Messier 12

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Globular cluster in the constellation Ophiuchus

title: "Messier 12" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["globular-clusters", "ophiuchus", "messier-objects", "ngc-objects", "astronomical-objects-discovered-in-1764", "discoveries-by-charles-messier"] description: "Globular cluster in the constellation Ophiuchus" topic_path: "general/globular-clusters" source: "https://en.wikipedia.org/wiki/Messier_12" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Globular cluster in the constellation Ophiuchus ::

| name=Messier 12 | image=[[Image:M12 Adam Block.jpg|300px]] | caption=Globular cluster Messier 12 in Ophiuchus | credit= | epoch=J2000 | class=IX | constellation=Ophiuchus | ra= | dec= | dist_ly=5.04 ± | appmag_v=6.7 | size_v=16.0 | mass_msol= | radius_ly=37.2 lydistance × sin( diameter_angle / 2 ) = 37.2 ly radius | v_hb= | metal_fe = –1.14 | age = 13.8 ± 1.1 Gyr | notes= | names=NGC 6218

Messier 12 or M 12 (also designated NGC 6218) is a globular cluster in the constellation of Ophiuchus. It was discovered by the French astronomer Charles Messier on May 30, 1764, who described it as a "nebula without stars". In dark conditions this cluster can be faintly seen with a pair of binoculars. Resolving the stellar components requires a telescope with an aperture of 8 in or greater. In a 10 in scope, the granular core shows a diameter of 3 (arcminutes) surrounded by a 10 halo of stars.

M12 is roughly 3°

A study published in 2006 concluded that this cluster has an unusually low number of low-mass stars. The authors surmise that they were stripped from the cluster by passage through the relatively matter-rich plane of the Milky Way.

Image:M12 Hubble.jpg|Messier 12 core by HST Image:ESO-Messier 12-Phot-04a-06.jpg| The Central Part of Messier 12. Credit: ESO Image:M12map.png|Map showing the location of M12

Notes

References

| title=Deep-Sky Companions: The Messier Objects | first1=Stephen James | last1=O'Meara | first2=David H. | last2=Levy | publisher=Cambridge University Press | postscript=. | year=1998 | isbn=978-0521553322 | page=68 | url=https://books.google.com/books?id=jis4evHuuzUC&pg=PA68 }}

References

  1. "Messier 12".
  2. (11 March 2015). "Messier 12: Gumball Globular {{!}} Messier Objects".
  3. (August 1927). "A Classification of Globular Clusters". Harvard College Observatory Bulletin.
  4. (December 2010). "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters". The Astronomical Journal.
  5. (May 2010). "Accreted versus in situ Milky Way globular clusters". [[Monthly Notices of the Royal Astronomical Society]].
  6. (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.
  7. "M 12".
  8. (2010). "Go-To Telescopes Under Suburban Skies". Springer.
  9. (February 7, 2006). "How to Steal a Million Stars?". [[ESO]].
  10. (2007). "Illustrated guide to astronomical wonders". [[O'Reilly Media, Inc.]].
  11. (2021). "Isochrone fitting of Galactic globular clusters – III. NGC 288, NGC 362, and NGC 6218 (M12)". Monthly Notices of the Royal Astronomical Society.

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globular-clustersophiuchusmessier-objectsngc-objectsastronomical-objects-discovered-in-1764discoveries-by-charles-messier