HD 3167
Star in the constellation Pisces / From Wikipedia, the free encyclopedia
HD 3167 is a single,[4] orange-hued star in the zodiac constellation of Pisces that hosts a system with three exoplanets.[8][9] The star is too faint to be seen with the naked eye, having an apparent visual magnitude of 8.97.[2] The distance to HD 3167 can be determined from its annual parallax shift of 21.1363 mas as measured by the Gaia space observatory,[1] 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.[10] Since it was first photographed during the Palomar observatory sky survey in 1953, it had moved over 12.5″ by 2017.[5] The star is moving away from the Earth with an average heliocentric radial velocity of +19.5 km/s.[4]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Pisces |
Right ascension | 00h 34m 57.524s[1] |
Declination | +04° 22′ 53.28″[1] |
Apparent magnitude (V) | 8.97[2] |
Characteristics | |
Evolutionary stage | Main sequence |
Spectral type | K0 V[3] |
B−V color index | 0.827±0.021 |
Variable type | Constant[2] |
Astrometry | |
Radial velocity (Rv) | +19.5±0.1[4] km/s |
Proper motion (μ) | RA: +107.569 mas/yr[1] Dec.: −173.334 mas/yr[1] |
Parallax (π) | 21.1363 ± 0.0187 mas[1] |
Distance | 154.3 ± 0.1 ly (47.31 ± 0.04 pc) |
Absolute magnitude (MV) | 5.67[2] |
Details[5][6] | |
Mass | 0.837+0.053 −0.043 M☉ |
Radius | 0.880+0.012 −0.013 R☉ |
Luminosity | 0.56[2] 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[3] and no significant variability.[2] The star has 86% of the mass of the Sun and 86% of the Sun's radius.[5] It is a chromospherically inactive[4] star and is radiating 56%[2] 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.[5]
In 2019, a group of astronomers first 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.[11] Later, in October 2021, the third planet (HD 3167 b) was found to orbit around the equator of the star instead, while confirming the other planets' orbital inclinations from the 2019 study.[12][13]