2012/07/13 by Bun'ei Sato, Masashi Omiya, Hiroki Harakawa +8 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.1093/pasj/64.6.135
21 pages, 14 figures, accepted for publication in PASJ
arxiv created 2012/07/13 · openalex publication_date 2012/12/25 · arxiv updated 2015/06/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report the detections of substellar companions orbiting around seven evolved intermediate-mass stars from precise Doppler measurements at Okayama Astrophysical Observatory. o UMa (G4 II-III) is a giant with a mass of 3.1 Msun and hosts a planet with minimum mass of m2sini=4.1 MJ in an orbit with a period P=1630 d and an eccentricity e=0.13. This is the first planet candidate (< 13 MJ) ever discovered around stars more massive than 3 Msun. o CrB (K0 III) is a 2.1 Msun giant and has a planet of m2sini=1.5 MJ in a 187.8 d orbit with e=0.19. This is one of the least massive planets ever discovered around ~2 Msun stars. HD 5608 (K0 IV) is an 1.6 Msun subgiant hosting a planet of m2sini=1.4 MJ in a 793 d orbit with e=0.19. The star also exhibits a linear velocity trend suggesting the existence of an outer, more massive companion. 75 Cet (G3 III:) is a 2.5 Msun giant hosting a planet of m2sini=3.0 MJ in a 692 d orbit with e=0.12. The star also shows possible additional periodicity of about 200 d and 1880 d with velocity amplitude of ~7--10 m/s, although these are not significant at this stage. nu Oph (K0 III) is a 3.0 Msun giant and has two brown-dwarf companions of m2sini= 24 MJ and 27 MJ, in orbits with P=530.3 d and 3190 d, and e=0.126 and 0.17, respectively, which were independently announced by Quirrenbach et al. (2011). The ratio of the periods is close to 1:6, suggesting that the companions are in mean motion resonance. We also independently confirmed planets around k CrB (K0 III-IV) and HD 210702 (K1 IV), which had been announced by Johnson et al. (2008) and Johnson et al. (2007a), respectively. All of the orbital parameters we obtained are consistent with the previous results.