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".[8] 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 (20 cm) or greater.[9] In a 10 in (25 cm) scope, the granular core shows a diameter of 3′ (arcminutes) surrounded by a 10′ halo of stars.[8]
M12 is roughly 3°[9] northwest from the cluster M10 and 5.6° east southeast from star Lambda Ophiuchi. It is also located near the 6th magnitude 12 Ophiuchi.[10] The cluster is about 16,400 light-years (5,000 parsecs)[3] from Earth and has a spatial diameter of about 75 light-years. The brightest stars of M12 are of 12th magnitude. M10 and M12 are only a few thousand light-years away from each other and each cluster would appear at about magnitude 4.5 from the other.[10] With a Shapley-Sawyer rating of IX,[1] it is rather loosely packed for a globular and was once thought to be a tightly concentrated open cluster. Thirteen variable stars have been recorded in this cluster. M12 is approaching us at a velocity of 16 km/s.[11]
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.[12]
^ abShapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin, 849 (849): 11–14, Bibcode:1927BHarO.849...11S.
^ abGoldsbury, 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.
^ abcGontcharov, George A.; Khovritchev, Maxim Yu; Mosenkov, Aleksandr V.; Il'In, Vladimir B.; Marchuk, Alexander A.; Savchenko, Sergey S.; Smirnov, Anton A.; Usachev, Pavel A.; Poliakov, Denis M. (2021). "Isochrone fitting of Galactic globular clusters – III. NGC 288, NGC 362, and NGC 6218 (M12)". Monthly Notices of the Royal Astronomical Society. 508 (2): 2688–2705. arXiv:2109.13115. doi:10.1093/mnras/stab2756.
^"Messier 12". SEDS Messier Catalog. Retrieved 27 April 2022.
^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.
messier, also, designated, 6218, globular, cluster, constellation, ophiuchus, discovered, french, astronomer, charles, messier, 1764, described, nebula, without, stars, dark, conditions, this, cluster, faintly, seen, with, pair, binoculars, resolving, stellar,. 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 8 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 20 cm or greater 9 In a 10 in 25 cm scope the granular core shows a diameter of 3 arcminutes surrounded by a 10 halo of stars 8 Messier 12Globular cluster Messier 12 in OphiuchusObservation data J2000 epoch ClassIX 1 ConstellationOphiuchusRight ascension16h 47m 14 18s 2 Declination 01 56 54 7 2 Distance16 44 0 16 kly 5 04 0 05 kpc 3 Apparent magnitude V 6 7 4 Apparent dimensions V 16 0 Physical characteristicsMass8 7 104 5 M Radius37 2 ly NB 1 Metallicity Fe H displaystyle begin smallmatrix left ce Fe ce H right end smallmatrix 1 14 6 dexEstimated age13 8 1 1 Gyr 3 Other designationsNGC 6218 7 See also Globular cluster List of globular clustersM12 is roughly 3 9 northwest from the cluster M10 and 5 6 east southeast from star Lambda Ophiuchi It is also located near the 6th magnitude 12 Ophiuchi 10 The cluster is about 16 400 light years 5 000 parsecs 3 from Earth and has a spatial diameter of about 75 light years The brightest stars of M12 are of 12th magnitude M10 and M12 are only a few thousand light years away from each other and each cluster would appear at about magnitude 4 5 from the other 10 With a Shapley Sawyer rating of IX 1 it is rather loosely packed for a globular and was once thought to be a tightly concentrated open cluster Thirteen variable stars have been recorded in this cluster M12 is approaching us at a velocity of 16 km s 11 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 12 Messier 12 core by HST The Central Part of Messier 12 Credit ESO Map showing the location of M12Contents 1 See also 2 Notes 3 References 4 External linksSee also editList of Messier objectsNotes edit distance sin diameter angle 2 37 2 ly radiusReferences edit a b Shapley Harlow Sawyer Helen B August 1927 A Classification of Globular Clusters Harvard College Observatory Bulletin 849 849 11 14 Bibcode 1927BHarO 849 11S 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 a b c Gontcharov George A Khovritchev Maxim Yu Mosenkov Aleksandr V Il In Vladimir B Marchuk Alexander A Savchenko Sergey S Smirnov Anton A Usachev Pavel A Poliakov Denis M 2021 Isochrone fitting of Galactic globular clusters III NGC 288 NGC 362 and NGC 6218 M12 Monthly Notices of the Royal Astronomical Society 508 2 2688 2705 arXiv 2109 13115 doi 10 1093 mnras stab2756 Messier 12 SEDS Messier Catalog Retrieved 27 April 2022 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 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 M 12 SIMBAD Centre de donnees astronomiques de Strasbourg Retrieved 2006 11 15 a b Thompson Robert Bruce Thompson Barbara Fritchman 2007 Illustrated guide to astronomical wonders DIY science O Reilly Series O Reilly Media Inc p 137 ISBN 978 0596526856 a b Monks Neale 2010 Go To Telescopes Under Suburban Skies Patrick Moore s Practical Astronomy Series Springer p 118 ISBN 978 1441968500 a b O Meara Stephen James Levy David H 1998 Deep Sky Companions The Messier Objects Cambridge University Press p 68 ISBN 978 0521553322 Messier 12 Gumball Globular Messier Objects www messier objects com 11 March 2015 Retrieved 2015 08 17 How to Steal a Million Stars ESO February 7 2006 archived from the original on February 8 2007 External links edit nbsp Wikimedia Commons has media related to Messier 12 Messier 12 SEDS Messier pages Messier 12 Galactic Globular Clusters Database page Stolen stars article at Universe Today Messier 12 Amateur astrophotographer hgg with a Celestron 9 25 Messier 12 on WikiSky DSS2 SDSS GALEX IRAS Hydrogen a X Ray Astrophoto Sky Map Articles and imagesPortals nbsp Astronomy nbsp Stars nbsp Outer space Retrieved from https en wikipedia org w index php title Messier 12 amp oldid 1162380132, wikipedia, wiki, book, books, library,
