HD 126129 and HD 126128
Triple star system in the constellation of Boötes
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HD 126129 and HD 126128 form a triple star in the northern constellation of Boötes. HD 126128 is a very close pair which lies at an angular separation of 6.250″ from the brightest member of the trio, HD 126129.[7]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes[1] |
| HD 126129 | |
| Right ascension | 14h 23m 22.69548s[2] |
| Declination | +08° 26′ 47.8266″[2] |
| Apparent magnitude (V) | 5.04[3] |
| HD 126128 | |
| Right ascension | 14h 23m 22.59914s[4] |
| Declination | +08° 26′ 41.6666″[4] |
| Apparent magnitude (V) | 6.74[3] (7.50 + 7.70)[5] |
| Characteristics | |
| HD 126129 | |
| Evolutionary stage | main sequence[6] |
| Spectral type | A0V[7] |
| U−B color index | −0.08[8] |
| B−V color index | −0.02[8] |
| HD 126128 | |
| Spectral type | F0V + F2V[7] |
| U−B color index | −0.01[8] |
| B−V color index | +0.43[8] |
| Astrometry | |
| HD 126129 | |
| Radial velocity (Rv) | −22.6[9] km/s |
| Proper motion (μ) | RA: −75.188[2] mas/yr Dec.: −9.265[2] mas/yr |
| Parallax (π) | 14.3216±0.1123 mas[2] |
| Distance | 228 ± 2 ly (69.8 ± 0.5 pc) |
| HD 126128 | |
| Radial velocity (Rv) | −17.6[9] km/s |
| Proper motion (μ) | RA: −83.783[4] mas/yr Dec.: −4.601[4] mas/yr |
| Parallax (π) | 9.7572±0.7363 mas[10] |
| Distance | 330 ± 30 ly (102 ± 8 pc) |
| Orbit[11] | |
| Primary | B |
| Name | C |
| Period (P) | 40.0 yr |
| Semi-major axis (a) | 0.24″ |
| Eccentricity (e) | 0.25 |
| Inclination (i) | 42° |
| Details | |
| HD 126129 | |
| Mass | 2.4[2] M☉ |
| Radius | 2.4[2] R☉ |
| Luminosity | 47[2] L☉ |
| Surface gravity (log g) | 3.95[2] cgs |
| Temperature | 9,729[2] K |
| Rotational velocity (v sin i) | 133[6] km/s |
| Age | 381[2] Myr |
| B | |
| Mass | 1.37 M☉ |
| Rotational velocity (v sin i) | 133[12] km/s |
| C | |
| Mass | 1.31 M☉ |
| Other designations | |
| BD+09°2882, HIP 70327, ADS 9247, WDS J14234+0827[13] | |
| HD 126129: HD 126129, HR 5386, SAO 120426 | |
| HD 126128: HD 126128, HR 5385 | |
| Database references | |
| SIMBAD | data |
| HD 126129 | |
| HD 126128 | |
The Hipparcos parallax for the combined triple is 15.17±0.42 mas, suggesting a distance around 215 light years.[14] The Gaia DR3 parallax for HD 126129 (component A) indicates a distance close to 228 light years. Gaia DR3 does not contain a parallax for the BC pair HD 126128, but Gaia DR2 indicates an approximate distance of 330 light years. However, the stars are treated as being related and both are considered members of the IC 2391 supercluster.[15]