Iodine-Cell Spectroscopy at Okayama Astrophysical Observatory: First Results

• Published in: Publications of the Astronomical Society of Japan 2002-02, Vol.54 (1), p.113-120
• Main Authors: Takeda, Yoichi, Sato, Bun’ei, Kambe, Eiji, Watanabe, Etsuji, Miyazaki, Hideaki, Wada, Setsuko, Ando, Hiroyasu, Masuda, Seiji, Izumiura, Hideyuki, Koyano, Hisashi, Maehara, Hideo, Norimoto, Yuji, Okada, Takafumi, Shimizu, Yasuhiro, Uraguchi, Fumihiro, Yanagisawa, Kenshi, Yoshida, Michitoshi, Okada, Norio, Kawanomoto, Satoshi, Miyama, Shoken M.
• Format: Article
• Language: English
• ISSN: 0004-6264; 2053-051X
• DOI: 10.1093/pasj/54.1.113

Toward the aims of spectroscopically searching for planetary systems around stars, or detecting oscillations of solar-type stars for stellar seismology, we have started an experimental project of very precise determinations of stellar radial velocity variations based on the iodine-cell ( $\mathrm{I}_{2}$ cell) technique at Okayama Astrophysical Observatory. We here report on the first preliminary results of test observations for two planet-harboring stars ( $\upsilon $ And and $\tau $ Boo) based on data obtained by using the newly developed $\mathrm{I}_{2}$ cell and processed with a practical and quick analysis method. We confirmed that the internal statistical error can be as small as $5 \hbox{--} 6 \,\mathrm{m} \,\mathrm{s}^{-1}$ at best. Then, the resulting radial velocity solutions turned out to be in reasonable agreement with the well-established predicted variations over a time span of 4–5 days; the $O-C$ deviations indicate that a short-time-scale precision of $\sim 15\,\mathrm{m} \,\mathrm{s}^{-1}$ has been accomplished in a practical sense.