A Neptune-sized Exoplanet Consistent with a Pure Rock Composition [EPA]

http://arxiv.org/abs/1601.07608


We report the discovery of BD+20594b, a Neptune-sized exoplanet consistent with a pure rock composition, made using photometry from Campaign 4 of the two-wheeled Kepler (K2) mission. The host star is a bright ($V=11.04$, $K_s = 9.37$), slightly metal poor ([Fe/H]$=-0.15\pm 0.05$ dex) solar analogue located at $152.1^{+9.7}_{-7.4}$ pc from Earth, for which we find a radius of $R_*=0.928^{+0.055}_{-0.040}R_\odot$ and a mass of $M_* = 0.961^{+0.032}_{-0.029}M_\odot$. A joint analysis of the K2 photometry and HARPS radial velocities reveal that the planet is in a $\approx 42$ day orbit around its host star, has a radius of $2.23^{+0.14}_{-0.11}R_\oplus$, and a mass of $16.3^{+6.0}_{-6.1}M_\oplus$. The data at hand are most consistent with a pure rock composition with a low volatile content, potentially making it a rare exception among Neptune-sized exoplanets discovered so far.

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N. Espinoza, R. Brahm, A. Jordan, et. al.
Fri, 29 Jan 16
16/52

Comments: 11 pages, 11 figures. Submitted to ApJ