To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

How to transfigure the Wikipedia

Would you like Wikipedia to always look as professional and up-to-date? We have created a browser extension. It will enhance any encyclopedic page you visit with the magic of the WIKI 2 technology.

Try it — you can delete it anytime.

Install in 5 seconds
4,5
Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.
Great Wikipedia has got greater.
.
Leo
Newton
Brights
Milds

Messier 72

From Wikipedia, the free encyclopedia

Messier 72
M72 from Hubble Space Telescope; 3.44′ view
Observation data (J2000 epoch)
ClassIX[1]
ConstellationAquarius
Right ascension20h 53m 27.70s[2]
Declination–12° 32′ 14.3″[2]
Distance54.57 ± 1.17 kly (16.73 ± 0.36 kpc)[3]
Apparent magnitude (V)9.3[4]
Apparent dimensions (V)6.6'
Physical characteristics
Mass1.68×105[5] M☉
Metallicity = –1.48 ± 0.03[3] dex
Estimated age9.5 Gyr[6]
Other designationsNGC 6981, GCl 118[7]
See also: Globular cluster, List of globular clusters
Wikimedia Commons has media related to Messier 72.

Messier 72 (also known as M72 or NGC 6981) is a globular cluster in the south west of the very mildly southern constellation of Aquarius.

Observational history and guide

M72 was discovered by astronomer Pierre Méchain in 1780.[a] His countryman Charles Messier looked for it 36 days later, and included it in his catalog.[8] Both opted for the then-dominant of the competing terms for such objects, considering it a faint nebula rather than a cluster. With a larger instrument, astronomer John Herschel called it a bright "cluster of stars of a round figure". Astronomer Harlow Shapley noted a similarity to Messier 4 and 12.[9]

It is visible in a good night sky as a faint nebula in a telescope with a 6 cm (2.4 in) aperture. The surrounding field stars become visible from a 15 cm (5.9 in)-aperture device. One of 25 cm (9.8 in) will allow measurement of an angular diameter of 2.5 ′. At 30 cm (12 in) the core is clear: its 1.25 ′ diameter, meaning a broad spread; and small parts scarcer in stars to the south and east.[10]

Properties

Based upon a 2011 census of variable stars, the cluster is 54.57 ± 1.17 kly (16.73 ± 0.36 kpc) away from the Sun.[3] It has an estimated combined mass of 168,000[5] solar masses (M☉) and is around 9.5 billion years old. The core region has a density of stars that is radiating 2.26 times solar luminosity (L☉) per cubic parsec.[6] There are 43 identified variable stars in the cluster.[3]

Map showing location of M72

See also

References and footnotes

  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. ^ a b 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. ^ a b c d Figuera Jaimes, R.; et al. (October 2011), Henney, W. J.; Torres-Peimbert, S. (eds.), "XIII Latin American Regional IAU Meeting: (item) The Globular Cluster NGC 6981: Variable stars population, physical parameters and astrometry", Revista Mexicana de Astronomía y Astrofísica, Serie de Conferencias, vol. 40, pp. 235–236, Bibcode:2011RMxAC..40..235F.
  4. ^ "Messier 72". SEDS Messier Catalog. Archived from the original on 1 July 2022. Retrieved 30 April 2022.
  5. ^ a b 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.
  6. ^ a b Sollima, A.; et al. (April 2008), "The correlation between blue straggler and binary fractions in the core of Galactic globular clusters", Astronomy and Astrophysics, 481 (3): 701–704, arXiv:0801.4511, Bibcode:2008A&A...481..701S, doi:10.1051/0004-6361:20079082, S2CID 3088769
  7. ^ "NGC 6981". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-16.
  8. ^ Garfinkle, Robert A. (1997), Star-Hopping: Your Visa to Viewing the Universe, Cambridge University Press, p. 266, ISBN 978-0521598897
  9. ^ Burnham, Robert (1978), Burnham's Celestial Handbook: An Observer's Guide to the Universe Beyond the Solar System, Dover Books on Astronomy Series, vol. 1 (2nd ed.), Courier Dover Publications, pp. 188–189, ISBN 978-0486235677
  10. ^ Luginbuhl, Christian B.; Skiff, Brian A. (1998), Observing Handbook and Catalogue of Deep-Sky Objects (2nd ed.), Cambridge University Press, p. 25, ISBN 978-0521625562
  1. ^ on August 29

External links


This page was last edited on 30 December 2023, at 07:01
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.
Contact WIKI 2
Introduction
Terms of Service
Privacy Policy