TY - JOUR
T1 - A 1.9 EARTH RADIUS ROCKY PLANET and the DISCOVERY of A NON-TRANSITING PLANET in the KEPLER-20 SYSTEM
AU - Buchhave, Lars A.
AU - Dressing, Courtney D.
AU - Dumusque, Xavier
AU - Rice, Ken
AU - Vanderburg, Andrew
AU - Mortier, Annelies
AU - Lopez-Morales, Mercedes
AU - Lopez, Eric
AU - Lundkvist, Mia S.
AU - Kjeldsen, Hans
AU - Affer, Laura
AU - Bonomo, Aldo S.
AU - Charbonneau, David
AU - Cameron, Andrew Collier
AU - Cosentino, Rosario
AU - Figueira, Pedro
AU - Fiorenzano, Aldo F. M.
AU - Harutyunyan, Avet
AU - Haywood, Raphaëlle D.
AU - Johnson, John Asher
AU - Latham, David W.
AU - Lovis, Christophe
AU - Malavolta, Luca
AU - Mayor, Michel
AU - Micela, Giusi
AU - Molinari, Emilio
AU - Motalebi, Fatemeh
AU - Nascimbeni, Valerio
AU - Pepe, Francesco
AU - Phillips, David F.
AU - Piotto, Giampaolo
AU - Pollacco, Don
AU - Queloz, Didier
AU - Sasselov, Dimitar
AU - Ségransan, Damien
AU - Sozzetti, Alessandro
AU - Udry, Stéphane
AU - Watson, Chris
PY - 2016/11/11
Y1 - 2016/11/11
N2 - 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⊕ has recently been proposed by several articles in the literature. Kepler-20b (∼ 1.9 R⊕) 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∗= 0.948 ± 0.051 M⊙and = R∗ = 0.964 ± 0.018 R⊙). Kepler-20b is a 1.868-0.034+0.006 planet in a 3.7 day period with a mass of 9.70-1.44+1.41M⊕, resulting in a mean density of 8.2-1.3+1.5, 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+3.08M⊕ and an orbital period of ∼34 days in the gap between Kepler-20f (P ∼ 11 days) and Kepler-20d (P ∼ 78 days).
AB - 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⊕ has recently been proposed by several articles in the literature. Kepler-20b (∼ 1.9 R⊕) 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∗= 0.948 ± 0.051 M⊙and = R∗ = 0.964 ± 0.018 R⊙). Kepler-20b is a 1.868-0.034+0.006 planet in a 3.7 day period with a mass of 9.70-1.44+1.41M⊕, resulting in a mean density of 8.2-1.3+1.5, 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+3.08M⊕ and an orbital period of ∼34 days in the gap between Kepler-20f (P ∼ 11 days) and Kepler-20d (P ∼ 78 days).
KW - planetary systems
KW - planets and satellites: composition
KW - stars: individual
KW - techniques: radial velocities
UR - http://www.scopus.com/inward/record.url?scp=85009100612&partnerID=8YFLogxK
U2 - 10.3847/0004-6256/152/6/160
DO - 10.3847/0004-6256/152/6/160
M3 - Article
AN - SCOPUS:85009100612
SN - 0004-6256
VL - 152
JO - Astronomical Journal
JF - Astronomical Journal
IS - 6
M1 - 160
ER -
