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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. 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. Bibcode:2010ApJ...721..395F. arXiv:1003.1717Freely accessible. 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. Bibcode:2000A&A...361L..13C. arXiv:astro-ph/0008091Freely accessible. 
  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. Bibcode:2006A&A...458..453V. arXiv:astro-ph/0609008Freely accessible. 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. Bibcode:2004A&A...423..155M. arXiv:astro-ph/0404450Freely accessible. 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. Bibcode:2005ApJ...625L.111S. arXiv:astro-ph/0504474Freely accessible. doi:10.1086/431307.