GRS 1915+105
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Aquila |
| Right ascension | 19h 15m 11.6s |
| Declination | +10° 56′ 44″ |
| Characteristics | |
| Evolutionary stage | Microquasar |
| Spectral type | KIII |
| Astrometry | |
| Parallax (π) | 0.120±0.009 mas |
| Distance | 28,000 ly (8,600+2,000 −1,600 pc) |
| Details | |
| Black hole | |
| Mass | 12.4+2.0 −1.8 M☉ |
| Other designations | |
| V1487 Aquilae, Granat 1915+105, Nova Aquilae 1992, Granat 1915+10, INTEGRAL1 112 | |
| Database references | |
| SIMBAD | data |
GRS 1915+105 or V1487 Aquilae is an X-ray binary star system containing a main sequence star and a black hole. Transfer of material from the star to the black hole generates a relativistic jet, making this a microquasar system. The jet exhibits apparent superluminal motion.
It was discovered on August 15, 1992 by the WATCH all-sky monitor aboard Granat. "GRS" stands for "GRANAT source", "1915" is the right ascension (19 hours and 15 minutes) and "105" reflects the approximate declination (10 degrees and 56 arcminutes). The near-infrared counterpart was determined by spectroscopic observations.
The binary system lies 11,000 parsecs away in Aquila. The black hole in GRS 1915+105 is 10 to 18 solar masses. The black hole rotates at least 950 times per second, giving it a spin parameter >0.82 (1.0 is the theoretical maximum).