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Messier 92
Center of M92 by HST; 1.44′ view
Observation data (J2000 epoch)
Class	IV
Constellation	Hercules
Right ascension	17 17 07.39
Declination	+43° 08′ 09.4″
Distance	26.7×10^ ly (8.2 kpc)
Apparent magnitude (V)	6.4
Apparent dimensions (V)	14' arc minutes
Physical characteristics
Mass	2.0×10 M☉
Radius	54 ly
Metallicity	${\displaystyle {\begin{smallmatrix}\left\end{smallmatrix}}}$ = –2.32 dex
Estimated age	14.2 Gyr
Other designations	M92, NGC 6341, GCl 59
See also: Globular cluster, List of globular clusters

Messier 92 (also known as M92, M 92, or NGC 6341) is a globular cluster of stars in the northern constellation of Hercules.

Discovery

It was discovered by Johann Elert Bode on December 27, 1777, then published in the Berliner Astronomisches Jahrbuch during 1779. It was inadvertently rediscovered by Charles Messier on March 18, 1781, and added as the 92nd entry in his catalogue. William Herschel first resolved individual stars in 1783.

Visibility

It is one of the brighter of its sort in apparent magnitude in the northern hemisphere and in its absolute magnitude in the galaxy, but it is often overlooked by amateur astronomers due to angular proximity to bright cluster Messier 13, about 20% closer. Though when compared to M13, M92 is only slightly less bright, but about 1/3 less extended. It is visible to the naked eye under very good viewing conditions. With a small telescope, M92 can be seen as a nebulous smudge even in a severely light-polluted sky, and can be further resolved in darker conditions.

Characteristics

It is also one of the galaxy's oldest clusters. It is around 16×10^ ly (4.9 kpc) above/below the galactic plane and 33×10^ ly (10 kpc) from the Galactic Center. It is about 26,700 light-years away from the Solar System.The half-light radius, or radius containing the upper half of its light emission, is 1.09 arcminutes (′), while the tidal radius, the broadest standard measure, is 15.17′. It appears only slightly flattened: its minor axis is about 89% ± 3% of the major.

Characteristic of other globulars, it has little of the elements other than hydrogen and helium; astronomers term this low metallicity. Specifically, relative to the Sun, its iron abundance is  = –2.32 dex, which is 0.5% of 1.0, on this logarithmic scale, the solar abundance. This puts the estimated age range for the cluster at 11 ± 1.5 billion years.

Its true diameter is 108 ly, and may have a mass corresponding to 330,000 suns.

The cluster is not yet in, nor guaranteed to undergo, core collapse and the core radius figures as about 2 arcseconds (″). It is an Oosterhoff type II (OoII) globular cluster, which means it belongs to the group of metal-poor clusters with longer period RR Lyrae variable stars. The 1997 Catalogue of Variable Stars in Globular Clusters listed 28 candidate variable stars in the cluster, although only 20 have been confirmed. As of 2001, there are 17 known RR Lyrae variables in Messier 92. 10 X-ray sources have been detected within the 1.02 arcminute half-mass radius of the cluster, of which half are candidate cataclysmic variable stars.

M92 is approaching us at 112 km/sec. Its coordinates indicate that the Earth's North Celestial Pole periodically passes less than one degree of this cluster during the precession of Earth's axis. Thus, M92 was a "Polarissima Borealis", or "North Cluster", about 12,000 years ago (10,000 BC), and it will again in about 14,000 years (16,000 AD).

The multiple stellar populations in this cluster, revealing that it hosts at least two stellar generations of stars named 1G and 2G, as well as two distinct groups of 2G stars (2GA and 2GB). The helium abundances of 2GA and 2GB stars have higher mass fractions than that of the 1G stars by 0.01 and 0.04, respectively.

Gallery

• Messier 92 - wide field view from the Isaac Newton Group of Telescopes
• Map showing how Messier 92 figures in the two-dimensional sky, in the east of Hercules. Maps set by convention against a southern horizon, such that east is left.
• Messier 92 by the Sloan Digital Sky Survey
• Messier 92 by HST; 3.5′ view
• Messier 92 captured by the James Webb Space Telescope’s NIRCam instrument

See also

• List of Messier objects

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. ^ 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. ^ Chen, C. W.; Chen, W. P. (October 2010), "Morphological Distortion of Galactic Globular Clusters", The Astrophysical Journal, 721 (2): 1790–1819, Bibcode:2010ApJ...721.1790C, doi:10.1088/0004-637X/721/2/1790
4. "Messier 92". SEDS Messier Catalog. Retrieved 30 April 2022.
5. 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 M_PD on Table 1.
6. distance × sin( diameter_angle / 2 ) = 54 ly. radius
7. 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.
8. Paust, Nathaniel E. Q.; Chaboyer, Brian; Sarajedini, Ata (June 2007), "BVI Photometry and the Luminosity Functions of the Globular Cluster M92", The Astronomical Journal, 133 (6): 2787–2798, arXiv:astro-ph/0703167, Bibcode:2007AJ....133.2787P, doi:10.1086/513511, S2CID 13160815
9. "M 92". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-17.
10. Bode (1779). "Zweyter Theil 20. Beobachtung des Kometen von 1779 und Entdeckung einiger neuen Nebelsterne ". Astronomisches Jahrbuch oder Ephemeriden für das Jahr 1782 [Astronomical Yearbook or Ephemerides for the Year 1782.] (in German). Berlin, (Germany): George Jacob Decker. p. 156. From p. 156: " ich am 27. Decemb. 1777 einen neuen, mir nicht bekannten Nebelfleck im Herkules, südwestlich unter dem Stern ⍳ an dessen Fusse entdeckt, der sich in einer mehrentheils runden Figur mit einem blassen Lichtschimmer zeigt." ( on the 27th December 1777, I discovered a new nebula, which was unknown to me, in Hercules, southwest under the star ⍳ at his feet, which appears as a mostly round shape with a pale glimmer.)
11. Kanas, Nick (2007), Star maps: history, artistry, and cartography, Springer-Praxis books in popular astronomy, Springer, p. 180, ISBN 978-0387716688
12. Garfinkle, Robert A. (1997), Star-Hopping: Your Visa to Viewing the Universe, Cambridge University Press, p. 131, ISBN 978-0521598897
13. Frommert, Hartmut; Kronberg, Christine (September 2, 2007), "Messier 92", SEDS, The Munich Astro Archive, archived from the original on 2016-03-04, retrieved 2012-04-08
14. ^ Drukier, G. A.; et al. (March 2007), "The Global Kinematics of the Globular Cluster M92", The Astronomical Journal, 133 (3): 1041–1057, arXiv:astro-ph/0611246, Bibcode:2007AJ....133.1041D, doi:10.1086/510721, S2CID 15452502
15. Since 10 = 0.00513.
16. Di Cecco, A.; Becucci, R.; Bono, G.; Monelli, M.; Stetson, P. B.; Degl'Innocenti, S.; Moroni, P. G. Prada; Nonino, M.; Weiss, A.; Buonanno, R.; Calamida, A. (2010-06-27). "On the absolute age of the Globular Cluster M92". Publications of the Astronomical Society of the Pacific. 122 (895): 991–999. arXiv:1006.5217. Bibcode:2010PASP..122..991D. doi:10.1086/656017.
17. ^ "Messier Object 92". www.messier.seds.org. Retrieved 2022-05-28.
18. Kopacki, G. (2003), "Variable stars in the globular cluster M 92", Astronomy and Astrophysics, 369 (3): 862–870, arXiv:astro-ph/0211042, Bibcode:2001A&A...369..862K, doi:10.1051/0004-6361:20010155, S2CID 116811988
19. Lu, Ting-Ni; et al. (August 2011), "Chandra and HST Studies of the X-Ray Sources in Galactic Globular Cluster M92" (PDF), The Astrophysical Journal, 736 (2): 158, Bibcode:2011ApJ...736..158L, doi:10.1088/0004-637X/736/2/158, hdl:1721.1/95659, S2CID 54766335
20. Ferraro, F. R.; Paltrinieri, B.; Fusi Pecci, F.; Rood, R. T.; Dorman, B. (1998-01-01). "Faint UV Objects in the Core of Ggcs: a New Subclass of Cvs?". Ultraviolet Astrophysics Beyond the IUE Final Archive. 413: 561. Bibcode:1998ESASP.413..561F.
21. World, FTT. "Astronomers discover new insights into multiple stellar populations in Messier 92 using James Webb".

1. On March 18

External links

• Messier 92 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
• Messier 92 @ SEDS Messier pages
• Messier 92, Galactic Globular Clusters Database page
• Merrifield, Michael; Crowther, Paul. "M92 – Globular Cluster". Deep Sky Videos. Brady Haran.
• NASA Astronomy Picture of the Day: Comet Garradd and M92 (4 February 2012)

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v t e Messier objects
List	M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 M13 M14 M15 M16 M17 M18 M19 M20 M21 M22 M23 M24 M25 M26 M27 M28 M29 M30 M31 M32 M33 M34 M35 M36 M37 M38 M39 M40 M41 M42 M43 M44 M45 M46 M47 M48 M49 M50 M51 M52 M53 M54 M55 M56 M57 M58 M59 M60 M61 M62 M63 M64 M65 M66 M67 M68 M69 M70 M71 M72 M73 M74 M75 M76 M77 M78 M79 M80 M81 M82 M83 M84 M85 M86 M87 M88 M89 M90 M91 M92 M93 M94 M95 M96 M97 M98 M99 M100 M101 M102 M103 Added M104 M105 M106 M107 M108 M109 M110
See also	Caldwell catalogue Catalogue of Nebulae and Clusters of Stars Herschel 400 Catalogue Index Catalogue New General Catalogue Revised New General Catalogue
Category Commons Portal

v t e Constellation of Hercules
Hercules–Corona Borealis Great Wall Hercules in Chinese astronomy List of stars in Hercules
Stars	Bayer α (Rasalgethi) β (Kornephoros) γ δ (Sarin) ε ζ η θ ι κ (Marsic) λ (Maasym) μ ν ξ ο π ρ σ τ υ φ χ ψ ψ ω (Cujam) Flamsteed 14 29 (h) 30 (g) 42 45 (l) 52 60 68 (u) 69 (e) 72 (w) 89 93 98 99 (b) 102 104 (A) 106 109 110 111 112 32 Oph Variable X AC AM BL DI DQ V446 V533 V772 V777 V838 V1674 HR 6669 6697 6806 HD 146389 (Irena) 147506 (Hunor) 149026 (Ogma) 152843 154345 155358 156668 159062 164595 164922 Other BD +17° 3248 Furuhjelm 46 GD 362 Gliese 623 Gliese 638 Gliese 649 Gliese 686 GJ 3991 HAT-P-14 (Franz) HAT-P-18 HAT-P-67 Hercules X-1 GSC 02620-00648 Ross 640 TrES-3 (Pipoltr) TOI-561 TYC 1031-1262-1 WASP-103 WISE 1738+2732 WISE 1741+2553
Exoplanets 14 Herculis b c HAT-P-14b (Sissi) HD 149026 b (Smertrios) HD 164922 b c TOI-561 b WASP-103b
Star clusters Messier 13 Messier 92 NGC 6229 Palomar 14
Nebulae Abell 39 NGC 6210
Galaxies	NGC 6028 6039 6040 6041 6042 6043 6044 6045 6046 6047 6052 6053 6054 6055 6056 6057 6061 6078 6158 6166 6181 6207 6212 6239 6261 6263 6308 6452 6560 Other 1ES 1741+196 2MASX J16270254+4328340 3C 345 3C 346 A2261-BCG Arp 272 (NGC 6050 and IC 1179) AT2018cow IC 1182 IC 1189 Hercules Dwarf Hercules A IC 1192 IC 4617 Markarian 501 MCG+07-33-027 PGC 2046648 QSR J1819+3845 RX J1633.3+4718 UGC 11105
Galaxy clusters Abell 2152 Abell 2199 Hercules Cluster Hercules Superclusters Zwicky's Triplet
Astronomical events LBG-2377
Category

• Globular clusters
• Hercules (constellation)
• Messier objects
• NGC objects
• Astronomical objects discovered in 1777
• Discoveries by Johann Elert Bode