| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 03h 40m 49.5246s[1] |
| Declination | +31° 49′ 34.6489″[1] |
| Apparent magnitude (V) | 8.78[2] |
| Characteristics | |
| Evolutionary stage | main-sequence star[3] |
| Spectral type | K0[2] |
| Astrometry | |
| Radial velocity (Rv) | 8.26[1] km/s |
| Proper motion (μ) | RA: 40.576[1]mas/yr Dec.: −94.254[1]mas/yr |
| Parallax (π) | 30.6433±0.1071 mas[4] |
| Distance | 106.4 ± 0.4 ly (32.6 ± 0.1 pc) |
| Details[5] | |
| 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[3] km/s |
| Age | 4.14±3.63 Gyr |
| Other designations | |
| BD+31 630,Gaia DR2 217334764042444288,HD 22781,HIP 17187,TYC 2355-246-1,GSC 02355-00246,2MASS J03404953+3149345[1] | |
| Database references | |
| SIMBAD | data |
HD 22781, is a single star about106 light-years away. It is aK-type main-sequence star. The star’s age is poorly constrained at4.14±3.63 billion years, but is likely similar to that of theSun.[5] HD 22781 is heavily depleted inheavy elements, having just 45% of Sun's concentration of iron,[2] yet is comparatively rich in carbon, having 90% of Sun`s abundance.[5]
An imaging survey in 2012 has failed to find any stellar companions, suggesting HD 22781 is a single star.[6]
In 2011 atransitingsuperjovian planet orbrown dwarfb was detected on an extremelyeccentric orbit.[3] It is located just outside of the conservativehabitable zone of the parent star.[7] Planets around such metal-poor stars are rare; the only three known similar cases areHD 111232 andHD 181720.[8]
In 2012, a radial velocity data review indicated there are no additional giant planets in the system.[9]
| 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 | — | — |
