High-contrast imaging of intermediate-mass giants with long-term radial velocity trends

Tsuguru Ryu, Bun'Ei Sato, Masayuki Kuzuhara, Norio Narita, Yasuhiro H. Takahashi, Taichi Uyama, Tomoyuki Kudo, Nobuhiko Kusakabe, Jun Hashimoto, Masashi Omiya, Hiroki Harakawa, Lyu Abe, Hiroyasu Ando, Wolfgang Brandner, Timothy D. Brandt, Joseph C. Carson, Thayne Currie, Sebastian Egner, Markus Feldt, Miwa GotoCarol A. Grady, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Saeko S. Hayashi, Krzysztof G. Hełminiak, Thomas Henning, Klaus W. Hodapp, Shigeru Ida, Miki Ishii, Yoichi Itoh, Masanori Iye, Hideyuki Izumiura, Markus Janson, Eiji Kambe, Ryo Kandori, Gillian R. Knapp, Eiichiro Kokubo, Jungmi Kwon, Taro Matsuo, Satoshi Mayama, Michael W. McElwain, Kyle Mede, Shoken Miyama, Jun Ichi Morino, Amaya Moro-Martin, Tetsuo Nishimura, Tae Soo Pyo, Eugene Serabyn, Takuya Suenaga, Hiroshi Suto, Ryuji Suzuki, Michihiro Takami, Naruhisa Takato, Yoichi Takeda, Hiroshi Terada, Christian Thalmann, Edwin L. Turner, Makoto Watanabe, John Wisniewski, Toru Yamada, Michitoshi Yoshida, Hideki Takami, Tomonori Usuda, Motohide Tamura

Research output: Contribution to journalArticle

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Abstract

A radial velocity (RV) survey for intermediate-mass giants has been in operation for over a decade at Okayama Astrophysical Observatory (OAO). The OAO survey has revealed that some giants show long-term linear RV accelerations (RV trends), indicating the presence of outer companions. Direct-imaging observations can help clarify what objects generate these RV trends. We present the results of high-contrast imaging observations of six intermediate-mass giants with long-term RV trends using the Subaru Telescope and HiCIAO camera. We detected co-moving companions to γ Hya B (0.61-0.14+0.12M), HD 5608 B (0.10 ± 0.01M), and HD 109272 B (0.28 ± 0.06 M). For the remaining targets (ι Dra, 18 Del, and HD 14067), we exclude companions more massive than 30-60 M Jup at projected separations of 1″-7″. We examine whether these directly imaged companions or unidentified long-period companions can account for the RV trends observed around the six giants. We find that the Kozai mechanism can explain the high eccentricity of the inner planets ι Dra b, HD 5608 b, and HD 14067 b.

Original languageEnglish (US)
Article number127
JournalAstrophysical Journal
Volume825
Issue number2
DOIs
StatePublished - Jul 10 2016

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • binaries: general
  • methods: observational
  • planetary systems
  • techniques: high angular resolution
  • techniques: radial velocities

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    Ryu, T., Sato, BE., Kuzuhara, M., Narita, N., Takahashi, Y. H., Uyama, T., Kudo, T., Kusakabe, N., Hashimoto, J., Omiya, M., Harakawa, H., Abe, L., Ando, H., Brandner, W., Brandt, T. D., Carson, J. C., Currie, T., Egner, S., Feldt, M., ... Tamura, M. (2016). High-contrast imaging of intermediate-mass giants with long-term radial velocity trends. Astrophysical Journal, 825(2), [127]. https://doi.org/10.3847/0004-637X/825/2/127