NGC 6638
NGC 6638 is a globular cluster in the constellation Sagittarius. It is magnitude 9.5 and diameter 2 arc minutes, class VI. It is a half degree east of Lambda Sagittarii. It is a member of the Milky Way.[3]
| NGC 6638 | |
|---|---|
 | |
| Observation data (J2000 epoch) | |
| Class | VI |
| Constellation | Sagittarius |
| Right ascension | 18h 30m 56.2s |
| Declination | −25° 29′ 45″ |
| Distance | 31.3 ± 1.6 kly (9.6 ± 0.5 kpc)[1] |
| Apparent magnitude (V) | 9.5 |
| Apparent dimensions (V) | 2′ |
| Physical characteristics | |
| Mass | 1.89×105[1] M☉ |
| Other designations | GCl 95, C 1827-255[2] |
The globular cluster was discovered in 1784 by the astronomer William Herschel with his 18.7-inch telescope and the discovery was later entered in the New General Catalogue.
References
- Oliveira, R. A. P.; Ortolani, S.; Barbuy, B.; Kerber, L. O.; Maia, F. F. S.; Bica, E.; Cassisi, S.; Souza, S. O.; Pérez-Villegas, A. (2022). "Precise distances from OGLE-IV member RR Lyrae stars in six bulge globular clusters". Astronomy & Astrophysics. 657: A123. arXiv:2110.13943. Bibcode:2022A&A...657A.123O. doi:10.1051/0004-6361/202141596. S2CID 239998638.
- "NGC 6638". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-02-11.
- Harris, W.E. (1996). "A Catalog of Parameters for Globular Clusters in the Milky Way". The Astronomical Journal. 112: 1487. Bibcode:1996AJ....112.1487H. doi:10.1086/118116.
- Robert Burnham, Jr, Burnham's Celestial Handbook: An observer's guide to the universe beyond the solar system, vol 3, p.1557
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