GRO J0422+32 explained

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

The mass of the black hole in GRO J0422+32 falls in the range 3.66 to 4.97 solar masses.^[4] This is the smallest yet found for any stellar black hole, and near the theoretical upper mass limit (~2.7) for a neutron star. Further analysis in 2012 calculated a mass of, which raises questions as to what the object actually is.^[5]

It is also known to have a companion M-type main-sequence star, V518 Per,^[6] 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

• List of nearest black holes

Notes and References

1. 1993IAUC.5781....2H . Gro J0422+32 . Harmon . B. A. . Fishman . G. J. . Paciesas . W. S. . Briggs . M. S. . International Astronomical Union Circular . 1993 . 5781 . 2 .
2. 1992IAUC.5597....3M . Gro J0422+32 = GRS 0417+335 . McCrosky . R. E. . Mueller . J. . Schmeer . P. . International Astronomical Union Circular . 1992 . 5597 . 3 .
3. Ling . J. C. . Wm . Wheaton . A. . 2003 . BATSE Soft γ-Ray Observations of GROJ0422+32 . Astrophys. J. . 584 . 1. 399–413 . astro-ph/0210673 . 2003ApJ...584..399L . 10.1086/345602 . 118954541 .
4. 2003ApJ...599.1254G . GRO J0422+32: The Lowest Mass Black Hole? . The Astrophysical Journal . 599 . 2 . 1254–1259 . 2003 . Gelino, Dawn M. . Harrison, Thomas E. . 10.1086/379311. astro-ph/0308490 . 17785067 .
5. 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. 2012ApJ...757...36K. 10.1088/0004-637x/757/1/36. 1205.1805 . 118452794.
6. General Catalogue of Variable Stars, 3rd ed. (1971) Moscow