K2-280b——一颗围绕轻度演化恒星的低密度温热亚土星
地球与行星天体物理
2020-07-29 v1 太阳与恒星天体物理
摘要
我们独立发现并详细表征了 K2-280b，这是一颗来自 K2 第 7 观测周期的凌星低密度温热亚土星，处于周期为 19.9 天、中等偏心率的轨道中（e = 0.35_{-0.04}^{+0.05}）。对高精度 HARPS、HARPS-N 和 FIES 视向速度测量以及 K2 测光数据的联合分析表明，K2-280b 的半径为 R_b = 7.50 ± 0.44 R_Earth，质量为 M_b = 37.1 ± 5.6 M_Earth，平均密度为 0.48_{-0.10}^{+0.13} g/cm^3。宿主恒星是一颗轻度演化的 G7 型恒星，有效温度 T_{eff} = 5500 ± 100 K，表面重力 log(g) = 4.21 ± 0.05 (cgs)，铁丰度 [Fe/H] = 0.33 ± 0.08 dex，推断质量为 M_star = 1.03 ± 0.03 M_sun，半径为 R_star = 1.28 ± 0.07 R_sun。我们讨论了 K2-280b 对于检验亚土星行星形成情景以及当前这组在太阳系中缺失的引人入胜的行星族群的重要性。
引用
@article{arxiv.2007.07939,
title = {K2-280b -- a low density warm sub-Saturn around a mildly evolved star},
author = {Grzegorz Nowak and Enric Palle and Davide Gandolfi and Hans J. Deeg and Teruyuki Hirano and Oscar Barragán and Masayuki Kuzuhara and Fei Dai and Rafael Luque and Carina M. Persson and Malcolm Fridlund and Marshall C. Johnson and Judith Korth and John H. Livingston and Sascha Grziwa and Savita Mathur and Artie P. Hatzes and Jorge Prieto-Arranz and David Nespral and Diego Hidalgo and Maria Hjorth and Simon Albrecht and Vincent Van Eylen and Kristine W. F. Lam and William D. Cochran and Massimiliano Esposito and Szilárd Csizmadia and Eike W. Guenther and Petr Kabath and Pere Blay and Rafael Brahm and Andrés Jordán and Néstor Espinoza and Felipe Rojas and Núria Casasayas Barris and Florian Rodler and Roi Alonso Sobrino and Juan Cabrera and Ilaria Carleo and Alexander Chaushev and Jerome de Leon and Philipp Eigmüller and Michael Endl and Anders Erikson and Akihiko Fukui and Iskra Georgieva and Lucía González-Cuesta and Emil Knudstrup and Mikkel N. Lund and Pilar Montañes Rodríguez and Felipe Murgas and Norio Narita and Prajwal Niraula and Martin Pätzold and Heike Rauer and Seth Redfield and Ignasi Ribas and Marek Skarka and Alexis M. S. Smith and Jano Subjak},
journal= {arXiv preprint arXiv:2007.07939},
year = {2020}
}
备注
14 pages, 9 figures, 5 tables, accepted for publication in MNRAS