HD 3167
HD 3167 is a single, orange-hued star in the zodiac constellation of Pisces that hosts a system with three exoplanets. The star is too faint to be seen with the naked eye, having an apparent visual magnitude of 8.97. The distance to HD 3167 can be determined from its annual parallax shift of 21.1363 mas as measured by the Gaia space observatory, yielding a range of 154 light years. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.204″ per year. Since it was first photographed during the Palomar observatory sky survey in 1953, it had moved over 12.5″ by 2017. The star is moving away from the Earth with an average heliocentric radial velocity of +19.5 km/s.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pisces |
| Right ascension | 00h 34m 57.524s |
| Declination | +04° 22′ 53.28″ |
| Apparent magnitude (V) | 8.97 |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | K0 V |
| B−V color index | 0.827±0.021 |
| Variable type | Constant |
| Astrometry | |
| Radial velocity (Rv) | +19.5±0.1 km/s |
| Proper motion (μ) | RA: +107.569 mas/yr Dec.: −173.334 mas/yr |
| Parallax (π) | 21.1363 ± 0.0187 mas |
| Distance | 154.3 ± 0.1 ly (47.31 ± 0.04 pc) |
| Absolute magnitude (MV) | 5.67 |
| Details | |
| Mass | 0.837+0.053 −0.043 M☉ |
| Radius | 0.880+0.012 −0.013 R☉ |
| Luminosity | 0.56 L☉ |
| Surface gravity (log g) | 4.47±0.05 cgs |
| Temperature | 5,261±60 K |
| Metallicity [Fe/H] | 0.04±0.05 dex |
| Rotational velocity (v sin i) | 1.7±1.1 km/s |
| Age | 7.8±4.3 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an ordinary K-type main-sequence star with a stellar classification of K0 V and no significant variability. The star has 86% of the mass of the Sun and 86% of the Sun's radius. It is a chromospherically inactive star and is radiating 56% of the Sun's luminosity from its photosphere at an effective temperature of 5,261 K. The spin of the star displays a relatively low projected rotational velocity of around 1.7 km/s. It has a near solar metallicity – a term astronomers use for the proportion of elements other than hydrogen and helium in a stellar atmosphere.
In October 2021, astronomers reported that the orbits of the detected exoplanets hosted by the star are oddly unusual: two planets (HD 3167 c; HD 3167 d) revolve around the star on polar orbits, i.e. orbits that pass over the poles of the star, whereas the third planet (HD 3167 b) orbits around the equator of the star instead.