LB-1

LB-1
Observation data
Epoch J2000      Equinox J2000
Constellation Gemini
Right ascension 06h 11m 49.0763s[1]
Declination +22° 49′ 32.686″[1]
Apparent magnitude (V) 11.51
Astrometry
Proper motion (μ) RA: -0.067[1] mas/yr
Dec.: -1.889[1] mas/yr
Parallax (π)0.4403 ± 0.0856 mas[1]
Distanceapprox. 7,000 ly
(approx. 2,300 pc)
Orbit[2]
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[2]
stripped helium star
Mass1.5±0.4 M☉
Luminosity630 L☉
Surface gravity (log g)3.0±0.2 cgs
Temperature12700±500 K
Be star
Mass7±2 M☉
Luminosity1,260 L☉
Surface gravity (log g)4.0±0.3 cgs
Temperature18000±2000 K
Database references
SIMBADdata

LB-1 is a binary star system in the constellation Gemini. In 2019 a paper in Nature proposed the system contained an unusually massive stellar black hole outside of ordinary single stellar evolution parameters.[3] 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.[2][4]

  1. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c Cite error: The named reference Shenar_etal_2020 was invoked but never defined (see the help page).
  3. ^ "Scientists have discovered a 'monster' black hole that's so big it shouldn't exist". CNN. 29 November 2019. Retrieved 31 December 2020.
  4. ^ "Scientists keep debunking 'monster black hole' discovery. So, what's the deal with binary system LB1?". Space.com. May 2020. Retrieved 31 December 2020.