2003/03/25 by Debra A. Fischer, Geoffrey W. Marcy, R. Paul Butler +6 · 5 citations
Physics and Astronomy · #Stellar, planetary, and galactic studies #Astrophysics and Star Formation Studies #Astro and Planetary Science #Physics #Astrophysics #Exoplanet #Orbital period #O-type main-sequence star #Astronomy #Planet #Planetary system #Orbital inclination #A-type main-sequence star #Starspot #Stars #Rotation period #K-type main-sequence star #Binary number #T Tauri star
paper · doi:10.1086/367889
openalex publication_date 2003/03/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We report the detection of three extrasolar planets from the Lick and Keck observatories. The F8 V star HD 40979 has a companion with orbital period P = 263.1 ± 3 days, eccentricity e = 0.25 ± 0.05, and velocity semiamplitude K = 101.2 ± 5.6 m s -1 . The inferred semimajor axis is 0.83 AU and M sin i = 3.28 M Jup . Observations of planetary companions orbiting the G6 V star HD 12661 and the G4 IV star HD 38529 have already been published, and here we report additional, longer period companions for both of these stars. The outer companion to HD 12661 has P c = 1444.5 ± 12.5 days, e c = 0.20 ± 0.04, and K c = 27.6 ± 2.5 m s -1 . Adopting a stellar mass of 1.07 M ☉ , we find M c sin i = 1.57 M Jup and a semimajor axis of 2.56 AU. The second companion to HD 38529 has P c = 2174 ± 30 days, e c = 0.36 ± 0.05, and K c = 170.5 ± 9 m s -1 . The assumed mass of 1.39 M ☉ for HD 38529 yields M c sin i = 12.7 M Jup and a semimajor axis of 3.68 AU. Photometric observations at Fairborn Observatory reveal low-amplitude brightness variations in HD 40979 and HD 38529 due to rotational modulation in the visibility of photospheric starspots, and they yield rotation periods of 7.0 and 35.7 days, respectively, very different from the planetary orbital periods. The orbital parameters of these two systems are compared with updated parameters for all of the known multiple-planet systems. Updated velocities are provided for the ϒ Andromedae system.