HD 20781
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Fornax |
| Right ascension | 03h 20m 02.94286s |
| Declination | −28° 47′ 01.7905″ |
| Apparent magnitude (V) | 8.48 |
| Characteristics | |
| Spectral type | K0V |
| B−V color index | 0.82 |
| Astrometry | |
| Radial velocity (Rv) | 40.27±0.12 km/s |
| Proper motion (μ) | RA: 348.869±0.015 mas/yr Dec.: −66.614±0.019 mas/yr |
| Parallax (π) | 27.8123±0.0239 mas |
| Distance | 117.3 ± 0.1 ly (35.96 ± 0.03 pc) |
| Absolute magnitude (MV) | 5.70 |
| Details | |
| Mass | 0.7 M☉ |
| Luminosity | 0.49±0.04 L☉ |
| Surface gravity (log g) | 4.37±0.05 cgs |
| Temperature | 5256±29 K |
| Metallicity [Fe/H] | −0.11±0.02 dex |
| Rotation | 46.8±4.4 d |
| Rotational velocity (v sin i) | 1.1 km/s |
| Other designations | |
| CD–29° 1229, HIP 15526, LTT 1581, SAO 168468, 2MASS J03200291-2847016, Gaia DR1 5060105892897388288 | |
| Database references | |
| SIMBAD | data |
HD 20781 is a star which is part of a wide binary system with HD 20782. The companion star has a very large angular separation of 252 arcsec, corresponding to 9080 AU at the distance of HD 20782. Both stars possess their own planetary systems in S type orbits, with a total of five known planets around both stars. This is the first known example of planets being found orbiting both components of a wide binary system. HD 20781 has no noticeable starspot activity.