NGC 6535
| NGC 6535 | |
|---|---|
 | |
| Observation data (J2000 epoch) | |
| Class | XI[citation needed] |
| Constellation | Serpens |
| Right ascension | 18h 03m 50.51s[1] |
| Declination | −00° 17′ 51.5″[1] |
| Distance | 22 kly (6.8 kpc)[2] |
| Apparent magnitude (V) | 9.85[3] |
| Physical characteristics | |
| Mass | (2.21±0.78)×104[4] M☉ |
| Metallicity | = −1.95±0.04[4] dex |
| Estimated age | 12.75 Gyr[4] |
| Other designations | NGC 6535, C 1801-003, Glc 83[5] |
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NGC 6535 is a globular cluster of stars located at a distance of 22,200 light years from Earth in the equatorial constellation of Serpens, and is listed in the New General Catalogue. Its discovery is usually attributed to astronomer John Russell Hind in 1852.[6][7] However, Wolfgang Steinicke has uncovered evidence that William Herschel's first discovery was actually NGC 6535, which he observed on 24 August 1780.[8]
This is a halo globular cluster located close to the galactic bulge[2] at a distance of 13 kly (3.9 kpc) from the Galactic Center.[4] It has an estimated age of 12.75 billion years.[4] For a object of its type, NGC 6535 has a relatively low mass of 2.2×104 times the mass of the Sun.[4] The core radius is 2.3 ly (0.71 pc) and the tidal radius is 50 ly (15.3 pc).[2] It has an unusually high mass-to-light ratio of 11.[4]
The cluster is suspected to harbour an intermediate-mass black hole in its center.[2] Unusually for a low-mass globular cluster, it has multiple generations of stars.[4] Rather small and sparse for a globular cluster,[9] this cluster contains no known RR Lyrae variables, which is unusual for a globular cluster. Nine blue stragglers have been discovered.[10]
References
[edit]- ^ a b Goldsbury, Ryan; et al. (December 2010). "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters". The Astronomical Journal. 140 (6): 1830–1837. arXiv:1008.2755. Bibcode:2010AJ....140.1830G. doi:10.1088/0004-6256/140/6/1830. S2CID 119183070.
- ^ a b c d Askar, Abbas; et al. (2016). "MOCCA-SURVEY Database I: Is NGC 6535 a dark star cluster harbouring an IMBH?". Monthly Notices of the Royal Astronomical Society. 464 (3): 3090–3100. arXiv:1607.08275. doi:10.1093/mnras/stw2573.
- ^ Dalessandro, Emanuele; et al. (November 2012). "Ultraviolet Properties of Galactic Globular Clusters with Galex. II. Integrated Colors". The Astronomical Journal. 144 (5): 13. arXiv:1208.5698. Bibcode:2012AJ....144..126D. doi:10.1088/0004-6256/144/5/126. S2CID 56419886. 126.
- ^ a b c d e f g h Bragaglia, A.; et al. (2017), "NGC 6535: The lowest mass Milky Way globular cluster with a Na-O anti-correlation?", Astronomy & Astrophysics, 607: A44, arXiv:1708.07705, doi:10.1051/0004-6361/201731526, S2CID 119235401
- ^ "NGC 6535". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 16 May 2017.
- ^ Hille, Karl (24 February 2015). "Hubble Sees an Ancient Globular Cluster". NASA. Retrieved 10 March 2021.
- ^ Seligman, Courtney. "New General Catalog Objects: NGC 6500 - 6549". cseligman.com. Retrieved 10 March 2021.
- ^ "Photos". www.klima-luft.de. Retrieved 10 March 2021.
- ^ Testa, Vincenzo; et al. (2001). "Horizontal-Branch Morphology and Dense Environments: Hubble Space Telescope Observations of Globular Clusters NGC 2298, 5897, 6535, and 6626". The Astronomical Journal. 121 (2): 916–934. Bibcode:2001AJ....121..916T. doi:10.1086/318752. S2CID 118936939.
- ^ Sarajedini, Ata (1994). "CCD Photometry of the Galactic globular cluster NGC 6535 in the B and V Passbands". Publications of the Astronomical Society of the Pacific. 106: 404. Bibcode:1994PASP..106..404S. doi:10.1086/133392.
