http://arxiv.org/abs/1806.08368
We report the discovery of a compact multi-planet system orbiting the relatively nearby (78pc) and bright ($K=8.9$) K-star, EPIC248435473 (K2-XXX). We identify up to six possible planets orbiting EPIC248435473 with estimated periods of P$b$ = 0.66, P${.02}$ = 6.1, P$c$ = 7.8, P$_d$ = 14.7, P$_e$ = 19.5, and P${.06}$ = 56.7 days and radii of R$P$ = 2.9 R${\oplus}$, 0.579 R${\oplus}$, 0.637 R${\oplus}$, 2.644 R${\oplus}$, 2.446 R${\oplus}$, and 0.81 R$_{\oplus}$, respectively. We are able to confidently validate the planetary nature of four of these planets (P$_b$ = 0.66d, P$_c$ = 7.8d, P$_d$ = 14.7d, and P$_e$ = 19.5d), while classifying the other two as planetary candidates (EPIC248435473.02 & .06). From a simultaneous fit of all 6 possible planets, we find that EPIC248435473 b’s orbit has an inclination of 76.5$^{\circ}$ while the other five planets have inclinations of 88-90$^{\circ}$. This observed mutual misalignment may indicate that EPIC248435473 b formed differently from the other planets in the system. The brightness of the host star and the relatively large size of the sub-Neptune sized planets d and e make them well-suited for atmospheric characterization efforts with facilities like the Hubble Space Telescope and upcoming James Webb Space Telescope. We also identify an 8.5-day transiting planet candidate orbiting EPIC248435395, a co-moving companion to EPIC248435473.
J. Rodriguez, J. Becker, J. Eastman, et. al.
Mon, 25 Jun 18
10/54
Comments: 18 pages, 12 figures, 7 tables, Submitted to the AAS Journals
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