HD 114762
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Coma Berenices |
| Right ascension | 13h 12m 19.74107s |
| Declination | +17° 31′ 01.6303″ |
| Apparent magnitude (V) | 7.30 + 15.00 |
| Characteristics | |
| A | |
| Evolutionary stage | Main sequence |
| Spectral type | F9V |
| B−V color index | 0.525 |
| B | |
| Evolutionary stage | Main sequence |
| Spectral type | sdM9 |
| J−K color index | 0.70 |
| Astrometry | |
| Radial velocity (Rv) | 49.63±0.18 km/s |
| Proper motion (μ) | RA: −580.999 mas/yr Dec.: 1.062 mas/yr |
| Parallax (π) | 26.1979±0.1082 mas |
| Distance | 124.5 ± 0.5 ly (38.2 ± 0.2 pc) |
| Orbit | |
| Companion | HD 114762 Ab |
| Period (P) | 83.91712±0.00064 d |
| Semi-major axis (a) | 0.361±0.012 AU |
| Eccentricity (e) | 0.3442±0.0012 |
| Inclination (i) | 2.8±0.6° |
| Periastron epoch (T) | 2449969.202±0.048 |
| Argument of periastron (ω) (primary) | 201.3±1.0° |
| Semi-amplitude (K1) (primary) | 0.6201±0.00085 km/s |
| Details | |
| HD 114762 A | |
| Mass | 1.046±0.040 M☉ |
| Radius | 1.24±0.05 R☉ |
| Surface gravity (log g) | 4.18±0.03 cgs |
| Temperature | 5869±13 K |
| Metallicity [Fe/H] | −0.72+0.05 −0.07 dex |
| Age | 12±4 Gyr |
| HD 114762 Ab | |
| Mass | 0.293+0.103 −0.056 M☉ |
| HD 114762 B | |
| Mass | 0.0879 M☉ |
| Radius | 0.100 R☉ |
| Luminosity | 0.00043 L☉ |
| Surface gravity (log g) | 5.381 cgs |
| Temperature | 2,645 K |
| Metallicity [Fe/H] | −0.71 dex |
| Age | ~10 Gyr |
| Other designations | |
| BD+18 2700, HD 114762, HIP 64426, SAO 100458, 2MASS J13121982+1731016 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
HD 114762 is a triple star system approximately 125 light-years (38.2 pc) away in the constellation Coma Berenices. It consists of a yellow-white F-type main-sequence star (HD 114762 A) and two red dwarf companions (HD 114762 Ab & HD 114762 B) approximately 0.36 & 130 AU distant. Both are low-metal subdwarfs. Planets around such metal-poor stars are rare (three known cases are HD 22781, HD 111232, and HD 181720). A telescope or strong binoculars are needed to view the primary. HD 114762 had been used by scientists as a "standard star", one whose radial velocity is well established, but with the discovery of the spectroscopic companion HD 114762 Ab its usefulness as a standard has been called into question.
The red dwarf companion is classified as an ultra-cool dwarf, with a spectral type around M9. With a visual magnitude of 15 and separated from the primary by only three arcseconds, it can only be seen with a powerful telescope. It is estimated to be around 10 billion years old, although the properties of such low-mass stars are very similar across a wide range of ages. It is calculated have only 8% of the mass of the Sun, a tenth of its radius, and with a temperature of about 2,645 K it produces less than a thousandth of its luminosity.