HD 109749
HD 109749 is a binary star system about 206 light years away in the constellation of Centaurus. The pair have a combined apparent visual magnitude of 8.08, which is too faint to be visible to the naked eye. The primary component has a close orbiting exoplanet companion. The system is drifting closer with a heliocentric radial velocity of −13.2 km/s.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 12h 37m 16.379s |
| Declination | −40° 48′ 43.63″ |
| Apparent magnitude (V) | 8.08 |
| Characteristics | |
| Spectral type | G3 IV or G3 V + K5 V |
| B−V color index | 0.714±0.021 |
| Astrometry | |
| Radial velocity (Rv) | −13.24±0.18 km/s |
| Proper motion (μ) | RA: −157.308 mas/yr Dec.: −6.357 mas/yr |
| Parallax (π) | 15.8134 ± 0.0263 mas |
| Distance | 206.3 ± 0.3 ly (63.2 ± 0.1 pc) |
| Absolute magnitude (MV) | 4.34 |
| Details | |
| HD 109749 A | |
| Mass | 1.10 M☉ |
| Radius | 1.21±0.02 R☉ |
| Luminosity | 1.55±0.02 L☉ |
| Surface gravity (log g) | 4.32±0.02 cgs |
| Temperature | 5,860±39 K |
| Metallicity [Fe/H] | 0.25±0.05 dex |
| Rotation | 34 d |
| Rotational velocity (v sin i) | 2.5±0.5 km/s |
| Age | 4.10±0.70 Gyr |
| HD 109749 B | |
| Mass | 0.78 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
The primary component, HD 109749 A, is a G-type subgiant star with a spectral type of G3IV, indicating it is an evolved star with a luminosity higher than that of a main sequence star. It has a mass of 1.14 M☉ and a radius of 1.21 R☉. The star is shining with a luminosity of 1.55 L☉ and has an effective temperature of 5,860 K. Evolutionary models estimate an age of 4.1 billion years. HD 109749 A is chromospherically inactive and has a high metallicity, with an iron abundance 178% of Sun's.
The secondary, HD 109749 B, is a K-type main sequence star with an apparent magnitude of 10.3. It has a mass of about 0.78 M☉ and is located at a separation of 8.4 arcseconds, which corresponds to a projected separation of 490 AU. This star has the same proper motion as the primary and seems to be at the same distance, confirming they form a physical binary system.