Globular Cluster Messier 72

Messier 72
Messier 72: Image taken with the Hubble Space Telescope [245]

History

The globular cluster was discovered by Pierre Méchain on the night of August 29th to 30th, 1780 and again visited and confirmed by Charles Messier on the night of October 4th to 5th. He described it as «faintly shining like the previous one [M 71] with a small star next to it.» [196, 281]

Physical Properties

M 72 is 17 kpc (55'500 light years) from Earth and 12.9 kpc (47'000 light years) from the galactic center. It has the mass of 168'000 suns. [148, 251]

«Revised New General Catalogue and Index Catalogue» Dr. Wolfgang Steinicke, 2021 [277]
DesignationNGC 6981
TypeGCL (IX)
Right Ascension20h 53m 27.9s
Declination-12° 32' 11"
Diameter6.60 arcmin
Visual magnitude9.2 mag
Dreyer Descriptionglobular, pB, pL, R, gmCM, rrr
IdentificationM 72, GCL 118

Finder Chart

M 72 is located in the constellation Aquarius. On the line between the stars Albali (ε Aquarii) and θ Capricorni, it lies roughly in the first third. About 1° 20' east of it is the small star group M 73. The best observation time is August to October.

Chart M 72
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

References

148CATALOG OF PARAMETERS FOR MILKY WAY GLOBULAR CLUSTERS: Compiled by William E. Harris, McMaster University, revision: December 2010; physwww.mcmaster.ca/~harris/mwgc.dat (2021-01-03)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
245Bucking the trend; esahubble.org/images/potw1921a (2021-01-22)
251«Young Radio Pulsars in Galactic Globular Clusters» Jason Boyles, Duncan R. Lorimer, Phil J. Turk, Robert Mnatsakanov, Ryan S. Lynch, Scott M. Ransom, Paulo C. Freire, Khris Belczynski; The Astrophysical Journal, Volume 742, Number 1; DOI:10.1088/0004-637X/742/1/51
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
281«Catalogue Nébuleuses et des Amas D'Étoiles» Observées à Paris, par M. Messier, à l'Observatoire de la Marine, hôtel de Clugni, rue des Mathurins. «Connoissance des temps ou connoissance des mouvements célestes, pour l'année bissextile 1784 » Page 227; gallica.bnf.fr/ark:/12148/bpt6k6514280n/f235 (2021-02-21)