An Accurate Mass Determination for Kepler-1655b, a Moderately Irradiated World with a Significant Volatile Envelope

May 2018 • 2018AJ....155..203H

Authors • Haywood, Raphaëlle D. • Vanderburg, Andrew • Mortier, Annelies • Giles, Helen A. C. • López-Morales, Mercedes • Lopez, Eric D. • Malavolta, Luca • Charbonneau, David • Collier Cameron, Andrew • Coughlin, Jeffrey L. • Dressing, Courtney D. • Nava, Chantanelle • Latham, David W. • Dumusque, Xavier • Lovis, Christophe • Molinari, Emilio • Pepe, Francesco • Sozzetti, Alessandro • Udry, Stéphane • Bouchy, François • Johnson, John A. • Mayor, Michel • Micela, Giusi • Phillips, David • Piotto, Giampaolo • Rice, Ken • Sasselov, Dimitar • Ségransan, Damien • Watson, Chris • Affer, Laura • Bonomo, Aldo S. • Buchhave, Lars A. • Ciardi, David R. • Fiorenzano, Aldo F. • Harutyunyan, Avet

Abstract • We present the confirmation of a small, moderately irradiated (F = 155 ± 7 F ) 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 R . We acquired 95 high-resolution spectra with Telescopio Nazionale Galileo/HARPS-N, enabling us to characterize the host star and determine an accurate mass for Kepler-1655b of 5.0{+/- }2.83.1 {M}\oplus 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.


IPAC Authors


David Ciardi

Senior Scientist