1. THE KEPLER-454 SYSTEM: A SMALL, NOT-ROCKY INNER PLANET, A JOVIAN WORLD, and A DISTANT COMPANION
- Author
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Gettel, S, Gettel, S, Charbonneau, D, Dressing, CD, Buchhave, LA, Dumusque, X, Vanderburg, A, Bonomo, AS, Malavolta, L, Pepe, F, Cameron, AC, Latham, DW, Udry, S, Marcy, GW, Isaacson, H, Howard, AW, Davies, GR, Aguirre, VS, Kjeldsen, H, Bedding, TR, Lopez, E, Affer, L, Cosentino, R, Figueira, P, Fiorenzano, AFM, Harutyunyan, A, Johnson, JA, Lopez-Morales, M, Lovis, C, Mayor, M, Micela, G, Molinari, E, Motalebi, F, Phillips, DF, Piotto, G, Queloz, D, Rice, K, Sasselov, D, Ségransan, D, Sozzetti, A, Watson, C, Basu, S, Campante, TL, Christensen-Dalsgaard, J, Kawaler, SD, Metcalfe, TS, Handberg, R, Lund, MN, Lundkvist, MS, Huber, D, Chaplin, WJ, Gettel, S, Gettel, S, Charbonneau, D, Dressing, CD, Buchhave, LA, Dumusque, X, Vanderburg, A, Bonomo, AS, Malavolta, L, Pepe, F, Cameron, AC, Latham, DW, Udry, S, Marcy, GW, Isaacson, H, Howard, AW, Davies, GR, Aguirre, VS, Kjeldsen, H, Bedding, TR, Lopez, E, Affer, L, Cosentino, R, Figueira, P, Fiorenzano, AFM, Harutyunyan, A, Johnson, JA, Lopez-Morales, M, Lovis, C, Mayor, M, Micela, G, Molinari, E, Motalebi, F, Phillips, DF, Piotto, G, Queloz, D, Rice, K, Sasselov, D, Ségransan, D, Sozzetti, A, Watson, C, Basu, S, Campante, TL, Christensen-Dalsgaard, J, Kawaler, SD, Metcalfe, TS, Handberg, R, Lund, MN, Lundkvist, MS, Huber, D, and Chaplin, WJ
- Abstract
Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like star that hosts a transiting planet candidate in a 10.6 day orbit. From spectroscopy, we estimate the stellar temperature to be 5687 ± 50 K, its metallicity to be [m/H] = 0.32 ± 0.08, and the projected rotational velocity to be v sin i < 2.4 km s-1. We combine these values with a study of the asteroseismic frequencies from short cadence Kepler data to estimate the stellar mass to be , the radius to be 1.066 ± 0.012 Ro, and the age to be Gyr. We estimate the radius of the 10.6 day planet as 2.37 ± 0.13 R⊕. Using 63 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 36 observations made with the HIRES spectrograph at the Keck Observatory, we measure the mass of this planet to be 6.8 ± 1.4 M⊕. We also detect two additional non-transiting companions, a planet with a minimum mass of 4.46 ± 0.12 MJ in a nearly circular 524 day orbit and a massive companion with a period >10 years and mass >12.1 MJ. The 12 exoplanets with radii <2.7 R⊕ and precise mass measurements appear to fall into two populations, with those <1.6 R⊕ following an Earth-like composition curve and larger planets requiring a significant fraction of volatiles. With a density of 2.76 ± 0.73 g cm-3, Kepler-454b lies near the mass transition between these two populations and requires the presence of volatiles and/or H/He gas.
- Published
- 2016