeling through INternet Informatics (GEMINI) (Report for September 25, 2000-September 30, 2003).  

National Technical Information Service (NTIS)

GEMINI (Geo-Engineering Modeling through INternet Informatics) is a public-domain web application focused on analysis and modeling of petroleum reservoirs and plays (http://www.kgs.ukans. edu/Gemini/index.html). GEMINI creates a virtual project by 'on-the...

W. L. Watney J. H. Doveton

2004-01-01

241

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.

1997-01-01

242

STEM Planet  

NSDL National Science Digital Library

STEM Planet is a well designed website that is aimed at students of all levels and ages. The site is comprised of "employees of the National Network of Digital Schools (NNDS), a non-profit developer of the Lincoln Interactive online curriculum." These employees believe that students "succeed when their educational program offers a wide variety of learning opportunities." Visitors to the site will find that the learning opportunities consist of DIY experiments, discussion topics, polls, quizzes and activities. Some examples include making a homemade battery, origami engineering, taking a quiz on space phenomena, and exploring quantum mechanics. Visitors can join and comment on the Science, Technology, Engineering and Math "discussions" by simply registering on the site. Those only interested in reading the comments made in the forums under the discussion tab need not register. The "Experts" tab allows visitors to see all the great minds behind STEM Planet, including an extremely bright 14 year old.

2012-02-07

243

GQ Lup, 2M1207, and AB Pic: Planet companion candidates imaged directly and their relevance in orbital dynamics and mass estimation via theoretical models, via  

NASA Astrophysics Data System (ADS)

In 2005, evidence was presented for three exo-planets imaged directly: GQ Lup, 2M1207, and AB Pic. In all three cases, a faint red object is co-moving with a young nearby star. The masses of these companions are determined thru theoretical models, which are under dispute and have not yet been tested successfully in the relevant parameter range of young ages and low masses. We show that being co-moving with another star and having a late spectral type is necessary, but not sufficient for being gravitationally bound. We discuss the relevance of these three wide visual binary systems for orbital dynamics and testing theoretical models. We will also present new images from 2005 and 2006 to investigate orbital motion of GQ Lup b around GQ Lup A.

Neuhaeuser, R.; Mugrauer, M.; Seifahrt, A.

2007-08-01

244

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

245

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.

246

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

247

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

248

Data Processing Discovery Agents in the Gemini Science Archive  

NASA Astrophysics Data System (ADS)

Data Processing Discovery Agents (Discovery Agents or DAs in short) represent one of the key design concepts of the newly released Gemini Science Archive (GSA). It is a simple but promising solution for decomposing the functionality of the increasingly complex astronomical data archive systems. This paper presents the rationale behind this concept and discusses its main characteristics with examples from the GSA.

Damian, A.; Hill, N.; Dowler, P.; Bohlender, D.; Goliath, S.; Gaudet, S.; Melnychuk, G.; Aspin, C.

2005-12-01

249

Illustration of relative sizes of Mercury, Gemini and Apollo spacecraft  

NASA Technical Reports Server (NTRS)

Artist concept illustrating the relative sizes of the one-man Mercury spacecraft, the two-man Gemini spacecraft, and the three-man Apollo spacecraft. Also shows line drawing of launch vehichles to show their relative size in relation to each other.

1987-01-01

250

Gemini GMOS-IFU Observations of the Biggest Black Holes  

Microsoft Academic Search

We have been using Gemini GMOS-IFU observations to study the central kinematics in brightest cluster galaxies (BCGs) to measure their central black hole masses. The largest galaxies, and especially BCGs, offer special insight into galaxy formation and evolution because they represent the extremes of these processes. Black holes are now believed to be essential components of galaxies, and their evolutionary

S. E. Busch; K. Gebhardt; T. R. Lauer; R. van der Marel

2003-01-01

251

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.

252

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.

253

Planet Hunter: A Astrometric Search of 65 Nearby Stars for Earth-Mass Planets  

NASA Astrophysics Data System (ADS)

Planet Hunter is a proposed spaceborne optical interferometer that can measure positions of bright stars with a precision of 1 microarcsec relative to reference stars. It can detect Earth-mass planets orbiting 1 AU from Sun-like stars within 20 pc. Planet Hunter can detect rocky planets in the habitable zone of 65 nearby FGK stars and determine the planet masses unambiguously, as well as masses of ice-giants and gas giants within 5 AU. Planet Hunter can also determine the full set orbital parameters of the planets it detects, including eccentricity and the 7-D orbit. The resulting ephemeris can predict the intervals of time when the planet resides outside the inner working angle, making spectroscopy possible by future imaging missions. The program is currently a NASA Astrophysics Strategic Mission Concept Study, carried out mostly at JPL.

Marcy, Geoffrey W.

2009-01-01

254

Planet Ocean  

NASA Astrophysics Data System (ADS)

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

Afonso, Isabel

2014-05-01

255

Long period planets from dynamical relaxation  

Microsoft Academic Search

Recent imaging campaigns indicate the likely existence of massive planets (~\\u000a1-10 MJ) on ~1000 year orbits about a few percent of stars. Such objects are\\u000anot easily explained in most current planet formation models. In this Letter we\\u000ause ensembles of 100 N-body simulations to evaluate the potential for planet\\u000ascattering during relaxation of dynamically active systems to explain

Caleb Scharf; Kristen Menou

2008-01-01

256

The AAO's Gemini High-Resolution Optical SpecTrograph (GHOST) concept  

NASA Astrophysics Data System (ADS)

The Gemini High-Resolution Optical SpecTrograph (GHOST) will fill an important gap in the current suite of Gemini instruments. We will describe the Australian Astronomical Observatory (AAO)-led concept for GHOST, which consists of a multi-object, compact, high-efficiency, fixed-format, fiber-fed design. The spectrograph itself is a four-arm variant of the asymmetric white-pupil echelle Kiwispec spectrograph, Kiwisped, produced by Industrial Research Ltd. This spectrograph has an R4 grating and a 100mm pupil, and separate cross-disperser and camera optics for each of the four arms, carefully optimized for their respective wavelength ranges. We feed this spectrograph with a miniature lensletbased IFU that sub-samples the seeing disk of a single object into 7 hexagonal sub-images, reformatting this into a slit with a second set of double microlenses at the spectrograph entrance with relatively little loss due to focal-ratio degradation. This reformatting enables high spectral resolution from a compact design that fits well within the relatively tight GHOST budget. We will describe our baseline 2-object R~50,000 design with full wavelength coverage from the ultraviolet to the silicon cutoff, as well as the high-resolution single-object R~75,000 mode.

Ireland, Michael J.; Barnes, Stuart; Cochrane, David; Colless, Matthew; Connor, Peter; Horton, Anthony; Gibson, Steve; Lawrence, Jon; Martell, Sarah; McGregor, Peter; Nicolle, Tom; Nield, Kathryn; Orr, David; Robertson, J. G.; Ryder, Stuart; Sheinis, Andrew; Smith, Greg; Staszak, Nick; Tims, Julia; Xavier, Pascal; Young, Peter; Zheng, Jessica

2012-09-01

257

The structure and morphology of gold nanoparticles produced in cationic gemini surfactant systems  

NASA Astrophysics Data System (ADS)

Potential applications of gold nanoparticles (GNP) are strictly connected with their size and shape. The influence of different dicationic (gemini) surfactants, alkyloxymethylimidazolium derivatives derivatives, on the structure and morphology of GNP was studied. The synthesis of nanoparticles was performed in the presence of various gemini surfactants—dodecyloxymethylimidazolium nitrate (IMI_NO3_C4_C12), propionate (IMI_PROP_C4_C12) and 3,3'-[1,9-(2,8-dioxanonane)]bis-(1-nonyloxymethylimidazolium) chloride (IMI_Cl_oxyC7_C9), used as stabilizers and templates for obtaining different size and shape of gold nanoparticles. The samples obtained were examined using transmission electron microscopy (TEM), small angle scattering of synchrotron radiation (SAXS), UV-vis spectroscopy and NMR PFG spectroscopy. For the obtained solutions of nanoparticles the plasmon resonance was observed at the wavelengths corresponding to the presence of gold nanoparticles of sizes ranging from 5-100 nm, with a significant shift towards higher wavelength for the samples prepared with addition of dicationic surfactants. TEM images evidence the presence of gold nanoparticles with tetrahedral and spherical morphology in solutions prepared with the surfactants IMI_PROP_C4_C12, IMI_NO3_C4_C12, and those of spherical morphology, but strongly aggregated, in the solution with the cationic surfactant IMI_Cl_oxyC7_C9.

Murawska, Magdalena; Wiatr, Michalina; Nowakowski, Pawe?; Szutkowski, Kosma; Skrzypczak, Andrzej; Kozak, Maciej

2013-12-01

258

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

PubMed

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

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

2013-01-01

259

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

260

Extrasolar Planets: New Clues for Planet Formation  

Microsoft Academic Search

Approximately 50 low-mass companions to solar type stars have been discovered using high precision radial velocity techniques. Recent discoveries include planets with minimum masses below that of Saturn, many systems with indications of multiple planets, and a jovian-mass companion to one of the nearest stars to the sun, epsilon Eridani. We review the present status of extrasolar planet candidates. The

W. D. Cochran

2000-01-01

261

PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS  

SciTech Connect

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

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

2009-07-10

262

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

263

GIRMOS: an infrared multi-object spectrograph for Gemini  

NASA Astrophysics Data System (ADS)

Gemini have funded a design study to investigate the technologies needed in a versatile multi-object spectrograph for IR astronomy. We report on our investigations into wide- field spectroscopy using multiple integral-field units (MIFUs) to match particular areas of interest to the available detector(s). Such technologies enable integral field spectroscopy of several targets over a much wider field than can be covered with a single IFU. A brief overview of the scientific rationale for a multipel0IFU capability matched to multi-conjugate adaptive optics, and with its wider uncorrected field, on Gemini is given. A proposed method of deploying MIFUs is then described along with the optical consequences of the method.

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

2000-08-01

264

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

265

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

266

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

267

Overview of future ground and space imaging capabilities  

NASA Astrophysics Data System (ADS)

This talk serves as an introduction to the session and context of future exoplanet direct imaging capabilities on the ground and in space. The emphasis of the presentation is on short-medium term. On the ground a new generation of instrument (Gemini Planet Imager, VLT-SPHERE, Magellan AO) are beginning their operations with considerable improvement over the previous capabilities. In space, while HST continues operations and provides high-contrast capabilities, JWST will offer several coronagraphs both on the NIRCam and MIRI instrument as well as an aperture masking mode on NIRISS. The possibility of a coronagraphy on WFIRST/AFTA also opens new possibilities for space-based coronagraphy in the medium term.

Soummer, Remi

2014-06-01

268

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

269

Compaction of DNA by gemini surfactants: effects of surfactant architecture.  

PubMed

The interaction between bacteriophage T4 DNA and cationic gemini surfactants was studied by the use of fluorescence microscopy. Upon addition of surfactant, DNA undergoes a transition from random coil to globule, with an intermediate coexistence region. The state behavior of a DNA-gemini surfactant system was found to depend on spacer length, valency, head group size, and tail length. A series of alkanediyl-alpha,omega-bis-(dimethylalkylammonium bromide) surfactants with fixed tail length and variable spacer length s showed a minimum of compaction efficiency at s=6 due to the competition between entropy loss and enthalpy gain. This occurs at roughly the same spacer length at which the critical micellization concentration shows a maximal value (at s=5). In comparison with a single-tailed divalent surfactant (12-3-1) it was shown that the two-tailed equivalent (12-3-12) was more efficient in compacting DNA. A series of gemini surfactants based on cationic peptides with a alpha,omega-diamino alkyl spacer showed similar behavior upon changing the spacer length. Additionally, two surfactants based on diastereomers of tartaric acid with hexadecanoic acid tails and alpha,omega-diaminopropanyl and spermidine head groups, respectively, showed effects of head group size that depended strongly on entropy effects. The dependence on valency of the head group is found to be similar to what is known for mono- and multivalent ions, the latter being more efficient per unit of charge. PMID:16290792

Karlsson, Lisa; van Eijk, Marcel C P; Söderman, Olle

2002-08-15

270

A Virtual Field Trip to the Gemini Observatory  

NASA Astrophysics Data System (ADS)

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

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

2010-01-01

271

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

272

The Nine Planets: Small Bodies  

NSDL National Science Digital Library

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

Arnett, Bill

273

Commission 53: Extrasolar Planets  

Microsoft Academic Search

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

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

2009-01-01

274

Dance of the Planets  

ERIC Educational Resources Information Center

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

Riddle, Bob

2005-01-01

275

Mission to Planet Earth  

NSDL National Science Digital Library

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

276

GEMINI 12 [GT-12] ASTRONAUTS LOVELL AND ALDRIN RETURN GREETED BY CROWDS  

NASA Technical Reports Server (NTRS)

KENNEDY SPACE CENTER, FLA.--Astronauts James A. Lovell, Jr., and Edwin Aldrin, Jr., receive ovation from Kennedy Space Center personnel upon their arrival back at their launch site at Cape Kennedy after successful space flight. NASA, Air Force contractor personnel who had worked on the Gemini program gathered at the landing strip on the Cape to welcome the return of the crew of Gemini 12, the final flight in the Gemini program.

1966-01-01

277

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

278

Synthesis and antimicrobial characterization of novel l-lysine gemini surfactants pended with reactive groups  

Microsoft Academic Search

A series of novel quaternary ammonium gemini surfactants of l-lysine containing ester group were synthesized with high yield rate. The antibacterial and antifungal activities of these gemini surfactants were evaluated by quantifying the minimal inhibitory concentration (MIC). The results indicated that the quaternary ammonium gemini surfactants exhibited improved activity against a broad spectrum of Gram-positive and Gram-negative bacteria as well

Hong Tan; Huining Xiao

2008-01-01

279

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

280

Separation of acidic and basic proteins by capillary electrophoresis using gemini surfactants and gemini-capped nanoparticles as buffer additives  

Microsoft Academic Search

This paper demonstrated simultaneous separation of acidic and basic proteins using cationic gemini surfactants as buffer additives\\u000a in capillary electrophoresis. We showed that even at a low concentration (0.1 mmol·L?1) of alkanediyl-?,?-bis(dimethyloctadecylammonium bromide) (18-s-18), the wall adsorption of both acidic and basic proteins could be effectively suppressed under acidic conditions. Smaller\\u000a micelle size (e.g., s = 5–8) is more effective

Qian Liu; YanQing Li; YanMin Yang; ShouZhuo Yao

2009-01-01

281

X-MIME: An Imaging X-ray Spectrometer for Detailed Study of Jupiter's Icy Moons and the Planet's X-ray Aurora  

NASA Technical Reports Server (NTRS)

Remote observations with the Chandra X-ray Observatory and the XMM-Newton Observatory have shown that the Jovian system is a source of x-rays with a rich and complicated structure. The planet's polar auroral zones and its disk are powerful sources of x-ray emission. Chandra observations revealed x-ray emission from the Io Plasma Torus and from the Galilean moons Io, Europa, and possibly Ganymede. The emission from these moons is certainly due to bombardment of their surfaces of highly energetic protons, oxygen and sulfur ions from the region near the Torus exciting atoms in their surfaces and leading to fluorescent x-ray emission lines. Although the x-ray emission from the Galilean moons is faint when observed from Earth orbit, an imaging x-ray spectrometer in orbit around these moons, operating at 200 eV and above with 150 eV energy resolution, would provide a detailed mapping (down to 40 m spatial resolution) of the elemental composition in their surfaces. Such maps would provide important constraints on formation and evolution scenarios for the surfaces of these moons. Here we describe the characteristics of X-MIME, an imaging x-ray spectrometer under going a feasibility study for the JIMO mission, with the ultimate goal of providing unprecedented x-ray studies of the elemental composition of the surfaces of Jupiter's icy moons and Io, as well as of Jupiter's auroral x-ray emission.

Elsner, R. F.; Ramsey, B. D.; Waite, J. H.; Rehak, P.; Johnson, R. E.; Cooper, J. F.; Swartz, D. A.

2004-01-01

282

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

283

Supermassive Planets or Ultralight Brown Dwarfs? A New Population of Wide Substellar Companions  

NASA Astrophysics Data System (ADS)

Numerous radial velocity and direct imaging studies have noted a deficit of brown dwarf companions to (solar-type) stars at a range of orbital separations. Yet, recent higher-contrast observations have revealed a number of substellar companions in orbits as wide as 300-900 AU, including some with masses near and below 15Mjup. These exciting discoveries hint at a population of substellar companions, with mass ratios as low as 0.01, particularly around >1 Msun stars. These objects may represent the bottom end of the stellar companion mass function or the top end of the planet population, though both scenarios pose challenges to conventional formation models. Here we propose to determine the frequency and characteristics of ultra-low-mass companions to stars of solar mass and above, by targeting a sample of 141 members of the nearby ( 118-145 pc), young ( 5-13 Myr) Sco-Cen association, with GeminiSouth/NICI. These stars have never been observed with AO before, and are prime targets for future GPI and JWST campaigns. The multiplicity information that an AO survey like this provides is a vital target selection criterion for such surveys.

Jayawardhana, Ray; Janson, Markus; Bonavita, Mariangela; Lafreniere, David; Gizis, John; Menou, Kristen

2011-02-01

284

The EXPLORE Project: A Deep Search for Transiting Extrasolar Planets  

Microsoft Academic Search

We propose a search for transiting short-period extrasolar planets using the MOSAIC wide-field imagers on the KPNO 4m and CTIO 4m telescopes. Our goal is to detect transiting planets and to derive statistics of planet frequency, radius, and mass for stars ranging from types early G to late K. Planet transits will be detected via 1% photometric precision lightcurves with

Gabriela Mallen-Ornelas; Howard Yee; Tim M. Brown; Michael D. Gladders; G. M. Mallén-Fullerton; Kaspar von Braun; Cullen Blake; Brian Lee; Sara Ellison

2002-01-01

285

The Dependence of Signal-To-Noise Ratio (S/N) Between Star Brightness and Background on the Filter Used in Images Taken by the Vulcan Photometric Planet Search Camera  

NASA Technical Reports Server (NTRS)

The Vulcan Photometric Planet Search is the ground-based counterpart of Kepler Mission Proposal. The Kepler Proposal calls for the launch of telescope to look intently at a small patch of sky for four year. The mission is designed to look for extra-solar planets that transit sun-like stars. The Kepler Mission should be able to detect Earth-size planets. This goal requires an instrument and software capable of detecting photometric changes of several parts per hundred thousand in the flux of a star. The goal also requires the continuous monitoring of about a hundred thousand stars. The Kepler Mission is a NASA Discovery Class proposal similar in cost to the Lunar Prospector. The Vulcan Search is also a NASA project but based at Lick Observatory. A small wide-field telescope monitors various star fields successively during the year. Dozens of images, each containing tens of thousands of stars, are taken any night that weather permits. The images are then monitored for photometric changes of the order of one part in a thousand. These changes would reveal the transit of an inner-orbit Jupiter-size planet similar to those discovered recently in spectroscopic searches. In order to achieve a one part in one thousand photometric precision even the choice of a filter used in taking an exposure can be critical. The ultimate purpose of an filter is to increase the signal-to-noise ratio (S/N) of one's observation. Ideally, filters reduce the sky glow cause by street lights and, thereby, make the star images more distinct. The higher the S/N, the higher is the chance to observe a transit signal that indicates the presence of a new planet. It is, therefore, important to select the filter that maximizes the S/N.

Mena-Werth, Jose

1998-01-01

286

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 ...

Larsen, Mr.

2008-11-25

287

Exploring the Planets: Comparing the Planets  

NSDL National Science Digital Library

Comparative planetology is a scientific discipline in which researchers seek to understand the planets by comparing their similarities and examining their differences. Some planets have similarities because the materials of which they are made and the processes that have shaped them are similar. However, each planet has a unique character, due to the intensity and length of time the processes have operated. At this site, selected planets are compared on the basis of their atmospheres, volcanoes, impact craters, wind, water and ice. In each instance, photographs are displayed side by side for direct comparison.

288

Gap Structure around Planets in Protoplanetary Disks  

NASA Astrophysics Data System (ADS)

In a protoplanetary disk, a large planet is able to create a gap, which is a low surface density annulus region along the planet orbit, by a gravitational interaction with the disk. If the planet is massive enough, the gap terminates the gaseous inflow across the orbit of planet. Thus, the gap formation is thought to be a possible mechanism that creates the transitional disks with the inner holes, which have been revealed by SED observations and direct imaging. The formation of the disk gap also influences the planet itself. Because of the gap formation, the mode of the planet migration changes from Type I to II. The gap also fairly reduces the gas accretion into the planet. Since such a co-evolution of a protoplanetary disk and planets would be a key process that governs the origin of the diversity of exo-planetary systems, it has been studied by many authors. However, the co-evolution of a protoplanetary disk and planets still has a large uncertainty because of the complexity of the gap formation. In this study, we examined the surface density profile of the gap, by using one-dimensional viscous accretion disk model with a simple model of a planet torque. In our calculation, we did not assume the Keplerian disk rotation, and took into account the disk rotation law altered by the steep surface density gradient in the gap, in a self-consistent way. We found that the altered rotation law significantly affects the resultant surface density profile especially for narrow and deep gaps. Furthermore, we checked our one-dimensional gap calculation by performing two-dimensional hydrodynamical simulations of gap formation with the FARGO code, for various planet masses, and disk parameters (i.e., the disk scale height and the viscosity). Our one-dimensional gap calculation can reproduce precisely results of the hydrodynamic simulations for wide range of the planet mass and disk parameters.

Kanagawa, Kazuhiro; Muto, Takayuki; Tanaka, Hidekazu; Tanigawa, Takayuki; Takeuchi, Taku

2013-07-01

289

Eastern Mediterranean as seen from Gemini 7 spacecraft  

NASA Technical Reports Server (NTRS)

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

1965-01-01

290

Gemini all-sky camera for laser guide star operation  

NASA Astrophysics Data System (ADS)

As part of its Safe Aircraft Localization and Satellite Acquisition System (SALSA), Gemini is building an All Sky Camera (ASCAM) system to detect aircrafts in order to prevent propagation of the laser that could be a safety hazard for pilots and passengers. ASCAM detections, including trajectory parameters, are made available to neighbor observatories so they may compute impact parameters given their location. We present in this paper an overview of the system architecture, a description of the software solution and detection algorithm, some performance and on-sky result.

Bec, Matthieu; Rigaut, Francois J.; Trancho, Gelys; Boccas, Maxime; Collao, Fabian; Daruich, Felipe; d'Orgeville, Céline; Lazo, Manuel; Maltes, Diego; Perez, Gabriel; Vergara, Vicente; Vucina, Tomislav; Sheehan, Michael P.

2008-08-01

291

EUCLID microlensing planet search  

NASA Astrophysics Data System (ADS)

The discovery of extrasolar planets is arguably the most exciting development in astrophysics during the past 15 years, rivalled only by the detection of dark energy. Two projects unite the communities of exoplanet scientists and cosmologists: the proposed ESA M class mission EUCLID and the large space mission WFIRST, top ranked by the Astronomy 2010 Decadal Survey report. The later states that: "Space-based microlensing is the optimal approach to providing a true statistical census of planetary systems in the Galaxy, over a range of likely semi-major axes". They also add: "This census, combined with that made by the Kepler mission, will determine how common Earth-like planets are over a wide range of orbital parameters" We will present a status report of the results obtained by microlensing on exoplanets, the new objectives of the next generation of ground based wide field imager networks. We will finally present the fantastic prospect offered by space based microlensing at the horizon 2020-2025.

Beaulieu, J.-P.; Tisserand, P.; Batista, V.

2013-09-01

292

Genetic diversity of Mexican brook lamprey Lampetra (Tetrapleurodon) geminis (Alvarez del Villar, 1966)  

Microsoft Academic Search

Lampreys are the only surviving representatives of the oldest known vertebrates. The Mexican lamprey L. geminis (nonparasitic), is particularly interesting, because it is an endemic, biogeographical relict, and a threatened species. RAPD markers were used to describe genetic diversity in L. geminis A total of 77 specimens were collected from five populations, three in the R'o Grande de Morelia-Cuitzeo basin

Omar Mejía; Oscar J. Polaco; Gerardo Zúñiga

2004-01-01

293

Jovian Planet Finder optical system  

NASA Astrophysics Data System (ADS)

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

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

2003-02-01

294

HIGH-CONTRAST 3.8 {mu}m IMAGING OF THE BROWN DWARF/PLANET-MASS COMPANION TO GJ 758  

SciTech Connect

We present L'-band (3.8 {mu}m) MMT/Clio high-contrast imaging data for the nearby star GJ 758, which was recently reported by Thalmann et al. to have one -- possibly two -- faint comoving companions (GJ 758B and 'C', respectively). GJ 758B is detected in two distinct data sets. Additionally, we report a possible detection of the object identified by Thalmann et al. as 'GJ 758C' in our more sensitive data set, though it is likely a residual speckle. However, if it is the same object as that reported by Thalmann et al. it cannot be a companion in a bound orbit. GJ 758B has an H - L' color redder than nearly all known L-T8 dwarfs. Based on comparisons with the COND evolutionary models, GJ 758B has T {sub e} {approx} 560 K{sup +150K}{sub -90 K}{sup +150 K) and a mass ranging from {approx}10-20 M{sub J} if it is {approx}1 Gyr old to {approx} 25-40 M{sub J} if it is 8.7 Gyr old. GJ 758B is likely in a highly eccentric orbit, e {approx} 0.73{sup +0.12}{sub -0.21}, with a semimajor axis of {approx}44 AU{sup +32 AU){sub -14 AU}. Though GJ 758B is sometimes discussed within the context of exoplanet direct imaging, its mass is likely greater than the deuterium-burning limit and its formation may resemble that of binary stars rather than that of Jovian-mass planets.

Currie, Thayne [NASA-Goddard Space Flight Center, Greenbelt, MD (United States); Bailey, Vanessa; Rodigas, Timothy; Hinz, Phil [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Fabrycky, Daniel; Murray-Clay, Ruth [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2010-10-01

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.

Duroseau, Wendy

2012-04-30

296

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

297

Portraits of distant worlds: Characterizing the atmospheres of extrasolar planets  

NASA Astrophysics Data System (ADS)

This thesis presents observational studies of the atmospheres of extrasolar planets, including the first longitudinal temperature profile of an extrasolar planet and the first detection of a temperature inversion in the atmosphere of an extrasolar planet. Our observations target four eclipsing gas-giant planets known as "hot Jupiters"; as a result of their short orbital periods we expect these planets to be tidally locked, with day-night circulation patterns and atmospheric chemistries that differ significantly from those of Jupiter. The first two chapters of this thesis describe infrared observations of the secondary eclipses of HD 209458b and TrES-4 with the Spitzer Space Telescope . By measuring the decrease in flux as the planet passes behind its parent star, we can characterize the infrared emission spectra of these planets and from that learn something about their dayside pressure-temperature profiles. Our observations reveal that these two planets have spectra with water bands in emission, requiring the presence of an atmospheric temperature inversion between 0.1 - 0.01 bars. The third chapter describes a ground-based search for thermal emission from TrES-1 using L -band grism spectroscopy with the NIRI instrument on Gemini North. Unlike Spitzer photometry, which is limited to broad bandpasses at these wavelengths, grism spectroscopy offers the opportunity to resolve specific features in the planetary emission spectrum. We find that our precision is limited by our ability to correct for time-varying slit losses from pointing drift and seeing changes, and place an upper limit on the depth of the planet's secondary eclipse in this band. The fourth and fifth chapters describe observations of the infrared phase variations of the hot Jupiter HD 189733b in the 8 and 24 mm Spitzer bands. By monitoring the changes in the brightness of this planet as it rotates around its parent star we can determine how much energy is circulated from the perpetually-illuminated day side around to the night side. We then invert these data to produce a longitudinal temperature profile for the planet, allowing us to resolve the locations of prominent hot and cold regions in the planet's atmosphere.

Knutson, Heather Ann

2009-06-01

298

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

299

The interfacial tension between oil and gemini surfactant solution [rapid communication  

NASA Astrophysics Data System (ADS)

The interfacial tensions between oil and solution of cationic gemini surfactants have been measured. It is found that gemini surfactants are more effective and efficient than corresponding conventional surfactants in reducing the interfacial tension and can lower the tension of kerosene-water interface to ultra-low at very low concentration without other additives. It is also found that gemini surfactants can reduce the interfacial tension to ultra-low only at a certain concentration range. The addition of salt results in more effectiveness of surfactant in reducing the tension of kerosene-water interface and shows that gemini surfactant has a good synergism with salt. For crude oil from Zhongyuan Oil Field of China, gemini surfactant is more effective on lowering crude oil-water tension and has an excellent ability in reducing the tension of crude oil-water interface. However, when the oil is hexadecane, ultra-low interfacial tension is not observed.

Chen, Hong; Han, Lijuan; Luo, Pingya; Ye, Zhongbin

2004-03-01

300

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.

301

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

302

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

303

Evaporation of extrasolar planets  

Microsoft Academic Search

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

A. Lecavelier Des Etangs

2010-01-01

304

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

305

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

306

Complexation of DNA with cationic gemini surfactant in aqueous solution.  

PubMed

Interactions between DNA and the cationic gemini surfactant trimethylene-1,3-bis(dodecyldimethylammonium bromide) (12-3-12) in aqueous solution have been investigated by UV-vis transmittance, zeta potential, and fluorescence emission spectrum. Complexes of DNA and gemini surfactant are observed in which the negative charges of DNA are neutralized by cationic surfactants effectively. The DNA-induced micelle-like structure of the surfactant due to the electrostatic and hydrophobic interactions is determined by the fluorescence spectrum of pyrene. It is found that the critical aggregation concentration (CAC) for DNA/12-3-12 complexes depends little on the addition of sodium bromide (NaBr) because of the counterbalance salt effect. However, at high surfactant concentration, NaBr facilitates the formation of larger DNA/surfactant aggregates. Displacement of ethidium bromide (EB) by surfactant evidently illustrates the strong cooperative binding between surfactant and DNA. In contrast to that in the absence of surfactant, the added NaBr at high surfactant concentration influences not only the binding of surfactant with DNA, but also the stability of DNA/EB complex. PMID:17631886

Zhao, Xiaofang; Shang, Yazhuo; Liu, Honglai; Hu, Ying

2007-10-15

307

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

308

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

309

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

310

Planet Masses and Densities  

NASA Astrophysics Data System (ADS)

The masses of Kepler planet candidates remain unknown until some dynamical technique measures the gravitational effect of that planet on either the star (with RV measurements) or other planets (with TTVs). Measuring planet masses is particularly important as, when combined with the transit-based planet radii, they yield the bulk density of the planets, constraining conditions in the interior, notably the amount of metal, rock, water, and gas. For planets smaller than 2 Earth-radii, the transition from Neptune-like to rocky planets is particularly intriguing, bearing on formation, evolution, and habitability. We report precise (2 m/s) Doppler RVs for 15 host stars of Kepler planet candidates. New RV techniques are now employed for faint stars of 13th mag, notably long-slit sky subtraction and statistical priors for the PSF and wavelength scale in the Doppler analysis. The RV observations are timed at moments near orbital quadrature to maximize the RV differences. We obtained 10-20 RVs for each of 15 host stars of Kepler planet candidates, with typical exposure times of 30 min. The RVs are fit with Keplerian models that include all transisting planets and their known ephemerides from the Kepler photometry. The two free parameters are only the masses of the planets and RV zero point. Both random and systematic errors will not be correlated with orbital phase, ensuring that the RV signal-to-noise improves as the square root of the number of RV observations. Orbital fits provide planet mass, density, and in some cases contraints on eccentricity. For RV non-detections, MCMC analyses provide upper limits to planet mass and density.

Marcy, Geoffrey W.

2012-05-01

311

Wave of a Planet  

NASA Technical Reports Server (NTRS)

This plot tells astronomers that a fifth planet is in orbit around the star 55 Cancri, making the star the record-holder for hosting the most known exoplanets.

As planets circle around their stars, they cause the stars to wobble back and forth in a regular pattern. By looking for this motion in a star, scientists can find planets that can't be seen with telescopes.

The wobble caused by the fifth planet discovered around 55 Cancri is represented here by the sinuous line in blue. The actual data points are yellow and error bars are the lines above and below the yellow dots. The cycle of the wobble indicates that the planet circles around its star about every 260 days. The amplitude of the wobble indicates that the planet is a giant at least 45 times the mass of Earth.

The wobbles caused by the other four planets has been removed from this plot, to reveal that caused by the fifth. The departure from a perfect sine wave suggests the planet's orbit is not perfectly circular.

Because 55 Cancri has multiple planets, the star had to be observed for a long time before astronomers could find and confirm its fifth planet. These data were collected over a period of 18 years using both the Lick Observatory near San Jose, Calif., and the W.M. Keck Observatory in Hawaii.

2007-01-01

312

Habitable Planets: Observational Arguments  

NASA Astrophysics Data System (ADS)

Observations of extrasolar planets and protostellar disks suggest that rocky worlds form commonly around young stars. At least 8% of stars are observed to have saturn- and jupiter-mass planets within 3 AU, and more planets are likely beyond 3 AU. The mass distribution of planets rises steeply with decreasing mass (Marcy & Butler 2000), implying that more small planets form than giant ones. Elliptical, rather than circular, orbits predominate among the 35 known planets beyond 0.2 AU. New Doppler and astrometric techniques may reveal planets having masses as low as 10 Earth-masses. Protoplanetary disks surround over half of young stars, with disk masses typically over 10X that of Jupiter. Their energy distributions from IR and mm-wave observations yield dust emissivities that imply the rapid growth (within 0.1 Myr) of dust particles to millimeter size. Thus, theoretical predictions of quick growth of rocky planets is supported. One may rationally estimate that 50% of all stars form with a retinue of rocky orbiting bodies. However, a nemesis looms for the survival of earths: dynamical scattering and ejection. The ubiquity of eccentric orbits among jupiters orbiting from 0.2--3 AU suggests that gravitational scattering among planets and planetesimals is a common phenomenon (see the following presentation by H. Levison). If so, the circular orbits and survival of the lowest mass, terrestrial planets are jeopardized. We acknowledge funding from NASA, NSF, and Sun Microsystems.

Marcy, G.; Butler, R. P.; Vogt, S. S.; Fischer, D. A.

2000-12-01

313

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

314

The synthesis and properties of a new nonionic Gemini surfactant  

NASA Astrophysics Data System (ADS)

A new Gemini nonionic surfactant was prepared, taking anhydrous glucose, glycol, maleic anhydride, lauric acid as main materials, and the reaction was carried out by three steps. Firstly, glycol glucoside was synthesized by the direct glycosidation of the anhydrous glucose with glycol in the presence of acidic catalyst. The synthesis and the characterization of this have been reported previously.Secondly, reaction intermediate was prepared by ring opening reaction of maleic anhydride with glycol glucoside. The last, primary hydroxyl group in glucose of reaction intermediate was esterified with lauric acid for synthesis of target product. It was analyzed and characterized by IR, 1HNMR and 13CNMR. Besides, the critical micelle concentration (cmc) and the corresponding surface tension of the target product were measured to be 8.87×10-3molL-1 and 20.70mNm-1 (20°C), respectively.

Ren, Yanmei; Lv, Tong; Wang, Qi; Tian, Zhenxing

2010-07-01

315

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

316

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

317

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.

318

Formation of giant planets  

NASA Astrophysics Data System (ADS)

We present calculations of giant planet formation based on extended core-accretion planet formation models taking into account disk structure and evolution and migration of the protoplanet. We show that these models lead to giant planet formation timescales compatible with disk lifetimes. Using these models, we show that we can reproduce the bulk internal structure of Jupiter and Saturn, as well as the enrichment in volatile species measured in situ by the Galileo probe (for Jupiter), and from the Earth (for Saturn). We then apply these models to the formation of the three Neptune mass planet system recently discovered by the HARPS collaboration (Lovis et al. 2006), and show that the two outer planets are likely to have accreted large amounts of water ice during their formation. Finally, the comparison with the extrasolar planets will be presented by C. Mordasini (this meeting, abstract EPSC2006-A-00672) using a Monte-Carlo approach.

Alibert, Y.; Mordasini, C.; Benz, W.

319

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

320

Earthshine and Extrasolar Planets  

Microsoft Academic Search

The search for life on extrasolar planets requires first that we find terrestrial-mass planets around nearby stars, and second that we determine habitability and search for signs of life. The Terrestrial Planet Finder missions, a Coronagraph (TPF-C) and an Interferometer (TPF-I in the US, also Darwin in Europe) are designed to carry out these tasks. This talk will focus on

W. A. Traub; L. Kaltenegger; M. C. Turnbull; K. W. Jucks

2006-01-01

321

Pulse of the Planet  

NSDL National Science Digital Library

The Pulse of the Planet audio programs provide listeners with two-minute sound portraits of Planet Earth, tracking the rhythms of nature, culture and science worldwide and blending interviews and extraordinary natural sound. Pulse of the Planet is broadcast over public and commercial stations around the world. Site materials include a link to the current day's program, featured stories, and to archives of daily programs.

322

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

323

Outlook: Testing Planet Formation Theories  

NASA Astrophysics Data System (ADS)

The discovery of the first planetary companion to a solar-type star by Mayor and Queloz (1995) launched the extrasolar planetary systems era. Observational and theoretical progress in this area has been made at a breathtaking pace since 1995, as evidenced by this workshop. We now have a large and growing sample of extrasolar gas giant planets with which to test our theories of their formation and evolution. The two competing theories for the formation of gas giant planets, core accretion and disk instability, appear to have testable predictions: (i) Core accretion seems to require exceptionally long-lived disks, implying that gas giants should be somewhat rare, while disk instability can occur in even the shortest-lived disk, implying that gas giants should be abundant. The ongoing census of gas giants by the spectroscopic search programs will determine the frequency of gas giants on Jupiter-like orbits within the next decade. (ii) Core accretion takes millions of years to form gas giants, while disk instability forms gaseous protoplanets in thousands of years. Determining the epoch of gas giant planet formation by searching for astrometric wobbles indicative of gas giant companions around young stars with a range of ages (˜ 0.1 Myr to ˜ 10 Myr) should be possible with the Space Interferometry Mission (SIM). (iii) Core accretion would seem to be bolstered by a higher ratio of dust to gas, whereas disk instability occurs equally well for a range of dust opacities. Determining whether a high primordial metallicity is necessary for gas giant planet formation can be accomplished by spectroscopic and astrometric searches for gas giants around metal-poor stars. Eventually, ice giant planets will be detectable as well. If ice giants are found to be much more frequent that gas giants, this may imply that core accretion occurs, but usually fails to form a gas giant. Terrestrial planets will be detected through photometry by Kepler and Eddington, astrometry by SIM, and imaging by Terrestrial Planet Finder and Darwin. Ultimately these detections will clarify the process of Earth formation by collisional accumulation, the only contending theory.

Boss, A. P.

324

Terrestrial planet formation.  

PubMed

Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

Righter, K; O'Brien, D P

2011-11-29

325

Terrestrial planet formation  

PubMed Central

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

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

2011-01-01

326

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

327

GeMini: The next-generation mechanically-cooled germanium spectrometer  

Microsoft Academic Search

The next-generation mechanically-cooled germanium spectrometer has been developed. GeMini (MINIature GErmanium spectrometer) has been designed to bring high-resolution gamma-ray spectroscopy to a range of demanding field environments. Intended applications include short-notice inspections, border patrol, port monitoring and emergency response, where positive nuclide identification of radioactive materials is required but power and liquid cryogen are not easily available. GeMini weighs 2.75

M. Burks

2008-01-01

328

Conceptual design for a high-resolution infrared spectrograph for the 8-m Gemini telescopes  

Microsoft Academic Search

The High-Resolution Near-InfraRed Spectrograph (HRNIRS) concept for the Gemini telescopes combines a seeing limited R ~ 70000 cross-dispersed mode and an MCAO-fed near diffraction-limited R ~ 30000 multi-object mode into a single compact instrument operating over the 1 - 5 mum range. The HRNIRS concept was developed in response to proposals issued through the Aspen instrument process by Gemini. Here

Kenneth H. Hinkle; Stephen Eikenberry; Richard Joyce; Ming Liang; Gary Muller; Ed Hileman; Jim French; Jian Ge; Chris Packham; Roger Julian; Taft Armandroff; Neil Gaughan; David Sprayberry

2006-01-01

329

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

330

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

331

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

332

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

333

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

334

Theory of planet formation  

Microsoft Academic Search

We review the current theoretical understanding how growth from micro-meter sized dust to massive giant planets occurs in disks around young stars. After introducing a number of observational constraints from the solar system, from observed protoplanetary disks, and from the extrasolar planets, we simplify the problem by dividing it into a number of discrete stages which are assumed to occur

Christoph Mordasini; Hubert Klahr; Yann Alibert; Willy Benz; Kai-Martin Dittkrist

2010-01-01

335

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.

2007-07-03

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

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

338

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

339

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.

340

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.

341

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.

342

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.

2011-04-03

343

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.

344

Releve de planetes geantes autour d'etoiles proches par imagerie directe et optimisation d'une technique d'imagerie multibande  

NASA Astrophysics Data System (ADS)

The primary goal of this thesis is the search for exoplanets using direct imaging. Given the small angular separation and the very large luminosity ratio between a planet and its star this task is very difficult. The approach adopted for the present work is differential imaging, which consists in obtaining a reference image of the point-spread function (PSF) of the star, and subtracting this reference image from a target image to remove the stellar signal. Initially, two tools aimed at improving the quality of this subtraction are developed. The first is a new instrumental concept that makes it possible to increase the correlation of images obtained at different wavelengths in simultaneous spectral differential imaging. This concept consists in placing a holographic diffuser at the entrance focal plane of a multi-channel camera in order to break the coherence of the wavefront entering the camera; this largely reduces the effect of optical aberrations in the camera on the structure of the PSF recorded in each channel. A prototype based on this concept provided an attenuation of the PSF by a factor 12-15, an improvement by a factor ˜5 compared to the attenuation obtained without a diffuser. The second tool developed is a new algorithm allowing to combine several reference images of the stellar PSF together to form a reference image more faithful to the target image. The application of this algorithm to an angular differential imaging sequence of observations yielded an improvement in sensitivity by a factor of up to 3. Finally, the results of a search for giant planets around 85 nearby young stars are presented; this search was done with the Gemini North telescope. The sensitivity of the observations, expressed in difference of magnitudes at 1.6 mum between a planet and its star, is typically 9.5 at 0.5 ?, 12.9 at 1?, 15 at 2?, and 16.5 at 5?. For a typical target star, a 100 million year old K0 star located at 22 pc from the Sun, these sensitivities allow the detection of planets more massive than 2 MJup with a projected separation between 40 and 200 UA. Overall, more than 300 candidate exoplanets were identified around 54 of the stars observed; a follow-up of 48 of these stars has confirmed that their candidates are all unrelated background stars. A statistical analysis of the results indicates that, by assuming a mass function dn/dm ? m-1.1 and a semi-major axis distribution d n/da ? a-1 the upper limits on the fraction of stars with at least one planet of mass 0.5--13 MJup are 28% for the interval 10--25 AU, 13% for 25--50 AU, and 9.3% for 50--200 AU, with a 95% credibility. Keywords: exoplanets, high-contrast imaging, image processing, astronomical instrumentation

Lafreniere, David

345

A Systematic Deuteration Survey in the Gemini OB1 Molecular Cloud  

NASA Astrophysics Data System (ADS)

Recent maps of dust continuum emission from molecular clouds at submillimeter wavelengths have made it possible to survey and to study the chemistry of entire core and clump populations within a single cloud. One very strong chemical process in star-forming regions is the fractionation of deuterium in molecules which results in an increase in the deuterium ratio many orders of magnitude over the ISM [D]/[H] ratio and provides a chemical probe of cold, dense regions. We present a survey of DCO+ 3-2 emission toward the clump population in the high-mass, star-forming Gemini OB1 molecular cloud complex identified from 1.1 mm continuum imaging by the Bolocam Galactic Plane Survey (BGPS). The peak 1.1 mm continuum positions of 52 clumps were observed with the 10m Heinrich Hertz Submillimeter Telescope operated by the Arizona Radio Observatory. We compare to observations of HCO+ and H13CO+ from the BGPS spectroscopic survey of Shirley et al. to determine the deuterium ratio. We find that DCO+ emission is detected toward 90% of the clumps with a median deuterium ratio of a few percent. DCO+ fractionation anti-correlates with gas kinetic temperature and linewidth, a measure of the amount of turbulence within the clumps.

Shirley, Yancy L.

2014-01-01

346

Revealing a new symbiotic X-ray binary with Gemini Near-infrared Integral Field Spectrograph  

NASA Astrophysics Data System (ADS)

We use K-band spectroscopy of the counterpart to the rapidly variable X-ray transient XMMU J174445.5-295044 to identify it as a new symbiotic X-ray binary. XMMU J174445.5-295044 has shown a hard X-ray spectrum (we verify its association with an INTEGRAL/Imager on-Board the INTEGRAL Satellite 18-40 keV detection in 2013 using a short Swift/X-Ray Telescope observation), high and varying NH, and rapid flares on time-scales down to minutes, suggesting wind accretion on to a compact star. We observed its near-infrared counterpart using the Near-infrared Integral Field Spectrograph at Gemini-North, and classify the companion as ˜M2 III. We infer a distance of 3.1^{+1.8}_{-1.1} kpc (conservative 1? errors), and therefore calculate that the observed X-ray luminosity (2-10 keV) has reached to at least 4 × 1034 erg s-1. We therefore conclude that the source is a symbiotic X-ray binary containing a neutron star (or, less likely, black hole) accreting from the wind of a giant.

Bahramian, Arash; Gladstone, Jeanette C.; Heinke, Craig O.; Wijnands, Rudy; Kaur, Ramanpreet; Altamirano, Diego

2014-06-01

347

Near-Infrared Observations of GQ Lup b Using the Gemini Integral Field Spectrograph NIFS  

NASA Astrophysics Data System (ADS)

We present new JHK spectroscopy (R ~ 5000) of GQ Lup b, acquired with the Near-Infrared Integral Field Spectrograph and the adaptive optics system ALTAIR at the Gemini North telescope. Angular differential imaging was used in the J and H bands to suppress the speckle noise from GQ Lup A; we show that this approach can provide improvements in signal-to-noise ratio (S/N) by a factor of 2-6 for companions located at subarcsecond separations. Based on high-quality observations and Global Astrometric lnterferometer for Astrophysics synthetic spectra, we estimate the companion effective temperature to T eff = 2400 ± 100 K, its gravity to log g = 4.0 ± 0.5, and its luminosity to log(L/L sun) = -2.47 ± 0.28. Comparisons with the predictions of the DUSTY evolutionary tracks allow us to constrain the mass of GQ Lup b to 8-60 M Jup, most likely in the brown dwarf regime. Compared with the spectra published by Seifahrt and collaborators, our spectra of GQ Lup b are significantly redder (by 15%-50%) and do not show important Pa? emission. Our spectra are in excellent agreement with the lower S/N spectra previously published by McElwain and collaborators.

Lavigne, Jean-François; Doyon, René; Lafrenière, David; Marois, Christian; Barman, Travis

2009-10-01

348

Wide Tertiary Companions to Nearby Spectroscopic Binaries: A Close Look with Gemini-North AO  

NASA Astrophysics Data System (ADS)

We report on the preliminary findings of a multi-epoch, common proper motion (CPM) search for tertiary companions to known, nearby spectroscopic binary systems. Simulations of the star forming environment indicate that, in order to produce the very small separations of such systems, a third member can carry away angular momentum, tightening the binary. This third member typically has a low-mass and remains bound to the system. We use NIRI-Altair AO imaging on Gemini-North to search for close tertiary companions to a sample of 91 spectroscopic binaries. We collect the data in two narrow-band filters separated by approximately one year. The two filters are centered just outside of the 1.6 ?m methane feature (CH4short) and just inside it (CH4long). This allows for two forms of candidate identification: 1) CPM and 2) methane dropout if the object is a T dwarf. At this time, we have obtained and analyzed 60 multi-epoch fields. We confirm a previously known CPM companion and identify three sub-stellar candidates and two M dwarf candidates.

Allen, P. R.; Close, L.

2011-12-01

349

RADIO GALAXY 3C 230 OBSERVED WITH GEMINI LASER ADAPTIVE-OPTICS INTEGRAL-FIELD SPECTROSCOPY  

SciTech Connect

The Altair laser-guide-star adaptive optics facility combined with the near-infrared integral-field spectrometer on Gemini North have been employed to study the morphology and kinematics of 3C 230 at z = 1.5, the first such observations of a high-redshift radio galaxy. These suggest a bi-polar outflow spanning 0.''9 ({approx}16 kpc projected distance for a standard {Lambda} CDM cosmology) reaching a mean relative velocity of 235 km s{sup -1} in redshifted H{alpha} +[N II] and [S II] emission. Structure is resolved to 0.''1 (0.8 kpc), which is well correlated with optical images from the Hubble Space Telescope and Very Large Array radio maps obtained at similar spatial resolution. Line diagnostics suggest that over the 10{sup 7} yr to 10{sup 8} yr duration of its active galactic nucleus activity, gas has been ejected into bright turbulent lobes at rates comparable to star formation, although constituting perhaps only 1% of the baryonic mass in the galaxy.

Steinbring, Eric [Herzberg Institute of Astrophysics, National Research Council Canada, Victoria, BC V9E 2E7 (Canada)

2011-11-15

350

Lab results of the circular phase mask concepts for high-contrast imaging of exoplanets  

NASA Astrophysics Data System (ADS)

Circular phase mask concepts represent promising options for high contrast imaging and spectroscopy of exo-planets. Depending on their design, they can either work as a diffraction suppression system or as a focal plane wavefront sensor. While the apodized Roddier coronagraph uses a ?-phase mask to obtain complete suppression of the star image in monochromatic light, the Zernike sensor uses a ?/2-phase mask to measure the residual aberrations in the focal plane by encoding them into intensity variations in the relayed pupil. Implementations of the Zernike sensor can be considered in exoplanet imagers such as VLT-SPHERE, Gemini planet imager, Palomar-P1640 or Subaru-SCExAO to enlarge their capabilities. However, such concepts have not been validated experimentally up to now. Our goal is to perform lab demonstration of this concept on our visible coronagraph testbed at LAM and to propose an upgrade design for SPHERE. In this communication, we report on results of lab measurements of the Zernike sensor and determine its sensitivity to small wavefront errors.

N'Diaye, Mamadou; Dohlen, Kjetil; Fusco, Thierry; El Hadi, Kacem; Soummer, Rémi; Cuevas, Salvador; Zerrad, Myriam; Ferrari, Marc

2012-09-01

351

Ocean Planet: Rough Planet Earth without Ocean  

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.

Pape, Dave; Feldman, Gene

1994-04-29

352

Cellular uptake of polyurethane nanocarriers mediated by gemini quaternary ammonium.  

PubMed

The effective passage of drug formulations into tumor cells is a key factor in the development of nanoscale delivery systems. However, rapid cellular uptake with reduced toxicity remains a great challenge for efficient and safe delivery. In this study, we first use gemini quaternary ammonium (GQA) as a cell internalization promoter to enhance the cellular uptake of drug nanocarriers. It is found that a twenty times faster cell internalization could be achieved by introducing GQA into biodegradable multiblock polyurethane nanomicelles, as confirmed by flow cytometry and confocal laser scanning microscopy (CLSM) studies. Meanwhile, an added methoxyl-poly(ethylene glycol) (mPEG) outer corona could protect these cationic micelles from cytotoxicity at high concentrations, as verified by methyl tetrazolium (MTT) assay. Moreover, GQA not only acts as an enhancer for rapid cellular entry, but also plays an important role in controlled self-assembly and high drug loading capacity. Our work offers a new understanding on the role of cationic surfactants; and provides a facile and economical approach for the design of versatile drug nanocarriers to achieve efficient delivery and good biocompatibility. PMID:21907404

Ding, Mingming; He, Xueling; Wang, Zhigao; Li, Jiehua; Tan, Hong; Deng, Hua; Fu, Qiang; Gu, Qun

2011-12-01

353

Numerical Simulations of Airflow at Gemini Telescope Sites  

NASA Astrophysics Data System (ADS)

In order to determine the optimum location of the Gemini 8 meter telescopes it is desirable to know the airflow characteristics at the proposed sites. Similarly, a determination of the height of the telescope pier requires some knowledge of the thickness of the turbulent boundary layer under various conditions at the proposed sites. On site testing provides valuable data but over a limited range of wind conditions and only at specific points. In order to better understand the ambient wind flow at the proposed sites, three dimensional hydrodynamic simulations of the airflow over the top of Mauna Kea and over Cerro Pachon in Chile were carried out with the facilities at the San Diego Supercomputer Center. The results of these calculations will be presented. They show that the summit ridge at Mauna Kea to be an excellent site, though the off ridge locations are less desirable, and that either of the proposed sites on Cerro Pachon will meet the desired criteria. They also show that a telescope pier height of 15-20m will place the telescopes above the turbulent boundary layer under almost all conditions.

Charles, Richard; De Young, David S.

1993-12-01

354

A Metric for Exo-Planet Detectability  

NASA Astrophysics Data System (ADS)

There are many architectures being proposed for direct imaging of planets around other stars. To compare the performance of these systems, we need a consistent metric to quantify whether and how well a given planet or range of planets can be observed. This is also critical for deriving a specific mission design for a given architecture. In this paper, we look at this issue in the context of the New Worlds Observer (NWO) architecture. We develop a metric for how well a given planet can be seen by a given system. We then apply this metric to a range of NWO systems and explore how this affects the mission design. We find that the central starlight suppression and the geometrical Inner Working Angle (IWA) are not good ways to describe an external occulter system's ability to detect an exo-planet. Instead, for a given mission design, there will be a range of IWA depending on the relationship between the planet brightness and the suppression provided by the starshade. We explore this relationship and discuss its implications for the design of an NWO mission.

Glassman, Tiffany M.; Polidan, R.; Lo, A.

2007-12-01

355

Reading the Signatures of Extrasolar Planets in Debris Disks  

NASA Technical Reports Server (NTRS)

An extrasolar planet sculpts the famous debris dish around Fomalhaut; probably ma ny other debris disks contain planets that we could locate if only we could better recognize their signatures in the dust that surrounds them. But the interaction between planets and debris disks involves both orbital resonances and collisions among grains and rocks in the disks --- difficult processes to model simultanemus]y. I will describe new 3-D models of debris disk dynamics that incorporate both collisions and resonant trapping of dust for the first time, allowing us to decode debris disk images and read the signatures of the planets they contain.

Kuchner, Marc J.

2009-01-01

356

The planets and life.  

NASA Technical Reports Server (NTRS)

It is pointed out that planetary exploration is not simply a program designed to detect life on another planet. A planet similar to earth, such as Mars, when studied for evidence as to why life did not arise, may turn out to be scientifically more important than a planet which has already produced a living system. Of particular interest after Mars are Venus and Jupiter. Jupiter has a primitive atmosphere which may well be synthesizing organic molecules today. Speculations have been made concerning the possibility of a bio-zone in the upper atmosphere of Venus.

Young, R. S.

1971-01-01

357

Minor Planet Center  

NASA Technical Reports Server (NTRS)

This paper reports on the activities of the Minor Planet Center for the year of 1998. The main product of this center is the Minor Planet Circulars, augmented by the Minor Planet Circulars Supplement which is a new series introduced in 1997 to include the actual observations, which are now only summarized MPC. The introduction of the Daily Orbit Update (DOU) lists all the orbits computed and identification found since the previous issue. There has been a fivefold increase in the reported Near Earth Objects, which includes the addition of 55 potentially hazardous asteroids.

Marsden, Brian G.

1999-01-01

358

Pulse of the Planet  

NSDL National Science Digital Library

This site contains the archive for Pulse of the Planet, which provides its listeners with a two-minute sound portrait of Planet Earth, tracking the rhythms of nature, culture and science worldwide and blending interviews and extraordinary natural sound. Pulse of the Planet is broadcast over 320 public and commercial stations around the world and on the Voice of America and the Armed Forces Radio Network. In addition to the sound clips there are associated feature stories on everything from particle physics to the birds of the Pantanal and seasonal stories describing the ways that people interact with their environment.

2008-04-14

359

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.

360

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

361

Formation of Planets Around the Sun and Other Stars.  

ScienceCinema

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.

362

Protostars and planets II  

SciTech Connect

This book presents papers on protostars and planets. Topics covered include molecular clouds and star formation, physical conditions in isolated dark globules, infrared spectroscopy of protostars and young stellar objects, and molecular cloud cores.

Black, D.C.; Matthews, M.S.

1985-01-01

363

Kepler's Multiple Planet Systems  

NASA Technical Reports Server (NTRS)

Among the 1800 Kepler targets that have candidate planets, 20% have two or more candidate planets. While most of these objects have not yet been confirmed as true planets, several considerations strongly suggest that the vast majority of these multi-candidate systems are true planetary systems. Virtually all candidate systems are stable, as tested by numerical integrations (assuming a nominal mass-radius relationship). Statistical studies performed on these candidates reveal a great deal about the architecture of planetary systems, including the typical spacing of orbits and flatness of planetary systems. The distribution of observed period ratios shows that the vast majority of candidate pairs are neither in nor near low-order mean motion resonances. Nonetheless, there are small but statistically significant excesses of candidate pairs both in resonance and spaced slightly too far apart to be in resonance, particularly near the 2:1 resonance. The characteristics of the confirmed Kepler multi-planet systems will also be discussed.

Lissauer, Jack J.

2012-01-01

364

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 even give us clues to the atmospheric history of these planets. This presentation 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 around "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/high school age audiences. However, we also show a scaled-down version that has been used with elementary school age audiences.

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

2013-12-01

365

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

366

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

367

Which stars have planets?  

NASA Technical Reports Server (NTRS)

The question of predicting which stars have planetary systems is discussed, with special attention given to the work of Nakano (1988), who combined scaling arguments with his theory (Nakano, 1987) of formation of planets in the solar system to estimate planetary growth rates around stars of various masses. It is argued that, in addition to stellar mass, the process of planet formation depends on other parameters, such as angular momentum and collisions. The existence of binary and multiple star systems of varying type demonstrates that angular momentum variations can play a crucial role, while the fact that the solar system has four giant planets and four terrestrial planets is considered to be due to the effects of random impacts and scatterings. It is concluded that, at present, the concept of determining what types of planetary systems are to be expected about stars of varying masses cannot be resolved.

Lissauer, J. J.

1989-01-01

368

The Antarctic Planet Interferometer  

NASA Astrophysics Data System (ADS)

The Antarctic Planet Interferometer is a 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 temperatures 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, M.; Lloyd, J.; Traub, W.; Walker, C.; Stark, A.; Lawson, P.; Storey, J.; Coudé du Foresto, V.; Fossat, E.; Ireland, M.; Burrows, A.; Vakili, F.

2003-12-01

369

Planets Around Neutron Stars  

NASA Technical Reports Server (NTRS)

The objective of this proposal was to continue investigations of neutron star planetary systems in an effort to describe and understand their origin, orbital dynamics, basic physical properties and their relationship to planets around normal stars. This research represents an important element of the process of constraining the physics of planet formation around various types of stars. The research goals of this project included long-term timing measurements of the planets pulsar, PSR B1257+12, to search for more planets around it and to study the dynamics of the whole system, and sensitive searches for millisecond pulsars to detect further examples of old, rapidly spinning neutron stars with planetary systems. The instrumentation used in our project included the 305-m Arecibo antenna with the Penn State Pulsar Machine (PSPM), the 100-m Green Bank Telescope with the Berkeley- Caltech Pulsar Machine (BCPM), and the 100-m Effelsberg and 64-m Parkes telescopes equipped with the observatory supplied backend hardware.

Wolszczan, Alexander; Kulkarni, Shrinivas R; Anderson, Stuart B.

2003-01-01

370

Changing Planet: Ocean Acidification  

NSDL National Science Digital Library

This video discusses the impact of higher amounts of carbon dioxide absorbed by the oceans on marine organisms and how they are adapting to the new environment. Changing Planet is produced in partnership with the National Science Foundation.

2011-03-04

371

Managing Planet Earth.  

ERIC Educational Resources Information Center

Discusses the human use of the planet earth. Describes the global patterns and the regional aspects of change. Four requirements for the cultivation of leadership and institutional competence are suggested. Lists five references for further reading. (YP)

Clark, William C.

1989-01-01

372

Future Missions to Study Signposts of Planets  

NASA Technical Reports Server (NTRS)

This talk will focus on debris disks, will compare ground and space and will discuss 2 proposed missions, Exoplanetary Circumstellar Environments And Disk Explorer (EXCEDE) and Zodiac II. At least 2 missions have been proposed for disk imaging. The technology is largely in hand today. A small mission would do excellent disk science, and would test technology for a future large mission for planets.

Traub, Wesley A.

2011-01-01

373

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.

374

Formation of the Outer Planets  

Microsoft Academic Search

Models of the origins of gas giant planets and ‘ice’ giant planets are discussed and related to formation theories of both smaller objects (terrestrial planets) and larger bodies (stars). The most detailed models of planetary formation are based upon observations of our own Solar System, of young stars and their environments, and of extrasolar planets. Stars form from the collapse,

Jack J. Lissauer

2005-01-01

375

Extrasolar Planets Orbiting Active Stars  

Microsoft Academic Search

New discoveries of transiting extrasolar planets are reported weekly. Ground based surveys as well as space borne observatories like CoRoT and Kepler are responsible for filling the statistical voids of planets on distant stellar systems. I want to discuss the stellar activity and its impact on the discovery of extrasolar planets. Up to now the discovery of small rocky planets

Jörg Weingrill

2011-01-01

376

The Secret Planet  

Microsoft Academic Search

\\u000a Planet X? That was discovered long ago. But NASA is keeping it secret, undoubtedly in close collaboration with observatories\\u000a throughout the world. The planet goes around the Sun every 3,600 years in an elongated orbit and is currently on a collision\\u000a course with the Earth. The disastrous portents of that imminent encounter – probably in 2012 – are visible everywhere.

Govert Schilling

377

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

378

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

379

The Atmospheres of Extrasolar Planets  

NASA Technical Reports Server (NTRS)

In this chapter we examine what can be learned about extrasolar planet atmospheres by concentrating on a class of planets that transit their parent stars. As discussed in the previous chapter, one way of detecting an extrasolar planet is by observing the drop in stellar intensity as the planet passes in front of the star. A transit represents a special case in which the geometry of the planetary system is such that the planet s orbit is nearly edge-on as seen from Earth. As we will explore, the transiting planets provide opportunities for detailed follow-up observations that allow physical characterization of extrasolar planets, probing their bulk compositions and atmospheres.

Richardson, L. J.; Seager, S.

2007-01-01

380

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

381

Planetans—oceanic planets  

NASA Astrophysics Data System (ADS)

The development of principles, systems, and instruments enable the detection of exoplanets with 6-8 Earth masses or less. The launches of specialized satellites, such as CoRoT (2006) and Kepler (2009), into orbits around the Earth have enabled the discovery of new exoplanetary systems. These missions are searching for relatively low-mass planets by observing their transits over the disks of their parent stars. At the same time, supporting studies of exoplanets using ground-based facilities (that measure Keplerian components of radial velocities) are in progress. The properties of at least two objects discovered by different methods, Kepler-22 and GJ 1214b, suggested that there was another class of celestial bodies among the known types of extrasolar planets: planetans, or oceanic planets. The structure of Kepler-22 and GJ 1214b suggest that they can be these oceanic planets. In this paper, we consider to what extent this statement is valid. The consideration of exoplanet Gl 581g as an oceanic planet is more feasible. Some specific features of the physical nature of these unusual planets are presented.

Ksanfomality, L. V.

2014-01-01

382

Building a virtual planet  

NASA Technical Reports Server (NTRS)

The virtual Planetary Laboratory (VPL) is a recently funded 5-yr project, which seeks toimprove our understanding of the range of plausible environments and the likely signatures for life on extrasolar terrestrial planets. To achieve these goals we are developing a suite of innovative modeling tools to simulate the environments and spectra of extrasolar planets. The core of the VPL IS a coupled radiative transfer/climate/chemistry model, which is augmented by interchangeable modules which characterize geological, exogenic, atmospheric escape, and life processes. The VPL is validated using data derived from terrestrial planets within our own solar system. The VPL will be used to explore the plausible range of atmospheric composittions and globally averaged spectra for extrasolar planets and for early Earth, and will improve our understanding of the effect of life on a planet's atmospheric spectrum and composition. The models will also be used to create a comprehensive spectral catalog to provide recommendations on the optimum wavelength range, spectral resolution, and instrument sensitivity required to characterize extrasolar terrestrial planets. Although developed by our team, the VPL is envisioned to be a comprehensive and flexible tool, which can be collaboratively used by the broader planetary science and astrobiology communities. This presentation will describe the project concept, the tasks involved, and will outline current progress to date. This work is funded by the NASA Astrobiology Institute.

Meadows, V. S.

2002-01-01

383

Evaporation of extrasolar planets  

NASA Astrophysics Data System (ADS)

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

Lecavelier Des Etangs, A.

2010-12-01

384

Photoinduced demulsification of emulsions using a photoresponsive gemini surfactant.  

PubMed

This Article reports on the influence of light irradiation on the stability of emulsions prepared using a photoresponsive gemini surfactant (C7-azo-C7) having an azobenzene skeleton as a spacer. When mixtures of trans C7-azo-C7 aqueous solution and n-octane are homogenized, stable emulsions are obtained in a specific region of weight fraction and surfactant concentration. Fluorescence microscopy observations using a small amount of fluorescent probes show that the stable emulsions are oil-in-water (O/W)-type. UV irradiation of stable O/W emulsions promotes the cis isomerization of trans C7-azo-C7 and leads to the coalescence of the oil (octane) droplets in the emulsions, that is, demulsification. While the equilibrated interfacial tension (IFT) between aqueous trans C7-azo-C7 solution and octane is almost the same as that between aqueous cis C7-azo-C7 and octane, the occupied area per molecule for C7-azo-C7 at octane/water interface decreases with the cis photoisomerization of trans isomer. Dynamic IFT measurement shows that UV irradiation to the interface between aqueous trans C7-azo-C7 solution and octane brings about an increase in the interfacial tension, indicating that the Gibbs free energy at the interface increases. From these results, the cis isomerization of trans C7-azo-C7 molecules at the O/W interface due to UV irradiation leads to direct contact between the water and octane phases, because of the reduction of molecular area at the interface, and subsequently makes the emulsions demulsified. PMID:24354334

Takahashi, Yutaka; Fukuyasu, Kengo; Horiuchi, Tatsuya; Kondo, Yukishige; Stroeve, Pieter

2014-01-14

385

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

386

A novel synthesis of SO(3)H type gemini surfactant having semifluoroalkyl group as hydrophobic group.  

PubMed

In this work, novel SO(3)H type Gemini surfactants having semifluoroalkyl group (RfCH(2)CH-: Rf = C(4)F(9), C(6)F(13), C(8)F(17)) as hydrophobic group were successively synthesized by the radical addition of fluoroalkyl to 1,4-pentadiene using fluoroalkyl iodide and AIBN as initiator, and the following thiocyanization (-SCN), conversion to -SH, and oxidation to SO(3)H as hydrophilic group. Similarly, the common 1+1 type semifluoroalkyl surfactants having SO(3)H were synthesized. Surfactant properties of their sodium salts (cmc, gamma(cmc), pC(20), Gamma(cmc), and A) were investigated by measuring surface tension. As expected, the cmc value of Gemini surfactant whose fluoroalkyl is C(4)F(9) was more than one order of magnitude smaller than that of the corresponding 1+1 type. Other properties also showed the excellent efficiency of Gemini structure to reduce the surface tension. PMID:20720379

Kawase, Tokuzo; Iidzuka, Jun-ichi; Oida, Tatsuo

2010-01-01

387

Planet-Metallicity Correlation For Planets of Different Sizes  

NASA Astrophysics Data System (ADS)

Metallicity of exoplanet systems can serve as a critical diagnosis on the planet formation mechanisms. Previous studies took followup observations to measure metallicity of a sample of Kepler planet candidates host stars. It is shown in these studies that planet-metallicity exists for large planets (RP ? 4 RE), but there is a lack of such correlation for smaller planets. We use a sample 1166 multi-planet candidates from Kepler Objects of Interest and with metallicity estimation from Kepler Input Catalog to study the planet-metallicity correlation. The sample is a factor of 3-4 larger than those in previous studies. Unlike previous studies, we consider both detections and non-detections of planet candidates. We use a ratio between the number of planet candidates and the number of searched stars (planet-star ratio) in a RP -[Fe/H] parameter space as an estimation of planet frequency. For orbital period within 100 days, we found a strong planet-metallicity correlation for gas giant planets (5 RE ? RP ? 22 RE). Planet frequency is 2.6 times higher for the super-solar metallicity group ([Fe/H] ? 0.0) than the sub-solar metallicity group ([Fe/H] ? 0.0). For Neptune-like planets (2 RE ? RP ? 5 RE ), planet frequency for the metal-rich sample is 1.4 times higher than the metal-poor sample, but this conclusion depends on corrections for different stellar populations of two metallicity groups. Planet frequency correlation with metallicity for small-radii planets (RP ? 2 RE) is consistent with non-positive correlation.

Wang, Ji

2014-01-01

388

Gemini/GMOS Spectroscopy of Faint z=6 Ly-alpha Line Emitters in The Hubble Ultra Deep Field  

NASA Astrophysics Data System (ADS)

Redshift 6, one billion years after the Big Bang, marks the end of the reionization epoch. A crucial question is whether the UV flux from young starbursts at this redshift is sufficient to achieve this reionzation. We have used the Lyman break technique to identify candidate star-forming galaxies at this redshift in deep HST/ACS images. Using the Hubble Ultra Deep Field, we identified i-band drop-outs as faint as z(AB)=28.5mag, corresponding to unobscured star-formation rates of 1Msun/yr at z 6. Spectroscopic confirmation of this population is crucial, to guard against low-redshift interlopers (Extremely Red Objects at z 1-2 and low-mass Galactic stars) and to study the Lyman-alpha emission line properties of z 6 galaxies. We have undertaken the deepest spectroscopy yet to achieve this. The Gemini Lyman-Alpha at Reionisation Era project (GLARE) has obtained 36 hours of spectroscopy on a single GMOS slitmask from Gemini-South, with a spectral resolution of lambda/Delta(lambda) 1000. This resolving power is sufficient to see the characteristic asymmetric Lyman-alpha profile, and reject the [OII] emission line doublet from lower redshift sources. We have secured spectroscopic redshifts for the some of the faintest continuum-selected objects yet, and place tight constraints on the equivalent width of Lyman-alpha emission for much of our i-drop sample. We find that the fraction of galaxies with little or no emission is similar to that at z 3, but that the z 6 population has a tail of sources with high rest frame equivalent widths. Possible explanations for this effect include a tendency towards stronger line emission in faint sources, which may arise from extreme youth or low metallicity in the Lyman-break population at high redshift, or possibly a top-heavy initial mass function.

Bunker, Andrew J.; Stanway, E. R.; Glazebrook, K.; Abraham, R. G.; Rhoads, J.; Malhotra, S.; Crampton, D.; Colless, M.; Chiu, K.; GLARE project (Gemini Lyman-Alpha at Reionzation Era)

2007-07-01

389

Structural and transfection properties of amine-substituted gemini surfactant-based nanoparticles  

SciTech Connect

Increases in DNA transfection efficiencies for non-viral vectors can be achieved through rational design of novel cationic building blocks. Based on previous results examining DNA condensation by polyamines, novel gemini surfactants have been designed that incorporate aza or imino substituents within the spacer group in order to increase interactions with DNA and potentially improve their DNA transfection ability. Transfection efficiencies and cell toxicity of gemini nanoparticles constructed from plasmid DNA, gemini surfactant, and a neutral lipid were measured in COS7 cells using a luciferase assay. Structural properties of nanoparticles were examined by using circular dichroism, particle size, zeta potential, and small-angle X-ray scattering (SAXS) measurements. The incorporation of aza and imino substituents within the spacer group was observed to enhance the transfection ability of gemini surfactants. Incorporation of an imino group in the structure of the 1,9-bis(dodecyl)-1,1,9,9-tetramethyl-5-imino-1,9-nonanediammonium dibromide surfactant (12-7NH-12) resulted in a statistically significant (p < 0.01) 9-fold increase in transfection compared to an unsubstituted gemini surfactant and a 3-fold increase compared to the corresponding aza-substituted compound. A pH-dependent transition in size and zeta potential was observed to occur at pH 5.5 for complexes formed from the 12-7NH-12 compound. SAXS results show weakly ordered structures and the presence of multiple phases. The incorporation of a pH-active imino group within the spacer of the gemini surfactant results in a significant increase in transfection efficiency that can be related to both pH-induced changes in nanoparticle structure and the formation of multiple phases that more readily allow for membrane fusion that may facilitate DNA release.

Wettig,S.; Badea, I.; Donkuru, M.; Verrall, R.; Foldvari, M.

2007-01-01

390

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.

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

2013-01-01

391

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

392

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

393

Limits on Stellar Companions to Exoplanet Host Stars with Eccentric Planets  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

394

Understanding the effect of the spacer length on adsorption of gemini surfactants onto steel surface in acid medium  

NASA Astrophysics Data System (ADS)

Corrosion inhibition of carbon steel in 1 M hydrochloride acid by gemini surfactants alkanediyl-?,?-bis(dimethyl dodecylammonium bromide) with different spacer lengths (designated as 12- s-12, s = 2, 3 or 6) was studied using the weight loss method. When monolayer forms on the metal surface below or near critical micelle concentrations (CMCs) of the gemini surfactants, it can be found that gemini surfactant with long spacer (12-6-12) tends to be adsorbed with two hydrophilic ionic groups onto the metal surface site, while gemini surfactants with short spacer (12-2-12 and 12-3-12) tend to be adsorbed with one hydrophilic group onto the meta surface site and the other hydrophilic group is free in solution phase, and further increase in surfactant concentration results in the formation of multilayer. Possible adsorption mechanisms of these gemini surfactants with different spacer lengths above and below their CMCs were discussed in detail, respectively.

Qiu, Ling-Guang; Xie, An-Jian; Shen, Yu-Hua

2005-06-01

395

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

396

Formation of Planets Around the Sun and Other Stars  

ScienceCinema

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.

397

Tour of Planet with Extreme Temperature Swings  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Click on the image for the movie

This animation shows a computer simulation of the planet HD 80606b from an observer located at a point in space lying between the Earth and the HD 80606 system. The animation starts 2.2 days before the moment of close approach and ends 8.9 days later. The blue areas are reflected starlight (the blue color arises mainly from absorption by sodium and potassium in the planetary atmosphere). Red regions are areas of the planet that are glowing with their own intrinsic heat.

The point of closest approach and maximum heating occurs about 4.5 seconds into the animation. As the planet whips around the star, we see the evolving thermal storm patterns across its unilluminated side. The planet's transit behind its star (as would be seen from Earth four seconds into the animation) is not shown in this simulation.

These theoretical models allow astronomers to better understand weather patterns on distant planets. While direct telescopic observations of the atmospheres of such worlds may be many decades away, such simulations give us a clue to what we may see when it becomes possible.

2009-01-01

398

Coacervation and aggregate transitions of a cationic ammonium gemini surfactant with sodium benzoate in aqueous solution.  

PubMed

Coacervation in an aqueous solution of cationic ammonium gemini surfactant hexamethylene-1,6-bis(dodecyldimethylammonium bromide) (C12C6C12Br2) with sodium benzoate (NaBz) has been investigated at 25 °C by turbidity titration, light microscopy, dynamic light scattering, cryogenic temperature transmission electron microscopy (Cryo-TEM), scanning electron microscopy (SEM), isothermal titration calorimetry, ? potential and (1)H NMR measurements. There is a critical NaBz concentration of 0.10 M, only above which coacervation can take place. However, if the NaBz concentration is too large, coacervation also becomes difficult. Coacervation takes place at a very low concentration of C12C6C12Br2 and exists in a very wide concentration region of C12C6C12Br2. The phase behavior in the NaBz concentration from 0.15 to 0.50 M includes spherical micelles, threadlike micelles, coacervation, and precipitation. With increasing NaBz concentration, the phase boundaries of coacervation shift to higher C12C6C12Br2 concentration. Moreover, the C12C6C12Br2-NaBz aggregates in the coacervate are found to be close to charge neutralized. The Cryo-TEM and SEM images of the coacervate shows a layer-layer stacking structure consisting of a three-dimensional network formed by the assembly of threadlike micelles. Long, dense and almost uncharged threadlike micelles are the precursors of coacervation in the system. PMID:24651935

Wang, Ruijuan; Tian, Maozhang; Wang, Yilin

2014-03-21

399

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-infrared wavelengths. These non-ice materials are concentrated at disrupted surface regions, providing a diagnostic probe for the chemistry and characteristics of the liquid ocean beneath. Leading but potentially competing theories on the composition of these hydrated non-ice materials suggest either sulfuric acid-water mixtures (Carlson et al., 1999) or hydrated magnesium/sodium salts (McCord et al., 1999). Recent reanalysis of Galileo-NIMS observations suggest a mixture of both - hydrated salts are present at all longitudes but the sulfuric acid hydrates are localized on the trailing side. We present preliminary analysis of new ground-based Gemini disk-resolved spectroscopy of Europa using the Near-Infrared Integrated Field Spectrometer (NIFS), taken in late 2011, at H (1.49 - 1.80 ?m) and K bands (1.99 - 2.40 ?m) with spectral resolving powers of ~ 5300. At these NIR wavelengths, with spectral resolution much better than Galileo-NIMS, the spectral absorption and continuum characteristics of these ice and non-ice materials can be separated out. In addition, the spatial resolution potentially allows identification of localized materials whose signature would be diluted in disk-integrated spectra. These observations of the trailing hemisphere use Altair adaptive optics to achieve spatial resolutions of 0.1" (~310 km per pixel) or better, potentially leading to better identification of the non-ice materials and their spatial distributions. References Carlson, R.W., R.E. Johnson, and M.S. Anderson 1999. Sulfuric acid on Europa and the radiolytic sulfur cycle. Science 286, 97-99. McCord, T. et al. 1999. Hydrated salt minerals on Europa's surface from the Galileo Near- Infrared Mapping Spectrometer (NIMS) investigation. J. Geophys. Res. 104, 11827

Tsang, C.; Spencer, J. R.; Grundy, W. M.; Dalton, J. B.

2012-12-01

400

Living Planet Report 1999  

NSDL National Science Digital Library

The second edition of the World Wildlife Fund's (WWF) Living Planet Report (last discussed in the October 9, 1998 Scout Report) has been placed online. The report attempts to quantify the speed at which nature is disappearing from Earth and trace human pressures on the natural environment. The first part of the report, the Living Planet Index (LPI), measures natural wealth and how it has changed between 1970 and 1995. According to the WWF, the LPI declined by 30 percent in this period, indicating that the world has lost "30 per cent of its natural wealth in the space of one generation." The second part of the Living Planet Report examines six causes of global environmental change related to human consumption of renewable and non-renewable resources.Users may view an executive summary and highlights of the report or download the full text in .pdf.

1999-01-01

401

Coldest Imaged Companion of a Sun-Like Star  

NASA Astrophysics Data System (ADS)

In May and August 2009, we and collaborators used Adaptive Optics H-band direct-imaging to discover a 28 AU (projected separation) planet or brown-dwarf companion to the solar-type star GJ 758. The measured photometry and astrometry indicated a 10-40 Jupiter mass bound companion with a temperature of 550-640K. The discovery (submitted in Sep 2009 to Science Express) marks the coldest companion of a star ever imaged in thermal light. The companion is also a candidate for the coldest object ever thermally imaged outside our solar system. We propose to use Gemini NIRI to conduct multi-band photometry and astrometry of this remarkable object. The astrometry, combined with the previous data, will allow us to observe significant orbital motion, thus constraining semi-major axis, eccentricity, and object mass. Photometry (in J, H, K-cont, CH4-short, and CH4-long filters) will provide better constraints on object temperature and mass, while also giving us a first-ever glimpse into the atmosphere of the coldest imaged companion of a sun-like star.

Carson, Joseph; Thalmann, Christian; Janson, Markus; Goto, Miwa; McElwain, Michael; Feldt, Markus; Henning, Thomas; Tamura, Motohide

2010-02-01

402

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.

403

Protostars and planets II  

SciTech Connect

Various papers on the formation of stars and planets are presented. The general topics addressed include: molecular clouds and star formation, young stellar objects and circumstellar disks, chemistry and grains in molecular clouds and the solar nebula, formation of giant planets, and models of the solar nebula and other planetary systems. Individual papers address: molecular cloud cores, physical conditions in isolated dark globules, rotation in dark clouds, and turbulence in molecular clouds. Also discussed are: fragmentation and hierarchical structure in the interstellar medium, formation of bound stellar clusters, ambient radiation field of young solar systems, and magnetic fields.

Black, D.C.; Matthews, M.S.

1985-01-01

404

Play Dough Planets  

NSDL National Science Digital Library

This is a lesson about planet sizes. Learners will demonstrate the size (volume) differences between Earth, Earthâs Moon, and Mars. An extension to estimate the distance between the Earth and the Moon, and the Earth and Mars, using the scale of the play dough planets' sizes is provided. Advance preparation of the play dough (recipie provided) is required. This is lesson 3 of 16 in the MarsBots learning module. It was adapted from 3-D Model of the Earth and Moon, an activity in The Universe at Your Fingertips.

405

How giant planets cool  

NASA Astrophysics Data System (ADS)

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

Guillot, T.

2006-12-01

406

Mission to Planet Earth  

NASA Technical Reports Server (NTRS)

Mission to Planet Earth (MTPE) is NASA's concept for an international science program to produce the understanding needed to predict changes in the Earth's environment. NASA and its interagency and international partners will place satellites carrying advanced sensors in strategic Earth orbits to gather multidisciplinary data. A sophisticated data system will process and archive an unprecedented amount of information about the Earth and how it works as a system. Increased understanding of the Earth system is a basic human responsibility, a prerequisite to informed management of the planet's resources and to the preservation of the global environment.

Tilford, Shelby G.; Asrar, Ghassem; Backlund, Peter W.

1994-01-01

407

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

408

Space based microlensing planet searches  

NASA Astrophysics Data System (ADS)

The discovery of extra-solar planets is arguably the most exciting development in astrophysics during the past 15 years, rivalled only by the detection of dark energy. Two projects unite the communities of exoplanet scientists and cosmologists: the proposed ESA M class mission EUCLID and the large space mission WFIRST, top ranked by the Astronomy 2010 Decadal Survey report. The later states that: "Space-based microlensing is the optimal approach to providing a true statistical census of planetary systems in the Galaxy, over a range of likely semi-major axes". They also add: "This census, combined with that made by the Kepler mission, will determine how common Earth-like planets are over a wide range of orbital parameters". We will present a status report of the results obtained by microlensing on exoplanets and the new objectives of the next generation of ground based wide field imager networks. We will finally discuss the fantastic prospect offered by space based microlensing at the horizon 2020-2025.

Beaulieu, Jean-Philippe; Tisserand, Patrick; Batista, Virginie

2013-04-01

409

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

410

Earth as an Extrasolar Planet  

NASA Astrophysics Data System (ADS)

The NASA Astrobiology Institute's Virtual Planetary Laboratory 3-D line-by-line, multiple-scattering spectral Earth model generates spatially- and temporally-resolved synthetic spectra and images of Earth. The model can be used to simulate Earth's spectrum as it would appear to a distant observer at arbitrary viewing geometry over wavelengths from the far-ultraviolet to the far-infrared on timescales from minutes to years. We have validated our model against data from NASA's EPOXI mission, which obtained spatially- and temporally-resolved visible photometric (0.3-1.0 um) and near-infrared spectroscopic (1.05-4.8 um) observations of Earth on three dates. Further validations include comparisons to photometric Earthshine observations (0.4-0.7 um) which span a wide range of Earth phase as well as comparisons to date-specific, high spectral resolution mid-infrared observations (6-15 um) of Earth acquired by the Atmospheric Infrared Sounder aboard NASA's Aqua satellite. To reproduce the available observations we have run the model at a spatial resolution of almost 200 pixels, an atmospheric resolution of 48 pixels, and a cloud treatment with 4 categories of water clouds. Our validated model can now be used as a tool for feasibility studies for future space-based planet detection missions (e.g., NASA's Terrestrial Planet Finder). The model can also be used to better understand sensitivity to global signatures of habitability and life in disk-integrated spectra of Earth. Example applications include an investigation into the ability of Earth's atmosphere and clouds to obscure direct surface temperature measurements from thermal-infrared observations as well as a study of the phase-dependent contribution of Earth's ocean "glint spot” to the overall brightness of the planet. The "glint spot" is generated by specular reflection of sunlight on Earth's oceans and could potentially be used to detect oceans on extrasolar planets. Both clouds and oceans exhibit phase-dependent reflectance behaviors, possibly obscuring the detection of, or eliminating, the ocean glint.

Robinson, Tyler D.; Meadows, V.; Crisp, D.

2010-10-01

411

Finding Planets around other stars  

NASA Video Gallery

Just as the Earth revolves around the sun, our closest star, other planets might orbit the stars you see in the night sky. Think of all the planets in the universe that may be just the right distan...

412

NASA: Planet Quest - The Search for Another Earth  

NSDL National Science Digital Library

This website addresses NASA's goal of embarking on a series of missions to find and characterize planets around stars other than the sun to help determine if life exists on other planets. Users can view the fascinating video summarizing the missions and can take an interactive quiz to test their knowledge of the realities of extraterrestrial life and space exploration. The site presents an interesting historical account of the stars, planets, and also life studies. Individuals can learn about the use of inferometry, planet imaging, and formation flying in the TPF, SIM, Kepler, and other missions. One of the site's best assets is the continually updated New Worlds Atlas, where users can explore the planets of the Universe in 3-D. Visitors can also find numerous games, simulations, animations, videos, and educational activities.

413

Planets With Detectable Life  

Microsoft Academic Search

This workshop honors Michel Mayor for his watershed detection of the first extrasolar planetary system in 1995. It is worth remembering that prior to this discovery, there was an intense debate among well-qualified scientists as to whether or not other planetary systems existed. Now we have come to know over 100 planets circling other stars, with more discoveries announced almost

Tobias Owen

2006-01-01

414

Twist planet drive  

NASA Technical Reports Server (NTRS)

A planetary gear system includes a sun gear coupled to an annular ring gear through a plurality of twist-planet gears, a speeder gear, and a ground structure having an internal ring gear. Each planet gear includes a solid gear having a first half portion in the form of a spur gear which includes vertical gear teeth and a second half portion in the form of a spur gear which includes helical gear teeth that are offset from the vertical gear teeth and which contact helical gear teeth on the speeder gear and helical gear teeth on the outer ring gear. One half of the twist planet gears are preloaded downward, while the other half are preloaded upwards, each one alternating with the other so that each one twists in a motion opposite to its neighbor when rotated until each planet gear seats against the sun gear, the outer ring gear, the speeder gear, and the inner ring gear. The resulting configuration is an improved stiff anti-backlash gear system.

Vranish, John M. (Inventor)

1996-01-01

415

The Artificial Planet  

NASA Astrophysics Data System (ADS)

An interim milestone for interstellar space travel is proposed: the artificial planet. Interstellar travel will require breakthroughs in the areas of propulsion systems, energy systems, construction of large space structures, protection from space & radiation effects, space agriculture, closed environmental & life support systems, and many other areas. Many difficult problems can be attacked independently of the propulsion and energy challenges through a project to establish an artificial planet in our solar system. Goals of the project would include construction of a large space structure, development of space agriculture, demonstration of closed environmental & life support systems over long time periods, selection of gravity level for long-term spacecraft, demonstration of a self-sufficient colony, and optimization of space colony habitat. The artificial planet would use solar energy as a power source. The orbital location will be selected to minimize effects of the Earth, yet be close enough for construction, supply, and rescue operations. The artificial planet would start out as a construction station and evolve over time to address progressive goals culminating in a self-sufficient space colony.

Glover, D. R.

416

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.

417

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

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

Tilt of planets  

Microsoft Academic Search

Most planets have their axis of rotation tilted with respect to the normal to the plane of the orbit. The planetary magnetic field is also tilted and is also inclined with respect to the axis of rotation. So far, there has been no satisfactory explanation. Chaotic stability is like accepting the tilts as they happen to be there. Giant impacts

J. N. Nanda

1999-01-01

420

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