Regular radial velocity variations in nine G- and K-type giant stars: Eight planets and one planet candidate

• DOI: 10.1093/pasj/psab112
• Publication Date: 2021-11-11T12:09:33Z
• Authors: Huan-Yu Teng; Bun’ei Sato; Takuya Takarada; Masashi Omiya; Hiroki Harakawa; Hideyuki Izumiura; Eiji Kambe; Yoichi Takeda; Michitoshi Yoshida; Yoichi Itoh; Hiroyasu Ando; Eiichiro Kokubo
• Keywords: Giant planet; Radial velocity; Giant star

We report the detection of radial velocity variations in nine evolved G- and K-type giant stars. The observations were conducted at Okayama Astrophysical Observatory. Planets or planet candidates can best explain these regular variations. However, a coincidence near 280-day variability among five them prevents us from fully ruling out stellar origins for some variations, since all stars behave similarly properties. In hypotheses to RV planets (including one candidate) may survive close boundary so-called "planet desert" around stars, having orbital periods between 255 555 days. Besides, they are least-massive detected with minimum masses 0.45$M_{\rm{J}}$ 1.34$M_{\rm{J}}$. further investigated other our detection, yet none better variation. With it is convinced that year-long variation amplitude down 15 $\rm{m\ s^{-1}}$ detectable. Moreover, we performed simulations confirm detectability Finally, explored intermediate-mass likewise found 4 Jupiter mass gap (e.g. Santo et al. 2017), which probably population.