A 1.9 Earth Radius Rocky Planet and the Discovery of a Non-Transiting Planet in the Kepler-20 System
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Author
Buchhave, Lars A.
Dressing, Courtney D.
Dumusque, Xavier
Rice, Ken
Mortier, Annelies
Lopez-Morales, Mercedes
Lopez, Eric
Lundkvist, Mia S.
Kjeldsen, Hans
Affer, Laura
Bonomo, Aldo S.
Cameron, Andrew Collier
Cosentino, Rosario
Figueira, Pedro
Fiorenzano, Aldo F. M.
Harutyunyan, Avet
Lovis, Christophe
Malavolta, Luca
Mayor, Michel
Micela, Giusi
Molinari, Emilio
Motalebi, Fatemeh
Nascimbeni, Valerio
Pepe, Francesco
Piotto, Giampaolo
Pollacco, Don
Queloz, Didier
Ségransan, Damien
Sozzetti, Alessandro
Udry, Stéphane
Watson, Chris
Note: Order does not necessarily reflect citation order of authors.
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https://doi.org/10.3847/0004-6256/152/6/160Metadata
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Buchhave, Lars A., Courtney D. Dressing, Xavier Dumusque, Ken Rice, Andrew Vanderburg, Annelies Mortier, Mercedes Lopez-Morales, et al. 2016. A 1.9 Earth Radius Rocky Planet and the Discovery of a Non-Transiting Planet in the Kepler-20 System. The Astronomical Journal 152, no. 6: 160. doi:10.3847/0004-6256/152/6/160.Abstract
Kepler-20 is a solar-type star (V = 12.5) hosting a compact system of five transiting planets, all packed within the orbital distance of Mercury in our own solar system. A transition from rocky to gaseous planets with a planetary transition radius of ~1.6 ${R}_{\oplus }$ has recently been proposed by several articles in the literature. Kepler-20b (${R}_{p}$ ~ 1.9 ${R}_{\oplus }$) has a size beyond this transition radius; however, previous mass measurements were not sufficiently precise to allow definite conclusions to be drawn regarding its composition. We present new mass measurements of three of the planets in the Kepler-20 system that are facilitated by 104 radial velocity measurements from the HARPS-N spectrograph and 30 archival Keck/HIRES observations, as well as an updated photometric analysis of the Kepler data and an asteroseismic analysis of the host star (${M}_{\star }$ = $0.948\pm 0.051$ ${M}_{\odot }$ and ${R}_{\star }$ = $0.964\pm 0.018$ ${R}_{\odot }$). Kepler-20b is a ${1.868}_{-0.034}^{+0.066}$ ${R}_{\oplus }$ planet in a 3.7 day period with a mass of ${9.70}_{-1.44}^{+1.41}$ ${M}_{\oplus }$, resulting in a mean density of ${8.2}_{-1.3}^{+1.5}$ ${\rm{g}}\,{\mathrm{cm}}^{-3}$, indicating a rocky composition with an iron-to-silicate ratio consistent with that of the Earth. This makes Kepler-20b the most massive planet with a rocky composition found to date. Furthermore, we report the discovery of an additional non-transiting planet with a minimum mass of ${19.96}_{-3.61}^{+3.08}$ ${M}_{\oplus }$ and an orbital period of ~34 days in the gap between Kepler-20f (P ~ 11 days) and Kepler-20d (P ~ 78 days).Other Sources
https://arxiv.org/pdf/1608.06836.pdfTerms of Use
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