NGC 6642

NGC 6642
Image of NGC 6642 was created from visible and infrared images taken with the Wide Field Channel of the Advanced Camera for Surveys.
Observation data (J2000 epoch)
Class	V?
Constellation	Sagittarius
Right ascension	18^h 31^m 54.23^s[1]
Declination	−23° 28′ 34.1″
Distance	26.7 ± 2.3 kly (8.2 ± 0.7 kpc)[2]
Apparent dimensions (V)	48"
Physical characteristics
Mass	1.09×10^5[3] M☉
Metallicity	${\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}}$ = –1.26[3] dex
Other designations	Cr 381, C 1828-235, ESO 522-32, GCl 97, Mel 203

NGC 6642 is a globular cluster located 26,700 light-years from Earth,^[2] in the constellation Sagittarius. Many "blue stragglers" (stars which seemingly lag behind in their rate of aging) have been spotted in this globular, and it is known to be lacking in low-mass stars.^[4]

References

1. "SIMBAD query results". SIMBAD Astronomical Database. Retrieved 6 February 2012.
2. 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.
3. Boyles, J.; et al. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal, 742 (1): 51, arXiv:1108.4402, Bibcode:2011ApJ...742...51B, doi:10.1088/0004-637X/742/1/51, S2CID 118649860.
4. Balbinot, E.; Santiago, B. X.; Bica, E.; Bonatto, C. (1 July 2009). "The globular cluster NGC 6642: evidence for a depleted mass function in a very old cluster". Monthly Notices of the Royal Astronomical Society. 396 (3): 1596–1602. arXiv:0903.4325. Bibcode:2009MNRAS.396.1596B. doi:10.1111/j.1365-2966.2009.14819.x. S2CID 15354065.

External links

• Media related to NGC 6642 at Wikimedia Commons