HD 22781
Star in the constellation Perseus
From Wikipedia, the free encyclopedia
HD 22781, is a single star about 106 light-years away. It is a K-type main-sequence star. The star’s age is poorly constrained at 4.14±3.63 billion years, but is likely similar to that of the Sun.[6] HD 22781 is heavily depleted in heavy elements, having just 45% of Sun's concentration of iron,[3] yet is comparatively rich in carbon, having 90% of Sun's abundance.[6]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Perseus[1] |
| Right ascension | 03h 40m 49.5246s[2] |
| Declination | +31° 49′ 34.6489″[2] |
| Apparent magnitude (V) | 8.78[3] |
| Characteristics | |
| Evolutionary stage | main-sequence star[4] |
| Spectral type | K0[3] |
| Astrometry | |
| Radial velocity (Rv) | 8.26[2] km/s |
| Proper motion (μ) | RA: 40.576[2] mas/yr Dec.: −94.254[2] mas/yr |
| Parallax (π) | 30.6433±0.1071 mas[5] |
| Distance | 106.4 ± 0.4 ly (32.6 ± 0.1 pc) |
| Absolute magnitude (MV) | +6.21[1] |
| Details[6] | |
| Mass | 0.75±0.02 M☉ |
| Radius | 0.70±0.02 R☉ |
| Surface gravity (log g) | 4.57±0.04 cgs |
| Temperature | 5175±15 K |
| Metallicity [Fe/H] | −0.35±0.02 dex |
| Rotational velocity (v sin i) | 1.73[4] km/s |
| Age | 4.14±3.63 Gyr |
| Other designations | |
| BD+31 630, HD 22781, HIP 17187, TYC 2355-246-1, GSC 02355-00246, 2MASS J03404953+3149345, Gaia DR2 217334764042444288[2] | |
| Database references | |
| SIMBAD | data |
An imaging survey in 2012 has failed to find any stellar companions, suggesting HD 22781 is a single star.[7]
Planetary system
In 2011 a transiting superjovian planet or brown dwarf b was detected on an extremely eccentric orbit.[4] It is located just outside of the conservative habitable zone of the parent star.[8] Planets around such metal-poor stars are rare; the only three known similar cases are HD 111232 and HD 181720.[9]
In 2012, a radial velocity data review indicated there are no additional giant planets in the system.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥13.65±0.97 MJ | 1.167±0.039 | 528.07±0.14 | 0.8191±0.0023 | — | — |