Cannabaceae

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GRS 1915+105

A near-infrared (K band) light curve for V1487 Aquilae, adapted from Neil et al. (2007)[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Aquila
Right ascension 19h 15m 11.6s[2]
Declination +10° 56′ 44″[2]
Characteristics
Evolutionary stage Microquasar[3]
Spectral type KIII[4]
Astrometry
Parallax (π)0.120 ± 0.009 mas[3]
Distance28,000 ly
(8,600+2,000
−1,600[3] pc)
Details
Black hole
Mass12.4+2.0
−1.8[3][contradictory] M☉
Other designations
V1487 Aquilae, Granat 1915+105, Nova Aquilae 1992, Granat 1915+10, INTEGRAL1 112
Database references
SIMBADdata

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.[5] "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.[6]

The binary system lies 11,000 parsecs away[7] in Aquila. The black hole in GRS 1915+105 is 10 to 18 solar masses[8][contradictory]. The black hole rotates at least 950 times per second, giving it a spin parameter >0.82 (1.0 is the theoretical maximum).[9][10]

Galactic superluminal source

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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 superluminal motion velocities.[11]

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.[7]

Growth regulation

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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.[12]

See also

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References

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  1. ^ Neil, Ethan T.; Bailyn, Charles D.; Cobb, Bethany E. (March 2007). "Infrared Monitoring of the Microquasar GRS 1915+105: Detection of Orbital and Superhump Signatures". The Astrophysical Journal. 657 (1): 409–414. arXiv:astro-ph/0610480. Bibcode:2007ApJ...657..409N. doi:10.1086/510287. S2CID 15959057.
  2. ^ a b Liu, Q. Z; Van Paradijs, J; Van Den Heuvel, E. P. J (2007). "A catalogue of low-mass X-ray binaries in the Galaxy, LMC, and SMC (Fourth edition)". Astronomy and Astrophysics. 469 (2): 807. arXiv:0707.0544. Bibcode:2007A&A...469..807L. doi:10.1051/0004-6361:20077303. S2CID 14673570.
  3. ^ a b c d Reid, M. J; McClintock, J. E; Steiner, J. F; Steeghs, D; Remillard, R. A; Dhawan, V; Narayan, R (2014). "A Parallax Distance to the Microquasar GRS 1915+105 and a Revised Estimate of its Black Hole Mass". The Astrophysical Journal. 796 (1): 2. arXiv:1409.2453. Bibcode:2014ApJ...796....2R. doi:10.1088/0004-637X/796/1/2. S2CID 9800558.
  4. ^ Abubekerov, M. K; Antokhina, E. A; Cherepashchuk, A. M; Shimanskii, V. V (2006). "The mass of the compact object in the low-mass X-ray binary 2S 0921-630". Astronomy Reports. 50 (7): 544. arXiv:1201.4689. Bibcode:2006ARep...50..544A. doi:10.1134/S1063772906070043. S2CID 40984265.
  5. ^ Castro-Tirado, A. J; Brandt, S; Lund, N (1992). "Grs 1915+105". IAU Circ. 5590: 2. Bibcode:1992IAUC.5590....2C.
  6. ^ Castro-Tirado, A. J; Geballe, T. R; Lund, N (1996). "Infrared Spectroscopy of the Superluminal Galactic Source GRS 1915+105 During the September 1994 Outburst". Astrophysical Journal Letters. 461 (2): L99. Bibcode:1996ApJ...461L..99C. doi:10.1086/310009. S2CID 122041186.
  7. ^ a b Fender, R. P; Garrington, S. T; McKay, D. J; Muxlow, T. W. B; Pooley, G. G; Spencer, R. E; Stirling, A. M; Waltman, E. B (1999). "MERLIN observations of relativistic ejections from GRS 1915+105". Monthly Notices of the Royal Astronomical Society. 304 (4): 865. arXiv:astro-ph/9812150. Bibcode:1999MNRAS.304..865F. doi:10.1046/j.1365-8711.1999.02364.x. S2CID 144364.
  8. ^ Greiner, J. (2001). "GRS 1915+105". arXiv:astro-ph/0111540.
  9. ^ Jeffrey E. McClintock; Rebecca Shafee; Ramesh Narayan; Ronald A. Remillard; Shane W. Davis; Li-Xin Li (2006). "The Spin of the Near-Extreme Kerr Black Hole GRS 1915+105". Astrophysical Journal. 652 (1): 518–539. arXiv:astro-ph/0606076. Bibcode:2006ApJ...652..518M. doi:10.1086/508457. S2CID 1762307.
  10. ^ Jeanna Bryne. "Pushing the Limit: Black Hole Spins at Phenomenal Rate". space.com. Retrieved 2017-11-25.
  11. ^ Mirabel, I. F; Rodríguez, L. F (1994). "A superluminal source in the Galaxy". Nature. 371 (6492): 46. Bibcode:1994Natur.371...46M. doi:10.1038/371046a0. S2CID 4347263.
  12. ^ "An Erratic Black Hole Regulates Itself" (Press release). NASA. 2009-03-25. Archived from the original on 2017-07-09. Retrieved 2009-04-16.
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source: https://en.wikipedia.org/wiki/GRS_1915%2B105

One thought on “Cannabaceae”

  1. Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
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