HR 8442
Spectroscopic binary star in the constellation Cepheus
From Wikipedia, the free encyclopedia
HR 8442 is a spectroscopic binary star in the constellation Cepheus. The primary is a G type giant star while the secondary's spectral type is unknown.[5]
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Cepheus[1] |
| Right ascension | 22h 07m 09.634s[2] |
| Declination | +58° 50′ 26.58″[2] |
| Apparent magnitude (V) | 6.32[3] |
| Characteristics | |
| Spectral type | G8.6 III[4] |
| U−B color index | 0.63[3] |
| B−V color index | 0.88[3] |
| Astrometry | |
| Radial velocity (Rv) | −7.37±0.03[5] km/s |
| Proper motion (μ) | RA: −16.09±0.41[2] mas/yr Dec.: −22.30±0.41[2] mas/yr |
| Parallax (π) | 4.80±0.46 mas[2] |
| Distance | 680 ± 70 ly (210 ± 20 pc) |
| Absolute magnitude (MV) | −0.3±0.2[5] |
| Orbit[5] | |
| Primary | HR 8442A |
| Name | HR 8442B |
| Period (P) | 737.4±0.4 days |
| Eccentricity (e) | 0.308±0.007 |
| Periastron epoch (T) | 54113.3±2.1 |
| Argument of periastron (ω) (secondary) | 61.9±1.3° |
| Semi-amplitude (K1) (primary) | 5.55±0.04 km/s |
| Details | |
| Mass | 2.97[6] M☉ |
| Radius | 14.4[7] R☉ |
| Luminosity | 143[7] L☉ |
| Surface gravity (log g) | 3.21[8] cgs |
| Temperature | 5261±40[6] K |
| Rotational velocity (v sin i) | 1.8[9] km/s |
| Age | 0.35[6] Gyr |
| Other designations | |
| BD+58 2393, FK5 3770, HD 210220, HIP 109190, HR 8442, SAO 34072 | |
| Database references | |
| SIMBAD | data |
The spectroscopic binary nature of the star was first noticed by Jose Renan de Medeiros and Michel Mayor using radial velocity measurements from the Coravel spectrometer at Haute-Provence Observatory.[10] Roger Griffin then placed the star on his observing program at Cambridge Observatory leading to an orbital solution being published in 2015.[5]