An accurate mass determination for Kepler-1655b, a moderately-irradiated world with a significant volatile envelope

• Published in: arXiv.org
• Main Authors: Haywood, R D, Vanderburg, A, Mortier, A, Giles, H A C, López-Morales, M, Lopez, E D, Malavolta, L, Charbonneau, D, A Collier Cameron, Coughlin, J L, Dressing, C D, Nava, C, Latham, D W, Dumusque, X, Lovis, C, Molinari, E, Pepe, F, Sozzetti, A, Udry, S, Bouchy, F, Johnson, J A, Mayor, M, Micela, G, Phillips, D, Piotto, G, Rice, K, Sasselov, D, Ségransan, D, Watson, C, Affer, L, Bonomo, A S, Buchhave, L A, Ciardi, D R, Fiorenzano, A F, Harutyunyan, A
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 23.03.2018
• Subjects: Gaussian process; Light curve; Physics - Earth and Planetary Astrophysics; Regression analysis
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1803.08820

We present the confirmation of a small, moderately-irradiated (F = 155 +/- 7 Fearth) Neptune with a substantial gas envelope in a P=11.8728787+/-0.0000085-day orbit about a quiet, Sun-like G0V star Kepler-1655. Based on our analysis of the Kepler light curve, we determined Kepler-1655b's radius to be 2.213+/-0.082 Rearth. We acquired 95 high-resolution spectra with TNG/HARPS-N, enabling us to characterize the host star and determine an accurate mass for Kepler-1655b of 5.0+3.1/-2.8 Mearth via Gaussian-process regression. Our mass determination excludes an Earth-like composition with 98\% confidence. Kepler-1655b falls on the upper edge of the evaporation valley, in the relatively sparsely occupied transition region between rocky and gas-rich planets. It is therefore part of a population of planets that we should actively seek to characterize further.