文章基本信息

标题：Three planets around HD 27894
其他标题：A close-in pair with a 2:1 period ratio and an eccentric Jovian planet at 5.4 AU⋆
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作者：T. Trifonov ; T. Trifonov ; M. Kürster 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2017
卷号：602
页码：1-5
DOI：10.1051/0004-6361/201731044
语种：English
出版社：EDP Sciences
摘要：Aims. Our new program with HARPS aims to detect mean motion resonant planetary systems around stars which were previously reported to have a single bona fide planet, often based only on sparse radial velocity data. Methods. Archival and new HARPS radial velocities for the K2V star HD 27894 were combined and fitted with a three-planet self-consistent dynamical model. The best-fit orbit was tested for long-term stability. Results. We find clear evidence that HD 27894 is hosting at least three massive planets. In addition to the already known Jovian planet with a period Pb≈ 18 days we discover a Saturn-mass planet with Pc≈ 36 days, likely in a 2:1 mean motion resonance with the first planet, and a cold massive planet (≈5.3 MJup) with a period Pd ≈ 5170 days on a moderately eccentric orbit (ed = 0.39). Conclusions. HD 27894 is hosting a massive, eccentric giant planet orbiting around a tightly packed inner pair of massive planets likely involved in an asymmetric 2:1 mean motion resonance. HD 27894 may be an important milestone for probing planetary formation and evolution scenarios.
关键词：entechniques: radial velocitiesplanetary systemsplanets and satellites: dynamical evolution and stability