HD 103197 is a star with a planetary companion in the southern constellation of Centaurus. It has an apparent visual magnitude of 9.40,[2] which is too faint to be viewed with the naked eye. Based on parallax measurements, HD 103197 is located at a distance of 187 light years from the Sun. It is drifting closer with a radial velocity of −4.6 km/s.[1]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 11h 52m 52.97822s[1] |
| Declination | –50° 17′ 34.1592″[1] |
| Apparent magnitude (V) | 9.40[2] |
| Characteristics | |
| Spectral type | K1V(p)[3] |
| Apparent magnitude (B) | 10.26[2] |
| Apparent magnitude (J) | 7.916±0.023[2] |
| Apparent magnitude (H) | 7.600±0.051[2] |
| Apparent magnitude (K) | 7.426±0.027[2] |
| B−V color index | 0.860±0.023[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.55±0.21[1] km/s |
| Proper motion (μ) | RA: –80.938[1] mas/yr Dec.: +7.188[1] mas/yr |
| Parallax (π) | 17.4700 ± 0.0294 mas[1] |
| Distance | 186.7 ± 0.3 ly (57.24 ± 0.10 pc) |
| Absolute magnitude (MV) | 5.79[2] |
| Details | |
| Mass | 0.90[4] M☉ |
| Radius | 0.95±0.02[1] R☉ |
| Luminosity | 0.566+0.002 −0.001[1] L☉ |
| Surface gravity (log g) | 4.40±0.11[4] cgs |
| Temperature | 5,303±58[4] K |
| Metallicity [Fe/H] | 0.21±0.04[4] dex |
| Rotation | 51±5 d[4] |
| Rotational velocity (v sin i) | 0.602[5] km/s |
| Age | 4.872±4.294[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is a K-type main-sequence star with a stellar classification of K1V(p). In 1978, N. Houk noted that the cores of the star's H and K lines are weakly in emission; hence the 'p' code indicating a spectral peculiarity.[3] The star is an estimated five billion years old with a projected rotational velocity of approximately 0.6 km/s[5] and it appears to be very inactive. It has 90% of the mass and 95% of the radius of the Sun. Its metal content is five-eighths greater than in the Sun.[4]
In 2009, a gas giant exoplanet companion was discovered using the radial velocity method. This object is orbiting the host star at a distance of 0.249 AU (37.2 Gm) and a period of 47.84 d, with what is assumed to be a circular orbit.[4]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥31.2 ± 2.0 M🜨 | 0.249 ± 0.004 | 47.84 ± 0.03 | 0.0(fixed) | — | — |