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]
See also: Globular cluster, List of globular clusters

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

1. 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.
2. "NGC 6638". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-02-11.
3. 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

External links

• Media related to NGC 6638 at Wikimedia Commons
• NGC 6638