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An Understanding of the Shoulder of Giants: Jovian Planets around Late K Dwarf Stars and the Trend with Stellar Mass

Gaidos, Eric and Fischer, Debra A. and Mann, Andrew W. and Howard, Andrew W. (2013) An Understanding of the Shoulder of Giants: Jovian Planets around Late K Dwarf Stars and the Trend with Stellar Mass. Astrophysical Journal, 771 (1). Art. No. 18. ISSN 0004-637X.

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Analyses of exoplanet statistics suggest a trend of giant planet occurrence with host star mass, a clue to how planets like Jupiter form. One missing piece of the puzzle is the occurrence around late K dwarf stars (masses of 0.5-0.75 M ☉ and effective temperatures of 3900-4800 K). We analyzed four years of Doppler radial velocity (RVs) data for 110 late K dwarfs, one of which hosts two previously reported giant planets. We estimate that 4.0% ± 2.3% of these stars have Saturn-mass or larger planets with orbital periods <245 days, depending on the planet mass distribution and RV variability of stars without giant planets. We also estimate that 0.7% ± 0.5% of similar stars observed by Kepler have giant planets. This Kepler rate is significantly (99% confidence) lower than that derived from our Doppler survey, but the difference vanishes if only the single Doppler system (HIP 57274) with completely resolved orbits is considered. The difference could also be explained by the exclusion of close binaries (without giant planets) from the Doppler but not Kepler surveys, the effect of long-period companions and stellar noise on the Doppler data, or an intrinsic difference between the two populations. Our estimates for late K dwarfs bridge those for solar-type stars and M dwarfs, and support a positive trend with stellar mass. Small sample size precludes statements about finer structure, e.g., a "shoulder" in the distribution of giant planets with stellar mass. Future surveys such as the Next Generation Transit Survey and the Transiting Exoplanet Satellite Survey will ameliorate this deficiency.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Gaidos, Eric0000-0002-5258-6846
Fischer, Debra A.0000-0003-2221-0861
Mann, Andrew W.0000-0003-3654-1602
Howard, Andrew W.0000-0001-8638-0320
Additional Information:© 2013 The American Astronomical Society. Received 2013 April 17; accepted 2013 May 11; published 2013 June 11. This research was supported by NSF Grant AST-09-08406 and NASA Grants NNX10AI90G and NNX11AC33G to E.G. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. E.G. and D.F. thank the University of Hawaii and Yale Time Allocation Committees for the allocations of Keck nights used for this project. The Kepler mission is funded by the NASA Science Mission Directorate, and data were obtained from the Mukulski Archive at the Space Telescope Science Institute, funded by NASA Grant NNX09AF08G, and the NASA Exoplanet Archive at IPAC.
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:astrobiology – planetary systems – planets and satellites: formation – stars: fundamental parameters – techniques: radial velocities
Issue or Number:1
Record Number:CaltechAUTHORS:20170621-125925800
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Official Citation:Eric Gaidos et al 2013 ApJ 771 18
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78420
Deposited By: Tony Diaz
Deposited On:21 Jun 2017 20:12
Last Modified:29 Nov 2019 03:03

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