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Messier 13
Globular cluster Messier 13 in Hercules
Observation data (J2000 epoch)
Class	V
Constellation	Hercules
Right ascension	16 41 41.24
Declination	+36° 27′ 35.5″
Distance	22.2 kly (6.8 kpc)
Apparent magnitude (V)	5.8
Apparent dimensions (V)	20 arcminutes
Physical characteristics
Absolute magnitude	–8.5
Mass	6×10 M☉
Radius	84 ly
Metallicity	${\displaystyle {\begin{smallmatrix}\left\end{smallmatrix}}}$ = –1.33 dex
Estimated age	11.65 Gyr
Notable features	One of the best-known clusters of the Northern Hemisphere
Other designations	NGC 6205
See also: Globular cluster, List of globular clusters

Messier 13, or M13 (also designated NGC 6205 and sometimes called the Great Globular Cluster in Hercules, the Hercules Globular Cluster, or the Great Hercules Cluster), is a globular cluster of several hundred thousand stars in the constellation of Hercules.

Discovery and visibility

Messier 13 was discovered by Edmond Halley in 1714, and cataloged by Charles Messier on June 1, 1764, into his list of objects not to mistake for comets; Messier's list, including Messier 13, eventually became known as the Messier catalog. It is located at right ascension 16 41.7, declination +36° 28'. Messier 13 is often described by astronomers as the most magnificent globular cluster visible to northern observers.

About one third of the way from Vega to Arcturus, four bright stars in Hercules form the Keystone asterism, the broad torso of the hero. M13 can be seen in this asterism 2⁄3 of the way north (by west) from Zeta to Eta Herculis. With an apparent magnitude of 5.8, Messier 13 may be visible to the naked eye with averted vision on dark nights. Messier 13 is prominent in traditional binoculars as a bright, round patch of light. Its diameter is about 23 arcminutes and it is readily viewable in small telescopes. At least four inches of telescope aperture resolves stars in Messier 13's outer extent as small pinpoints of light. However, only larger telescopes resolve stars further into the center of the cluster. The cluster is visible throughout the year from latitudes greater than 36 degrees north, with the longest visibility during Northern Hemisphere spring and summer.

Nearby to Messier 13 is NGC 6207, a 12th-magnitude edge-on galaxy that lies 28 arcminutes directly northeast. A small galaxy, IC 4617, lies halfway between NGC 6207 and M13, north-northeast of the large globular cluster's center. At low powers the cluster is bracketed by two seventh-magnitude stars.

Characteristics

About 145 light-years in diameter, M13 is composed of several hundred thousand stars, with estimates varying from around 300,000 to over half a million. The brightest star in the cluster is a red giant, the variable star V11, also known as V1554 Herculis, with an apparent visual magnitude of 11.95. M13 is 22,200 to 25,000 light-years away from Earth, and the globular cluster is one of over one hundred that orbit the center of the Milky Way.

The stars in this cluster are firmly in the Population II category, markedly lower in metals than Population I stars like the Sun and most other stars in the Sun's close proximity. M13 as a whole has only about 4.6% as much iron as the Sun does.

Single stars in this globular cluster were first resolved in 1779. Compared to the stars in the neighborhood of the Sun, the stars of the M13 population are more than a hundred times more densely packed. They are so close together that they sometimes collide and produce new stars. The newly formed, young stars, known as "blue stragglers", are particularly interesting to astronomers.

The last three variables (V63, V64 and V65) were discovered from Spain in April 2021, March 2022 and January 2024, respectively.

Arecibo message

The 1974 Arecibo message, which contained encoded information about the human race, DNA, atomic numbers, Earth's position and other information, was beamed from the Arecibo Observatory radio telescope towards Messier 13 as an experiment in contacting potential extraterrestrial civilizations in the cluster. M13 was chosen because it was a large, relatively close star cluster that was available at the time and place of the ceremony. The cluster will move through space during the transit time; opinions differ as to whether or not the cluster will be in a position to receive the message by the time that it arrives.

Literary references

• The science fiction novellas "Sucker Bait" by Isaac Asimov and the novel Question and Answer by Poul Anderson take place on Troas, a world within M13.
• In the German science fiction series Perry Rhodan, M13 is the location of Arkon, the homeworld of the race of Arkonides.
• In author Dan Simmons' Hyperion Cantos the Hercules cluster is where a copy of Earth was secretly recreated after the original was destroyed.
• In his novel The Sirens of Titan, Kurt Vonnegut writes "Every passing hour brings the Solar System forty-three thousand miles closer to Globular Cluster M13 in Hercules—and still there are some misfits who insist that there is no such thing as progress."
• Messier 13 is the home of the antagonistic aliens in the 1977 space opera The War in Space, who hail from the third planet of a system orbiting a star called Yomi.
• Deliberately engineering a star in Messier 13 to go nova was part of the Cybermen's complicated plot in the 1968 Doctor Who story The Wheel in Space.

Gallery

• M13 is in the "armpit" of the constellation Hercules.
• Heart of the Hercules Globular Cluster, Hubble image
• Hubble images comparing M13 and M3

See also

• List of globular clusters
• Lists of astronomical objects
• Messier object
• New General Catalogue

References

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. ^ Thompson, Robert Bruce & Thompson, Barbara Fritchman (2007). Illustrated Guide to Astronomical Wonders: From Novice to Master Observer. DIY science. O'Reilly Media, Inc. p. 258. ISBN 978-0596526856.
3. ^ Goldsbury, Ryan; Richer, Harvey B.; Anderson, Jay; Dotter, Aaron; Sarajedini, Ata; Woodley, Kristin (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.
4. Paust, Nathaniel E. Q.; Reid, I. Neill; Piotto, Giampaolo; et al. (February 2010), "The ACS Survey of Galactic Globular Clusters. VIII. Effects of Environment on Globular Cluster Global Mass Functions", The Astronomical Journal, 139 (2): 476–491, Bibcode:2010AJ....139..476P, doi:10.1088/0004-6256/139/2/476, hdl:2152/34371, S2CID 120965440.
5. ^ "M 13". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-15.
6. Leonard, Peter J. T.; Richer, Harvey B.; Fahlman, Gregory G. (1992), "The mass and stellar content of the globular cluster M13", Astronomical Journal, 104: 2104, Bibcode:1992AJ....104.2104L, doi:10.1086/116386.
7. distance × sin(diameter_angle / 2) = 84 ly radius
8. ^ 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.
9. ^ Garner, Rob (2017-10-06). "Messier 13 (The Hercules Cluster)". NASA. Retrieved 2018-04-23.
10. "Messier 13 (M13) - The Great Hercules Cluster - Universe Today". Universe Today. 2016-05-09. Retrieved 2018-04-23.
11. "M 13". Messier Objects Mobile -- Charts, Maps & Photos. 2016-10-16. Retrieved 2018-04-23.
12. "How to See the Great Hercules Cluster of Stars". Space.com. Retrieved 2018-04-23.
13. "M13: Great Cluster in Hercules | EarthSky.org". earthsky.org. Retrieved 2018-03-26.
14. "NGC 6207". Skyhound. Retrieved 26 March 2023.
15. ^ O'Meara, Stephen James (1998), Deep-Sky Companions: The Messier Objects, Foreword by David H. Levy, Cambridge University Press, p. 69, ISBN 978-0521553322.
16. Samus, N. N.; Pastukhova, E. N.; Durlevich, O. V.; Kazarovets, E. V.; Kireeva, N. (2020), "The 83rd Name-List of Variable Stars. Variables in Globular Clusters and Novae", Peremennye Zvezdy (Variable Stars) 40, No. 8, 40 (8): 8, Bibcode:2020PZ.....40....8S, doi:10.24411/2221-0474-2020-10009
17. "Control Telescope :: Stars & Nebulae". Retrieved 2021-11-22.
18. "Star Cluster". Retrieved 2021-11-22.
19. Klaes, Larry (2005-11-30). "Making Contact". Ithaca Times. Archived from the original on 2009-01-07. Retrieved 2007-07-27.
20. "It's the 25th anniversary of Earth's first attempt to phone E.T." 1999-11-12. Archived from the original on 2008-08-02. Retrieved 2018-06-28.
21. "Science 2.0". In regard to the email from. Archived from the original on 2015-09-24. Retrieved 2015-04-15.

External links

• Messier 13, SEDS Messier pages
• Red Giant variable stars
• L199 (V63), a new variable star in M13
• Variability of L261 in M13 (V64)
• Study of the variable stars V10 and C6 in M13 (V65)
• Messier 13, Galactic Globular Clusters Database page
• Messier 13, High-resolution LRGB image based on 2-hour total exposure
• Messier 13, Amateur astrophotographer (hgg) photo using the 9.25" Celestron Telescope (85-min. exposure)
• M13 Hercules Globular photo detail Dark Atmospheres
• Variable Stars in M13. II.The Red Variables and the Globular Cluster Period-Luminosity Relation
• Variable Stars in M13. III. The Cepheid Variables and their Relation to Evolutionary Changes in Metal-Poor BL Her Stars.
• Messier 13, Image by Waid Observatory
• NightSkyInfo.com – M13, the Hercules Globular Cluster
• Photometric study of the V2 cepheid in M13
• Period, Amplitude and Light Curve of V38 in M13
• Great Globular Cluster in Hercules (Messier 13/NGC 6205)
• Rothery, David; Bauer, Amanda; Dhillon, Vik; Lawrence, Pete; Chapman, Allan; Fohring, Dora. "M13 – Hercules Globular Cluster". Deep Sky Video. Brady Haran. Retrieved December 3, 2024.
• Messier 13 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

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

• Astronomy
• Stars
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• Globular clusters
• Hercules (constellation)
• Messier objects
• Milky Way
• NGC objects
• Astronomical objects discovered in 1714