Messier 80

Messier 80 (also known as M80 or NGC 6093) is a globular cluster in the constellation Scorpius. It was discovered by Charles Messier in 1781.

Messier 80
A Hubble Space Telescope (HST) image of M80.
Credit: HST/NASA/ESA.
Observation data (J2000 epoch)
ClassII[1]
ConstellationScorpius
Right ascension16h 17m 02.41s[2]
Declination–22° 58′ 33.9″[2]
Distance32.6 kly (10.0 kpc)[3]
Apparent magnitude (V)+7.87[4]
Apparent dimensions (V)10′.0
Physical characteristics
Mass5.02×105[5] M☉
Radius48 ly
Metallicity = –1.47[6] dex
Estimated age12.54 Gyr[6]
Other designationsM80, NGC 6093, GCl 39[4]

This star cluster is, as to its angle from the solar system, midway between α Scorpii (Antares) and β Scorpii in a field in this galaxy that is rich in nebulæ. In a good night sky can be viewed, below the 67th parallel north with modest amateur telescopes as a mottled ball of light, though figuring only briefly every day at quite nearby latitudes restrictively low on the south horizon.

It has an apparent diameter of about 10 ′, and being about 32,600 light-years (10,000 pc) away, translates into a true (spatial) diameter of about 95 light-years. It contains several hundred thousand stars, and ranks among the densest globular clusters in the Milky Way. It is at more than twice the distance of the Galactic Center in regions considered the Galactic halo.

It hosts relatively many blue stragglers, stars that appear to be much younger than the cluster. It is thought these have lost part of their outer layers due to close encounters with other cluster members or perhaps from collisions between stars in the dense cluster. Images from the Hubble Space Telescope have shown pronounced districts of these stragglers in M80, suggesting the center of the cluster to have a very high capture and collision rate.

On May 21, 1860, a nova was found in M80 that delivered a magnitude of +7.0 to telescopes, binoculars and astute eyes. This variable star, given designation T Scorpii, reached an absolute magnitude of −8.5, briefly outshining the cluster.

References
  1. 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. 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.
  3. Paust, Nathaniel E. Q.; et al. (February 2010), "The ACS Survey of Galactic Globular Clusters. VIII. Effects of Environment on Globular Cluster Global Mass Functions", The Astronomical Journal, 139 (2): 476–491, Bibcode:2010AJ....139..476P, doi:10.1088/0004-6256/139/2/476, hdl:2152/34371.
  4. "M 80". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 16, 2006.
  5. 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.
  6. 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.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.