Browsing by Subject "planets and satellites: fundamental parameters"

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A Correlation Between The Eclipse Depths Of Kepler Gas Giant Candidates And The Metallicities Of Their Parent Stars
(2012-06) Dodson-Robinson, Sarah E.; Dodson-Robinson, Sarah E.
Previous studies of the interior structure of transiting exoplanets have shown that the heavy-element content of gas giants increases with host star metallicity. Since metal-poor planets are less dense and have larger radii than metal-rich planets of the same mass, one might expect that metal-poor stars host a higher proportion of gas giants with large radii than metal-rich stars. Here I present evidence for a negative correlation at the 2.3 sigma level between eclipse depth and stellar metallicity in the Kepler gas giant candidates. Based on Kendall's tau statistics, the probability that eclipse depth depends on star metallicity is 0.981. The correlation is consistent with planets orbiting low-metallicity stars being, on average, larger in comparison with their host stars than planets orbiting metal-rich stars. Furthermore, since metal-rich stars have smaller radii than metal-poor stars of the same mass and age, a uniform population of planets should show a rise in median eclipse depth with [M/H]. The fact that I find the opposite trend indicates that substantial changes in the gas giant interior structure must accompany increasing [M/H]. I investigate whether the known scarcity of giant planets orbiting low-mass stars could masquerade as an eclipse depth-metallicity correlation, given the degeneracy between metallicity and temperature for cool stars in the Kepler Input Catalog. While the eclipse depth-metallicity correlation is not yet on firm statistical footing and will require spectroscopic [Fe/H] measurements for validation, it is an intriguing window into how the interior structure of planets and even the planet formation mechanism may be changing with Galactic chemical evolution.
New Observational Constraints On The Nu Andromedae System With Data From The Hubble Space Telescope And Hobby-Eberly Telescope
(2010-06) McArthur, Barbara E.; Benedict, G. Fritz; Barnes, Rory; Martioli, Elder; Korzennik, Sylvain; Nelan, Ed; Butler, R. Paul; McArthur, Barbara E.; Benedict, G. Fritz; Martioli, Elder
We have used high-cadence radial velocity (RV) measurements from the Hobby-Eberly Telescope with existing velocities from the Lick, Elodie, Harlan J. Smith, and Whipple 60 '' telescopes combined with astrometric data from the Hubble Space Telescope Fine Guidance Sensors to refine the orbital parameters and determine the orbital inclinations and position angles of the ascending node of components v And A c and d. With these inclinations and using M(*) = 1.31M(circle dot) as a primary mass, we determine the actual masses of two of the companions: And A c is 13.98+ 2.3 -5.3 MJUP, and. And A d is 10.25(-3.3)(+0.7) M(JUP). These measurements represent the first astrometric determination of mutual inclination between objects in an extrasolar planetary system, which we find to be 29 degrees.9 +/- 1 degrees. The combined RV measurements also reveal a long-period trend indicating a fourth planet in the system. We investigate the dynamic stability of this system and analyze regions of stability, which suggest a probable mass of v And A b. Finally, our parallaxes confirm that v And B is a stellar companion of v And A.
Planetary Candidates Observed By Kepler. V. Planet Sample from Q1-Q12 (36 Months)
(2015-03) Rowe, Jason F.; Coughlin, Jeffrey L.; Antoci, Victoria; Barclay, Thomas; Batalha, Natalie M.; Borucki, William J.; Burke, Christopher J.; Bryson, Steven T.; Caldwell, Douglas A.; Campbell, Jennifer R.; Catanzarite, Joseph H.; Christiansen, Jessie L.; Cochran, William; Gilliland, Ronald L.; Girouard, Forrest R.; Haas, Michael R.; Helminiak, Krzysztof G.; Henze, Christopher E.; Hoffman, Kelsey L.; Howell, Steve B.; Huber, Daniel; Hunter, Roger C.; Jang-Condell, Hannah; Jenkins, Jon M.; Klaus, Todd C.; Latham, David W.; Li, Jie; Lissauer, Jack J.; McCauliff, Sean D.; Morris, Robert L.; Mullally, F.; Ofir, Aviv; Quarles, Billy; Quintana, Elisa; Sabale, Anima; Seader, Shawn; Shporer, Avi; Smith, Jeffrey C.; Steffen, Jason H.; Still, Martin; Tenenbaum, Peter; Thompson, Susan E.; Twicken, Joseph D.; Van Laerhoven, Christa; Wolfgang, Angie; Zamudio, Khadeejah A.; Cochran, William D.
The Kepler mission discovered 2842 exoplanet candidates with 2 yr of data. We provide updates to the Kepler planet candidate sample based upon 3 yr (Q1-Q12) of data. Through a series of tests to exclude false-positives, primarily caused by eclipsing binary stars and instrumental systematics, 855 additional planetary candidates have been discovered, bringing the total number known to 3697. We provide revised transit parameters and accompanying posterior distributions based on a Markov Chain Monte Carlo algorithm for the cumulative catalog of Kepler Objects of Interest. There are now 130 candidates in the cumulative catalog that receive less than twice the flux the Earth receives and more than 1100 have a radius less than 1.5 R-circle plus. There are now a dozen candidates meeting both criteria, roughly doubling the number of candidate Earth analogs. A majority of planetary candidates have a high probability of being bonafide planets, however, there are populations of likely false-positives. We discuss and suggest additional cuts that can be easily applied to the catalog to produce a set of planetary candidates with good fidelity. The full catalog is publicly available at the NASA Exoplanet Archive.
Validation Of Kepler's Multiple Planet Candidates. III. Light Curve Analysis And Announcement Of Hundreds Of New Multi-Planet Systems
(2014-03) Rowe, Jason F.; Bryson, Stephen T.; Marcy, Geoffrey W.; Lissauer, Jack J.; Jontof-Hutter, Daniel; Mullally, Fergal; Gilliland, Ronald L.; Issacson, Howard; Ford, Eric; Howell, Steve B.; Borucki, William J.; Haas, Michael; Huber, Daniel; Steffen, Jason H.; Thompson, Susan E.; Quintana, Elisa; Barclay, Thomas; Still, Martin; Fortney, Jonathan; Gautier, T. N., III; Hunter, Roger; Caldwell, Douglas A.; Ciardi, David R.; Devore, Edna; Cochran, William; Jenkins, Jon; Agol, Eric; Carter, Joshua A.; Geary, John; Cochran, William
The Kepler mission has discovered more than 2500 exoplanet candidates in the first two years of spacecraft data, with approximately 40% of those in candidate multi-planet systems. The high rate of multiplicity combined with the low rate of identified false positives indicates that the multiplanet systems contain very few false positive signals due to other systems not gravitationally bound to the target star. False positives in the multi-planet systems are identified and removed, leaving behind a residual population of candidate multi-planet transiting systems expected to have a false positive rate less than 1%. We present a sample of 340 planetary systems that contain 851 planets that are validated to substantially better than the 99% confidence level; the vast majority of these have not been previously verified as planets. We expect similar to two unidentified false positives making our sample of planet very reliable. We present fundamental planetary properties of our sample based on a comprehensive analysis of Kepler light curves, ground-based spectroscopy, and high-resolution imaging. Since we do not require spectroscopy or high-resolution imaging for validation, some of our derived parameters for a planetary system may be systematically incorrect due to dilution from light due to additional stars in the photometric aperture. Nonetheless, our result nearly doubles the number verified exoplanets.