HD 155876
Star in the constellation Hercules
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HD 155876, also known as Gliese 661, is a nearby binary star system, consisting of two very similar red dwarfs, located in the constellation Hercules.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules[1] |
| Right ascension | 17h 12m 07.9117s[2] |
| Declination | +45° 39′ 57.216″[2] |
| Apparent magnitude (V) | 9.52[3] |
| Characteristics | |
| A | |
| Evolutionary stage | main sequence[4] |
| Spectral type | M3[4] |
| B | |
| Evolutionary stage | main sequence[4] |
| Spectral type | M4[4] |
| Astrometry | |
| Radial velocity (Rv) | −30.9±0.5[5] km/s |
| Proper motion (μ) | RA: +348.59±5.68 mas/yr[2] Dec.: −1624.84±6.80 mas/yr[2] |
| Parallax (π) | 156.66±1.37 mas[6] |
| Distance | 20.8 ± 0.2 ly (6.38 ± 0.06 pc) |
| Absolute magnitude (MV) | +10.31[1] |
| Orbit[4] | |
| Period (P) | 12.9512±0.0096 yr |
| Semi-major axis (a) | 0.7620±0.0015″ |
| Eccentricity (e) | 0.7430±0.008 |
| Inclination (i) | 149.14±0.25° |
| Longitude of the node (Ω) | 160.0±1.3° |
| Periastron epoch (T) | 1991.032±0.011[a] |
| Argument of periastron (ω) (secondary) | 99.0±1.0° |
| Details | |
| A | |
| Mass | 0.379±0.035[7] M☉ |
| Radius | 0.37±0.07[8] R☉ |
| Luminosity | 0.018[9] L☉ |
| Temperature | 3,422±100[8] K |
| Metallicity [Fe/H] | −0.31±0.17[10] dex |
| B | |
| Mass | 0.369±0.035[7] M☉ |
| Radius | 0.37±0.07[8] R☉ |
| Temperature | 3,422±100[8] K |
| Metallicity [Fe/H] | −0.31±0.17[10] dex |
| Other designations | |
| BD+45°2505, GJ 661, HD 155876, HIP 84140, WDS J17121+4540, KUI 79,[11] Furuhjelm 46[12] | |
| A: LFT 1326, LHS 433, LTT 15095, NLTT 44362 | |
| B: LFT 1327, LHS 434, LTT 15096, NLTT 44363 | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
The star's duplicity was discovered by the Dutch astronomer Gerard Kuiper in 1934 in a systematic survey for duplicity of the known stars within about 25 parsecs from the Sun, carried out with the 36-inch telescope of the Lick Observatory.[13] HD 155876 is the nearest "true" (i. e. not brown dwarf) star system in Hercules; however, there is a brown dwarf in this constellation located closer, WISE 1741+2553.
Notes
- Fractional Besselian year