A pair of giant planets around the evolved intermediate-mass star hd 47366: multiple circular orbits or a mutually retrograde configuration
Article
Article Title | A pair of giant planets around the evolved intermediate-mass star hd 47366: multiple circular orbits or a mutually retrograde configuration |
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ERA Journal ID | 1057 |
Article Category | Article |
Authors | Sato, Bun’ei (Author), Wang, Liang (Author), Liu, Yu-Juan (Author), Zhao, Gang (Author), Omiya, Masashi (Author), Harakawa, Hiroki (Author), Nagasawa, Makiko (Author), Wittenmyer, Robert A. (Author), Butler, Paul (Author), Song, Nan (Author), He, Wei (Author), Zhao, Fei (Author), Kambe, Eiji (Author), Noguchi, Kunio (Author), Ando, Hiroyasu (Author), Izumiura, Hideyuki (Author), Okada, Norio (Author), Yoshida, Michitoshi (Author), Takeda, Yoichi (Author), Itoh, Yoichi (Author), Kokubo, Eiichiro (Author) and Ida, Shigeru (Author) |
Journal Title | The Astrophysical Journal: an international review of astronomy and astronomical physics |
Journal Citation | 819 (1) |
Article Number | 59 |
Number of Pages | 11 |
Year | 2016 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-637X |
1538-4357 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/0004-637X/819/1/59 |
Web Address (URL) | https://iopscience.iop.org/article/10.3847/0004-637X/819/1/59 |
Abstract | We report the detection of a double planetary system around the evolved intermediate-mass star HD 47366 from precise radial-velocity measurements at the Okayama Astrophysical Observatory, Xinglong Station, and Australian Astronomical Observatory. The star is a K1 giant with a mass of 1.81 ± 0.13 M⊙, a radius of 7.30 ± 0.33 R⊙, and solar metallicity. The planetary system is composed of two giant planets with minimum masses of 1.75-0.17+0.20 MJ and 1.86-0.15+0.16 MJ, orbital periods of 363.3-2.4+2.5 days and 684.7-4.9+5.0 days, and eccentricities of 0.089-0.060+0.079 and 0.278-0.094+0.067, respectively, which are derived by a double Keplerian orbital fit to the radial-velocity data. The system adds to the population of multi-giant-planet systems with relatively small orbital separations, which are preferentially found around evolved intermediate-mass stars. Dynamical stability analysis for the system revealed, however, that the best-fit orbits are unstable in the case of a prograde configuration. The system could be stable if the planets were in 2:1 mean-motion resonance, but this is less likely, considering the observed period ratio and eccentricity. A present possible scenario for the system is that both of the planets have nearly circular orbits, namely the eccentricity of the outer planet is less than ∼0.15, which is just within 1.4σ of the best-fit value, or the planets are in a mutually retrograde configuration with a mutual orbital inclination larger than 160°. |
Keywords | stars; HD 47366; techniques; radial velocities |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | For access to this article, please click on the URL link provided. |
Byline Affiliations | Tokyo Institute of Technology, Japan |
Key Laboratory of Optical Astronomy, China | |
National Astronomical Observatory of Japan, Japan | |
Kurume University, Japan | |
University of New South Wales | |
Carnegie Institution of Washington, United States | |
Hiroshima University, Japan | |
University of Hyogo, Japan | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q3x43/a-pair-of-giant-planets-around-the-evolved-intermediate-mass-star-hd-47366-multiple-circular-orbits-or-a-mutually-retrograde-configuration
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