NGC 6752

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NGC 6752
NGC 6752 Hubble WikiSky.jpg
NGC 6752 by Hubble Space Telescope; 3.5′ view
Observation data (J2000 epoch)
Class VI [1]
Constellation Pavo
Right ascension 19h 10m 52.11s [2]
Declination –59° 59′ 04.4″ [2]
Distance 13.0  kly (4.0  kpc) [3]
Apparent magnitude (V)5.4 [4]
Apparent dimensions (V)20.4′
Physical characteristics
Mass1.4×105 [5]   M☉
VHB13.7
Metallicity  = –1.24 [6] dex
Estimated age11.78  Gyr [6]
Other designations Caldwell 93
See also: Globular cluster, List of globular clusters

NGC 6752 (also known as Caldwell 93 and nicknamed the Great Peacock Globular [7] ) is a globular cluster in the constellation Pavo. [8] It is the fourth-brightest globular cluster in the sky, after Omega Centauri, 47 Tucanae and Messier 22, respectively. It is best seen from June to October in the Southern Hemisphere. [9]

Contents

NGC 6752 was first identified by one James Dunlop of Parramatta on 30 June 1826, who described it as an irregular bright nebula which could be resolved into a cluster of many stars, highly compressed at the centre. This corresponds with a core region densely populated with stars around 1.3 light-years in diameter, which indicates it has undergone core collapse. The cluster lies around 13,000 light-years distant and is one of the closer globular clusters to Earth. It also lies 17,000 light-years away from the galactic centre. [8] It belongs to Shapley–Sawyer Concentration Class VI, namely of intermediate density, [1] and has been calculated to be 11.78  billion years old. [6] There are many binary stars in the system, as well as blue stragglers, which are likely to have been formed by collisions and mergers of smaller stars.

The apparent magnitude of the cluster is 5.4, so it can be seen with the unaided eye. [8] However this depends on good viewing conditions with a minimum of light pollution. [9] With binoculars it can be seen to cover an area three quarters the size of the full moon. It lies 1.5 degrees east of 5th-magnitude Omega Pavonis. [8] The nearest bright star is Peacock, which lies 3.25 degrees north and 9.25 degrees east. [9]

Six X-ray sources have been identified in the cluster's core by the Chandra X-Ray Observatory. [9]

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<span class="mw-page-title-main">Messier 70</span> Globular cluster in the constellation 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 1261</span> Globular cluster in the constellation Horologium

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<span class="mw-page-title-main">NGC 6362</span> Globular cluster in the constellation Ara

NGC 6362 is a globular cluster in the constellation Ara, lying close to Apus in the southern sky. A telescope with a 150mm primary mirror is required to resolve the stars within this irregularly shaped cluster. British astronomer James Dunlop first observed the cluster on 30 June 1826. It is located about 25,000 light-years from Earth and contains a number of blue stragglers.

<span class="mw-page-title-main">NGC 6352</span> Globular cluster in the constellation Ara

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<span class="mw-page-title-main">NGC 6496</span> Globular cluster in the constellation Scorpius

NGC 6496 is a globular cluster which is in the direction of the Milky Way's galactic bulge based on observations collected with the WFPC2 on board the Hubble Space Telescope. NGC 6496 was originally believed to be a member of the disc system of the Galactic Center, but scientists questioned this classification. It was instead suggested that NGC 6496, together with two other clusters, NGC 6624 and NGC 6637, could be halo clusters with strongly inclined orbits. NGC 6496 lies in the Southern sky at RA=17:59:03.68 and Dec=-44:15:57.4.

<span class="mw-page-title-main">NGC 6101</span> Globular cluster in the constellation Apus

NGC 6101 is a globular cluster in the constellation Apus, which was discovered by James Dunlop and catalogued by him as Δ68. It is located at a distance of about 47,600 light-years from the Sun and about 36,500 light-years from the Galactic Center of the Milky Way. It requires a telescope of at least 20 cm (7.9 in) aperture to resolve individual stars. Research revealed this cluster to contain an unexpected large number of black holes.

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

NGC 6541 is a globular cluster in the southern constellation of Corona Australis. It is estimated to be around 14 billion years old.

<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.

References

  1. 1 2 Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin, 849 (849): 11–14, Bibcode:1927BHarO.849...11S.
  2. 1 2 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.
  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. ↑ "NGC 6752". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2007-04-21.
  5. ↑ Marks, Michael; Kroupa, Pavel (August 2010), "Initial conditions for globular clusters and assembly of the old globular cluster population of the Milky Way", Monthly Notices of the Royal Astronomical Society, 406 (3): 2000–2012, arXiv: 1004.2255 , Bibcode:2010MNRAS.406.2000M, doi:10.1111/j.1365-2966.2010.16813.x, S2CID   118652005. Mass is from MPD on Table 1.
  6. 1 2 3 Forbes, Duncan A.; Bridges, Terry (May 2010), "Accreted versus in situ Milky Way globular clusters", Monthly Notices of the Royal Astronomical Society , 404 (3): 1203–1214, arXiv: 1001.4289 , Bibcode:2010MNRAS.404.1203F, doi:10.1111/j.1365-2966.2010.16373.x, S2CID   51825384.
  7. ↑ Chadwick, S; Cooper, I (11 December 2012). Imaging the Southern Sky. New York: Springer. p. 242. ISBN   978-1461447498.
  8. 1 2 3 4 O'Meara, Stephen James (2013). Deep-Sky Companions: Southern Gems. Cambridge University Press. pp. 410–12. Bibcode:2013dcsg.book.....O. ISBN   978-1-107-01501-2.
  9. 1 2 3 4 Mobberley, Martin (1999). The Caldwell Objects And How to Observe Them. Springer. pp. 194–95. ISBN   978-1-4419-0326-6.
  10. ↑ "Hubble fortuitously discovers a new galaxy in the cosmic neighbourhood". www.spacetelescope.org. Retrieved 31 January 2019.
  11. ↑ "Low Sodium Diet Key to Old Age for Stars". ESO Press Release. Retrieved 30 May 2013.


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