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Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 17h 45m 39.73s[1]
Declination −29° 00′ 29.7″[1]
Distance 26,000 ly
(8,000[2] pc)
Other designations
WR 101f
Database references

GCIRS 13E is an infrared and radio object near the galactic centre. It is believed to be a cluster of hot massive stars, possibly containing an intermediate-mass black hole (IMBH) at its centre.

GCIRS 13E was first identified as GCIRS 13, which was later resolved into two components GCIRS13E and W.[3] GCIRS 13E was initially modelled as a single object, possibly a binary system.[4] It was even classified as a Wolf-Rayet star because of its strong emission line spectrum, and named WR 101f.[5] It was then resolved into seven Wolf-Rayet and class O stars.[6] The highest-resolution infrared imaging and spectroscopy can now identify 19 objects in GCIRS 13E, of which 15 are dense gaseous regions. The remaining four objects are stars: WN8 and WC9 Wolf-Rayet stars; an OB supergiant; and a K3 giant.[2]

The motions of the members of GCIRS 13E appear to indicate a much higher mass than can be accounted for by the visible objects. It has been proposed that there may be an intermediate-mass black hole with a mass of about 1,300 M at its centre. There are a number of problems with this theory.[7] However, the true nature of the cluster remains unknown.[2]

GCIRS 13E is a small cluster dominated by a few massive stars. It is thought that massive stars cannot form so close to a supermassive black hole and since such massive stars have a short lifespan it is thought that GCIRS 13E must have migrated inward toward the central black hole within the past 10 million years, probably from about 60 light-years further out than its current orbit. The stars are possibly the remains of a globular cluster where a middleweight black hole such as could develop through runaway star collisions.[7]


  1. ^ a b Blum, R. D.; Ramírez, Solange V.; Sellgren, K.; Olsen, K. (2003). "Really Cool Stars and the Star Formation History at the Galactic Center". The Astrophysical Journal. 597: 323. arXiv:astro-ph/0307291Freely accessible. Bibcode:2003ApJ...597..323B. doi:10.1086/378380. 
  2. ^ a b c Fritz, T. K.; Gillessen, S.; Dodds-Eden, K.; Martins, F.; Bartko, H.; Genzel, R.; Paumard, T.; Ott, T.; Pfuhl, O.; Trippe, S.; Eisenhauer, F.; Gratadour, D. (2010). "GC-IRS13E—A Puzzling Association of Three Early-type Stars". The Astrophysical Journal. 721: 395. arXiv:1003.1717Freely accessible. Bibcode:2010ApJ...721..395F. doi:10.1088/0004-637X/721/1/395. 
  3. ^ Zhao, Jun-Hui; Goss, W. M. (1998). "Radio Continuum Structure of IRS 13 and Proper Motions of Compact H II Components at the Galactic Center". The Astrophysical Journal. 499 (2): L163. Bibcode:1998ApJ...499L.163Z. doi:10.1086/311374. 
  4. ^ Coker, R. F.; Pittard, J. M. (2000). "An X-ray binary model for the Galactic Center source IRS 13E". Astronomy and Astrophysics. 361: L13. arXiv:astro-ph/0008091Freely accessible. Bibcode:2000A&A...361L..13C. 
  5. ^ Van Der Hucht, K. A. (2006). "New Galactic Wolf-Rayet stars, and candidates. An annex to the VIIth Catalogue of Galactic Wolf-Rayet Stars". Astronomy and Astrophysics. 458 (2): 453. arXiv:astro-ph/0609008Freely accessible. Bibcode:2006A&A...458..453V. doi:10.1051/0004-6361:20065819. 
  6. ^ Maillard, J. P.; Paumard, T.; Stolovy, S. R.; Rigaut, F. (2004). "The nature of the Galactic Center source IRS 13 revealed by high spatial resolution in the infrared". Astronomy and Astrophysics. 423: 155. arXiv:astro-ph/0404450Freely accessible. Bibcode:2004A&A...423..155M. doi:10.1051/0004-6361:20034147. 
  7. ^ a b Schoedel, R.; A. Eckart; C. Iserlohe; R. Genzel; T. Ott (2005). "A Black Hole in the Galactic Center Complex IRS 13E?". Astrophys. J. 625 (2): L111–L114. arXiv:astro-ph/0504474Freely accessible. Bibcode:2005ApJ...625L.111S. doi:10.1086/431307.