Accounting for Multiplicity in Calculating Eta Earth. (arXiv:1905.01032v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Zink_J/0/1/0/all/0/1">Jon K. Zink</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hansen_B/0/1/0/all/0/1">Bradley M. S. Hansen</a>
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 $eta_{oplus}$ 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
$eta_{oplus}$ value of $0.34pm 0.02 frac{rm planets}{rm star}$. We also
consider the effects of multiplicity and the number of habitable planets each
system may contain. Our calculation indicates that $6.4pm0.5%$ of GK dwarfs
have more than one planet within their habitable zone. This optimistic
habitability criterion also suggests that $0.036pm0.009%$ of solar-like stars
will harbor 5 or more habitable planets. These tightly packed highly habitable
system should be extremely rare, but still possible. Even with our most
pessimistic criterion we still expect that $1.8pm0.2%$ of solar-like stars
harbor more than one habitable planet.
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 $eta_{oplus}$ 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
$eta_{oplus}$ value of $0.34pm 0.02 frac{rm planets}{rm star}$. We also
consider the effects of multiplicity and the number of habitable planets each
system may contain. Our calculation indicates that $6.4pm0.5%$ of GK dwarfs
have more than one planet within their habitable zone. This optimistic
habitability criterion also suggests that $0.036pm0.009%$ of solar-like stars
will harbor 5 or more habitable planets. These tightly packed highly habitable
system should be extremely rare, but still possible. Even with our most
pessimistic criterion we still expect that $1.8pm0.2%$ of solar-like stars
harbor more than one habitable planet.
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