HD 19467
HD 19467 is a star with an orbiting brown dwarf companion in the equatorial constellation of Eridanus. It has an apparent visual magnitude of 6.97, which is a challenge to view with the naked eye. The system is located at a distance of 104.5 light years based on parallax measurements, and is drifting further away with a radial velocity of 7 km/s. It has a high proper motion, traversing the celestial sphere at an angular rate of 0.258 arcsec yr−1. Based on the motion and chemical abundances of this star it has been considered a likely member of the Wolf 630 group of co-moving stars, although its age estimate is inconsistent with that assignment.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 03h 07m 18.575s |
| Declination | −13° 45′ 42.42″ |
| Apparent magnitude (V) | 6.97 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | G3 V + T5.5±1.0 |
| B−V color index | 0.645±0.010 |
| Astrometry | |
| Radial velocity (Rv) | 6.953±0.0003 km/s |
| Proper motion (μ) | RA: −8.694 mas/yr Dec.: −260.642 mas/yr |
| Parallax (π) | 31.2191 ± 0.024 mas |
| Distance | 104.47 ± 0.08 ly (32.03 ± 0.02 pc) |
| Absolute magnitude (MV) | 4.52 |
| Orbit | |
| Primary | HD 19467 A |
| Companion | HD 19467 B |
| Period (P) | 398+95 −93 yr |
| Semi-major axis (a) | 54±9 AU |
| Eccentricity (e) | 0.56±0.09 |
| Inclination (i) | 129.8+8.1 −5.1° |
| Longitude of the node (Ω) | 134.8±4.5° |
| Periastron epoch (T) | 2,512,264+12,428 −12,637 BJD |
| Argument of periastron (ω) (secondary) | 64.2+5.5 −6.3° |
| Details | |
| HD 19467 A | |
| Mass | 0.96±0.02 M☉ |
| Radius | 1.20±0.03 R☉ |
| Luminosity | 1.42±0.06 L☉ |
| Surface gravity (log g) | 4.28±0.04 cgs |
| Temperature | 5,747±40 K |
| Metallicity [Fe/H] | −0.11±0.01 dex |
| Rotation | 29.53±0.16 d |
| Rotational velocity (v sin i) | 1.6±0.5 km/s |
| Age | 5.4+1.9 −1.3 Gyr 10.06+1.16 −0.82 Gyr |
| HD 19467 B | |
| Mass | 65.4+5.9 −4.6 MJup |
| Luminosity | (6.49±0.98)×10−6 L☉ |
| Temperature | 978+20 −43 K |
| Metallicity [Fe/H] | −0.15±0.02 dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
The spectrum of HD 19467 presents as a G-type main-sequence star with a stellar classification of G3 V. It has been identified as a solar twin based on the similarity of its physical properties to the Sun. This is an older star, with age estimates range from 5.4 up to 10.1 billion years, depending on the study. It is considered a thin disk star, which should theoretically limit the age to no more than 8 billion years. The spin rate is correspondingly low with a rotation period of 29.5 days. Based on the abundance of iron, the metallicity is lower than solar. The level of magnetic activity in the star's chromosphere as well as X-ray emission are at most below the equivalent level in the Sun.