A Planet Orbiting the Star ρ Coronae Borealis

We report the discovery of near-sinusoidal radial velocity variations of the G0V star ρ CrB, with period 39.6 days and amplitude 67 m s-1. These variations are consistent with the existence of an orbital companion in a circular orbit. Adopting a mass of 1.0 M☉ for the primary, the companion has minimum mass about 1.1 Jupiter masses and orbital radius about 0.23 AU. Such an orbital radius is too large for tidal circularization of an initially eccentric orbit during the lifetime of the star, and hence we suggest that the low eccentricity is primordial, as would be expected for a planet formed in a dissipative circumstellar disk.

[1]  Hartmut Jahreiss,et al.  Preliminary Version of the Third Catalogue of Nearby Stars , 1991 .

[2]  D. Soderblom.  A survey of chromospheric emission and rotation among solar-type stars in the solar neighborhood. , 1985 .

[3]  R. Paul Butler,et al.  A Planet Orbiting 47 Ursae Majoris , 1996 .

[4]  M. Mayor,et al.  A Jupiter-mass companion to a solar-type star , 1995, Nature.

[5]  Chromospheric variations in main-sequence stars , 1978 .

[6]  J. Alexander.  The Chemical Composition and Ultra-Violet Excess of G Dwarfs , 1967 .

[7]  J. Silk.  On the fragmentation of cosmic gas clouds. II - Opacity-limited star formation , 1977 .

[8]  A. Boss.  Proximity of Jupiter-Like Planets to Low-Mass Stars , 1995, Science.

[9]  P. Charbonneau.  Genetic algorithms in astronomy and astrophysics , 1995 .

[10]  Tidal decay of close planetary orbits , 1996, astro-ph/9605059.

[11]  David F. Gray,et al.  Absence of a planetary signature in the spectra of the star 51 Pegasi , 1997, Nature.

[12]  G. Wallerstein,et al.  Abundances in G. Dwarfs.VI. a Survey of Field Stars. , 1962 .

[13]  P. Naur.  Magnitudes and Colors of Bright F Stars. , 1955 .

[14]  R. Paul Butler,et al.  The Planet around 51 Pegasi , 1997 .

[15]  Timothy M. Brown,et al.  THE AFOE: A SPECTROGRAPH FOR PRECISION DOPPLER STUDIES , 1994 .

[16]  N. Roman.  The Spectra of the Bright Stars of Types F5-K5. , 1952 .

[17]  Jack J. Lissauer,et al.  Urey Prize Lecture: On the Diversity of Plausible Planetary Systems , 1995 .

[18]  W. Soon,et al.  Magnetic Field and Rotation in Lower Main-Sequence Stars: An Empirical Time-Dependent Magnetic Bode's Relation? , 1996 .

[19]  T. L. Moore,et al.  Radial velocity observations of the sun at night , 1993 .

[20]  A. N. Argue.  UBV Photometry of 300 G and K Type Stars , 1962 .

[21]  David F. Gray,et al.  SPECTRAL LINE-DEPTH RATIOS AS TEMPERATURE INDICATORS FOR COOL STARS , 1994 .

[22]  Robert L. Kurucz,et al.  A calibration of Geneva photometry for B to G stars in terms of Teff, log g and $[M/H]$ , 1997 .

[23]  S. Baliunas,et al.  Rotation, convection, and magnetic activity in lower main-sequence stars , 1984 .

[24]  N. Roman.  A Catalogue of High-Velocity Stars. , 1955 .

[25]  S. Horner.  A Search for Pulsations in Four Late-Type Giants , 1996 .

[26]  D. F. Gray.  THE INFERRED COLOR INDEX OF THE SUN , 1992 .

[27]  G. C. Strobel.  Stars resembling the Sun , 1996 .

[28]  R. P. Butler,et al.  ATTAINING DOPPLER PRECISION OF 3 M S-1 , 1996 .

[29]  S. Arribas,et al.  Determination of effective temperatures for an extended sample of dwarfs and subdwarfs (F0-K5) , 1996 .