NGC 6642

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NGC 6642
Standing out from the Crowd.jpg
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 18h 31m 54.23s [1]
Declination −23° 28 34.1
Distance 26.7 ± 2.3  kly (8.2 ± 0.7  kpc) [2]
Apparent dimensions (V)48"
Physical characteristics
Mass1.09×105 [3]   M
Metallicity  = –1.26 [3] dex
Other designations Cr 381, C 1828-235, ESO 522-32, GCl 97, Mel 203
See also: Globular cluster, List of globular clusters

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]

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<span class="mw-page-title-main">NGC 6522</span> Globular cluster in the constellation of Sagittarius

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<span class="mw-page-title-main">NGC 6723</span> Globular cluster in the constellation Sagittarius

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<span class="mw-page-title-main">NGC 1851</span> Globular cluster in the constellation Columba

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<span class="mw-page-title-main">NGC 1261</span> Globular cluster in the constellation Horologium

NGC 1261 is a globular cluster of stars in the southern constellation of Horologium, first discovered by Scottish astronomer James Dunlop in 1826. The cluster is located at a distance of 53 kilolight-years from the Sun, and 59 kilolight-years from the Galactic Center. It is about 10.24 billion years old with 341,000 times the mass of the Sun. The cluster does not display the normal indications of core collapse, but evidence suggests it may have instead passed through a post core-collapse bounce state within the past two billion years. The central luminosity density is 2.22 L·pc−3, which is low for a globular cluster. Despite this, it has a Shapley–Sawyer Concentration Class of II, indicating a dense central concentration.

<span class="mw-page-title-main">Palomar 6</span>

Palomar 6 is a loose globular cluster in the constellation Ophiuchus that belongs to the Milky Way galaxy. It is a member of the Palomar Globular Clusters group. It is located about 25,000 light-years away from the Sun. It formed in what would become the bulge of the Milky Way. It is similar to other old-bulge globular clusters such as Messier 62, NGC 6522, NGC 6558, and Haute-Provence 1.

<span class="mw-page-title-main">NGC 6541</span> Globular cluster in the constellation Corona Australis

NGC 6541 is a globular cluster of stars in the southern constellation of Corona Australis. The globular cluster was discovered by Niccolò Cacciatore at the Palermo Astronomical Observatory, Sicily, on March 19, 1826. It was independently found by James Dunlop on July 3, 1826. The cluster has an apparent visual magnitude of 6.3 and an angular diameter of 15′. It is visible with binoculars or a small telescope.

<span class="mw-page-title-main">NGC 5286</span> Globular cluster in the constellation Centaurus

NGC 5286 is a globular cluster of stars located some 35,900 light years away in the constellation Centaurus. At this distance, the light from the cluster has undergone reddening from interstellar gas and dust equal to E(B – V) = 0.24 magnitude in the UBV photometric system. The cluster lies 4 arc-minutes north of the naked-eye star M Centauri. It was discovered by Scottish astronomer James Dunlop, active in Australia, and listed in his 1827 catalog.

<span class="mw-page-title-main">NGC 6441</span> Globular cluster in Scorpius

NGC 6441, sometimes also known as the Silver Nugget Cluster, is a globular cluster in the southern constellation of Scorpius. It was discovered by the Scottish astronomer James Dunlop on May 13, 1826, who described it as "a small, well-defined rather bright nebula, about 20″ in diameter". The cluster is located 5 arc minutes east-northeast of the star G Scorpii, and is some 43,000 light-years from the Sun.

References

  1. "SIMBAD query results". SIMBAD Astronomical Database. Retrieved 6 February 2012.
  2. 1 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. 1 2 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.