Astronomy:GRO J0422+32

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GRO J0422+32
Observation data
Epoch Astronomy:J2000.0      Equinox J2000.0 (ICRS)
Constellation Perseus
Right ascension  04h 21m 42.77s[1]
Declination +32° 54′ 26.7″[1]
Apparent magnitude (V) 13.2
Distance7,800[2] ly
(2,400 pc)
Spectral typeM4.5V[1] + Black hole
Other designations
V518 Per, GRO J0422+33, RLC2006 XB2, Granat 0417+335, Nova Persei 1992, Nova Persei 1993, ZGH2005 OS00676-097731 GRO J0422+32, ZGH2005 XS00676B3-003
Database references

GRO J0422+32[1] is an X-ray nova and black hole candidate that was discovered by the BATSE instrument on the CGRO satellite on 5 August 1992.[3][4] During outburst, it was observed to be stronger than the Crab Nebula gamma-ray source out to photon energies of about 500 keV.[2]

The mass of the black hole in GRO J0422+32 falls in the range 3.66 to 4.97 solar masses.[5] This is the smallest yet found for any stellar black hole, and near the theoretical upper mass limit (~2.7 M) for a neutron star. Further analysis in 2012 calculated a mass of 2.1 M, which raises questions as to what the object actually is.[6]

It is also known to have a companion M-type main-sequence star, V518 Per,[7] in the constellation Perseus. It has a magnitude of 13.5 in the B spectral band, and 13.2 in the visible band.

See also


  1. 1.0 1.1 1.2 1.3 "GRO J0422+32". SIMBAD. Centre de données astronomiques de Strasbourg. 
  2. 2.0 2.1 Ling, J. C.; Wm; Wheaton, A. (2003). "BATSE Soft γ-Ray Observations of GROJ0422+32". Astrophys. J. 584 (1): 399–413. doi:10.1086/345602. Bibcode2003ApJ...584..399L. 
  3. Harmon, A. et al. (1992) IAUC 5584
  4. Paciesas, W. et al. (1992), IAUC 5594
  5. Gelino, Dawn M.; Harrison, Thomas E. (2003). "GRO J0422+32: The Lowest Mass Black Hole?". The Astrophysical Journal 599 (2): 1254–1259. doi:10.1086/379311. Bibcode2003ApJ...599.1254G. 
  6. Kreidberg, Laura; Bailyn, Charles D.; Farr, Will M.; Kalogera, Vicky (2012). "Mass Measurements of Black Holes in X-ray Transients: is There a Mass Gap?". The Astrophysical Journal 757 (36): 17pp. doi:10.1088/0004-637x/757/1/36. Bibcode2012ApJ...757...36K. 
  7. General Catalogue of Variable Stars, 3rd ed. (1971) Moscow[page needed]