LB-1
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Gemini |
| Right ascension | 06h 11m 49.0763s |
| Declination | +22° 49′ 32.686″ |
| Apparent magnitude (V) | 11.51 |
| Characteristics | |
| Spectral type | B3Ve |
| U−B color index | −0.29 |
| B−V color index | +0.28 |
| Astrometry | |
| Proper motion (μ) | RA: -0.067 mas/yr Dec.: -1.889 mas/yr |
| Parallax (π) | 0.4403±0.0856 mas |
| Distance | approx. 7,000 ly (approx. 2,300 pc) |
| Orbit | |
| Period (P) | 78.80±0.01 d |
| Eccentricity (e) | 0.0±0.01 |
| Semi-amplitude (K1) (primary) | 52.9±0.1 km/s |
| Semi-amplitude (K2) (secondary) | 11.2±1.0 km/s |
| Details | |
| stripped helium star | |
| Mass | 1.5±0.4 M☉ |
| Radius | 5.4 R☉ |
| Luminosity | 630 L☉ |
| Surface gravity (log g) | 3.0±0.2 cgs |
| Temperature | 12700±500 K |
| Rotational velocity (v sin i) | 7±2 km/s |
| Be star | |
| Mass | 7±2 M☉ |
| Radius | 3.7 R☉ |
| Luminosity | 1,260 L☉ |
| Surface gravity (log g) | 4.0±0.3 cgs |
| Temperature | 18000±2000 K |
| Rotational velocity (v sin i) | 300±50 km/s |
| Other designations | |
| TIC 45796991, GSC 01877-00743, 2MASS J06114907+2249326 | |
| Database references | |
| SIMBAD | data |
LB-1 is a binary star system in the constellation Gemini. In 2019, a paper in Nature proposed that the system contained an unusually massive stellar black hole outside of ordinary single stellar evolution parameters. However, analyses in 2020 found the original 2019 conclusion to be incorrect. Some researchers now believe the system consists of a stripped B-type star and a massive rapidly rotating Be star.