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GR Muscae

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GR Muscae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Musca
Right ascension 12h 57m 37.153s[1]
Declination −69° 17′ 18.98″[1]
Apparent magnitude (V) 19.1[1]
Database references
SIMBADdata
Visual band light curves for GR Muscae, adapted from Cornelisse et al. (2013).[2]

GR Muscae, also known as 2S 1254-690 is a binary star system in the constellation Musca composed of a neutron star of between 1.2 and 1.8 times the mass of the Sun and a low-mass star likely to be around the mass of the Sun in close orbit.[2] A magnitude 19 blue star was pinpointed as the optical counterpart of the X-ray source in 1978.[3] Its apparent magnitude varies from 18 to 19.1 over a period of 0.16 days.[4]

While the optical counterpart to the X-ray source was identified in 1978, optical variability was not detected until 1980, when a bright flare was seen that increased the white-light flux by a factor of two in a time interval of about 1.7 seconds.[5] GR Muscae received its variable star designation in 1985.[6]

The neutron star has an accretion disk that takes around 6.74 days to complete a revolution, and is inclined at an angle to the incoming stream of material from the donor star.[2]

References

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  1. ^ a b c "GR Muscae – Low Mass X-ray Binary". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 9 March 2014.
  2. ^ a b c Cornelisse, R.; Kotze, M.M.; Casares, J.; Charles, P.A.; Hakala, P.J. (2013). "The Origin of the Tilted Disc in the Low-mass X-ray Binary GR Mus (XB 1254-690)". Monthly Notices of the Royal Astronomical Society. 436 (1): 910–20. arXiv:1309.4972. Bibcode:2013MNRAS.436..910C. doi:10.1093/mnras/stt1654. S2CID 119242800.
  3. ^ Griffiths, R.E.; Gursky, H.; Schwartz, D.A.; Schwarz, J.; Bradt, H.; Doxsey, R.E.; Charles, P.A.; Thorstensen, J. R. (1978). "Positions and Identifications for Galactic X-ray Sources 2A1822-371 and 2S1254-690". Nature. 276 (16): 247–49. Bibcode:1978Natur.276..247G. doi:10.1038/276247a0. S2CID 4372341.
  4. ^ "VSX : Detail for GR Mus". The International Variable Star Index. AAVSO.
  5. ^ Mason, K. O.; Middleditch, J.; Nelson, J. E.; White, N. E. (9 October 1980). "An optical burst from the star identified with the X-ray source 2S1254-690". Nature. 287 (5782): 516–518. Bibcode:1980Natur.287..516M. doi:10.1038/287516a0. Retrieved 8 October 2024.
  6. ^ Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Perova, N. B. (March 1985). "The 67th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 2681. Bibcode:1985IBVS.2681....1K. Retrieved 8 October 2024.