GRS 1915+105

From Wikipedia, the free encyclopedia
Jump to: navigation, search
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
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" reflects the approximate declination (10 degrees and 56 arcminutes). 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″