GRS 1915+105

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GRS 1915+105 or V1487 Aquilae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Aquila
Right ascension 19h 15m 11.6s
Declination +10° 56' 44"
Distance 40.000 ly
(11.000 pc)
Spectral type KIII
Other designations
V* V1487 Aquilae, Granat 1915+105, NOVA Aquilae 1992, Granat 1915+10, INTEGRAL1 112.
Database references

GRS 1915+105 or V1487 Aquilae is an X-ray binary star system which features a regular star and a black hole. It was discovered on August 15, 1992 by the WATCH all-sky monitor aboard Granat.[1] "GRS" stands for "GRANAT source", "1915" is the right ascension (19 hours and 15 minutes) and "105" is declination in units of 0.1 degree (i.e. its declination is 10.5 degrees). The near-infrared counterpart was confirmed by spectroscopic observations.[2] The binary system lies 11,000 parsecs away[3] in Aquila. GRS 1915+105 is the heaviest of the stellar black holes so far known in the Milky Way Galaxy,[4] with 10 to 18 times the mass of the Sun.[5] It is also a microquasar, and it appears that the black hole may rotate at 1,150 times per second.[6]

Galactic superluminal source[edit]

A sequence of MERLIN observation of the X-ray binary GRS 1915+105 taken over a few days.

In 1994, GRS 1915+105 became the first known galactic source that ejects material with apparent faster-than-light or superluminal velocities.[7]

Observations with high resolution radio telescopes such as VLA, MERLIN, and VLBI show a bi-polar outflow of charged particles, which emit synchrotron radiation at radio frequencies. These studies have shown that the apparent superluminal motion is due to a relativistic effect known as relativistic aberration, where the intrinsic velocity of ejecta is actually about 90% the speed of light.[3]

Growth regulation[edit]

Repeat observations by the Chandra X-Ray Observatory over the period of a decade have revealed what may be a mechanism for self-regulation of the rate of growth of GRS 1915+105. The jet of materials being ejected is occasionally choked off by a hot wind blowing off the accretion disk. The wind deprives the jet of materials needed to sustain it. When the wind dies down, the jet returns.[8]


External links[edit]

Coordinates: Sky map 19h 15m 11.6s, +10° 56′ 44″