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1

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 warm self-luminous extrasolar planets and polarimetry of circumstellar disks. It is the first such facility-class instrument deployed on a 8-m telescope, designed to be an order of magnitude more sensitive than existing high-contrast imaging capabilities. GPI has completed laboratory integration and testing, shipped to Gemini South, and is scheduled for first light in November 2013. I will present an overview of the GPI design and measured performance, and any first light results, including a public release of fully reduced data for selected targets. in 2014, GPI will be available for science validation, and in the second half of 2014, a large-scale exoplanet survey campaign will begin.

Macintosh, Bruce; Gemini Planet Imager instrument Team; Planet Imager Exoplanet Survey, Gemini; Observatory, Gemini

2014-01-01

2

Gemini Planet Imager One Button Approach  

E-print Network

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

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

2014-01-01

3

Gemini planet imager one button approach  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

4

First light of the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of GPI has been tuned for maximum sensitivity to faint planets near bright stars. During first light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-sigma contrast of $10^6$ at 0.75 arcseconds and $10^5$ at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-second exposure with minimal post-processing. Beta Pictoris b is observed at a separation of $434 \\pm 6$ milli-arcseconds and position angle $211.8 \\pm 0.5$ deg. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of three improvement in most parameters over previous solutions. The planet orbits at a semi-major axis of $9.0^{+0.8}_{-0.4}$ AU near the 3:2 resonance with the previously-known 6 AU asteroidal belt and is aligned with the inner warped disk. The observations give a 4% posterior probability of a transit of the planet in late 2017.

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

2014-09-01

5

The Gemini Planet Imager: First Light  

E-print Network

The Gemini Planet Imager (GPI) is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of GPI has been tuned for maximum sensitivity to faint planets near bright stars. During first light observations, we achieved an estimated H band Strehl ratio of 0.89 and a 5-sigma contrast of $10^6$ at 0.75 arcseconds and $10^5$ at 0.35 arcseconds. Observations of Beta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-second exposure with minimal post-processing. Beta Pictoris b is observed at a separation of $434 \\pm 6$ milli-arcseconds and position angle $211.8 \\pm 0.5$ deg. Fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of three improvement in most parameters over previous solutions. The planet ...

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

2014-01-01

6

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

7

Gemini Planet Imager First Light and Campaign Survey  

NASA Astrophysics Data System (ADS)

Detecting, characterizing, and modeling exoplanets are among the fastestgrowing and highest-profile fields in current international astrophysics research. With direct imaging, it is possible to investigate the frequency of planetary systems with an architecture similar to that of the Solar System by detecting Jupiter-like planets in orbits comparable to the location of the giant planets in the Solar System. The detection and characterization of a new population of wide orbit exoplanets is essential to obtain a full census of planetary systems and to provide crucial tests of planet formation and evolution theories. Directly imaged planets also present important systems for which the atmospheric properties can be characterized. Achieving this potential is the fundamental goal of the Gemini Planet Imager (GPI). GPI, a facility instrument for the Gemini South Observatory, will be the most sensitive planet imager ever constructed, an order of magnitude more powerful than current facilities and capable of discovering young (<1 GYr) planets from 5-100 AU. The Gemini Observatory has allocated our team 890 hours of telescope time to carry out the Gemini Planet Imager Exoplanet Survey (GPIES) - the largest single allocation in the history of Gemini. The GPIES survey is designed to observe ~600 young, nearby stars, at high sensitivity, optimized to provide detection and basic characterization of 20-50 1-10 MJ planets.

Patience, J.; Macintosh, B. A.; Graham, J. R.; Gpies Team

2014-03-01

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

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

10

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

2011-10-01

11

Gemini Planet Imager Observational Calibrations II: Detector Performance and Calibration  

E-print Network

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

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

2014-01-01

12

Gemini planet imager observational calibrations II: detector performance and calibration  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

13

The Gemini Planet Imager calibration wavefront sensor instrument  

Microsoft Academic Search

The Gemini Planet Imager is an extreme adaptive optics system that will employ an apodized-pupil coronagraph to make direct detections of faint companions of nearby stars to a contrast level of the 10-7 within a few lambda\\/D of the parent star. Such high contrasts from the ground require exquisite wavefront sensing and control both for the AO system as well

J. Kent Wallace; Rick S. Burruss; Randall D. Bartos; Thang Q. Trinh; Laurent A. Pueyo; Santos F. Fregoso; John R. Angione; J. Chris Shelton

2010-01-01

14

The Gemini planet imager: first light and commissioning  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

15

The Integral Field Spectrograph for the Gemini Planet Imager  

E-print Network

The Gemini Planet Imager (GPI) is a complex optical system designed to directly detect the self-emission of young planets within two arcseconds of their host stars. After suppressing the starlight with an advanced AO system and apodized coronagraph, the dominant residual contamination in the focal plane are speckles from the atmosphere and optical surfaces. Since speckles are diffractive in nature their positions in the field are strongly wavelength dependent, while an actual companion planet will remain at fixed separation. By comparing multiple images at different wavelengths taken simultaneously, we can freeze the speckle pattern and extract the planet light adding an order of magnitude of contrast. To achieve a bandpass of 20%, sufficient to perform speckle suppression, and to observe the entire two arcsecond field of view at diffraction limited sampling, we designed and built an integral field spectrograph with extremely low wavefront error and almost no chromatic aberration. The spectrograph is fully cr...

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

2014-01-01

16

Gemini planet imager integration to the Gemini South telescope software environment  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager is an extreme AO instrument with an integral field spectrograph (IFS) operating in Y, J, H, and K bands. Both the Gemini telescope and the GPI instrument are very complex systems. Our goal is that the combined telescope and instrument system may be run by one observer operating the instrument, and one operator controlling the telescope and the acquisition of light to the instrument. This requires a smooth integration between the two systems and easily operated control interfaces. We discuss the definition of the software and hardware interfaces, their implementation and testing, and the integration of the instrument with the telescope environment.

Rantakyrö, Fredrik T.; Cardwell, Andrew; Chilcote, Jeffrey; Dunn, Jennifer; Goodsell, Stephen; Hibon, Pascale; Macintosh, Bruce; Quiroz, Carlos; Perrin, Marshall D.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Winge, Claudia; Galvez, Ramon; Gausachs, Gaston; Hardie, Kayla; Hartung, Markus; Luhrs, Javier; Poyneer, Lisa; Thomas, Sandrine

2014-08-01

17

Gemini Planet Imager integration to the Gemini South telescope software environment  

E-print Network

The Gemini Planet Imager is an extreme AO instrument with an integral field spectrograph (IFS) operating in Y, J, H, and K bands. Both the Gemini telescope and the GPI instrument are very complex systems. Our goal is that the combined telescope and instrument system may be run by one observer operating the instrument, and one operator controlling the telescope and the acquisition of light to the instrument. This requires a smooth integration between the two systems and easily operated control interfaces. We discuss the definition of the software and hardware interfaces, their implementation and testing, and the integration of the instrument with the telescope environment.

Rantakyrö, Fredrik T; Chilcote, Jeffrey; Dunn, Jennifer; Goodsell, Stephen; Hibon, Pascale; Macintosh, Bruce; Quiroz, Carlos; Perrin, Marshall D; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Serio, Andrew; Winge, Claudia; Galvez, Ramon; Gausachs, Gaston; Hardie, Kayla; Hartung, Markus; Luhrs, Javier; Poyneer, Lisa; Thomas, Sandrine

2014-01-01

18

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

19

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

20

The Gemini Planet Imager calibration wavefront sensor instrument  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager is an extreme adaptive optics system that will employ an apodized-pupil coronagraph to make direct detections of faint companions of nearby stars to a contrast level of the 10-7 within a few lambda/D of the parent star. Such high contrasts from the ground require exquisite wavefront sensing and control both for the AO system as well as for the coronagraph. Un-sensed non-common path phase and amplitude errors after the wavefront sensor dichroic but before the coronagraph would lead to speckles which would ultimately limit the contrast. The calibration wavefront system for GPI will measure the complex wavefront at the system pupil before the apodizer and provide slow phase corrections to the AO system to mitigate errors that would cause a loss in contrast. The calibration wavefront sensor instrument for GPI has been built. We will describe the instrument and its performance.

Wallace, J. Kent; Burruss, Rick S.; Bartos, Randall D.; Trinh, Thang Q.; Pueyo, Laurent A.; Fregoso, Santos F.; Angione, John R.; Shelton, J. Chris

2010-07-01

21

The integral field spectrograph for the Gemini planet imager  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

22

Gemini planet imager observational calibrations V: astrometry and distortion  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

23

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

24

Gemini Planet Imager Observational Calibrations V: Astrometry and Distortion  

E-print Network

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

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

2014-01-01

25

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

26

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

E-print Network

Calibrating IR optical densities for the Gemini Planet Imager Extreme Adaptive Optics Coronagraph Drive, Rochester, NY 14620 USA f Precision Optical Imaging, 7466 West Henrietta Rd., Rush, NY 14543 g are comparable to the wavelength of the light, surface plasmon effects can complicate the optical density (OD) vs

27

Design of high-resolution variable size spatial filter for Gemini Planet Imager using flexure elements  

Microsoft Academic Search

This paper presents a design of a variable size spatial filter used in the wavefront sensor subsystem of the Gemini Planet Imager instrument. It describes an adjustable mechanism consisting of two slides forming a square aperture which can be varied in size between 1.8 and 6.7 mm. These slides are located on athermalized flexure mounts that move opposite to one

Vlad Reshetov; Joeleff Fitzsimmons

2008-01-01

28

Characterization of the atmospheric dispersion corrector of the Gemini planet imager  

NASA Astrophysics Data System (ADS)

An Atmospheric Dispersion Corrector (ADC) uses a double-prism arrangement to nullify the vertical chromatic dispersion introduced by the atmosphere at non-zero zenith distances. The ADC installed in the Gemini Planet Imager (GPI) was first tested in August 2012 while the instrument was in the laboratory. GPI was installed at the Gemini South telescope in August 2013 and first light occurred later that year on November 11th. In this paper, we give an overview of the characterizations and performance of this ADC unit obtained in the laboratory and on sky, as well as the structure of its control software.

Hibon, Pascale; Thomas, Sandrine; Dunn, Jennifer; Atwood, Jennifer; Saddlemyer, Leslie; Sadakuni, Naru; Goodsell, Stephen; Macintosh, Bruce; Graham, James; Perrin, Marshall; Rantakyro, Fredrik; Fesquet, Vincent; Serio, Andrew; Quiroz, Carlos; Cardwell, Andrew; Gausachs, Gaston; Savransky, Dmitry; Kerley, Dan; Hartung, Markus; Galvez, Ramon; Hardie, Kayla

2014-07-01

29

Characterization of the Atmospheric Dispersion Corrector of the Gemini Planet Imager  

E-print Network

An Atmospheric Dispersion Corrector (ADC) uses a double-prism arrangement to nullify the vertical chromatic dispersion introduced by the atmosphere at non-zero zenith distances. The ADC installed in the Gemini Planet Imager (GPI) was first tested in August 2012 while the instrument was in the laboratory. GPI was installed at the Gemini South telescope in August 2013 and first light occurred later that year on November 11th. In this paper, we give an overview of the characterizations and performance of this ADC unit obtained in the laboratory and on sky, as well as the structure of its control software.

Hibon, Pascale; Dunn, Jennifer; Atwood, Jenny; Saddlemyer, Les; Sadakuni, Naru; Goodsell, Stephen; Macintosh, Bruce; Graham, James; Perrin, Marshall; Rantakyrö, Fredrik; Fesquet, Vincent; Serio, Andrew; Quiroz, Carlos; Cardwell, Andrew; Gausachs, Gaston; Savransky, Dmitry; Kerley, Dan; Hartung, Markus; Galvez, Ramon; Hardie, Kayla

2014-01-01

30

Ground-Based Direct Detection of Exoplanets with the Gemini Planet Imager (GPI)  

E-print Network

The Gemini Planet (GPI) imager is an "extreme" adaptive optics system being designed and built for the Gemini Observatory. GPI combines precise and accurate wavefront control, diffraction suppression, and a speckle-suppressing science camera with integral field and polarimetry capabilities. GPI's primary science goal is the direct detection and characterization of young, Jovian-mass exoplanets. For systems younger than 2 Gyr exoplanets more massive than 6 MJ and semimajor axes beyond 10 AU are detected with completeness greater than 50%. GPI will also discover faint debris disks, explore icy moons and minor planets in the solar system, reveal high dynamic range main-sequence binaries, and study mass loss from evolved stars. This white paper explains the role of GPI in exoplanet discovery and characterization and summarizes our recommendations to the NSF-NASA-DOE Astronomy and Astrophysics Advisory Committee ExoPlanet Task Force.

James R. Graham; Bruce Macintosh; Rene Doyon; Don Gavel; James Larkin; Marty Levine; Ben Oppenheimer; David Palmer; Les Saddlemyer; Anand Sivaramakrishnan; Jean-Pierre Veran; Kent Wallace

2007-04-11

31

Gemini Planet Imager Observational Calibrations VI: Photometric and Spectroscopic Calibration for the Integral Field Spectrograph  

E-print Network

The Gemini Planet Imager (GPI) is a new facility instrument for the Gemini Observatory designed to provide direct detection and characterization of planets and debris disks around stars in the solar neighborhood. In addition to its extreme adaptive optics and corona graphic systems which give access to high angular resolution and high-contrast imaging capabilities, GPI contains an integral field spectrograph providing low resolution spectroscopy across five bands between 0.95 and 2.5 $\\mu$m. This paper describes the sequence of processing steps required for the spectro-photometric calibration of GPI science data, and the necessary calibration files. Based on calibration observations of the white dwarf HD 8049B we estimate that the systematic error in spectra extracted from GPI observations is less than 5%. The flux ratio of the occulted star and fiducial satellite spots within coronagraphic GPI observations, required to estimate the magnitude difference between a target and any resolved companions, was measur...

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

2014-01-01

32

Automated alignment and on-sky performance of the Gemini planet imager coronagraph  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) is a next-generation, facility instrument currently being commissioned at the Gemini South observatory. GPI combines an extreme adaptive optics system and integral field spectrograph (IFS) with an apodized-pupil Lyot coronagraph (APLC) producing an unprecedented capability for directly imaging and spectroscopically characterizing extrasolar planets. GPI's operating goal of 10-7 contrast requires very precise alignments between the various elements of the coronagraph (two pupil masks and one focal plane mask) and active control of the beam path throughout the instrument. Here, we describe the techniques used to automatically align GPI and maintain the alignment throughout the course of science observations. We discuss the particular challenges of maintaining precision alignments on a Cassegrain mounted instrument and strategies that we have developed that allow GPI to achieve high contrast even in poor seeing conditions.

Savransky, Dmitry; Thomas, Sandrine J.; Poyneer, Lisa A.; Dunn, Jennifer; Macintosh, Bruce A.; Sadakuni, Naru; Dillon, Daren; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Rantakyrö, Fredrik; Cardwell, Andrew; Serio, Andrew

2014-07-01

33

Automated Alignment and On-Sky Performance of the Gemini Planet Imager Coronagraph  

E-print Network

The Gemini Planet Imager (GPI) is a next-generation, facility instrument currently being commissioned at the Gemini South observatory. GPI combines an extreme adaptive optics system and integral field spectrograph (IFS) with an apodized-pupil Lyot coronagraph (APLC) producing an unprecedented capability for directly imaging and spectroscopically characterizing extrasolar planets. GPI's operating goal of $10^{-7}$ contrast requires very precise alignments between the various elements of the coronagraph (two pupil masks and one focal plane mask) and active control of the beam path throughout the instrument. Here, we describe the techniques used to automatically align GPI and maintain the alignment throughout the course of science observations. We discuss the particular challenges of maintaining precision alignments on a Cassegrain mounted instrument and strategies that we have developed that allow GPI to achieve high contrast even in poor seeing conditions.

Savransky, Dmitry; Poyneer, Lisa A; Dunn, Jennifer; Macintosh, Bruce A; Sadakuni, Naru; Dillon, Daren; Goodsell, Stephen J; Hartung, Markus; Hibon, Pascale; Rantakyrö, Fredrik; Cardwell, Andrew; Serio, Andrew

2014-01-01

34

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

35

On-sky vibration environment for the Gemini Planet Imager and mitigation effort  

NASA Astrophysics Data System (ADS)

The Gemini Planet Imager (GPI) entered on-sky commissioning and had its first-light at the Gemini South (GS) telescope in November 2013. GPI is an extreme adaptive optics (XAO), high-contrast imager and integral-field spectrograph dedicated to the direct detection of hot exo-planets down to a Jupiter mass. The performance of the apodized pupil Lyot coronagraph depends critically upon the residual wavefront error (design goal of 60nmRMS with <5 mas RMS tip/tilt), and therefore is most sensitive to vibration (internal or external) of Gemini's instrument suite. Excess vibration can be mitigated by a variety of methods such as passive or active dampening at the instrument or telescope structure or Kalman filtering of specific frequencies with the AO control loop. Understanding the sources, magnitudes and impact of vibration is key to mitigation. This paper gives an overview of related investigations based on instrument data (GPI AO module) as well as external data from accelerometer sensors placed at different locations on the GS telescope structure. We report the status of related mitigation efforts, and present corresponding results.

Hartung, Markus; Hayward, Tom; Saddlemyer, Les; Poyneer, Lisa; Cardwell, Andrew; Cavedoni, Chas; Cho, Myung; Chilcote, Jeffrey K.; Collins, Paul; Dillon, Daren; Galvez, Ramon; Gausachs, Gaston; Goodsell, Stephen; Guesalaga, Andrés.; Hibon, Pascale; Larkin, James; Macintosh, Bruce; Palmer, Dave; Sadakuni, Naru; Savransky, Dmitry; Serio, Andrew; Rantakyrö, Fredrik; Wallace, Kent

2014-08-01

36

The Gemini Deep Planet Survey  

NASA Astrophysics Data System (ADS)

We present the results of the Gemini Deep Planet Survey, a near-infrared adaptive optics search for giant planets and brown dwarfs around 85 nearby young stars. The observations were obtained with the Altair adaptive optics system at the Gemini North telescope, and angular differential imaging was used to suppress the speckle noise of the central star. Typically, the observations are sensitive to angular separations beyond 0.5" with 5 ? contrast sensitivities in magnitude difference at 1.6 ?m of 9.5 at 0.5", 12.9 at 1", 15.0 at 2", and 16.5 at 5". These sensitivities are sufficient to detect planets more massive than 2 MJ with a projected separation in the range 40-200 AU around a typical target. Second-epoch observations of 48 stars with candidates (out of 54) have confirmed that all candidates are unrelated background stars. A detailed statistical analysis of the survey results is presented. Assuming a planet mass distribution dn/dm~m-1.2 and a semimajor-axis distribution dn/da~a-1, the 95% credible upper limits on the fraction of stars with at least one planet of mass 0.5-13 MJ are 0.28 for the range 10-25 AU, 0.13 for 25-50 AU, and 0.093 for 50-250 AU; this result is weakly dependent on the semimajor-axis distribution power-law index. The 95% credible interval for the fraction of stars with at least one brown dwarf companion having a semimajor axis in the range 25-250 AU is 0.019+0.083-0.015, irrespective of any assumption on the mass and semimajor-axis distributions. The observations made as part of this survey have resolved the stars HD 14802, HD 166181, and HD 213845 into binaries for the first time. 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 Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).

Lafrenière, David; Doyon, René; Marois, Christian; Nadeau, Daniel; Oppenheimer, Ben R.; Roche, Patrick F.; Rigaut, François; Graham, James R.; Jayawardhana, Ray; Johnstone, Doug; Kalas, Paul G.; Macintosh, Bruce; Racine, René

2007-12-01

37

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

38

Performance of the integral field spectrograph for the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

39

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

40

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

E-print Network

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

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

2014-01-01

41

Status of the Integral Field Spectrograph for the Gemini Planet Imager  

NASA Astrophysics Data System (ADS)

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

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

2010-01-01

42

Gemini Planet Imager Observational Calibrations IX: Least-Squares Inversion Flux Extraction  

E-print Network

The Gemini Planet Imager (GPI) is an instrument designed to directly image planets and circumstellar disks from 0.9 to 2.5 microns (the $YJHK$ infrared bands) using high contrast adaptive optics with a lenslet-based integral field spectrograph. We develop an extraction algorithm based on a least-squares method to disentangle the spectra and systematic noise contributions simultaneously. We utilize two approaches to adjust for the effect of flexure of the GPI optics which move the position of light incident on the detector. The first method is to iterate the extraction to achieve minimum residual and the second is to cross-correlate the detector image with a model image in iterative extraction steps to determine an offset. Thus far, this process has made clear qualitative improvements to the cube extraction by reducing the Moir\\'{e} pattern. There are also improvements to the automated routines for finding flexure offsets which are reliable to with $\\sim0.5$ pixel accuracy compared to pixel accuracy prior. Fur...

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

2014-01-01

43

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

44

Gemini Planet Imager Observational Calibrations IV: Wavelength Calibration and Flexure Correction for the Integral Field Spectrograph  

E-print Network

We present the wavelength calibration for the lenslet-based Integral Field Spectrograph (IFS) that serves as the science instrument for the Gemini Planet Imager (GPI). The GPI IFS features a 2.7" x 2.7" field of view and a 190 x 190 lenslet array (14.3 mas/lenslet) operating in $Y$, $J$, $H$, and $K$ bands with spectral resolving power ranging from $R$ $\\sim$ 35 to 78. Due to variations across the field of view, a unique wavelength solution is determined for each lenslet characterized by a two-dimensional position, the spectral dispersion, and the rotation of the spectrum with respect to the detector axes. The four free parameters are fit using a constrained Levenberg-Marquardt least-squares minimization algorithm, which compares an individual lenslet's arc lamp spectrum to a simulated arc lamp spectrum. This method enables measurement of spectral positions to better than 1/10th of a pixel on the GPI IFS detector using Gemini's facility calibration lamp unit GCAL, improving spectral extraction accuracy compar...

Wolff, Schuyler G; Maire, Jérôme; Ingraham, Patrick J; Rantakyrö, Fredrik T; Hibon, Pascale

2014-01-01

45

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

46

Gemini Planet Imager Observational Calibrations VIII: Characterization and Role of Satellite Spots  

E-print Network

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

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

2014-01-01

47

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

48

Gemini Planet Imager Observational Calibrations III: Empirical Measurement Methods and Applications of High-Resolution Microlens PSFs  

E-print Network

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

Ingraham, Patrick; Perrin, Marshall D; Wolff, Schuyler G; Draper, Zachary H; Maire, Jerome; Marchis, Franck; Fesquet, Vincent

2014-01-01

49

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

50

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

SciTech Connect

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

Kataria, Tiffany; Simon, Michal [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)

2010-07-15

51

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

52

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

53

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

SciTech Connect

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

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

2013-10-10

54

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

E-print Network

When giant planets form, they grow by accreting gas and dust. HD 142527 is a young star that offers a scaled-up view of this process. It has a broad, asymmetric ring of gas and dust beyond \\about 100 AU and a wide inner gap. Within the gap, a low-mass stellar companion orbits the primary star at just \\about 12 AU, and both the primary and secondary are accreting gas. In an attempt to directly detect the dusty counterpart to this accreted gas, we have observed HD 142527 with the Gemini Planet Imager in polarized light at $Y$ band (0.95-1.14 \\microns). We clearly detect the companion in total intensity and show that its position and photometry are generally consistent with the expected values. We also detect a point-source in polarized light that may be spatially separated by \\about a few AU from the location of the companion in total intensity. This suggests that dust is likely falling onto or orbiting the companion. Given the possible contribution of scattered light from this dust to previously reported photo...

Rodigas, Timothy J; Weinberger, Alycia; Close, Laird; Hines, Dean C

2014-01-01

55

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

56

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

57

Results from the Gemini NICI Planet-Finding Campaign  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

58

The Gemini NICI Planet-Finding Campaign: Planet Frequency for Young Moving Group Stars  

NASA Astrophysics Data System (ADS)

We report results of a direct imaging survey for giant planets of a sample of 79 young FGK stars which are members of the ? Pic, TW Hya, AB Dor, Tucana-Horologium, or Hercules-Lyra moving groups and were observed as part of the Gemini-NICI Planet Finding Campaign. For this sample, we obtained median contrasts of ?(mag)=14.0 mag at 1'' in in combined ADI+SDI mode. We found numerous candidate companions in our survey images. The vast majority of these candidates were eliminated as background objects either from archival observations or NICI followup. However, four co-moving brown dwarf or stellar companions were discovered in the moving group sample, including PZ Tel B and CD -35 2722B. From a Bayesian analysis for a wide range of parameters and power-law models of planet distributions, we restrict the planet frequency for 1-20 M_{Jup} objects at semi-major axes from 10-150 AU to <10.5% or less at a 98% confidence level. This survey is the deepest search to date for giant planets around young Moving Group stars.

Biller, Beth A.; Liu, M. C.; Wahhaj, Z.; Nielsen, E. L.; Hayward, T. L.; Close, L. M.; Chun, M.; Ftaclas, C.; Toomey, D. W.; Gemini NICI Planet-Finding Campaign Team

2013-01-01

59

Gemini South Adaptive Optics Imager (GSAOI)  

Microsoft Academic Search

The Gemini South Adaptive Optics Imager (GSAOI) is the science camera and commissioning instrument for the Multi-Conjugate Adaptive Optics (MCAO) system on the Gemini South telescope. GSAOI is required to deliver diffraction-limited performance at near-infrared wavelengths over a 85\\

Peter McGregor; John Hart; Dejan Stevanovic; Gabe Bloxham; Damien Jones; Jan Van Harmelen; Jason Griesbach; Murray Dawson; Peter Young; Mark A. Jarnyk

2004-01-01

60

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

E-print Network

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

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

2013-01-01

61

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

62

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

SciTech Connect

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

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

2013-10-10

63

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

64

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

65

Gemini South Adaptive Optics Imager (GSAOI)  

NASA Astrophysics Data System (ADS)

The Gemini South Adaptive Optics Imager (GSAOI) is the science camera and commissioning instrument for the Multi-Conjugate Adaptive Optics (MCAO) system on the Gemini South telescope. GSAOI is required to deliver diffraction-limited performance at near-infrared wavelengths over a 85"×85" field of view. It must be delivered on a short timescale commensurate with MCAO delivery. GSAOI will use a high throughput, all-refractive optical design and a mosaic of four HAWAII-2RG detectors to form an imager focal plane of 4080x4080 pixels with a fixed scale of 0.02"/pixel. The On-Detector Guide Window (ODGW) capability of the HAWAII-2RG detectors will be used for flexure monitoring and as near-infrared substitutes for MCAO natural guide star wave front sensors. The imager will include a pupil viewer for accurate alignment to MCAO and defocus lenses to measure wave front phase errors at the science detector using the curvature technique. Non-common path wave front errors will be nulled by setting the base shapes of the three MCAO deformable mirrors. The science drivers, performance predictions, optical design issues, and detector system for the instrument are described.

McGregor, Peter; Hart, John; Stevanovic, Dejan; Bloxham, Gabe; Jones, Damien; Van Harmelen, Jan; Griesbach, Jason; Dawson, Murray; Young, Peter; Jarnyk, Mark A.

2004-09-01

66

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

67

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

SciTech Connect

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

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

2013-11-10

68

Instrumentation at Gemini Observatory  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

69

Direct imaging of multiple planets orbiting the star HR 8799  

SciTech Connect

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

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

2008-10-14

70

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

71

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

72

Image resolutions 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

73

The Gemini NICI Planet-Finding Campaign: The Offset Ring of HR 4796 A  

E-print Network

We present J, H, CH_4 short (1.578 micron), CH_4 long (1.652 micron) and K_s-band images of the dust ring around the 10 Myr old star HR 4796 A obtained using the Near Infrared Coronagraphic Imager (NICI) on the Gemini-South 8.1 meter Telescope. Our images clearly show for the first time the position of the star relative to its circumstellar ring thanks to NICI's translucent focal plane occulting mask. We employ a Bayesian Markov Chain Monte Carlo method to constrain the offset vector between the two. The resulting probability distribution shows that the ring center is offset from the star by 16.7+/-1.3 milliarcseconds along a position angle of 26+/-3 degrees, along the PA of the ring, 26.47+/-0.04 degrees. We find that the size of this offset is not large enough to explain the brightness asymmetry of the ring. The ring is measured to have mostly red reflectivity across the JHK_s filters, which seems to indicate micron-sized grains. Just like Neptune's 3:2 and 2:1 mean-motion resonances delineate the inner and...

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

2014-01-01

74

Gemini imaging of QSO host galaxies at z~2  

E-print Network

We present results of a Gemini adaptive optics (AO) imaging program to investigate the host galaxies of typical QSOs at z~2. Our aim is to study the host galaxies of typical, L*_qso QSOs at the epoch of peak QSO and star formation activity. The large database of faint QSOs provided by the 2dF QSO Redshift Survey allows us to select a sample of QSOs at z=1.75-2.5 which have nearby (<12 arcsecond separation) bright stars suitable for use as AO guide stars. We have observed a sample of 9 QSOs. The images of these sources have AO corrected full-width at half-maximum of between 0.11 and 0.25 arcseconds. We use multiple observations of point spread function (PSF) calibration star pairs in order to quantify any uncertainty in the PSF. We then factored these uncertainties into our modelling of the QSO plus host galaxy. In only one case did we convincingly detect a host (2QZ J133311.4+001949, at z=1.93). This host galaxy has K=18.5+-0.2 mag with a half-light radius, r_e=0.55+-0.1'', equivalent to ~3L*_gal assuming a simple passively evolving model. From detailed simulations of our host galaxy modelling process, we find that for four of our targets we should be sensitive to host galaxies that are equivalent to ~2L*_gal (passively evolved). Our non-detections therefore place tight constraints on the properties of L*_qso QSO host galaxies, which can be no brighter (after allowing for passive evolution) than the host galaxies of L*_qso AGN at low redshift, although the QSOs themselves are a factor of ~50 brighter. This implies that either the fueling efficiency is much greater at high redshift, or that more massive black holes are active at high redshift.

Scott Croom; David Schade; Brian Boyle; Tom Shanks; Lance Miller; Robert Smith

2004-01-21

75

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

76

Titan's Clouds from Gemini and Keck Adaptive Optics Imaging  

NASA Astrophysics Data System (ADS)

Using adaptive optics on the Gemini and Keck II telescopes, we found a thin haze and discrete clouds in Titan's south polar troposphere. The discrete clouds vary on timescales of a few hours. We propose a seasonal mechanism to explain the formation of this spring polar tropospheric haze. Assuming that the clouds are located in or above the haze, we suggest that convection within this haze layer triggers methane condensation; subsequent latent heat release leads to vigorous convection and formation of transient clouds. Our results have significant implications for planning the Cassini mission flybys of Titan. 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 National Science Foundation (NSF) on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina). This paper is based on observations obtained with the Adaptive Optics System Hokupa`a/QUIRC, developed and operated by the University of Hawaii Adaptive Optics Group, with support from the NSF.

Roe, H. G.; de Pater, I.; Macintosh, B. A.; McKay, C. P.

2002-12-01

77

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

78

Maintenance and operation of the adaptive optics module for NICI, the high-contrast coronagraphic imager of GEMINI observatory  

NASA Astrophysics Data System (ADS)

NICI, the high-contrast coronagraphic imager of Gemini observatory, primarily dedicated to planet hunting has been offered to the astronomical community since end of 2008. We present our experiences in operating and maintaining NICI's 85 element curvature adaptive optics (AO) system. A detailed study of NICI AO telemetry data is also most relevant to prepare the arrival of next generation instruments. We summarize the behavior of interaction matrices, control matrices and error transfer functions under different operational conditions; a detailed understanding of the system helps monitoring and optimizing performance. Furthermore, we describe tuning (membrane mirror stroke/extra focal distance) for non-optimal seeing conditions as well as for niche applications of NICI such as observing small moons and asteroids. We compare on-sky measurements to theory or simulations.

Hartung, Markus; Hayward, Tom L.; Chun, M.; Kellerer, A.

2010-07-01

79

Direct Imaging of Warm Extrasolar Planets  

SciTech Connect

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

Macintosh, B

2005-04-11

80

The M31 Dwarf Spheroidal Companion Andromeda V: g', r', and i' Imaging with the Gemini Multi-Object Spectrograph on Gemini North  

NASA Astrophysics Data System (ADS)

Images obtained in g', r', and i' with the Gemini Multi-Object Spectrograph (GMOS) on Gemini North are used to investigate the metallicity and stellar content of the M31 dwarf spheroidal companion galaxy Andromeda V. Red giant branch (RGB) stars are traced out to radii in excess of 126" from the galaxy center, indicating that And V extends over a diameter approaching 1 kpc. The mean g'-i' color of the RGB does not change with radius. Based on the slope of the RGB in the (i', g'-i') color-magnitude diagram, we conclude that the metallicity of And V is [Fe/H]=-2.2+/-0.1. This is lower than earlier estimates and places And V squarely on the relation between metallicity and integrated brightness defined by other dwarf spheroidal and dwarf elliptical galaxies. In contrast to many of the Galaxy's dwarf spheroidal companions, there is no evidence for a statistically significant population of luminous asymptotic giant branch stars near the center of the galaxy. 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 Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council of Canada (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).

Davidge, T. J.; Da Costa, G. S.; Jørgensen, Inger; Allington-Smith, J. R.

2002-08-01

81

Imaging Extrasolar Planets from the Ground  

Microsoft Academic Search

An approach to direct imaging of extrasolar planets is described, in which adaptive optics to correct atmospheric aberration are based on interferometric measurements made in the focal plane. In order to minimize the weak, residual speckles of the stellar halo, their complex amplitudes are first determined using photon-counting, spectrally-resolved imaging sensors. Corrections to both the corrugation and intensity of the

R. Angel

2003-01-01

82

Spaceprobe images and the Terrestrial Planets Section  

Microsoft Academic Search

With the formation of a new grouping within the Association - the Terrestrial Planets Section - there is scope for a fresh approach to BAA studies of Mercury, Venus and Mars, incorporating both Earth-based and spacecraft-derived information. Printing Options Send high resolution image to Level 2 Postscript Printer Send low resolution image to Level 2 Postscript Printer Send low resolution

G. J. Day

1981-01-01

83

Direct imaging of extra-solar planets  

SciTech Connect

Direct imaging of extra-solar planets may be possible with the new generation of large ground-based telescopes equipped with state- of- the-art adaptive optics (AO) systems to compensate for the blurring effect of the Earth`s atmosphere. The first of these systems is scheduled to begin operation in 1998 on the 10 in Keck II telescope. In this paper, general formulas for high-contrast imaging with AO systems are presented and used to calculate the sensitivity of the Keck AO system. The results of these calculations show that the Keck AO system should achieve the sensitivity necessary to detect giant planets around several nearby bright stars.

Olivier, S.S.; Max, V.E.; Brase, J.M.; Caffano, C.J.; Gavel, D.T.; Macintosh, B.A.

1997-03-01

84

Imaging Extrasolar Planets from the Ground  

NASA Astrophysics Data System (ADS)

An approach to direct imaging of extrasolar planets is described, in which adaptive optics to correct atmospheric aberration are based on interferometric measurements made in the focal plane. In order to minimize the weak, residual speckles of the stellar halo, their complex amplitudes are first determined using photon-counting, spectrally-resolved imaging sensors. Corrections to both the corrugation and intensity of the wavefront are then derived by Fourier transform and applied using a pair of deformable mirrors. In this way the systematic and non-common path errors of pupil wavefront sensing methods are avoided, and the resulting high accuracy correction should allow detection of giant extrasolar planets with existing large telescopes. With new ground-based telescopes of approximately 20 meter or larger aperture, detection and even spectroscopy of nearby earth-like planets should be possible.

Angel, R.

85

Imaging planets around nearby white dwarfs  

E-print Network

We suggest that Jovian planets will survive the late stages of stellar evolution, and that white dwarfs will retain planetary systems in wide orbits (>5AU). Utilising evolutionary models for Jovian planets, we show that infra-red imaging with 8m class telescopes of suitable nearby white dwarfs should allow us to resolve and detect companions >3Mjup. Detection of massive planetary companions to nearby white dwarfs would prove that such objects can survive the final stages of stellar evolution, place constraints on the frequency of main sequence stars with planetary systems dynamically similar to our own and allow direct spectroscopic investigation of their composition and structure.

M. R. Burleigh; F. J. Clarke; S. T. Hodgkin

2002-02-09

86

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

E-print Network

We present Sloan g and i imaging from the GMOS instrument on the Gemini North telescope for the globular cluster (GC) system around the Virgo galaxy NGC 4649 (M60). Our three pointings, taken in good seeing conditions, cover an area of about 90 sq. arcmins. We detect 2,151 unresolved sources. Applying colour and magnitude selection criteria to this source list gives 995 candidate GCs that is greater than 90% complete to a magnitude of i = 23.6, with little contamination from background galaxies. We find fewer than half a dozen potential Ultra Compact Dwarf galaxies around NGC 4649. Foreground extinction from the nearby spiral NGC 4647 is limited to be A_V GMOS spectra of the NGC 4649 GCs.

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

2004-08-23

87

Planet Detection Algorithm using Multiple Images with Independent Speckle Patterns  

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

88

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

SciTech Connect

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

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

2012-01-20

89

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

E-print Network

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

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

2008-02-28

90

Gemini surfactants  

Microsoft Academic Search

The literature, including patents, describing the emerging area of gemini surfactants is reviewed. The differences in structure\\/property\\u000a relationships between gemini and comparable conventional surfactants are described and discussed in terms of their predicted\\u000a performance properties. Supportive performance data are enumerated.

Milton J. Rosen; David J. Tracy

1998-01-01

91

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

92

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

E-print Network

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

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

2002-07-04

93

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

94

Planet signatures in collisionally active debris discs: scattered light images  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

95

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

96

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

E-print Network

We report the first independent, second-epoch (re-)detection of a directly-imaged protoplanet candidate. Using $L^\\prime$ high-contrast imaging of HD 100546 taken with the Near-Infrared Coronagraph and Imager (NICI) on Gemini South, we recover `HD 100546 b' with a position and brightness consistent with the original VLT/NaCo detection from Quanz et al, although data obtained after 2013 will be required to decisively demonstrate common proper motion. HD 100546 b may be spatially resolved, up to $\\approx$ 12-13 AU in diameter, and is embedded in a finger of thermal IR bright, polarized emission extending inwards to at least 0.3". Standard hot-start models imply a mass of $\\approx$ 15 $M_{J}$. But if HD 100546 b is newly formed or made visible by a circumplanetary disk, both of which are plausible, its mass is significantly lower (e.g. 1--7 $M_{J}$). Additionally, we discover a thermal IR-bright disk feature, possibly a spiral density wave, at roughly the same angular separation as HD 100546 b but 90 degrees awa...

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

2014-01-01

97

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

98

The Ion Mass Imager on the Planet-B spacecraft  

Microsoft Academic Search

The Ion Mass Imager (IMI) is a light-weight ion mass composition instrument for the Japanese Planet-B mission to be launched to Mars in 1998. The objective of the Planet-B mission is to study the Martian environment with emphasis on the upper atmosphere interaction with the solar wind. IMI measures positive ions with energies between 10 eV\\/q and 35 keV\\/q and

O. Norberg; M. Yamauchi; R. Lundin; S. Olsen; H. Borg; S. Barabash; M. Hirahara; T. Mukai; H. Hayakawa

1998-01-01

99

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

NASA Astrophysics Data System (ADS)

We present new L' (3.8 ?m) and Br? (4.05 ?m) data and reprocessed archival L' data for the young, planet-hosting star HR 8799 obtained with Keck/NIRC2, VLT/NaCo, and Subaru/IRCS. We detect all four HR 8799 planets in each data set at a moderate to high signal-to-noise ratio (S/N >~ 6-15). We fail to identify a fifth planet, "HR 8799 f," at r < 15 AU at a 5? confidence level: one suggestive, marginally significant residual at 0.''2 is most likely a point-spread function artifact. Assuming companion ages of 30 Myr and the Baraffe planet cooling models, we rule out an HR 8799 f with a mass of 5 MJ (7 MJ ), 7 MJ (10 MJ ), or 12 MJ (13 MJ ) at r proj ~ 12 AU, 9 AU, and 5 AU, respectively. All four HR 8799 planets have red early T dwarf-like L' – [4.05] colors, suggesting that their spectral energy distributions peak in between the L' and M' broadband filters. We find no statistically significant difference in HR 8799 cde's color. Atmosphere models assuming thick, patchy clouds appear to better match HR 8799 bcde's photometry than models assuming a uniform cloud layer. While non-equilibrium carbon chemistry is required to explain HR 8799 b and c's photometry/spectra, evidence for it from HR 8799 d and e's photometry is weaker. Future, deep-IR spectroscopy/spectrophotometry with the Gemini Planet Imager, SCExAO/CHARIS, and other facilities may clarify whether the planets are chemically similar or heterogeneous.

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

2014-11-01

100

Modeling Scattered Light Images from a Planet-Forming Disk  

Microsoft Academic Search

We calculate simulated images of a planet-forming circumstellar disk in scattered light emission. The simulated images bear no correlation to the vertically integrated surface density of the disk, but rather trace the density structure in the tenuous upper layers of the disk. Although the density at high altitudes are not directly related to activity at the midplane, the very existence

Hannah Jang-Condell; A. P. Boss

2006-01-01

101

Planets  

NSDL National Science Digital Library

Pick a planet and tell me 6 different facts you learned about that planet. First to help you remember your planets and which order they go in watch this video Afer the video you may take a few minutes and choose which game to play. Now go through these pictures and see how neat the planets look from space. Now click hereand here and research which planet you would ...

2012-04-11

102

eXtreme Adaptive Optics Planet Imager: Overview and status  

SciTech Connect

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

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

2004-08-18

103

Spectral differential imaging detection of planets about nearby stars  

NASA Technical Reports Server (NTRS)

Direct ground-based optical imaging of planets in orbit about nearby stars may be accomplished by spectral differential imaging using multiple passband acoustooptic filters with a CCD. This technique provides two essential results. First, it provides a means to modulate the stellar flux reflected from a planet while leaving the flux from the star and other sources in the same field of view unmodulated. Second, spectral differential imaging enables the CCD detector to achieve a sufficiently high dynamic range to locate planets near a star in spite of an integrated brightness differential of 5 x 10 to the 8th. Spectral differential imaging at nearby diffraction limited imaging conditions with telescope apodization can reduce the time to conduct a sensitive planetary search to a few hours in some cases. The feasibility of this idea is discussed here and shown to provide, in principle, the discrimination and sensitivity to detect a Jovian-class planet about stars at distances of about 10 parsecs. The detection of brown dwarfs is shown to be feasible as well.

Smith, W. Hayden

1987-01-01

104

Planets  

NSDL National Science Digital Library

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

Anderson, Ms.

2011-04-07

105

The lowest mass giant planet ever imaged around a star  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

106

Planets  

NSDL National Science Digital Library

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

107

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

E-print Network

coronagraphic data. We also demonstrate the performance of an astrometric and photometric grid that enables of comparative planetary science. Recent advances in adaptive optics (or AO, which corrects atmospheric the diffracted flood of light from a star to search its environs for planetary companions and faint

108

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

109

Gemini/GMOS Imaging of Globular Cluster Systems in Five Early-type Galaxies  

E-print Network

This paper presents deep high quality photometry of globular cluster (GC) systems belonging to five early-type galaxies covering a range of mass and environment. Photometric data were obtained with the Gemini North and Gemini South telescopes in the filter passbands g', r', and i'. The combination of these filters with good seeing conditions allows an excellent separation between GC candidates and unresolved field objects. Bimodal GC colour distributions are found in all five galaxies. Most of the GC systems appear bimodal even in the (g' -r') vs (r' -i') plane. A population of resolved/marginally resolved GC and Ultra Compact Dwarf candidates was found in all the galaxies. A search for the so-called "blue tilt" in the colour-magnitude diagrams reveals that NGC 4649 clearly shows that phenomenon although no conclusive evidence was found for the other galaxies in the sample. This "blue tilt" translates into a mass-metallicity relation given by Z \\propto M^0.28\\pm0.03 . This dependence was found using a new emp...

Faifer, Favio R; Norris, Mark A; Bridges, Terry; Forbes, Duncan A; Zepf, Stephen E; Beasley, Mike; Gebhardt, Karl; Hanes, David A; Sharples, Ray M

2011-01-01

110

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

111

Planets  

NSDL National Science Digital Library

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

Bhanks

2006-11-02

112

Imaging plasmas at the Earth and other planets  

NASA Astrophysics Data System (ADS)

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

Mitchell, D. G.

2006-05-01

113

Integral Field Spectroscopy at Gemini  

NASA Astrophysics Data System (ADS)

Integral field units (IFUs) and spectrographs will be an important part of the instrument complement at both Gemini 8-meter telescopes. An especially powerful aspect of this will be the combination of IFUs with high spatial resolution adaptive optics systems. Adaptive optics will produce near diffraction-limited images with resolution approximately a factor of two better than the Hubble Space Telescope at 2 microns. Coupled with the light-gathering power of 8-meter telescopes, this combination will be well-suited for spatially resolved studies of intermediate and high redshift galaxies. IFUs employing both lenslet/fiber and image slicer technologies will give Gemini integral field capability at wavelengths from 0.4 microns to 5 microns. This presentation will review current and planned integral field capability at Gemini will give early results from the recently commissioned IFU for the Gemini Multi-Object Spectrograph (GMOS). This work is supported by 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 Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil) and CONICET (Argentina).

Miller, B.

2001-12-01

114

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

115

The Science Case for the Planet Formation Imager (PFI)  

E-print Network

Among the most fascinating and hotly-debated areas in contemporary astrophysics are the means by which planetary systems are assembled from the large rotating disks of gas and dust which attend a stellar birth. Although important work has already been, and is still being done both in theory and observation, a full understanding of the physics of planet formation can only be achieved by opening observational windows able to directly witness the process in action. The key requirement is then to probe planet-forming systems at the natural spatial scales over which material is being assembled. By definition, this is the so-called Hill Sphere which delineates the region of influence of a gravitating body within its surrounding environment. The Planet Formation Imager project (PFI) has crystallized around this challenging goal: to deliver resolved images of Hill-Sphere-sized structures within candidate planet-hosting disks in the nearest star-forming regions. In this contribution we outline the primary science case...

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

2014-01-01

116

Outer planet Pioneer imaging communications system study. [data compression  

NASA Technical Reports Server (NTRS)

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

1974-01-01

117

GEOMETRIC PROCESSING OF DIGITAL IMAGES OF THE PLANETS.  

USGS Publications Warehouse

New procedures and software have been developed for geometric transformations 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.

Edwards, Kathleen

1987-01-01

118

Gemini Frontier Fields: Wide-field Adaptive Optics $K_s$-band Imaging of the Galaxy Cluster MACS J0416.1-2403  

E-print Network

The Hubble Space Telescope (HST) Frontier Fields Campaign targets six massive clusters of galaxies, exploiting the strong gravitational lensing effect to study the distant Universe. At Gemini South we observe the three southern-most clusters in Ks-band, overcoming HST/WFC3's sensitivity cut-off redwards of 1.7 microns. We use the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and the Gemini South Adaptive Optics Imager (GSAOI), delivering near diffraction-limited images on arcminute scales. In this paper we describe our public release of 100"x110" wide images of the first target, MACS J0416.1-2403. We have achieved an angular resolution of 0.07"-0.10", twice as high as HST/WFC3, with only one natural guide star. With a $5\\sigma$ depth of Ks=23.8 mag for extended sources our images are shallower than the HST/WFC3 images. The data were distortion corrected and registered with sub-pixel accuracy despite only a few low-S/N extended sources are visible in the individual exposures. This is a demonstration tha...

Schirmer, Mischa; Pessev, Peter; Garrel, Vincent; Winge, Claudia; Neichel, Benoit; Vidal, Fabrice

2014-01-01

119

SUBARU AND GEMINI HIGH SPATIAL RESOLUTION INFRARED 18 {mu}m IMAGING OBSERVATIONS OF NEARBY LUMINOUS INFRARED GALAXIES  

SciTech Connect

We present the results of a ground-based, high spatial resolution infrared 18 {mu}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 {mu}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 {mu}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 {mu}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 [Subaru Telescope, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Imase, Keisuke; Oi, Nagisa [Department of Astronomy, School of Science, Graduate University for Advanced Studies (SOKENDAI), Mitaka, Tokyo 181-8588 (Japan); Ichikawa, Kohei, E-mail: masa.imanishi@nao.ac.jp [Department of Astronomy, Kyoto University, Kyoto 606-8502 (Japan)

2011-05-15

120

Confirmation of the Planet around HD 95086 by Direct Imaging  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

121

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

E-print Network

as small as 0:2 MJup across a broad range of orbital separations. We present new calculations for planet subject to JSTOR Terms and Conditions #12;for planets on long period orbits, particularly in the absenceImaging Young Giant Planets From Ground and Space CHARLES A. BEICHMAN NASA Exoplanet Science

122

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

E-print Network

Imaging planets around nearby white dwarfs M. R. Burleigh,1P F. J. Clarke2P and S. T. Hodgkin2P 1. Key words: planetary systems ­ white dwarfs. 1 I NT RODU CTION Over 70 extra-solar planets have now in the brightness contrast between a planet and a white dwarf when compared to a main-sequence star, assuming

Burleigh, Matt

123

Predictions for Shepherding Planets in Scattered Light Images of Debris Disks  

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

124

Advancing the Gemini Observatory  

NASA Astrophysics Data System (ADS)

Gemini Science and User Meeting; San Francisco, California, 17-20 July 2012 More than 100 astronomers gathered in San Francisco to discuss results from the Gemini Observatory and to plan for its future. The Gemini Observatory consists of twin 8.1 meter diameter optical/infrared telescopes located on mountaintops in Hawai'i and Chile. Gemini was built and is operated by an international partnership that currently includes the United States, the United Kingdom, Canada, Chile, Australia, Brazil, and Argentina.

Hammel, Heidi B.; Levenson, Nancy A.

2012-11-01

125

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

126

High Contrast Imaging Testbed for the Terrestrial Planet Finder Coronagraph  

NASA Technical Reports Server (NTRS)

The Terrestrial Planet Finder (TPF) mission is planning to launch a visible coronagraphic space telescope in 2014. To achieve TPF science goals, the coronagraph must have extreme levels of wavefront correction (less than 1 Angstrom rms over controllable spatial frequencies) and stability to get the necessary suppression of diffracted starlight (approximately l0(exp -10)) contrast at an angular separation approximately 4 (lamda)/D). TPF Coronagraph's primary platform for experimentation is the High Contrast Imaging Testbed, which will provide laboratory validation of key technologies as well as demonstration of a flight-traceable approach to implementation. Precision wavefront control in the testbed is provided by a high actuator density deformable mirror. Diffracted light control is achieved through use of occulting or apodizing masks and stops. Contrast measurements will establish the technical feasibility of TPF requirements, while model and error budget validation will demonstrate implementation viability. This paper describes the current testbed design, development approach, and recent experimental results.

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

2004-01-01

127

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

128

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

129

ATMOSPHERIC DYNAMICS OF BROWN DWARFS AND DIRECTLY IMAGED GIANT PLANETS  

SciTech Connect

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

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

2013-10-20

130

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

131

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

132

A giant planet imaged in the disk of the young star beta Pictoris.  

PubMed

Here, we show that the approximately 10-million-year-old beta Pictoris system hosts a massive giant planet, beta Pictoris b, located 8 to 15 astronomical units from the star. This result confirms that gas giant planets form rapidly within disks and validates the use of disk structures as fingerprints of embedded planets. Among the few planets already imaged, beta Pictoris b is the closest to its parent star. Its short period could allow for recording of the full orbit within 17 years. PMID:20538914

Lagrange, A-M; Bonnefoy, M; Chauvin, G; Apai, D; Ehrenreich, D; Boccaletti, A; Gratadour, D; Rouan, D; Mouillet, D; Lacour, S; Kasper, M

2010-07-01

133

FIB machining of occulting masks for imaging of extrasolar planets  

NASA Astrophysics Data System (ADS)

We are developing the ability for Focused Ion Beam (FIB) machining of occulting masks for use in coronagraphs. These masks will be used as soft-edged Lyot stops to suppress light from stars and allow direct imaging of extrasolar planets. The FIB approach is attractive because it has the potential for higher precision than mechanical machining and for larger volumes than electron-beam lithography. The mask fabrication process is trifold: 1) a transparent material-currently, poly(methyl methacrylate) (PMMA)-is doped with dyes; 2) the mask shape is FIB milled into the material; and 3) the mask is coated with another layer of index-matching transparent absorber. Using a Zeiss NVision 40 FIB system, we have fabricated conical-shaped masks of various slopes in dye-doped PMMA. Inherent in this process is the advantage of control of the features through programming the ion beam track. We have also optically characterized these masks as well as the dye-doped absorbing material. We have found that the dye-doped PMMA has a very high absorbance, >1 OD.

Raja, Shilpa N.; Aziz, Michael J.; Foley, James W.; Tolls, Volker

2009-08-01

134

A Bayesian Planet-detection Algorithm Using Multiple Speckle-limited Images  

NASA Astrophysics Data System (ADS)

Current exoplanet searches with coronagraphic instruments have shown that one of the main limitations to high-contrast imaging is residual quasi-static speckle. Speckles look like the image of a planet, but have a different spectral behavior. They are formed from the same coherent source, the star, and are incoherent with the planet. Controlled changes in optical layout can lead to a changing speckle pattern in the image. Since the planet light does not interfere with the speckles, the image of the planet remains unchanged. Typically, part of the star light is redirected in order to create an interference pattern as seen in the image. In contrast, we seek to use existing adaptive optics systems to create a series of images with different speckle patterns. We developed an algorithm that uses Bayesian inference to take advantage of the changing speckle pattern across multiple images to determine the presence of a planet. As we change the speckle pattern across images, our algorithm accumulates evidence when an artifact does not change between images. Artifacts are identified by fitting a model to each image that incorporates a locally constant background, multiple point spread functions, and photon noise. The algorithm can incorporate desired missed detection and false alarm rates resulting in the integration time required for planet detection. This algorithm is verified through computer simulation and laboratory experiments. In both cases a star and planet are simulated using separate laser sources and the changing speckle pattern is achieved by changing the shape of a deformable mirror. Our work offers the opportunity to incorporate interference-based differentiation between speckles and planets into existing adaptive optics setups rather than requiring additional system components. Our algorithm can be integrated into the planning of observations to determine the required time to meet desired detection parameters.

Young, Elizabeth J.

2013-01-01

135

Gemini Detective  

NSDL National Science Digital Library

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

136

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

137

Gemini Rendezvous Docking Simulator  

NASA Technical Reports Server (NTRS)

Gemini Rendezvous Docking Simulator suspended from the roof of the Langley Research Center's aircraft hanger. Francis B. Smith wrote: 'The rendezvous and docking operation of the Gemini spacecraft with the Agena and of the Apollo Command Module with the Lunar Excursion Module have been the subject of simulator studies for several years. [This figure] illustrates the Gemini-Agena rendezvous docking simulator at Langley. The Gemini spacecraft was supported in a gimbal system by an overhead crane and gantry arrangement which provided 6 degrees of freedom - roll, pitch, yaw, and translation in any direction - all controllable by the astronaut in the spacecraft. Here again the controls fed into a computer which in turn provided an input to the servos driving the spacecraft so that it responded to control motions in a manner which accurately simulated the Gemini spacecraft.'

1964-01-01

138

Astrometric performance of the Gemini multi-conjugate adaptive optics system in crowded fields  

E-print Network

The Gemini Multi-conjugate adaptive optics System (GeMS) is a facility instrument for the Gemini-South telescope. It delivers uniform, near-diffraction-limited image quality at near-infrared wavelengths over a 2 arcminute field of view. Together with the Gemini South Adaptive Optics Imager (GSAOI), a near-infrared wide field camera, GeMS/GSAOI's combination of high spatial resolution and a large field of view will make it a premier facility for precision astrometry. Potential astrometric science cases cover a broad range of topics including exo-planets, star formation, stellar evolution, star clusters, nearby galaxies, black holes and neutron stars, and the Galactic center. In this paper, we assess the astrometric performance and limitations of GeMS/GSAOI. In particular, we analyze deep, mono-epoch images, multi-epoch data and distortion calibration. We find that for single-epoch, un-dithered data, an astrometric error below 0.2 mas can be achieved for exposure times exceeding one minute, provided enough star...

Neichel, Benoit; Rigaut, Francois; Ammons, S Mark; Carrasco, Eleazar R; Lassalle, Emmanuel

2014-01-01

139

Post processing of differential images for direct extrasolar planet detection from the ground  

Microsoft Academic Search

The direct imaging from the ground of extrasolar planets has become today a major astronomical and biological focus. This kind of imaging requires simultaneously the use of a dedicated high performance Adaptive Optics [AO] system and a differential imaging camera in order to cancel out the flux coming from the star. In addition, the use of sophisticated post-processing techniques is

J.-F. Sauvage; L. Mugnier; T. Fusco; G. Rousset

2006-01-01

140

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

NASA Technical Reports Server (NTRS)

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

Kuchner, Marc

2009-01-01

141

High-resolution Multi-band Imaging for Validation and Characterization of Small Kepler Planets  

E-print Network

High-resolution ground-based optical speckle and near-infrared adaptive optics images are taken to search for stars in close angular proximity to host stars of candidate planets identified by the NASA Kepler Mission. Neighboring stars are a potential source of false positive signals. These stars also blend into Kepler light curves, affecting estimated planet properties, and are important for an understanding of planets in multiple star systems. Deep images with high angular resolution help to validate candidate planets by excluding potential background eclipsing binaries as the source of the transit signals. A study of 18 Kepler Object of Interest stars hosting a total of 28 candidate and validated planets is presented. Validation levels are determined for 18 planets against the likelihood of a false positive from a background eclipsing binary. Most of these are validated at the 99% level or higher, including 5 newly-validated planets in two systems: Kepler-430 and Kepler-431. The stellar properties of the ca...

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

2014-01-01

142

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

E-print Network

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

Antoine Labeyrie

1996-02-19

143

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

144

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

SciTech Connect

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

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

2013-08-10

145

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

146

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

NASA Astrophysics Data System (ADS)

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

Bowler, Brendan Peter

147

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

SciTech Connect

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

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

2011-12-10

148

Computer vision applications for coronagraphic optical alignment and image processing  

E-print Network

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

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

2013-01-01

149

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

150

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

151

Compact imaging spectrometer with visible-infrared variable filters for Earth and planet observation  

Microsoft Academic Search

Compact spectrometers are of interest for space applications for both Earth observation and analysis of planet soil. The spectrometer here described is dedicated to Land imaging and is based on the use of linear variable filters for wavelength selection. This kind of filter is able to transmit the radiation in a narrow band (<20 nm) centered on a wavelength that

A. Piegari; A. Sytchkova; J. Bulir; M. Dami; G. Aroldi; B. Harnisch

2011-01-01

152

Models of gemini surfactants  

E-print Network

Gemini (dimeric) surfactants are composed of two monomeric surfactant molecules linked by a spacer chain. Their self-assembly behavior differs qualitatively from that of monomeric surfactants. We review the various theoretical attempts to account for the behavior of this new class of amphiphilic molecules.

Haim Diamant; David Andelman

2003-02-10

153

A High-Contrast Adaptive Optics Imaging Search for Giant Planets Around Young M Dwarfs  

NASA Astrophysics Data System (ADS)

Direct imaging planet searches are revealing the architecture of planetary systems at large separations (>10 AU) for the first time. Low-mass stars are generally being neglected from these surveys in part because of the dearth of known nearby young M dwarfs compared to young intermediate- and high-mass stars. As a result, there are few constraints on giant planet formation around low-mass stars at moderate (5-100 AU) separations. We present results from an ongoing high-contrast adaptive optics imaging survey of nearby (<30 pc) young (<300 Myr) M dwarfs with Keck-2/NIRC2 and Subaru/HiCIAO. Our survey is sensitive to planet masses of 6 MJup and 2 MJup at separations of 10 AU and 25 AU, respectively, for the median age (100 Myr) and distance (20 pc) of our sample. With a sample size of roughly 70 single M dwarfs, our survey 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. L.; Tamura, M.

2012-01-01

154

Possible planet-forming regions on submillimetre images  

Microsoft Academic Search

Submillimetre images of transition discs are expected to reflect the distribution of the optically thin dust. Former observation of three transition discs LkHalpha 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.

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

2012-01-01

155

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

156

Resolving an Asteroid Belt in a Multi-Planet System  

NASA Astrophysics Data System (ADS)

We propose to use MICHELLE at Gemini North to image at 11.6 microns a dust ring associated with the possible asteroid belt in the HR 8799 planetary system where three planets have been imaged (Marois et al. 2008). Our goal is to establish directly for the first time the size of a key component, so-called ring d, of this archetypal system's architecture. Thus far the dust ring's morphology has only been inferred from SED fitting. To quote one researcher, the detailed morphology of ring d "must be dynamically compatible with the presence of the outermost and innermost planets." Our imaging will establish the ring size, which will constrain models of the system dynamics and evolution. In addition, in conjunction with existing SED information, our images will permit substantive constraints on dust particle properties. This program is very feasible with MICHELLE, and we request a total time of 5.6 hours. We welcome this as classical time.

Telesco, Charles; Li, Dan; Moerchen, Margaret; Wright, Chris

2011-08-01

157

Direct imaging of nonsolar planets with infrared telescopes using apodized coronagraphs  

NASA Technical Reports Server (NTRS)

This research examines the use of modified Lyot coronagraphs with monolithic and segmented infrared telescopic systems for imaging nonsolar planets. These systems are investigated with the aim of reducing the effects of stellar diffracted energy on the planet image in the final image plane. A square telescope objective is best for this purpose. The associated coronagraph is composed of a cross-shaped apodizer in the first focal plane and either a square Lyot stop or circular corner Lyot stops in the corners of the pupil plane. The consequences of segmenting the aperture and the effects of various segment spacings and random piston and tilt errors of the individual segments are examined. A system to correct for the misalignments is proposed.

Mills, James P.; Gaiser, Steven L.; Diner, David J.; Watson, Steven M.

1991-01-01

158

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

159

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.

160

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

161

Planet Earth  

NSDL National Science Digital Library

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

162

A 4096 Element Continuous Facesheet MEMS Deformable Mirror for High-Contrast Imaging  

E-print Network

of less than 10nm RMS, a fill factor of 99.5%, and bandwidth greater than 5kHz. The packaging and high facesheet deformable mirror system is being developed for the Gemini Planet Imaging instrument, for high to provide structural support on electrical interconnections. Eight high density flex cables connect the DM

163

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

164

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

SciTech Connect

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

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

2013-07-01

165

Imaging Search for Dynamically Inferred Planets in Nearby Debris Disk Systems  

NASA Astrophysics Data System (ADS)

The nearby stars Eps Eri, Vega, and Fomalhaut all host large debris disks with morphological structures that can be interpreted as being due to dynamical influence from unseen giant planets residing in the systems. At the ages of the systems of a few hundred Myrs, such planets are expected to have cooled down to temperatures of ~200 K, which makes them unreachable from the ground due to their faintness at JHKL wavelengths and the prohibitively large thermal background at longer wavelengths. Spitzer, however, has the sensitivity required at 4.5 micron to detect such objects. As we have shown previously (Janson et al. 2012), a dedicated observing strategy and data reduction scheme can be used to improve the Spitzer contrast performance by more than an order of magnitude compared to conventional methods, which enables this degree of sensitivity down to separations of ~10'. The corresponding detection space provides an excellent match to the predicted properties of inferred companions in the three systems. Here, we propose to re-observe Fomalhaut to follow up a candidate companion detected in our previous image, and to observe Vega and Eps Eri to search for their inferred companions. In each case we will be sensitive to Jovian or sub-Jovian companions in the primary separation regions of interest, which is a factor 3 better mass sensitivity than previously achieved. These observations provide a unique opportunity to study far colder and more Jupiter-like planets than previously imaged.

Janson, Markus; Carson, Joe; Lafreniere, David; Spiegel, Dave; Quanz, Sascha; Thalmann, Christian; Amara, Adam

2012-12-01

166

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

167

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

168

The Planet Pipeline: Enabling Data Mining and Citizen Science with Hubble Space Telescope Solar System Images  

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 HST's standard data reduction pipelines are not optimized for moving target 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 "Planet Investigators" website, built on CosmoQuest infrastructure, will allow people to assist us in verifying our artifact rejections and assemble object catalogs. It is now easily possible to have each image inspected multiple times, and set up iterative processes that can converge on the optimal output with greater confidence. 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. 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

Deustua, S.; Mutchler, M.; Conti, A.; Viana, A.; Wong, M. H.; Gay, P.

2012-12-01

169

High Contrast L' Band Adaptive Optics Imaging to Detect Extrasolar Planets  

E-print Network

We are carrying out a survey to search for giant extrasolar planets around nearby, moderate-age stars in the mid-infrared L' and M bands (3.8 and 4.8 microns, respectively), using the Clio camera with the adaptive optics system on the MMT telescope. To date we have observed 7 stars, of a total 50 planned, including GJ 450 (distance about 8.55pc, age about 1 billion years, no real companions detected), which we use as our example here. We report the methods we use to obtain extremely high contrast imaging in L', and the performance we have obtained. We find that the rotation of a celestial object over time with respect to a telescope tracking it with an altazimuth mount can be a powerful tool for subtracting telescope-related stellar halo artifacts and detecting planets near bright stars. We have carried out a thorough Monte Carlo simulation demonstrating our ability to detect planets as small as 6 Jupiter masses around GJ 450. The division of a science data set into two independent parts, with companions requ...

Heinze, A; Sivanandam, S; Apai, D; Meyer, M; Heinze, Ari; Hinz, Phil; Sivanandam, Suresh; Apai, Daniel; Meyer, Michael

2006-01-01

170

High Contrast L' Band Adaptive Optics Imaging to Detect Extrasolar Planets  

E-print Network

We are carrying out a survey to search for giant extrasolar planets around nearby, moderate-age stars in the mid-infrared L' and M bands (3.8 and 4.8 microns, respectively), using the Clio camera with the adaptive optics system on the MMT telescope. To date we have observed 7 stars, of a total 50 planned, including GJ 450 (distance about 8.55pc, age about 1 billion years, no real companions detected), which we use as our example here. We report the methods we use to obtain extremely high contrast imaging in L', and the performance we have obtained. We find that the rotation of a celestial object over time with respect to a telescope tracking it with an altazimuth mount can be a powerful tool for subtracting telescope-related stellar halo artifacts and detecting planets near bright stars. We have carried out a thorough Monte Carlo simulation demonstrating our ability to detect planets as small as 6 Jupiter masses around GJ 450. The division of a science data set into two independent parts, with companions required to be detected on both in order to be recognized as real, played a crucial role in detecting companions in this simulation. We mention also our discovery of a previously unknown faint stellar companion to another of our survey targets, HD 133002. Followup is needed to confirm this as a physical companion, and to determine its physical properties.

Ari Heinze; Phil Hinz; Suresh Sivanandam; Daniel Apai; Michael Meyer

2006-06-19

171

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

Microsoft Academic Search

Within several days of A. Wesley’s announcement that Jupiter was hit by an object on UT 19 July 2009, we observed the impact site with (1) the Hubble Space Telescope (HST) at UV through visible (225–924nm) wavelengths, (2) the 10-m W.M. Keck II telescope in the near-infrared (1–5?m), and (3) the 8-m Gemini-North telescope in the mid-infrared (7.7–18?m). All observations

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

2010-01-01

172

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

NASA Astrophysics Data System (ADS)

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

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

2004-10-01

173

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

174

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

175

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

176

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

NASA Astrophysics Data System (ADS)

Context: Since the discovery of its dusty disk in 1984, ? Pictoris has become the prototype of young early-type planetary systems, and there are now various indications that a massive Jovian planet is orbiting the star at ~10 AU. However, no planets have been detected around this star so far. Aims: Our goal was to investigate the close environment of ? Pic, searching for planetary companion(s). Methods: Deep adaptive-optics L'-band images of ? Pic were recorded using the NaCo instrument at the Very Large Telescope. Results: A faint point-like signal is detected at a projected distance of ?8 AU from the star, within the northeastern extension of the dust disk. Various tests were made to rule out possible instrumental or atmospheric artefacts at a good confidence level. The probability of a foreground or background contaminant is extremely low, based in addition on the analysis of previous deep HST images. Its L'=11.2 apparent magnitude would indicate a typical temperature of ~1500 K and a mass of ~8 M_Jup. If confirmed, it could explain the main morphological and dynamical peculiarities of the ? Pic system. The present detection is unique among A-stars by the proximity of the resolved planet to its parent star. Its closeness and location inside the ? Pic disk suggest a formation process by core accretion or disk instabilities rather than binary-like formation processes. Based on observations collected at the European Southern Observatory, Chile, ESO (runs 072.C-0624(B) and 60.A-9026(A)) and on observations made with the Space Telescope Imaging Spectrograph onboard the NASA/ESA Hubble Space Telescope.

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

2009-01-01

177

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

NASA Astrophysics Data System (ADS)

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

Tan, Xianyu; Showman, Adam

2014-11-01

178

The Nine Planets: Jupiter  

NSDL National Science Digital Library

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

Arnett, Bill

179

The Nine Planets: Neptune  

NSDL National Science Digital Library

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

Arnett, Bill

180

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

181

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

182

Current and future facility instruments at the Gemini Observatory Joseph B. Jensen, Scot J. Kleinman, Douglas A. Simons,  

E-print Network

,4,5,6,7,8 On the Gemini-North telescope on Mauna Kea, Hawaii, Gemini operates the GMOS optical multi-object imaging access to the southern version of GMOS and the T-ReCS mid-IR thermal imager and spectrograph18 . NOAO

Bifano, Thomas

183

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

184

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

185

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

186

A crater 1.5 km across in the Venera-13 panoramic image taken on the surface of the planet  

NASA Astrophysics Data System (ADS)

The reprocessing of the archive data of the television experiment performed by the Venera-13 spacecraft in 1982 on the surface of the planet allowed an image of the nearby crater 1.5 km across to be obtained in detail. Its structural features apparently indicate its volcanic origin. All of the earlier acquired analogous images of such formations were composed only from the orbital radar data and correspond to the sizes of tens of kilometers.

Ksanfomality, L. V.

2014-11-01

187

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

188

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.

189

Gemini Multi-Object Spectrograph Upgrades: Hamamatsu CCDs and AO  

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

190

Gemini Observatory science operations plan  

Microsoft Academic Search

We review the Gemini Observatory science operations plan including the proposal submission, allocation and observation planning processes; the telescope operation model; and the scientific staffing plans and user support. Use of the telescope is shown via a sub-stellar companion search program to illustrate the planning tools and level of integration required between the observatory control, telescope control and data handling

Phil J. Puxley; Fred C. Gillett; Douglas A. Simons

1998-01-01

191

Welcome to the Planets  

NSDL National Science Digital Library

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

1995-01-01

192

The Planets  

NSDL National Science Digital Library

The students will learn about the planets and about their attributes. What do they need to support human life? What are the names of the planets in the solar system? The Nine Planets What are the physical properties of each planet? The Solar System - Pictures of the planets Now you can make your own planet! Make Your Own Planet ...

Rindlisbacher, Ms.

2006-10-04

193

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

NASA Technical Reports Server (NTRS)

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

Marley, Mark S.; Zahnle, Kevin

2014-01-01

194

AO operations at Gemini South  

NASA Astrophysics Data System (ADS)

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

Marin, Eduardo; Cardwell, Andrew; Pessev, Peter

2014-08-01

195

Band-limited image plane masks for the Terrestrial Planet Finder coronagraph: materials and designs for broadband performance.  

PubMed

Coronagraphs for detection and characterization of exosolar earthlike planets require accurate masks with broadband performance in the visible and near infrared spectrum. Design and fabrication of image plane masks capable of suppressing broadband starlight to 10(-10) level contrast presents technical challenges. We discuss basic approaches, material choices, designs, and fabrication options for image plane masks with particular focus on material properties to obtain adequate spectral performance. Based on theoretical analysis, we show that metals such as Pt and Ni, and alloys such as Inconel, may be employed as promising mask materials that can meet broadband performance requirements. PMID:18188191

Balasubramanian, Kunjithapatham

2008-01-10

196

A NICMOS direct imaging search for giant planets around the seven single white dwarfs in the Hyades  

NASA Astrophysics Data System (ADS)

We propose to use the NIC1 camera on HST to search for massive giant planets around the known seven single white dwarfs in the nearby Hyades cluster at sub-arcsec separations. At an age of 625 Myr, the white dwarfs had protogenitor masses of about 3 solar masses, and massive gaseous giant planets should have formed in the massive circumstellar disks around these ex Herbig A0 stars, probably at orbital separations similar or slightly larger than that of Jupiter {5 AU} in our own solar system. Such planets would have survived the post-Main Sequence mass loss of the parent star, and would have migrated outward adiabatically by a factor 4.5, equal to the ratio of initial to final stellar mass {3Mo/0.66Mo}, due to conservation of orbital angular momentum during the mass loss {AGB and PN} phase. Thus the orbital separation NOW would be 4.5 x 5 AU = 22.5 AU, which at the distance of the Hyades {45 pc} corresponds to 0.50 arcsec. Simulations with TinyTim then show that giant planets at this separation with masses in the range 6-12 Jupiter masses and apparent J and H magnitudes in the range 20.5-23.3 mag {from Baraffe or Burrows models} can be spatially resolved around the Hyades white dwarfs. Their J and H brightnesses are known to be 15 +/- 0.5 mag, implying a median star-planet brightness ratio of 1000:1 {7.5 mag}. This combination of dynamic range and orbital separation is observable with NICMOS, by subtracting images taken at two roll angles. Therefore, the proposed near-IR diffraction-limited observations in the F110W and F160W filters promise to resolve giant planets around low-mass stars for the first time. If successful, the observations would also prove that giant planets do form around early-type stars more massive than the Sun.

Zinnecker, Hans

2003-07-01

197

Self-assembly nano-structure of type I collagen adsorbed on Gemini surfactant LB monolayers.  

PubMed

The self-assembly nano-structures of type I collagen adsorbed on anionic Gemini surfactant LB monolayer were observed by using atomic force microscopy (AFM) images. It was found that the adsorption behavior and self-assembly structure of collagen could be controlled by the concentration of the collagen solution, adsorption interval and the properties of substrates. With the increase of the adsorption interval and concentration of collagen, the strands size of collagen changed. The self-assembly structures of collagen were also influenced by the interaction between collagen molecules and Gemini surfactant monolayer substrates. Finally, the adsorption behaviors of collagen molecules on cationic Gemini monolayer were compared with those on anionic Gemini monolayer. PMID:19157808

Xu, Shouhong; Liu, Aiping; Chen, Qibin; Lv, Mingyu; Yonese, Masakastu; Liu, Honglai

2009-04-01

198

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

199

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

200

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

201

First Light LBT AO Images of HR 8799 bcde at 1.65 and 3.3 Microns: New Discrepancies between Young Planets and Old Brown Dwarfs  

E-print Network

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 microns with the new LBT adaptive optics system, PISCES, and LBTI/LMIRCam. Our images offer an unprecedented view of the system, allowing us to obtain H and 3.3$ micron 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 microns compared to the equilibrium chemistry models used for field brown dwarfs, which predict that planets should be faint at 3.3 microns due to CH4 opacity. We attempt to model the planets with thick-cloudy, non-equilibrium chemistry atmospheres, but find that removing CH4 to fit the 3.3 micron photometry increases the predicted L' (3.8 microns) flux enough that it is inconsistent with observations. In an effort to fit the ...

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

2012-01-01

202

Development of an extremely coherent single-mode fiber bundle array for high-contrast imaging of extrasolar planets with visible Terrestrial Planet Finder  

NASA Astrophysics Data System (ADS)

We report results from development of a prototype extremely coherent single mode fiber optic array for the TPF visible nulling interferometer. This device is used to negate the effects of residual stellar leakage (scattering) due to imperfections in the TPF telescope optics and the visible nulling interferometer optical train. This prototype consists of 10 × 10 single mode fibers, V-groove arrays, two lenslet arrays (one at the front end and the other at the back end) and auxiliary mechanical components. This first development will pave a clear path for making a final coherent fiber array with ~ 1000 fibers. The final array, once fully functional, should be able to improve image contrast by another ~ 3 orders of magnitude after 6-7 orders of magnitude star light subtraction using the visible nulling interferometer to allow detection of earth-like planets as close as 0.1 arcseconds around stars at ~ 10 pc in space with a 4m size TPF. This concept combines all the advantages of a nulling interferometer with the simplicity of a modest size and modest optical quality single aperture telescope, which allows tremendous reduction of the total cost and simplicity of the operation of a visible TPF over other TPF approaches. This fiber array can also be used in the visible coronagraph for rejecting scattered light.

Ge, Jian; McDavitt, Daniel L.; Miller, Shane

2004-10-01

203

Which Planet Shall We Visit?  

NSDL National Science Digital Library

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

204

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

205

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

206

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

207

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

PubMed

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

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

2008-11-28

208

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

E-print Network

Jet Propulsion Laboratory California Institute of Technology JPL Postdoc Seminar Series February 10, 2011 Copyright 2011 California Institute of Technology. All rights reserved. Eric Cady (JPL) External. Eric Cady (JPL) External occulters February 10, 2011 2 / 46 #12;Introduction Planet-finding methods

209

Laboratory demonstration of coronagraph imaging for the detection of Earth-like planets  

Microsoft Academic Search

The detection and characterization of exoplanets around nearby stars is the main objective of several proposed space missions. The development of viable concepts will require the laboratory demonstration of optical wavefront correction and diffracted light suppression to the levels needed to detect Solar-System-like planets at visible wavelengths. Our laboratory setup captures the essential optical features of a space coronagraph. A

John T. Trauger; W. A. Traub

2006-01-01

210

Optical Images of an Exosolar Planet 25 Light Years from Earth  

SciTech Connect

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

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

2008-11-12

211

Gemini (dimeric) surfactant perturbation of the human erythrocyte*.  

E-print Network

Gemini (dimeric) surfactant perturbation of the human erythrocyte*. Martina Dubnièková1 studied the ability of di-cationic gemini surfactantsdi (amphiphiles), i.e. 1,4-butanediammonium, the so called gemini amphiphiles, the di-cationic gemini amphiphiles were synthe- sized and examined

Iglic, Ales

212

Orbit improvement from satellite imaging data obtainable from outer planet missions.  

NASA Technical Reports Server (NTRS)

Equations of motion are established for a dynamical system in which a spacecraft flies close to and interacts with an outer planet and one or more of its satellites. For the computation of the state and mass partials needed in a simultaneous orbit correction of n interacting bodies, a notably compact set of variational equations is derived. The above system of differential equations is integrated numerically on a computer. Spacecraft-satellite direction measurements accurate to plus or minus 10 sec were simulated along three representative trajectories (Mariner/Jupiter/Saturn 1977 missions) approaching Io, Titan, and Iapetus to within 41000, 13000, and 7000 km, respectively. The paper concludes with a brief discussion of the need for future work on the orbits of the satellites of the outer planets.

Aksnes, K.

1973-01-01

213

Gemini  

NASA Astrophysics Data System (ADS)

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

Murdin, P.

2000-11-01

214

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

215

A NICMOS Direct Imaging Search for Giant Planets around the Single White Dwarfs in the Hyades  

E-print Network

We report preliminary results from our search for massive giant planets (6-12 Jupiter masses) around the known seven single white dwarfs in the Hyades cluster at sub-arcsec separations. At an age of 625 Myr, the white dwarfs had progenitor masses of about 3 solar masses, and massive gaseous giant planets should have formed in the massive circumstellar disks around these ex-Herbig A0 stars, probably at orbital separations similar or slightly larger than that of Jupiter. Such planets would have survived the post-Main-Sequence mass loss of the parent star and would have migrated outward adiabatically to a distance of about 25 AU. At the distance of the Hyades (45 pc) this corresponds to an angular separation of 0.5 arcsec. J and H magnitudes of these giants are in the range of 20.5-23.3 mag, which can be resolved with NICMOS. The achieved sensitivities and contrast ratios agree well with simulations. Preliminary evaluation of the NICMOS data set did not reveal any evidence for neither planetary mass companions with masses down to about 10 Jupiter masses nor brown dwarfs around any of the seven white dwarfs for separations larger than 0.5 arcsec.

S. Friedrich; H. Zinnecker; W. Brandner; S. Correia; M. McCaughrean

2005-01-10

216

PRESIDENT KENNEDY AND OFFICIALS VIEW GEMINI SPACECRAFT  

NASA Technical Reports Server (NTRS)

President Kennedy with sunglasses, Senator G. C. Smathers (D- Fla.), George Low, NASA; Mr. James Webb, NASA, Astronaut Gordon Cooper, Astronaut Gus Grissom, Mr. M. G. Preston, MSC-Manager Fla. Operations, viewing Gemini S/C #1.

1963-01-01

217

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 scheme will offer monthly proposal submission opportunities, and proposals will be reviewed by the principal investigators or co-investigators of other proposals submitted during the same round. Here, we set out the design of the system and outline the plan for its implementation, leading to the launch of a pilot program at Gemini North in January 2015.

Mason, R. E.; Côté, S.; Kissler-Patig, M.; Levenson, N. A.; Adamson, A.; Emmanuel, C.; Crabtree, D.

2014-08-01

218

Control of the Gemini Cassegrain rotator  

NASA Astrophysics Data System (ADS)

The Gemini telescope control system calculates the orientation of the Cassegrain rotator in a way that allows the desired angle to be specified relative to any of the four supported tracking coordinate systems (FK4, FK5, geocentric apparent place and topocentric az/el) independently of the tracking frame of the mount. In addition, the actual, rather than demanded, position of the rotator mechanism is used in the calculation of the mount position so that the telescope is able to track a target with an off-axis pointing origin (By pointing origin we mean the nominated point in the focal plane to which the pointing refers; i.e. where the image of the celestial object being tracked will appear.) even when the rotator is not in position. The actual rotator position is also used in the calculation of guide star coordinates so that guide stars can be acquired before the rotator is in position. This feedback of the actual rotator position to the mount calculation results in some unexpected behavior, particularly near the zenith blind-spot where the mount may track either north or south of the zenith depending on the positions of the rotator and the nominated pointing origin. The algorithm used to calculate the desired rotator position and the measures taken to avoid the unpredictable behavior near the zenith are described.

Terrett, David L.

1997-09-01

219

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

Microsoft Academic Search

We discuss data reduction techniques and results from the Simultaneous Differential Imager (SDI) implemented at the VLT (Lenzen et al. 2004a) and the MMT. SDI uses a quad filter to take images simultaneously at 3 wavelengths surrounding the 1.62 mum methane bandhead found in the spectrum of cool brown dwarfs and gas giants. By performing a difference of images in

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

2004-01-01

220

Imaging of the Outer Planets and Satellites (Article published in the Space Science Reviews special issue on 'Outer Solar System Exploration - An Overview', ed. by J. E. Long and D. G. Rea.)  

Microsoft Academic Search

Imaging is the most widely applicable single means of exploring the outer planets and their satellites and also complements other planet-oriented instruments. Imaging generally is more effectively carried out from a three-axis stabilized spacecraft than from a spinning one. Both specific experimental and broader exploratory goals must be recognized. Photography of Jupiter from terrestrial telescopes has revealed features which were

Bruce C. Murray

1973-01-01

221

GEMINI-E3, un modèle d'équilibre général national - international économique, énergétique et environnemental  

Microsoft Academic Search

[eng] GEMINI-E3, A General National - International Economie, Energy and Environmental Equilibrium Model . by Alain L. Bernard and Marc Vielle . The three papers set out to present, in as educational a manner as possible, the findings of an experiment lasting over four years. The first theoretical and methodological paper gives as straightforward a presentation as possible of the

Marc Vielle; Alain L. Bernard

1998-01-01

222

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

223

The medical legacy of Gemini.  

PubMed

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

Berry, C A

1968-01-01

224

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

225

Suppressing Speckle Noise for Simultaneous Differential Extrasolar Planet Imaging (SDI) at the VLT and MMT  

E-print Network

We discuss the instrumental and data reduction techniques used to suppress speckle noise with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT. SDI uses a double Wollaston prism and a quad filter to take 4 identical images simultaneously at 3 wavelengths surrounding the 1.62 um methane bandhead found in the spectrum of cool brown dwarfs and gas giants. By performing a difference of images in these filters, speckle noise from the primary can be significantly attenuated, resulting in photon noise limited data past 0.5''. Non-trivial data reduction tools are necessary to pipeline the simultaneous differential imaging. Here we discuss a custom algorithm implemented in IDL to perform this reduction. The script performs basic data reduction tasks but also precisely aligns images taken in each of the filters using a custom shift and subtract routine. In our survey of nearby young stars at the VLT and MMT (see Biller et al., this conference), we achieved H band contrasts >25000 (5 sigma Delta F1(1.575 um) > 10.0 mag, Delta H > 11.5 mag for a T6 spectral type object) at a separation of 0.5" from the primary star. We believe that our SDI images are among the highest contrast astronomical images ever made from ground or space for methane rich companions.

Beth A. Biller; Laird M. Close; Rainer Lenzen; Wolfgang Brandner; Donald McCarthy; Eric Nielsen; Stephan Kellner; Markus Hartung

2006-01-03

226

Photon-limited synthetic-aperture imaging for planet surface studies.  

PubMed

The carrier-to-noise ratio that results from phase-sensitive heterodyne detection in a photon-limited synthetic-aperture ladar (SAL) is developed, propagated through synthetic-aperture signal processing, and combined with speckle to give the signal-to-noise ratio of the resultant image. Carrier- and signal-to-noise ratios are defined in such a way as to be familiar to the optical imaging community. Design equations are presented to show that a 10-microm SAL in orbit around Mars can give centimeter-class resolution with reasonable laser power. SAL is harder to implement in the short-wave infrared and is probably not practical at visible wavelengths unless many separate images can be averaged. Some tutorial information on phase-sensitive heterodyne detection and on synthetic-aperture signal processing and image formation is provided. PMID:12206219

Lucke, Robert L; Rickard, Lee J

2002-08-20

227

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

SciTech Connect

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). In the case of the 2-D monochromatic imager, the 12-mm-diam. filtered image is formed at [approximately]f/1 on the input photocathode of an intensified CCD camera (380 x 488 pixels). Regardless of the field of view of the instrument, none of the rays passing through the filter exceeds 4.5 deg to the filter normal. In the spectrograph mode, a slit is placed on the field lens (at the focus of the objective lens) and the 4-in. interference filter is replaced with a reflection grating. The spectrum is imaged at f/l onto the previously described detector with the spatial dimension of 380 pixels and the wavelength dimension of 488 pixels. The sensitivities of the systems are approximately 50 to 100 rayleigh seconds (Rs) (SNR[approximately]2). Examples of data taken with both of these instruments include detection and mapping of Jupiter's sodium magneto-nebula and stable auroral red (SAR) arcs in the terrestrial ionosphere.

Baumgardner, J.; Flynn, B.; Mendillo, M. (Boston Univ., MA (United States). Center for Space Physics)

1993-12-01

228

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

229

Summary analysis of the Gemini entry aerodynamics  

NASA Technical Reports Server (NTRS)

The aerodynamic data that were derived in 1967 from the analysis of flight-generated data for the Gemini entry module are presented. These data represent the aerodynamic characteristics exhibited by the vehicle during the entry portion of Gemini 2, 3, 5, 8, 10, 11, and 12 missions. For the Gemini, 5, 8, 10, 11, and 12 missions, the flight-generated lift-to-drag ratios and corresponding angles of attack are compared with the wind tunnel data. These comparisons show that the flight generated lift-to-drag ratios are consistently lower than were anticipated from the tunnel data. Numerous data uncertainties are cited that provide an insight into the problems that are related to an analysis of flight data developed from instrumentation systems, the primary functions of which are other than the evaluation of flight aerodynamic performance.

Whitnah, A. M.; Howes, D. B.

1972-01-01

230

The interfacial tension between oil and gemini surfactant solution  

Microsoft Academic Search

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

Hong Chen; Lijuan Han; Pingya Luo; Zhongbin Ye

2004-01-01

231

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

232

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

233

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

234

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

E-print Network

We present the results of our Hubble Space Telescope program and describe how our image analysis methods were used to re-evaluate the habitability of some of the most interesting Kepler planet candidates. Our program observed 22 KOI hosts, several of which were found to be multiple star systems unresolved by Kepler. We use our high-resolution imaging to provide a conversion to the Kepler photometric bandpass (Kp) from the F555W and F775W filters on WFC3/UVIS, and spatially resolve the stellar multiplicity of Kepler-296, KOI-2626, and KOI-3049. The binary system Kepler-296 has a projected separation of 0.217" (80 AU); KOI-2626 is a triple star system with a projected separation of 0.201" (70 AU) between the primary and secondary components and 0.161" (55 AU) between the primary and tertiary components; and the binary system KOI-3049 has a projected separation of 0.464" (225 AU). Using theoretical isochrones from the latest Victoria-Regina Stellar Models, we performed hierarchical fitting using our derived phot...

Star, Kimberly M; Wright, Jason T; Ciardi, David R

2014-01-01

235

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

236

Suppressing Speckle Noise for Simultaneous Differential Extrasolar Planet Imaging (SDI) at the VLT and MMT  

E-print Network

We discuss the instrumental and data reduction techniques used to suppress speckle noise with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT. SDI uses a double Wollaston prism and a quad filter to take 4 identical images simultaneously at 3 wavelengths surrounding the 1.62 um methane bandhead found in the spectrum of cool brown dwarfs and gas giants. By performing a difference of images in these filters, speckle noise from the primary can be significantly attenuated, resulting in photon noise limited data past 0.5''. Non-trivial data reduction tools are necessary to pipeline the simultaneous differential imaging. Here we discuss a custom algorithm implemented in IDL to perform this reduction. The script performs basic data reduction tasks but also precisely aligns images taken in each of the filters using a custom shift and subtract routine. In our survey of nearby young stars at the VLT and MMT (see Biller et al., this conference), we achieved H band contrasts >25000 (5 sigma D...

Biller, B A; Lenzen, R; Brandner, W; McCarthy, D; Nielsen, E; Kellner, S; Hartung, M; Biller, Beth A.; Close, Laird M.; Lenzen, Rainer; Brandner, Wolfgang; Carthy, Donald Mc; Nielsen, Eric; Kellner, Stephan; Hartung, Markus

2006-01-01

237

Initial Results From The AO International Deep Planet Search Around Young A Stars  

NASA Astrophysics Data System (ADS)

Throughout their evolution, A stars exhibit favorable physical conditions and indirect evidence of planet formation, such as extended protoplanetary disks at the pre-main sequence stage and debris disks in the main sequence phase. Recent breakthrough discoveries of planetary companions around young, dusty A stars have identified the first massive planets at wide orbital separation. In order to understand the frequency of such systems -- an important factor for formation scenarios -- we are conducting a near-infrared adaptive optics search for giant planets around nearby A stars, part the on-going International Deep Planet Search (IDPS). We present the preliminary results of this survey of 40 stars: 28 of them are nearby (<65 pc) young (<200 Myr) A stars, and the others are star identified as extremely young (<20 Myr) from spectral analysis. The observations were obtained with 8 meter-class telescopes (VLT and Gemini). The Locally Optimized Combination of Images (LOCI) was used to suppress the speckle noise of the central star and reach the detection level of giant planets and low-mass brown dwarfs at wide orbital separation. The median 5-sigma sensitivity of our observations is 9.5 mag at 0.5 arcseconds and 14 mag at separations of a few arcseconds, allowing us to reach limits 1 to 20 Mjup, depending on the target mass and age. We present an overview of the observations, data analysis and performance, followed by a statistical analysis of the survey results, which provide upper limits on the fractions of stars with giant planet and low mass brown dwarf companions.

Vigan, Arthur; Patience, J.; Galicher, R.; Marois, C.; Macintosh, B.; Song, I.; Doyon, R.; Zuckerman, B.; Lafrenière, D.; Barman, T.

2011-09-01

238

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

239

High-contrast planet imager for Kyoto 4m segmented telescope  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

240

Planet Eart Interactive  

E-print Network

Deadliest Catch Dirty Jobs Future Weapons Human Body Man Vs. Wild MythBuste Raw Planet Eart Shark-shaped-camera.html #12;Eye Glass Get LASIK. Sat. Surgeries - Be Back At Work By Mon. Free Consultation! www curved for capturing images, but up to now artificial vision systems have been limited to flat image

Rogers, John A.

241

Remote monitoring: An implementation on the Gemini System  

SciTech Connect

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

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

1996-12-31

242

Control of the Gemini Cassegrain rotator  

Microsoft Academic Search

The Gemini telescope control system calculates the orientation of the Cassegrain rotator in a way that allows the desired angle to be specified relative to any of the four supported tracking coordinate systems (FK4, FK5, geocentric apparent place and topocentric az\\/el) independently of the tracking frame of the mount. In addition, the actual, rather than demanded, position of the rotator

David L. Terrett

1997-01-01

243

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

244

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

245

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

246

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.

247

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.

248

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.

249

On the possibility of ground-based direct imaging detection of extra-solar planets: The case of TWA-7  

E-print Network

We show that {\\em ground-based} direct imaging detection of extra-solar planets is possible with current technology. As an example, we present evidence for a possible planetary companion to the young T Tauri star 1RXSJ104230.3$-$334014 (=TWA-7), discovered by ROSAT as a member of the nearby TW Hya association. In an HST NICMOS F160W image, an object is detected that is more than 9 mag fainter than TWA-7, located $2.445 \\pm 0.035^{\\prime \\prime}$ south-east at a position angle of $142.24 \\pm 1.34^{\\circ}$. One year later using the ESO-NTT with the SHARP speckle camera, we obtained H- and K-band detections of this faint object at a separation of $2.536 \\pm 0.077^{\\prime \\prime}$ and a position angle of $139.3 \\pm 2.1^{\\circ}$. Given the known proper motion of TWA-7, the pair may form a proper motion pair. If the faint object orbits TWA-7, then its apparent magnitudes of H=$16.42 \\pm 0.11$ and K=$16.34 \\pm 0.15$ mag yield absolute magnitudes consistent with a $\\sim 10^{6.5}$ yr old $\\sim 3$ M$_{\\rm jup}$ mass object according to the non-gray theory by Burrows et al. (1997). At $\\sim 55$ pc, the angular separation of $\\sim 2.5^{\\prime \\prime}$ corresponds to $\\sim 138$~AU. However, position angles and separations are slightly more consistent with a background object than with a companion.

R. Neuhaeuser; W. Brandner; A. Eckart; E. Guenther; J. Alves; T. Ott; N. Huelamo; M. Fernandez

1999-12-23

250

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

Microsoft Academic Search

We describe the Exoplanetary Circumstellar Environment and Disk Explorer (EXCEDE) SMEX mission to directly image starlight-scattering circumstellar material in the planet-forming regions of stars exhibiting thermal infrared emission above their stellar photospheric levels (a signpost of planetary systems in formation). EXCEDE will provide contrast-limited scattered-light detection sensitivities 100 to 1000 times more sensitive than the HST and JWST coronagraphs at

Thomas P. Greene; G. Schneider

2007-01-01

251

Direct imaging of the brown dwarf\\/planet-mass companions to HR 8799 and GJ 758 from 1 to 5 microns: Constraints on atmospheric properties  

Microsoft Academic Search

I describe new direct imaging data obtained from the MMT and Subaru for brown dwarf\\/planet-mass companions to GJ 758 and HR 8799. The data were obtained at a variety of broad\\/narrow-band filters covering 1 to 5 microns. Combining photometry from these data with that from the research literature and comparing them with exoplanet\\/brown dwarf atmosphere models, I constrain the temperatures,

T. Currie; P. Hinz; Y. Itoh; M. Fukagawa; V. Bailey; T. J. Rodigas; D. Fabrycky; R. Murray-Clay

2010-01-01

252

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

Microsoft Academic Search

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

R. Neuhaeuser; M. Mugrauer; A. Seifahrt

2007-01-01

253

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

254

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

NASA Astrophysics Data System (ADS)

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

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

2010-07-01

255

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

E-print Network

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

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

2010-01-01

256

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

E-print Network

We present new $L^\\prime$ (3.8 $\\mu m$) and Br-$\\alpha$ (4.05 $\\mu m$) data and reprocessed archival $L^\\prime$ data for the young, planet-hosting star HR 8799 obtained with Keck/NIRC2, VLT/NaCo and Subaru/IRCS. We detect all four HR 8799 planets in each dataset at a moderate to high signal-to-noise (SNR $\\gtrsim$ 6-15). We fail to identify a fifth planet, "HR 8799 f", at $r$ $filters. We find no statistically significant difference in HR 8799 ...

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

2014-01-01

257

The software design of the Gemini 8m telescopes Stephen Wampler  

E-print Network

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

258

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

SciTech Connect

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

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

2011-05-10

259

Extreme Planets  

NASA Technical Reports Server (NTRS)

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

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

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

2006-01-01

260

Planet formation  

Microsoft Academic Search

Models of planetary formation are developed using the present single example of a planetary system, supplemented by limited astrophysical observations of star-forming regions and circumstellar disks. The solar nebula theory and the planetesimal hypothesis are discussed. The latter is found to provide a viable theory of the growth of the terrestrial planets, the cores of the giant planets, and the

Jack J. Lissauer

1993-01-01

261

Planet Business  

NSDL National Science Digital Library

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

1996-01-01

262

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

263

Gemini 4 Recovery with Green Marker Dye  

NASA Technical Reports Server (NTRS)

Overhead view of the Gemini 4 spacecraft showing the yellow flotation collar used to stabilize the spacecraft in choppy seas. The green marker dye is highly visible from the air and is used as a locating aid. A crewmember is being hoisted aboard a U.S. Navy helicopter during recovery operations following the successful four-day, 62 revolution mission highlighted by Ed White's space walk.

1965-01-01

264

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

265

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

266

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.

267

Instrument Performance Monitoring at Gemini North  

NASA Astrophysics Data System (ADS)

An instrument performance monitoring (IPM) project at the Gemini North Observatory evaluates the delivered throughput and sensitivity of, among other instruments, the Near-Infrared Integral Field Spectrometer (NIFS), the Gemini Near-Infrared Spectrograph (GNIRS), and the Gemini Multi-Object Spectrograph (GMOS-N). Systematic observations of standard stars allow the quality of the instruments and mirror to be assessed periodically. An automated pipeline has been implemented to process and analyze data obtained with NIFS, GNIRS cross-dispersed (XD) and long slit (LS) modes, and GMOS (photometry and spectroscopy). We focus the discussion of this poster on NIFS and GNIRS. We present the spectroscopic throughput determined for ZJHK bands on NIFS, the XJHKLM band for GNIRS XD mode and the K band for GNIRS LS. Additionally, the sensitivity is available for the JHK bands in NIFS and GNIRS XD, and for the K band in GNIRS LS. We consider data taken as early as March 2011. Furthermore, the pipeline setup and the methods used to determine throughput and sensitivity are described.

Emig, Kimberly; Pohlen, M.; Chene, A.

2014-01-01

268

Cross-linking of micelles by gemini surfactants  

E-print Network

We investigate the effects of gemini surfactants, telechelic chain and lipids on the nature of micelles formed by conventional single-tail surfactants in water by carrying out Monte Carlo simulations. In a mixture of gemini and single-tail surfactants in water we find direct evidence of micelles of predominantly single-tail surfactants some of which are dynamically cross-linked by gemini surfactants when the concentrations of the geminis is only a few mole percent and their spacers are {\\it hydrophilic}. In contrast, mixtures of lipids and single-tail surfactants in water form only isolated micelles, each consisting of a mixture of both species, without cross-links.

Prabal K. Maiti; Kurt Kremer; Oliver Flimm; Debashish Chowdhury; Dietrich Stauffer

1999-12-01

269

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.

270

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.

271

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.

272

Near-infrared spectroscopic search for the close orbiting planet HD 75289b  

Microsoft Academic Search

We present a search for the near-infrared spectroscopic signature of the close orbiting extrasolar giant planet HD 75289b. We obtained ~230 spectra in the wavelength range 2.18-2.19 mum using the Phoenix spectrograph at Gemini South. By considering the direct spectrum, derived from irradiated model atmospheres, we search for the absorption profile signature present in the combined star and planet light.

J. R. Barnes; C. J. Leigh; H. R. A. Jones; Travis S. Barman; D. J. Pinfield; A. Collier Cameron; J. S. Jenkins

2007-01-01

273

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

274

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

275

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

E-print Network

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

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

2014-01-01

276

Irregular Satellites of the Planets  

NASA Technical Reports Server (NTRS)

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

Jewitt, David

2005-01-01

277

The Gemini MCAO bench: system overview and lab integration  

Microsoft Academic Search

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

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

2008-01-01

278

Compaction of DNA by Gemini Surfactants: Effects of Surfactant Architecture  

Microsoft Academic Search

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

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

2002-01-01

279

Micelle formation and CMC of gemini surfactants: a thermodynamic model  

Microsoft Academic Search

Gemini surfactants possess a structure resembling a pair of conventional single chain surfactants covalently connected by a spacer. The spacer can vary in length and chemical structure. In this paper, the aggregation behavior of gemini surfactants is examined on the basis of a free energy model developed by extending our theory for conventional surfactants. Free energy contributions beyond those considered

Terri A. Camesano; R. Nagarajan

2000-01-01

280

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

281

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

282

Antibacterial activity of gemini quaternary ammonium salts.  

PubMed

A series of gemini quaternary ammonium salts (chlorides and bromides), with various hydrocarbon chain and spacer lengths, were tested. These compounds exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria and were not mutagenic. The strongest antibacterial effect was observed for TMPG-10 Cl (against Pseudomonas aeruginosa ATCC 27853) and TMPG-12 Br (against Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 11229 and clinical ESBL(+) isolate 434) surfactants. These compounds inhibited the adhesion of Staphylococcus epidermidis ATCC 35984 to a polystyrene surface and eradicated biofilm formed by P. aeruginosa PAO1. The activity of studied compounds was dependent on hydrocarbon chain length. PMID:24236547

Ob??k, Ewa; Piecuch, Agata; Guz-Regner, Katarzyna; Dworniczek, Ewa

2014-01-01

283

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

284

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

285

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

286

Polymer fluctuation lubrication in hydrogel gemini interfaces.  

PubMed

Interfacial sliding speed and contact pressure between the sub-units of particulate soft matter assemblies can vary dramatically across systems and with dynamic conditions. By extension, frictional interactions between particles may play a key role in their assembly, global configuration, collective motion, and bulk material properties. For example, in tightly packed assemblies of microgels - colloidal microspheres made of hydrogel - particle stiffness controls the fragility of the glassy state formed by the particles. The interplay between particle stiffness and shear stress is likely mediated by particle-particle normal forces, highlighting the potential role of hydrogel-hydrogel friction. Here we study friction at a twinned "Gemini" interface between hydrogels. We construct a lubrication curve that spans four orders of magnitude in sliding speed, and find qualitatively different behaviour from traditional lubrication of engineering material surfaces; fundamentally different types of lubrication occur at the hydrogel Gemini interface. We also explore the role played by polymer solubility and hydrogel-hydrogel adhesion in hydrogel friction. We find that polymer network elasticity, mesh size, and single-chain relaxation times can describe friction at the gel-gel interface, including a transition between lubrication regimes with varying sliding speed. PMID:25287556

Pitenis, A A; Urueña, J M; Schulze, K D; Nixon, R M; Dunn, A C; Krick, B A; Sawyer, W G; Angelini, T E

2014-10-23

287

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

288

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

E-print Network

of the project. The Gemini Science Committee (GSC) is responsible for scientific oversight and advice. The GSCManagement of the Gemini 8­M Telescopes Project R. Kurz, M. Mountain Gemini Telescopes Project, 950 Project Richard Kurz and Matt Mountain Gemini 8­M Telescopes Project 950 N. Cherry Avenue, Tucson, AZ

289

Binary Planets  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

290

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.

291

What makes a planet habitable ?  

E-print Network

Jupiter, first discovery (*) · HD209458 b [RV + transit]: Hot Jupiter, 3.5 day period, 0.045 AU, 0.69 MJ a planet: large disk (*) (*): naked-eye star #12;#12;HR 8799 planets imaged by Keck #12;#12;Life on other with time -> challenge for life around young stars ·Stars get brighter with time -> HZ moves out ! We have

Guyon, Olivier

292

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

293

Planet Oobleck  

NSDL National Science Digital Library

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

Science, Lawrence H.

2011-01-01

294

Planet Math  

NSDL National Science Digital Library

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

295

Planet Ocean  

NSDL National Science Digital Library

From DiscoverySchool.com, Planet Ocean is a Web site developed for students in grade 5-8 to learn about the abundant life found in the world's vast marine environments. Students are introduced to oceanography, marine biology, food chains, and ecosystems. Teachers will appreciate the tips for using this site in the classroom and related resources, and almost anyone will appreciate the Amazing Facts found under each topic.

2002-01-01

296

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

297

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

298

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.

299

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

300

Structural Characterization of Novel Gemini Non-viral DNA  

SciTech Connect

The structural and physicochemical properties of novel cationic lipid-based DNA complexes have been investigated for the purpose of designing micro/nano-scale self-assembling delivery systems for cutaneous gene therapy. DNA/gemini surfactant (spacer n = 3-16; chain m = 12 or 16) complexes (1 : 10 charge ratio), with or without dioleoylphosphatidyl-ethanolamine (DOPE), designed for cellular transfection, were generally in the range of 100-200 nm as demonstrated by atomic force microscopy and particle size analysis. Small-angle X-ray scattering measurements indicated that the DNA/gemini complexes lacked long-range order, whereas DNA/gemini/DOPE complexes exhibited lamellar and polymorphic phases other than hexagonal. Correlation studies using transfection efficiency data in PAM 212 keratinocytes and in vitro skin absorption indicated that formulations containing gemini surfactants having the ability to induce structures other than lamellar in the resulting complexes, generally exhibited greater transfection activity and cutaneous absorption.

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

2006-01-01

301

Gemini-north multiobject spectrograph integration, test, and commissioning  

Microsoft Academic Search

The first of two Gemini Multi Object Spectrographs (GMOS) has recently begun operation at the Gemini-North 8m telescope. In this presentation we give an overview of the instrument and describe the overall performance of GMOS-North both in the laboratory during integration, and at the telescope during commissioning. We describe the development process which led to meeting the demanding reliability and

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

2003-01-01

302

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. PMID:22102870

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

2011-01-01

303

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.

304

Direct Imaging Of Long Period Radial Velocity Targets With NICI  

NASA Astrophysics Data System (ADS)

We are finally entering an era where radial velocity and direct imaging parameter spaces are starting to overlap. Radial velocity measurements provide us with a minimum mass for an orbiting companion (the mass as a function of the inclination of the system). By following up these long period radial velocity detections with direct imaging we can determine whether a trend seen is due to an orbiting planet at low inclination or an orbiting brown dwarf at high inclination. In the event of a non-detection we are still able to put a limit on the maximum mass of the orbiting body. The Anglo-Australian Planet Search is one of the longest baseline radial velocity planet searches in existence, amongst its targets are many that show long period trends in the data. Here we present our direct imaging survey of these objects with our results to date. ADI Observations have been made using NICI (Near Infrared Coronagraphic Imager) on Gemini South and analysed using an in house, LOCI-like, post processing.

Salter, Graeme S.; Tinney, Chris G.; Wittenmyer, Robert A.; Jenkins, James S.; Jones, Hugh R. A.; O'Toole, Simon J.

2014-01-01

305

Planet Earth  

NSDL National Science Digital Library

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

1986-01-01

306

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

307

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

NASA Technical Reports Server (NTRS)

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

Fayyad, U. M.

1995-01-01

308

SN 1987A after 18 Years: Mid-Infrared Gemini and Spitzer Observations of the Remnant  

NASA Astrophysics Data System (ADS)

Using the Gemini South 8 m telescope, we obtained high-resolution 11.7 and 18.3 ?m mid-IR images of SN 1987A on day 6526 since the explosion. All the emission arises from the equatorial ring. Nearly contemporaneous spectra obtained at 5-38 ?m with the Spitzer Space Telescope show that this is thermal emission from silicate dust that condensed out in the red giant wind of the progenitor star. The dust temperature is 166+18-12 K, and the emitting dust mass is 2.6+2.0-1.4×10-6 Msolar. Comparison of the Gemini 11.7 ?m image with Chandra X-ray images, HST UV-optical images, and ATCA radio synchrotron images shows generally good correlation across all wavelengths. If the dust resides in the diffuse X-ray-emitting gas then it is collisionally heated. The IR emission can then be used to derive the plasma temperature and density, which were found to be in good agreement with those inferred from the X-rays. Alternatively, the dust could reside in the dense UV-optical knots and be heated by the radiative shocks that are propagating through the knots. In either case the dust-to-gas mass ratio in the CSM 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. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the National Science Foundation (NSF) on behalf of the Gemini partnership: the NSF (United States), the Particle Physics and Astronomy research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).

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

2006-10-01

309

Altair at Gemini North: Full Sky Coverage Laser AO Correction at Visible Wavelengths  

NASA Astrophysics Data System (ADS)

We present two recent upgrades to the Gemini North Adaptive Optics(AO) system, Altair. These two upgrades provide 100% sky coverage forlow performance AO suitable for improving the natural seeing byfactors of 2 to 3 from blue visible wavelengths (350 nm) through thenear infrared (2.5 micron wavelengths). The first upgrade, dubbed LGS + P1 "Super Seeing" mode allowscorrection of high order aberrations with an on-axis Laser Guide Star(LGS) while tip/tilt correction is performed with a more distantperipheral wavefront sensor (P1). Most currently operating LGS AOsystems are limited in their sky coverage, primarily due to tip/tiltstar availability. Although P1 provides sub-optimal tip/tiltcorrection due to its distance from the science source, its patrolradius allows operation in LGS + P1 mode anywhere in the sky fromdeclinations of +70 degrees to -30 degrees. This mode was offered forscience use at Gemini North in 2013A. We will present typicalperformance and use from its first semester in science operation,where we expect to improve image quality by a factor 2 to 3 overseeing limited images. The second upgrade is the commissioning of the AO system to correct atvisible wavelengths, which is expected to be completed in late 2013.In this mode, Altair will feed the Gemini Multi-Object Spectrograph(GMOS), which is an optical imager as well as a long-slit, multi-slitand integral field unit spectrograph. We intend to replace thecurrent Altair science dichroic with a sodium notch filter, passingonly the 589nm wavelength light from the LGS to the AO system. Therest of the spectrum from 400 nm to the GMOS red cutoff at 1.1 micronsis intended as science capable light. Tip/tilt correction will beperformed close to the science target with the GMOS on-instrumentwavefront sensor or with P1 as in the P1+LGS mode discussed above. Weexpect an image quality improvement of roughly a factor 2 in this modeover seeing limited observations. Since exposure time to reach a given signal-to-noise ratio scalesroughly as the square of the image quality, these two upgradesrepresent a substantial efficiency improvement which is available tonearly all targets normally observed at Gemini North.

Trujillo, Chadwick; Ball, Jesse; Boccas, Maxime; Cavedoni, Chas; Christou, Julian; Coulson, Dolores; Ebbers, Angelic; Emig, Kimberly; Jorgensen, Inger; Kang, Stacy; Lai, Olivier; Matulonis, Anthony; McDermid, Richard; Miller, Bryan; Neichel, Benoit; Oram, Richard; Rigaut, François; Roth, Kathy; Schneider, Thomas; Stephens, Andy; Trancho, Gelys; Walls, Brian; White, John; Gemini Software Team

2013-12-01

310

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

311

Simulating Planet-Hunting in a Lab  

NASA Technical Reports Server (NTRS)

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

2007-01-01

312

The Extrasolar Planets Encyclopaedia  

NSDL National Science Digital Library

A full list of currently known Extrasolar Planets with frequently updated information on detection methods, current searches, and the Extrasolar Planets themselves. The site also includes information on reports and meetings concerning Extrasolar Planets.

Schneider, Jean

2005-06-07

313

Exploring Planet Sizes  

NASA Video Gallery

This lesson combines a series of activities to compare models of the size of Earth to other planets and the distances to other planets. Activities highlight space missions to other planets in our s...

314

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

315

Disposable Planet  

NSDL National Science Digital Library

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

2002-01-01

316

External Resource: Making a Model Planet  

NSDL National Science Digital Library

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

1900-01-01

317

Disks and Planets Around Massive White Dwarfs  

E-print Network

We predict the existence of dusty disks and possibly CO planets around massive white dwarfs. We show that the thermal emission from these disks should be detectable in the infrared. The planets may also be detectable either by direct IR imaging, spectroscopy, or using the pulsations of the white dwarfs.

M. Livio; J. E. Pringle; K. Wood

2005-08-31

318

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

319

Terrestrial Planet Geophysics  

NASA Astrophysics Data System (ADS)

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

Phillips, R. J.

2008-12-01

320

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

321

The Gemini Observatory Science Operations Plan Phil Puxley, Fred Gillett, Matt Mountain and Doug Simons  

E-print Network

The Gemini Observatory Science Operations Plan Phil Puxley, Fred Gillett, Matt Mountain and Doug Gemini Observatory Science Operations Plan Phil Puxley, Fred Gillett, Matt Mountain and Doug Simons Observatory science operations plan including the proposal submission, allocation and observation planning

322

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.

323

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

324

High-contrast 3.8 mum Imaging of the Brown Dwarf\\/Planet-mass Companion to GJ 758  

Microsoft Academic Search

We present L'-band (3.8 mum) 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 \\

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

2010-01-01

325

DEPARTMENT OF PHYSICS AND ASTRONOMY Extra-solar planets  

E-print Network

Burleigh Spitzer 4.5micron image GJ3483 (LTT3059 / WD0806-661) I am the white dwarf I maybe a planet... 130DEPARTMENT OF PHYSICS AND ASTRONOMY Extra-solar planets iscience seminar Dr. Matt Burleigh #12;Dr. Matt Burleigh A brief history of extra-solar planets · In the 16th century the Italian philosopher

Burleigh, Matt

326

The Trojan minor planets  

Microsoft Academic Search

There are (March, 1988) 3774 minor planets which have received a permanent number. Of these, there are some whose mean distance to the sun is very nearly equal to that of Jupiter, and whose heliocentric longitudes from that planet are about 60°, so that the three bodies concerned (sun, Jupiter, minor planet) make an approximate equilateral triangle. These minor planets,

Christopher E. Spratt

1988-01-01

327

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

328

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

E-print Network

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

Huang, Jianbin

329

Effect of the Hydrophilic Size on the Structural Phases of Aqueous Nonionic Gemini Surfactant Solutions  

E-print Network

Effect of the Hydrophilic Size on the Structural Phases of Aqueous Nonionic Gemini Surfactant there is no direct evidence for the presence of micelles. Introduction Gemini surfactants are composed of two or more surfactants with the same hydrophilic and hydrophobic groups. As a result, smaller amounts of Gemini

Colby, Ralph H.

330

Effects of Inorganic and Organic Salts on Aggregation Behavior of Cationic Gemini Surfactants  

E-print Network

Effects of Inorganic and Organic Salts on Aggregation Behavior of Cationic Gemini Surfactants) values of the cationic gemini surfactants. The ability to promote the surfactant aggregation decreases the aggregation of surfactants in quite different ways. In recent years, gemini surfactants have attracted great

Huang, Jianbin

331

The research on the vesicle formation and transformation in novel Gemini surfactant systems  

E-print Network

The research on the vesicle formation and transformation in novel Gemini surfactant systems Zhangyi systems. # 2003 Elsevier B.V. All rights reserved. Keywords: Gemini surfactant; Vesicle; Monolayer; p attentions [4Á/7]. In the mean time, some new types of surfactants, such as Gemini [8] and Bola [9], were

Huang, Jianbin

332

Gemini Surfactants at Solid-Liquid Interfaces: Control of Interfacial Aggregate Geometry  

E-print Network

Gemini Surfactants at Solid-Liquid Interfaces: Control of Interfacial Aggregate Geometry S. Manne of surfactant geometry by using gemini surfactants with varying tail and spacer lengths. On the anionic cleavage of orientations. Gemini or dimeric surfactants13 have been generating increasing interest owing to their superior

Aksay, Ilhan A.

333

Models of Gemini Surfactants HAIM DIAMANT and DAVID ANDELMAN Tel Aviv University,  

E-print Network

3 Models of Gemini Surfactants HAIM DIAMANT and DAVID ANDELMAN Tel Aviv University, Tel Aviv, Israel I. INTRODUCTION Gemini surfactants are composed of two monomeric surfactant molecules linked. Since their first systematic studies over a decade ago, gemini surfactants have been the subject

Andelman, David

334

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

E-print Network

ReceiVed: August 17, 2007; In Final Form: NoVember 18, 2007 Cationic gemini surfactant dimethylene-1 of sodium salicylate (NaSal) on the assembly formation and transition of this cationic gemini surfactant to explore the interaction between gemini surfactants and hydrotropic salts. The rich aggregation behavior

Huang, Jianbin

335

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

E-print Network

, Chile. The telescopes and auxiliary instrumentation will be international facilities open to the scienti within Gemini, we must support commu- nication to partner countries. As Gemini moves into scienti#12;c and administrative matters. The Gemini telescopes have been built by work packages subcontracted to sites throughout

336

User Interface for the Control of the Gemini Telescopes S. S. Smith and K. Gillies  

E-print Network

of the Gemini software system requires each principle system work package - Telescope Control System (TCS), Data Handling System, and Instruments - to provide at least an engineering interface. This allows the Gemini support associate (operator) interface. A second major consideration is that the Gemini design anticipates

337

Near infrared spectroscopic search for the close orbiting planet HD 75289b  

Microsoft Academic Search

We present a search for the near infrared spectroscopic signature of the\\u000aclose orbiting extrasolar giant planet HD 75289b. We obtained ~230 spectra in\\u000athe wavelength range 2.18 - 2.19 microns using the Phoenix spectrograph at\\u000aGemini South. By considering the direct spectrum, derived from irradiated model\\u000aatmospheres, we search for the absorption profile signature present in the\\u000acombined star

J. R. Barnes; C. J. Leigh; H. R. A. Jones; Travis S. Barman; D. J. Pinfield; A. Collier Cameron; J. S. Jenkins

2007-01-01

338

Direct Imaging of Fine Structures in Giant Planet-forming Regions of the Protoplanetary Disk Around AB Aurigae  

Microsoft Academic Search

We report high-resolution 1.6 mum polarized intensity (PI) images of the circumstellar disk around the Herbig Ae star AB Aur at a radial distance of 22 AU (0farcs15) up to 554 AU (3farcs85), 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 (lsim140 AU) of the

J. Hashimoto; M. Tamura; T. Muto; T. Kudo; M. Fukagawa; T. Fukue; M. Goto; C. A. Grady; T. Henning; K. W. Hodapp; M. Honda; S. Inutsuka; E. Kokubo; G. Knapp; M. W. McElwain; M. Momose; N. Ohashi; Y. K. Okamoto; M. Takami; E. L. Turner; J. Wisniewski; M. Janson; L. Abe; W. Brandner; J. Carson; S. Egner; M. Feldt; T. Golota; O. Guyon; Y. Hayano; M. Hayashi; S. Hayashi; M. Ishii; R. Kandori; N. Kusakabe; T. Matsuo; S. Mayama; S. Miyama; J.-I. Morino; A. Moro-Martin; T. Nishimura; T.-S. Pyo; H. Suto; R. Suzuki; N. Takato; H. Terada; C. Thalmann; D. Tomono; M. Watanabe; T. Yamada; H. Takami; T. Usuda

2011-01-01

339

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

340

Gemini multi-conjugate adaptive optics system review II: Commissioning, operation and overall performance  

E-print Network

The Gemini Multi-conjugate 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 microns- 2.5 microns) over a field of view of 120 arc seconds. GeMS is the first sodium layer based multi laser guide star adaptive optics system used in astronomy. It uses five laser guide stars distributed on a 60 arc seconds square constellation to measure for atmospheric distortions and two deformable mirrors to compensate for it. In this paper, the second devoted to describe the GeMS project, we present the commissioning, overall performance and operational scheme of GeMS. Performance of each sub-system is derived from the commissioning results. The typical image quality, expressed in full with 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 ...

Neichel, Benoit; 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

2014-01-01

341

A treatment procedure for Gemini North/NIFS data cubes: application to NGC 4151  

E-print Network

We present a detailed procedure for treating data cubes obtained with the Near-Infrared Integral Field Spectrograph (NIFS) of the Gemini North telescope. This process includes the following steps: correction of the differential atmospheric refraction, spatial re-sampling, Butterworth spatial filtering, 'instrumental fingerprint' removal and Richardson-Lucy deconvolution. The clearer contours of the structures obtained with the spatial re-sampling, the high spatial-frequency noise removed with the Butterworth spatial filtering, the removed 'instrumental fingerprints' (which take the form of vertical stripes along the images) and the improvement of the spatial resolution obtained with the Richardson-Lucy deconvolution result in images with a considerably higher quality. An image of the Br{\\gamma} emission line from the treated data cube of NGC 4151 allows the detection of individual ionized-gas clouds (almost undetectable without the treatment procedure) of the narrow-line region of this galaxy, which are also ...

Menezes, R B; Ricci, T V

2014-01-01

342

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

SciTech Connect

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

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

2012-02-15

343

Synthesis and characterization of glucosamide-based trisiloxane gemini surfactants  

Microsoft Academic Search

A new family of glucosamide-based trisiloxane gemini surfactants of the general formula (CH2OCH2)n (Me3SiOSiMeR1OSiMe3)2 (where R1=(CH2)3NR2(CH2)2NHCO (CHOH)4CH2OH; R2=CH2CH(OH)CH2OCH2; and n=0, 1, or 2) was prepared and characterized, both structurally and as aqueous surfactants. The monomer was prepared\\u000a by amidation of the precursor amine functional trisiloxane with d-gluconic acid ?-lactone. Gemini surfactants were then prepared by the alkylation of the precursor

Fu Han; Gaoyong Zhang

2004-01-01

344

Extrasolar Carbon Planets  

E-print Network

We suggest that some extrasolar planets silicon carbide and other carbon compounds. Pulsar planets and low-mass white dwarf planets are especially good candidate members of this new class of planets, but these objects could also conceivably form around stars like the Sun. This planet-formation pathway requires only a factor of two local enhancement of the protoplanetary disk's C/O ratio above solar, a condition that pileups of carbonaceous grains may create in ordinary protoplanetary disks. Hot, Neptune-mass carbon planets should show a significant paucity of water vapor in their spectra compared to hot planets with solar abundances. Cooler, less massive carbon planets may show hydrocarbon-rich spectra and tar-covered surfaces. The high sublimation temperatures of diamond, SiC, and other carbon compounds could protect these planets from carbon depletion at high temperatures.

Kuchner, M J; Kuchner, Marc J.

2005-01-01

345

Extrasolar Carbon Planets  

E-print Network

We suggest that some extrasolar planets silicon carbide and other carbon compounds. Pulsar planets and low-mass white dwarf planets are especially good candidate members of this new class of planets, but these objects could also conceivably form around stars like the Sun. This planet-formation pathway requires only a factor of two local enhancement of the protoplanetary disk's C/O ratio above solar, a condition that pileups of carbonaceous grains may create in ordinary protoplanetary disks. Hot, Neptune-mass carbon planets should show a significant paucity of water vapor in their spectra compared to hot planets with solar abundances. Cooler, less massive carbon planets may show hydrocarbon-rich spectra and tar-covered surfaces. The high sublimation temperatures of diamond, SiC, and other carbon compounds could protect these planets from carbon depletion at high temperatures.

Marc J. Kuchner; S. Seager

2005-04-08

346

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.

347

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

348

Gemini photographs of the world: A complete index  

NASA Technical Reports Server (NTRS)

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

Giddings, L. E.

1977-01-01

349

Surface properties of Gemini surfactants with pyrrolidinium head groups.  

PubMed

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

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

2012-03-15

350

Interactions between adsorbed layers of cationic gemini surfactants.  

PubMed

The forces acting between glass and between mica surfaces in the presence of two cationic gemini surfactants, 1,4 diDDAB (1,4-butyl-bis(dimethyldodecylammonium bromide)) and 1,12 diDDAB (1,12-dodecyl-bis(dimethyldodecylammonium bromide)), have been investigated below the critical micelle concentration (cmc) of the surfactants using two different surface force techniques. In both cases, it was found that a recharging of the surfaces occurred at a surfactant concentration of about 0.1 x cmc, and at all surfactant concentrations investigated repulsive double-layer forces dominated the interaction at large separations. At smaller separations, attractive forces, or regions of separation with (close to) constant force, were observed. This was interpreted as being due to desorption and rearrangement in the adsorbed layer induced by the proximity of a second surface. Analysis of the decay length of the repulsive double-layer force showed that the majority of the gemini surfactants were fully dissociated. However, the degree of ion pair formation, between a gemini surfactant and a bromide counterion, increased with increasing surfactant concentration and was larger for the gemini surfactant with a shorter spacer length. PMID:18052227

Blomberg, Eva; Verrall, Ronald; Claesson, Per M

2008-02-19

351

Cationic ester-containing gemini surfactants: Chemical hydrolysis and biodegradation  

Microsoft Academic Search

Two cationic gemini surfactants having ester bonds between the hydrophobic tail and the cationic moiety have been synthesized. The ester bonds were either with the ester carbonyl group away from the positive charge (esterquat type arrangement) or facing the positive charge (betaine ester type arrangement). The chemical hydrolysis of the surfactants was investigated and compared with the hydrolysis of the

A. R. Tehrani-Bagha; H. Oskarsson; C. G. van Ginkel; K. Holmberg

2007-01-01

352

Gemini Surfactants: New Synthetic Vectors for Gene Transfection  

Microsoft Academic Search

The superior surfactant properties of cationic gemini surfactants are applied to the complex problem of introducing genes into cells. Of almost 250 new compounds tested, of some 20 different structural types, a majority showed very good transfection activity in vitro. The surfactant is shown to bind and compact DNA efficiently, and struc- tural studies and calculations provide a working picture

Anthony J. Kirby; Patrick Camilleri; Jan B. F. N. Engberts; Martin C. Feiters; Roeland J. M. Nolte; Olle Söderman; Mark Bergsma; Paul C. Bell; Matthew L. Fielden; Cristina L. García Rodríguez; Philippe Guédat; Andreas Kremer; Caroli McGregor; Christele Perrin; Gaël Ronsin; Marcel C. P. van Eijk

2003-01-01

353

Partitioning of naphthalene to gemini surfactant-treated alumina  

Microsoft Academic Search

Partitioning of naphthalene to anionic surfactants adsorbed on alumina in the aqueous phase was studied for immobilization of the contaminant in the subsurface. Three anionic surfactants with different molecular structures were used: a conventional (sodium dodecylbenzene sulfonate, SDDBS), a gemini (dialkylated disulfonated diphenyl oxide with alkyl chain length of 12, DADS-C12), and a dianionic (monoalkylated disulfonated diphenyl oxide with alkyl

Deepak Neupane; Jae-Woo Park

2000-01-01

354

Simulating the Self-Assembly of Gemini (Dimeric) Surfactants  

Microsoft Academic Search

The morphologies and dynamics of aggregates formed by surfactant molecules are known to influence strongly performance properties spanning biology, household cleaning, and soil cleanup. Molecular dynamics simulations were used to investigate the morphology and dynamics of a class of surfactants, the gemini or dimeric surfactants, that are of potential importance in several industrial applications. Simulation results show that these surfactants

S. Karaborni; K. Esselink; P. A. J. Hilbers; B. Smit; J. Karthauser; N. M. van Os; R. Zana

1994-01-01

355

Adsorption Properties of Novel Gemini Surfactants with Nonidentical Head Groups  

Microsoft Academic Search

Novel environmentally friendly gemini surfactants, each with two hydrophilic and two hydrophobic groups, have been synthesized and their physicochemical properties investigated. One of the hydrophilic groups is a methyl-capped polyoxyethylene chain with mol wt 350, 550, and 750 g\\/mol, respectively, and the other is a sulfate group; the hydrophobic part of the surfactant is made from oleylnitrile. This nitrile derivative

E. Alami; K. Holmberg; J. Eastoe

2002-01-01

356

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

E-print Network

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

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

2014-01-01

357

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

NASA Astrophysics Data System (ADS)

We present the progress of characterization of a low-noise, photon counting Electron Multiplying Charged Coupled Device (EMCCD) operating in optical wavelengths and demonstrate possible solutions to the problems of Clock-Induced Charge (CIC) and other trapped charge through sub-bandgap illumination. Such a detector will be vital to the feasibility of future space-based direct imaging and spectroscopy missions for exoplanet characterization, and is scheduled to y on-board the AFTA-WFIRST mission. The 512×512 EMCCD is an e2v detector housed and clocked by a Nüvü Cameras controller. Through a multiplication gain register, this detector produces as many as 5000 electrons for a single, incident-photon-induced photoelectron produced in the detector, enabling single photon counting operation with read noise and dark current orders of magnitude below that of standard CCDs. With the extremely high contrasts (Earth-to-Sun flux ratio is ~ 10-10) and extremely faint targets (an Earth analog would measure 28th - 30th magnitude or fainter), a photon-counting EMCCD is absolutely necessary to measure the signatures of habitability on an Earth-like exoplanet within the timescale of a mission's lifetime, and we discuss the concept of operations for an EMCCD making such measurements.

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

2014-07-01

358

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

359

Evaluation of cellular uptake and intracellular trafficking as determining factors of gene expression for amino acid-substituted gemini surfactant-based DNA nanoparticles  

PubMed Central

Background Gene transfer using non-viral vectors offers a non-immunogenic and safe method of gene delivery. Cellular uptake and intracellular trafficking of the nanoparticles can impact on the transfection efficiency of these vectors. Therefore, understanding the physicochemical properties that may influence the cellular uptake and the intracellular trafficking can aid the design of more efficient non-viral gene delivery systems. Recently, we developed novel amino acid-substituted gemini surfactants that showed higher transfection efficiency than their parent compound. In this study, we evaluated the mechanism of cellular uptake of the plasmid/gemini surfactant/helper lipid nanoparticles and their effect on the transfection efficiency. Results Nanoparticles were incubated with Sf 1 Ep cells in the presence of different endocytic inhibitors and gene expression (interferon-?) was measured using ELISA. Clathrin-mediated and caveolae-mediated uptake were found to be equally contributing to cellular internalization of both P/12-7NH-12/L (parent gemini surfactant) and P/12-7NGK-12/L (amino acid-substituted gemini surfactant) nanoparticles. The plasmid and the helper lipid were fluorescently tagged to track the nanoparticles inside the cells, using confocal laser scanning microscopy. Transmission electron microscopy images showed that the P/12-7NGK-12/L particles were cylindrical while the P/12-7NH-12/L particles were spherical which may influence the cellular uptake behaviour of these particles. Dye exclusion assay and pH-titration of the nanoparticles suggested that high buffering capacity, pH-dependent increase in particle size and balanced DNA binding properties may be contributing to a more efficient endosomal escape of P/12-7NGK-12/L compared to the P/12-7NH-12/L nanoparticles, leading to higher gene expression. Conclusion Amino-acid substitution in the spacer of gemini surfactant did not alter the cellular uptake pathway, showing similar pattern to the unsubstituted parent gemini surfactant. Glycyl-lysine substitution in the gemini spacer improved buffering capacity and imparted a pH-dependent increase of particle size. This property conferred to the P/12-7NGK-12/L nanoparticles the ability to escape efficiently from clathrin-mediated endosomes. Balanced binding properties (protection and release) of the 12-7NGK-12 in the presence of polyanions could contribute to the facile release of the nanoparticles internalized via caveolae-mediated uptake. A more efficient endosomal escape of the P/12-7NGK-12/L nanoparticles lead to higher gene expression compared to the parent gemini surfactant. PMID:22296763

2012-01-01

360

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

361

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

362

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

E-print Network

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

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

2013-01-01

363

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

364

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

365

Planet Forming Protostellar Disks  

NASA Technical Reports Server (NTRS)

The proposal achieved many of its objectives. The main area of investigation was the interaction of young planets with surrounding protostellar disks. The topics of interest include: 1) Simulations of Planet-Disk Interactions; 2) Secular Interactions Between Inclined Planets and a Gaseous Disk; 3) On the Tilting of Protostellar Disks by Resonant Tidal Effects; 4) Three-Dimensional Waves in Thermally Stratified Disks; and 5) Predictions of the Distribution of Planets. A list of publications resulting from this grant is also presented.

Lubow, Stephen

2002-01-01

366

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.

367

Exploring the Planets: Mars  

NSDL National Science Digital Library

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

368

Peeking at the Planets.  

ERIC Educational Resources Information Center

Provides information about each of the planets in our solar system. Focuses on information related to the space missions that have visited or flown near each planet, and includes a summary of what is known about some of the features of each planet. (DDR)

Riddle, Bob

2002-01-01

369

Theory of Giant Planets  

Microsoft Academic Search

Giant planet research has moved from the study of a handful of solar system objects to that of a class of bodies with dozens of known members. Since the original 1995 discovery of the first extrasolar giant planets (EGPs), the total number of known examples has increased to ~80 (circa November 2001). Current theoretical studies of giant planets emphasize predicted

W. B. Hubbard; A. Burrows; J. I. Lunine

2002-01-01

370

Evaporation of extrasolar planets  

E-print Network

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

David Ehrenreich

2008-07-11

371

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

372

Terrestrials Dwarf Planets  

E-print Network

Terrestrials Gas Giants Ice Giants Dwarf Planets The Solar System #12;Neptune Uranus Saturn Jupiter & Helium atmospheres. #12;The Dwarf Planets are a new class of Solar System objects defined by the IAU Dwarf planets can have eccentric and highly inclined orbits. #12;The Solar System has 7 Giant Moons

Gaudi, B. Scott

373

The Trojan minor planets  

NASA Astrophysics Data System (ADS)

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

Spratt, Christopher E.

1988-08-01

374

Dunking the Planets  

NSDL National Science Digital Library

This is a demonstration about the density of the planets. Learners will compare the relative sizes and masses of scale models of the planets as represented by fruits and other foods. They will then dunk the "planets" in water to highlight the fact that even a large, massive planet - such as Saturn - can have low density. They discuss how a planet's density is related to whether it is mainly made up of rock or gas. This activity is part of Explore! Jupiter's Family Secrets, a series designed to engage children in space and planetary science in libraries and informal learning environments.

375

Planets Around Evolved Stars  

NASA Astrophysics Data System (ADS)

With searches of planets around evolved pulsating B sub-dwarfs, red giant stars, and white dwarfs underway, it is paramount to advance theoretical research in how stellar evolution affects the architecture of planetary systems. This will not only maximize the discovery potential of said searches, but also aid in the interpretation and understanding of planet formation in a broader context. To acquire a full picture of the planet´s survival process we compute the evolution of the planet´s orbit coupled with the evolution of the star from the main sequence all the way to the white dwarf domain. We explore the range of planetary masses that might survive a common envelope stage during the giant phases of the star and, finally, we investigate how the presence of a planet might influence the evolution of the star itself.

Villaver, Eva; Livio, M.

2011-09-01

376

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

377

FORMATION, SURVIVAL, AND DETECTABILITY OF PLANETS BEYOND 100 AU  

SciTech Connect

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

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

2009-05-10

378

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

379

Gemini surfactants affect the structure, stability, and activity of ribonuclease sa.  

PubMed

Gemini surfactants have important advantages, e.g., low micromolar CMCs and slow millisecond monomer ? micelle kinetics, for membrane mimetics and for delivering nucleic acids for gene therapy or RNA silencing. However, as a prerequisite, it is important to characterize interactions occurring between Gemini surfactants and proteins. Here NMR and CD spectroscopies are employed to investigate the interactions of cationic Gemini surfactants with RNase Sa, a negatively charged ribonuclease. We find that RNase Sa binds Gemini surfactant monomers and micelles at pH values above 4 to form aggregates. Below pH 4, where the protein is positively charged, these aggregates dissolve and interactions are undetectable. Thermal denaturation experiments show that surfactant lowers RNase Sa's conformational stability, suggesting that surfactant binds the protein's denatured state preferentially. Finally, Gemini surfactants were found to bind RNA, leading to the formation of large complexes. Interestingly, Gemini surfactant binding did not prevent RNase Sa from cleaving RNA. PMID:25133582

Amiri, Razieh; Bordbar, Abdol-Khalegh; Laurents, Douglas V

2014-09-11

380

Synthesis of organic rectorite with novel Gemini surfactants for copper removal  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

381

Thermodynamic Studies of Aqueous m– s– m Gemini Surfactant Systems  

Microsoft Academic Search

The specific conductance, surface tension, and apparent molar volume properties of aqueous solutions of two series of m–s–m gemini surfactants—one having a constant spacer s(=3) with m=8, 10, 12, and 16 and the other having a constant alkyl chain length m(=12) with variable spacer length 2?s?16—are reported. A surfactant with m=12 and having a p-xylyl (?) spacer was also studied

S. D. Wettig; R. E. Verrall

2001-01-01

382

Gemini surfactant–water mixtures: some physical–chemical properties  

Microsoft Academic Search

The phase diagram of the water-Gemini 16-4-16 system has been investigated and the phase boundaries were determined. DSC and optical microscopy were used to define the region of existence of the different phases. No liquid crystalline phases have been observed, however, a two-phase region and a wide gel phase follow the solution region. The solution region can be highly viscous,

Cesare Oliviero; Luigi Coppola; Camillo La Mesa; Giuseppe A Ranieri; M Terenzi

2002-01-01

383

Adsorption and Association in Aqueous Solutions of Dissymmetric Gemini Surfactant  

Microsoft Academic Search

A gemini surfactant with two hydrocarbon chains differing in length and with an ethylene spacer N,N-dimethyl-N-(2-(N?,N?-dimethyl-N?-dodecylammonio) ethyl) tetradecylammonium dibromide, 12–2–14, was synthesized and its physicochemical properties were studied by surface tension, conductometry, potentiometry, viscosimetry, and light scattering measurements, as well as by optical microscopy. Surface properties and thermodynamic parameters lie between those obtained for its symmetric counterparts, while association in

Maja Sikiri?; Ines Primoži?; Nada Filipovi?-Vincekovi?

2002-01-01

384

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

385

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

SciTech Connect

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

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

2007-01-18

386

[Selective algicidal activity of Gemini1231 biquaternary ammonium salt].  

PubMed

The growth-inhibiting effects of Gemini1231 surfactant on Prorocentrum donghaiense, Alexandrium tamarense, Gymnodinium sp., Heterosigma akashiwo, Skeletonema costatum , Platymonas helgolanidica and Platymonas subcordiforus were investigated. The results demonstrate that the growth of P. donghaiense, A. tamarense and H. akashiwo was strongly inhibited in medium containing Gemini1231 from 0.2 to 0.5 mg x L(-1), and the S. costatum was also inhibited at concentrations above 0.5 mg x L(-1). However, the effects of this surfactant on the growth of Gymnodinium sp. and two beneficial green microalgae tested were negligible under the same treatment, indicating the potential for the selective control of red tide organisms. In addition, the analysis of the correlation between the inhibitory effect of the Gemini1231 on the algae tested and fatty acid composition of the algae implied that the differences in the fatty acid composition, especially the proportion of PUFAs, were responsible for the species-specific responses to biquaternary ammonium salt. PMID:16850823

Wang, Xiu-lin; Li, Yan-bin; Gong, Liang-yu; Lu, Jin-ren; Han, Xiu-rong; Zhu, Chen-jian

2006-05-01

387

Easier Phase IIs: Recent Improvements to the Gemini User Tools  

NASA Astrophysics Data System (ADS)

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

Miller, Bryan; Nuñez, A.

2013-01-01

388

Efficient cell transfection with melamine-based gemini surfactants.  

PubMed

Gemini surfactants consisting of two melamine scaffolds connected by a n-hexyl linker and functionalized with a 1-propylammonium polar head and a lipophilic chain having variable carbon length (from C8 to C16) were synthesized. These were then used successfully for the transfection of A549, U87 MG, and Bristol 8 cell lines with maxGFP expressing plasmid. The transfection protocol was optimized appropriately (confluence, reagent/pcDNA ratio, compaction time, and transfection time) for each cell line. Under optimized conditions, the C12 and C14 melamine gemini surfactants showed little toxicity and remarkable transfection efficiency, superior to the gold-standard Lipofectamine 2000. These reagents were also able to efficiently transfect primary DRG neurons, which are notoriously difficult to transfect. The presence of serum completely inhibited the transfection capacity of these reagents. Owing to their ready availability, straightforward synthesis, high chemical stability (even in solution), ease of use (no formulation is required), improved transfection ability, and low toxicity, melamine-based gemini surfactants are very promising reagents for cellular DNA transfection. PMID:23297813

Perrone, Serena; Usai, Michele; Lazzari, Paolo; Tucker, Steven J; Wallace, Heather M; Zanda, Matteo

2013-02-20

389

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

390

A giant planet around HD95086 ?  

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

391

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

392

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

393

ConcepTest: Relative Planet Ages  

NSDL National Science Digital Library

How old are other planets in the Universe in comparison to the planets in our Solar System? a. Other planets are older than the planets in our Solar System. b. Other planets are younger than the planets in our ...

394

ExtraSolar Planets Finding Extrasolar Planets. I  

E-print Network

close to the star. #12;Orbits Planets do not orbit the Sun - they both orbit the center of mass Planets. III Transits Six planets have been found by transits. This requires an edge-on orbit. JupiterExtraSolar Planets #12;Finding Extrasolar Planets. I Direct Searches Direct searches are difficult

Walter, Frederick M.

395

The Sun, eight planets and three dwarf planets  

E-print Network

The Sun, eight planets and three dwarf planets are the largest bodies in our solar system. By 2006, 166 moons had been discovered orbiting the planets and dwarf planets. There are also thousands and collapse to become a white dwarf star the size of Earth. MERCURY Mercury is the closest planet to the Sun

Jarrett, Thomas H.

396

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.

397

Seismology of Giant Planets  

E-print Network

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

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

2014-01-01

398

Planet-crossing asteroid survey  

NASA Technical Reports Server (NTRS)

The planet-crossing asteroid survey was begun in 1973 in order to study those asteroids which may intersect the orbits of the inner planets. Throughout the history of the survey, many of the various classes of asteroids were investigated. The near-Earth objects including the Apollo, Amor, and Aten families were studied in addition to asteroids whose orbits cross that of Mars, and some objects which are generally confined to the main belt. Observing was done on the 18 inch Schmidt telescope at the Palomar Mtn. Observatory. Typically, two consecutive photographs of a favorable field are taken. The exposure times of the films are usually twenty minutes and ten minutes, respectively. The telescope is guided at sidereal rate, so that asteroids will leave short trailed images. The films are then scanned for trails. By comparing the two films, the direction and approximate rate of motion of an asteroid may be determined.

Wilder, P. D.

1984-01-01

399

Planet Formation - Overview  

NASA Technical Reports Server (NTRS)

Modern theories of star and planet formation are based upon observations of planets and smaller bodies within our own Solar System, exoplanets &round normal stars and of young stars and their environments. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. These models predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path.

Lissauer, Jack J.

2005-01-01

400

Planet - Disk Symbiosis  

E-print Network

Planets form in disks around young stars. Interactions with these disks cause them to migrate and thus affect their final orbital periods. We suggest that the connection between planets and disks may be deeper and involve a symbiotic evolution. By contributing to the outward transport of angular momentum, planets promote disk accretion. Here we demonstrate that planets sufficiently massive to open gaps could be the primary agents driving disk accretion. Those having masses below the gap opening threshold drift inward more rapidly than the disk material and can only play a minor role in its accretion. Eccentricity growth during gap formation may involve an even more intimate symbiosis. Given a small initial eccentricity, just a fraction of a percent, the orbital eccentricity of a massive planet may grow rapidly once a mass in excess of the planet's mass has been repelled to form a gap around the planet's orbit. Then, as the planet's radial excursions approach the gap's width, subsequent eccentricity growth slows so that the planet's orbit continues to be confined within the gap.

Re'em Sari; Peter Goldreich

2003-07-05

401

Synergistic adsorption of mixtures of cationic gemini and nonionic sugar-based surfactant on silica.  

PubMed

Adsorption behavior of cationic C(12)-C(4)-C(12) gemini surfactant on silica has been investigated, along with that of nonionic surfactant n-dodecyl-beta-D-maltoside (DM). While DM alone shows meager adsorption on silica, because of the lack of any electrostatic adsorption, cationic gemini adsorbs significantly on the oppositely charged silica surface. Due to the electrostatic nature of cationic gemini adsorption on silica, solution pH affects adsorption of C(12)-C(4)-C(12) gemini dramatically. Meanwhile, C(12)-C(4)-C(12) gemini hemimicelle size at silica/water interface does not seem to change with solution pH. For the mixtures of DM and cationic C(12)-C(4)-C(12) gemini, there is a sharp increase of DM adsorption at silica/water interface, up to 100 times more than DM alone. After mixing with DM, saturation adsorption of cationic C(12)-C(4)-C(12) gemini decreases, due to competition for adsorption sites from DM. At the same time, in its mixture with DM, there is an increased adsorption of C(12)-C(4)-C(12) gemini in the rising part of the adsorption isotherm. Hydrophobic chain-chain interactions, especially with two hydrophobic chains in one C(12)-C(4)-C(12) gemini molecule, and adsorbed C(12)-C(4)-C(12) gemini molecule acting as an anchor or nucleation sites for forming mixed aggregates with DM on silica surface, are attributed to the marked adsorption synergy between DM and cationic C(12)-C(4)-C(12) gemini. The adsorption of surfactants and their mixtures has a marked effect on silica surface charge and silica's wettability. PMID:19100990

Zhou, Qiong; Somasundaran, P

2009-03-15

402

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

E-print Network

We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities for all of the transiting planets (41 of 42 have a false-positive probability under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than 3X the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify 6 planets with densities above 5 g/cc, suggesting a mostly rocky interior f...

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

2014-01-01

403

MESSENGER: Exploring the Innermost Planet  

NASA Astrophysics Data System (ADS)

One of Earth's closest planetary neighbors, Mercury remained comparatively unexplored for the more than three decades that followed the three flybys of the innermost planet by the Mariner 10 spacecraft in 1974-75. Mariner 10 imaged 45% of Mercury's surface at about 1 km/pixel average resolution, confirmed Mercury's anomalously high bulk density and implied large fractional core size, discovered Mercury's internal magnetic field, documented that H and He are present in the planet's tenuous exosphere, and made the first exploration of Mercury's magnetosphere and solar wind environment. Ground-based astronomers later reported Na, K, and Ca in Mercury's exosphere; the presence of deposits in the floors of polar craters having radar characteristics best matched by water ice; and strong evidence from the planet's forced libration amplitude that Mercury has a fluid outer core. Spacecraft exploration of Mercury resumed with the selection for flight, under NASA's Discovery Program, of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. Launched in 2004, MESSENGER flew by the innermost planet three times in 2008-2009 en route to becoming the first spacecraft to orbit Mercury in March of this year. MESSENGER's first chemical remote sensing measurements of Mercury's surface indicate that the planet's bulk silicate fraction differs from those of the other inner planets, with a low-Fe surface composition intermediate between basalts and ultramafic rocks and best matched among terrestrial rocks by komatiites. Moreover, surface materials are richer in the volatile constituents S and K than predicted by most planetary formation models. Global image mosaics and targeted high-resolution images (to resolutions of 10 m/pixel) reveal that Mercury experienced globally extensive volcanism, including large expanses of plains emplaced as flood lavas and widespread examples of pyroclastic deposits likely emplaced during explosive eruptions of volatile-bearing magmas. Bright deposits within impact craters host fresh-appearing, rimless depressions or hollows, often displaying high-reflectance interiors and halos and likely formed through processes involving the geologically recent loss of volatiles. The tectonic history of Mercury, although dominated by near-global contractional deformation as first seen by Mariner 10, is more complex than first appreciated, with numerous examples of extensional deformation that accompanied impact crater and basin modification. Mercury's magnetic field is dominantly dipolar, but the field is axially symmetric and equatorially asymmetric, a geometry that poses challenges to dynamo models for field generation. The interaction between the solar wind and Mercury's magnetosphere, among the most dynamic in the solar system, serves both to replenish the exosphere and space weather the planet's surface. Plasma ions of planetary origin are seen throughout the sampled volume of Mercury's magnetosphere, with maxima in heavy-ion fluxes in the planet's magnetic-cusp regions. Bursts of energetic electrons, seen at most local times, point to an efficient acceleration mechanism operating within Mercury's magnetosphere on a regular basis that produces electrons with energies up to hundreds of keV on timescales of seconds.

Solomon, S. C.

2011-12-01

404

Photometry and dynamics of the minor merger AM 1219-430 with Gemini GMOS-S  

NASA Astrophysics Data System (ADS)

We present an observational study of the interaction effect on the dynamics and morphology of the minor merger AM 1219-430. This work is based on r' and g' images and long-slit spectra obtained with the Gemini Multi-Object Spectrograph at the Gemini South Telescope. We detected a tidal tail in the main galaxy (AM 1219A) and a bridge of material connecting the galaxies. In luminosity, AM 1219A is about 3.8 times brighter than the secondary (AM 1219B). The surface brightness profile of AM 1219A was decomposed into bulge and disc components. The profile shows a light excess of ˜53 per cent due to the contribution of star-forming regions, which is typical of starburst galaxies. On the other hand, the surface brightness profile of AM 1219B shows a lens structure in addition to the bulge and disc. The scalelengths and central magnitudes of the disc structure of both galaxies agree with the average values derived for galaxies with no sign of ongoing interaction or disturbed morphology. The Sérsic index (n < 2), the effective and scale radii of the bulge of both galaxies are typical of pseudo-bulges. The rotation curve of AM 1219A derived from the emission line of ionized gas is quite asymmetric, suggesting a gas perturbed by interaction. We explore all possible values of stellar and dark matter masses. The overall best-fitting solution for the mass distribution of AM 1219A was found with M/L for bulge and disc of Upsilon _b=2.8_{-0.4}^{+0.4} and Upsilon _d=2.4_{-0.2}^{+0.3}, respectively, and a Navarro et al. profile of M_{200}=2.0_{-0.4}^{+0.5}× 10^{12} M_{{?}} and c=16.0_{-1.1}^{+1.2}. The estimated dynamical mass is 1.6 × 1011 M?, within a radius of ˜10.6 kpc.

Hernandez-Jimenez, J. A.; Pastoriza, M. G.; Rodrigues, I.; Krabbe, A. C.; Winge, Cláudia; Bonatto, C.

2013-11-01

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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