The Occurrence of Rocky Habitable-zone Planets around Solar-like Stars from Kepler Data

Creators: Bryson, Steve; Kunimoto, Michelle; Kopparapu, Ravi K.; Coughlin, Jeffrey L.; Borucki, William J.; Koch, David; Silva Aguirre, Victor; Allen, Christopher; Barentsen, Geert; Batalha, Natalie M.; Berger, Travis; Boss, Alan; Buchhave, Lars A.; Burke, Christopher J.; Caldwell, Douglas A.; Campbell, Jennifer R.; Catanzarite, Joseph; Chandrasekharan, Hema; Chaplin, William J.; Christiansen, Jessie L.; Christensen-Dalsgaard, Jorgen; Ciardi, David R.; Clarke, Bruce D.; Cochran, William D.; Dotson, Jessie L.; Doyle, Laurance R.; Seperuelo Duarte, Eduardo; Dunham, Edward W.; Dupree, Andrea K.; Endl, Michael; Fanson, James L.; Ford, Eric B.; Fujieh, Maura; Gautier, Thomas N., III; Geary, John C.; Gilliland, Ronald L.; Girouard, Forrest R.; Gould, Alan; Haas, Michael R.; Henze, Christopher E.; Holman, Matthew J.; Howard, Andrew W.; Howell, Steve B.; Huber, Daniel; Hunter, Roger C.; Jenkins, Jon M.; Kjeldsen, Hans; Kolodziejczak, Jeffery; Larson, Kipp; Latham, David W.; Li, Jie; Meibom, Soren; Middour, Chris; Morris, Robert L.; Morton, Timothy D.; Mullally, Fergal; Mullally, Susan E.; Pletcher, David; Prša, Andrej; Quinn, Samuel N.; Quintana, Elisa V.; Ragozzine, Darin; Ramirez, Solange V.; Sanderfer, Dwight T.; Sasselov, Dimitar; Seader, Shawn E.; Shabram, Megan; Shporer, Avi; Smith, Jeffrey C.; Steffen, Jason H.; Still, Martin; Torres, Guillermo; Troeltzsch, John; Twicken, Joseph D.; Uddin, Akm Kamal; Van Cleve, Jeffrey E.; Voss, Janice; Weiss, Lauren; Welsh, William F.; Wohler, Bill; Zamudio, Khadeejah A.

Abstract

We present the occurrence rates for rocky planets in the habitable zones (HZs) of main-sequence dwarf stars based on the Kepler DR25 planet candidate catalog and Gaia-based stellar properties. We provide the first analysis in terms of star-dependent instellation flux, which allows us to track HZ planets. We define η⊕ as the HZ occurrence of planets with radii between 0.5 and 1.5 R⊕ orbiting stars with effective temperatures between 4800 and 6300 K. We find that η⊕ for the conservative HZ is between 0.37^(+0.48)_(−0.21) (errors reflect 68% credible intervals) and 0.60^(+0.90)_(−0.36) planets per star, while the optimistic HZ occurrence is between 0.58^(+0.73)_(−0.33) and 0.88^(+1.28)_(−0.51) planets per star. These bounds reflect two extreme assumptions about the extrapolation of completeness beyond orbital periods where DR25 completeness data are available. The large uncertainties are due to the small number of detected small HZ planets. We find similar occurrence rates between using Poisson likelihood Bayesian analysis and using Approximate Bayesian Computation. Our results are corrected for catalog completeness and reliability. Both completeness and the planet occurrence rate are dependent on stellar effective temperature. We also present occurrence rates for various stellar populations and planet size ranges. We estimate with 95% confidence that, on average, the nearest HZ planet around G and K dwarfs is ~6 pc away and there are ~4 HZ rocky planets around G and K dwarfs within 10 pc of the Sun.

Additional Information

© 2020 The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2020 September 1; revised 2020 October 19; accepted 2020 October 20; published 2020 December 22. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. We thank our anonymous reviewer for many helpful comments that improved the manuscript. We thank NASA, Kepler management, and the Exoplanet Exploration Office for their continued support of and encouragement for the analysis of Kepler data. R.K.K. acknowledges support from the GSFC Sellers Exoplanet Environments Collaboration, which is supported by the NASA Planetary Science Division's Research Program, and from NASA's NExSS Virtual Planetary Laboratory funded by the NASA Astrobiology Program under grant 80NSSC18K0829. Funding for the Stellar Astrophysics Centre is provided by the Danish National Research Foundation (grant DNRF106). V.S.A. acknowledges support from the Independent Research Fund Denmark (research grant 7027-00096B) and the Carlsberg Foundation (grant agreement CF19-0649). E.B.F. was supported by a grant from the Simons Foundation/SFARI (675601). E.B.F. acknowledges support from the NASA Kepler Participating Scientist Program, through grants #NNX08AR04G, #NNX12AF73G, and #NNX14AN76G. E.B.F. acknowledges support from Penn State's Eberly College of Science, Department of Astronomy & Astrophysics, Institute for Computational & Data Sciences, Center for Exoplanets and Habitable Worlds, and Center for Astrostatistics. E.S.D. acknowledges financial support from the National Council for Scientific and Technological Development (CNPQ) and the IFRJ. D.H. acknowledges support from the Alfred P. Sloan Foundation, the National Aeronautics and Space Administration (80NSSC19K0597), and the National Science Foundation (AST-1717000). S. Mathur acknowledges support from the Spanish Ministry with the Ramon y Cajal fellowship number RYC-2015-17697. L.M.W. is supported by the Beatrice Watson Parrent Fellowship and NASA ADAP Grant #80NSSC19K0597. Facility: Kepler. - Software: Python, Jupyter.

Attached Files

Published - Bryson_2021_AJ_161_36.pdf

Submitted - 2010.14812.pdf

Files

2010.14812.pdf

Files (8.5 MB)

Name	Size	Download all
2010.14812.pdf md5:e95f0e3bb8220a93e90d52346a46b0ae	4.2 MB	Preview Download
Bryson_2021_AJ_161_36.pdf md5:39e8a6774d88fe2758f63b8ed78a47d6	4.3 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes