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Accounting for multiplicity in calculating eta Earth

Zink, Jon K. and Hansen, Bradley M. S. (2019) Accounting for multiplicity in calculating eta Earth. Monthly Notices of the Royal Astronomical Society, 487 (1). pp. 246-252. ISSN 0035-8711. doi:10.1093/mnras/stz1246.

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Using the updated exoplanet population parameters of our previous study, which includes the planetary radius updates from Gaia DR2 and an inferred multiplicity distribution, we provide a revised η_⊕ calculation. This is achieved by sampling planets from our derived population model and determining which planets meet our criterion for habitability. To ensure robust results, we provide probabilities calculated over a range of upper radius limits. Our most optimistic criterion for habitability provides an η⊕ value of 0.34±0.02 (planets/star⁠). We also consider the effects of multiplicity and the number of habitable planets each system may contain. Our calculation indicates that 6.4±0.5 per cent of GK dwarfs have more than one planet within their habitable zone. This optimistic habitability criterion also suggests that 0.036±0.009 per cent of solar-like stars will harbour five or more habitable planets. These tightly packed highly habitable systems should be extremely rare, but still possible. Even with our most pessimistic criterion, we still expect that 1.8±0.2 per cent of solar-like stars harbour more than one habitable planet.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Zink, Jon K.0000-0003-1848-2063
Hansen, Bradley M. S.0000-0001-7840-3502
Additional Information:© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2019 April 30. Received 2019 April 19; in original form 2019 February 17. We would like to thank the anonymous referee for useful feedback. The simulations described here were performed on the University of California, Los Angles (UCLA) Hoffman2 shared computing cluster and using the resources provided by the Bhaumik Institute. We would also like to thank the UCLA Department of Physics and Astronomy for support of this project. This research has made use of the National Aeronautics and Space Administration (NASA) Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the NASA under the Exoplanet Exploration Program.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:methods: data analysis, methods: statistical, planets and satellites: fundamental parameters
Issue or Number:1
Record Number:CaltechAUTHORS:20190725-125944308
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Official Citation:Jon K Zink, Bradley M S Hansen, Accounting for multiplicity in calculating eta Earth, Monthly Notices of the Royal Astronomical Society, Volume 487, Issue 1, July 2019, Pages 246–252,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97414
Deposited By: George Porter
Deposited On:25 Jul 2019 21:19
Last Modified:16 Nov 2021 17:31

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