Messier 62

Messier 62 or M62, also known as NGC 6266, is a globular cluster of stars in the equatorial constellation of Ophiuchus. It was discovered on June 7, 1771 by Charles Messier, then added to his catalogue in 1779.[10]

M62 is at a distance of about 22.2 kly[3] from Earth and 5.5 kly from the Galactic center.[2] It is among the ten most massive and luminous globular clusters in the Milky Way, showing an integrated absolute magnitude of –9.18.[5] The cluster has an estimated mass of 1.22×106 M[3] and a mass-to-light ratio of 2.05±0.04 in the V band.[11] It has a projected ellipticity of 0.01, meaning is it essentially spherical.[12] The density profile of the cluster members suggests it has not yet undergone core collapse.[13] It has a core radius of 1.3 ly (0.39 pc), a half-mass radius of 9.6 ly (2.95 pc), and a half-light radius of 6.0 ly (1.83 pc). The stellar density at the core is 5.13 M per cubic parsec.[14] It has a tidal radius of 59 ly (18.0 pc).[7]

The cluster shows at least two distinct populations of stars, which most likely represent two separate episodes of star formation. Of the main sequence stars in the cluster, 79%±1% are from the first generation and 21%±1% from the second. The second generation is polluted by materials released by the first. In particular, the abundances of helium, carbon, magnesium, aluminium, and sodium differ between the two populations.[5]

Indications are this is an Oosterhoff type I, or "metal-rich" system. A 2010 study identified 245 variable stars in the cluster's field, of which 209 are RR Lyrae variables, four are Type II Cepheids, 25 are long period variables, and one is an eclipsing binary. The cluster may prove to be the galaxy's richest in terms of RR Lyrae variables.[15] It has six binary millisecond pulsars, including one (COM6266B) that is displaying eclipsing behavior from gas streaming off its companion.[16] There are multiple X-ray sources, including 50 within the half-mass radius.[13] 47 blue straggler candidates have been identified, formed from the merger of two stars in a binary system, and these are preferentially concentrated near the core region.[13]

It is hypothesized that this cluster may be host to an intermediate mass black hole (IMBH), and it is considered particularly suitable for searching for such an object. Examination of the proper motion of stars within 17 of the core does not require an IMBH to explain. However, simulations can not rule out an IMBH with a mass of a few thousand M. Based upon radial velocity measurements within an arcsecond of the core, Kiselev et al. (2008) made the claim that there is an IMBH with a mass in the range (1–9)×103 M.[11]

Messier 62
Messier62 - HST - Potw1915a
Messier 62 by the Hubble Space Telescope
Credit: ESA/Hubble & NASA, S. Anderson et al.
Observation data (J2000 epoch)
ClassIV[1]
ConstellationOphiuchus
Right ascension 17h 01m 12.60s[2]
Declination–30° 06′ 44.5″[2]
Distance22.2 kly (6.8 kpc)[3]
Apparent magnitude (V)+6.45[4]
Apparent dimensions (V)15
Physical characteristics
Absolute magnitude−9.18.[5]
Mass1.22×106[3] M
Radius49 ly[6]
Tidal radius59 ly.[7]
Metallicity = –1.02[8] dex
Estimated age11.78 Gyr[8]
Other designationsC 1658-300, GCl 51, M62, NGC 6266[9]

Gallery

Messier 62 Hubble WikiSky

Messier 62 by the Hubble Space Telescope; 1.65 field of view

M62HunterWilson

Globular Cluster M62 with amateur telescope.

M62map

Map showing the location of M62.

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. ^ a b c Di Criscienzo, M.; et al. (February 2006), "RR Lyrae-based calibration of the Globular Cluster Luminosity Function", Monthly Notices of the Royal Astronomical Society, 365 (4): 1357–1366, arXiv:astro-ph/0511128, Bibcode:2006MNRAS.365.1357D, doi:10.1111/j.1365-2966.2005.09819.x.
  3. ^ a b c d Boyles, J.; et al. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal, 742 (1): 51, arXiv:1108.4402, Bibcode:2011ApJ...742...51B, doi:10.1088/0004-637X/742/1/51.
  4. ^ Harris, W.E. (1996), "A Catalog of Parameters for Globular Clusters in the Milky Way", Astronomical Journal, 112: 1487, Bibcode:1996AJ....112.1487H, doi:10.1086/118116. Note: 1997 data update.
  5. ^ a b c Milone, A. P. (January 2015), "Helium and multiple populations in the massive globular cluster NGC 6266 (M 62)", Monthly Notices of the Royal Astronomical Society, 446 (2): 1672–1684, arXiv:1409.7230, Bibcode:2015MNRAS.446.1672M, doi:10.1093/mnras/stu2198.
  6. ^ distance × sin( diameter_angle / 2 ) = 49 ly. radius
  7. ^ a b Mackey, A. D.; van den Bergh, Sidney (June 2005), "The properties of Galactic globular cluster subsystems", Monthly Notices of the Royal Astronomical Society, 360 (2): 631–645, arXiv:astro-ph/0504142, Bibcode:2005MNRAS.360..631M, doi:10.1111/j.1365-2966.2005.09080.x.
  8. ^ a b 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.
  9. ^ "M 62". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 27, 2018.
  10. ^ Thompson, Robert; Thompson, Barbara (2007), Illustrated Guide to Astronomical Wonders: From Novice to Master Observer, DIY science, O'Reilly Media, Inc, p. 332, ISBN 978-0596526856.
  11. ^ a b McNamara, Bernard J.; et al. (February 2012), "A Search for an Intermediate-mass Black Hole in the Core of the Globular Cluster NGC 6266", The Astrophysical Journal, 745 (2): 7, Bibcode:2012ApJ...745..175M, doi:10.1088/0004-637X/745/2/175, 175.
  12. ^ McNamara, Bernard J.; McKeever, Jean (November 2011), "The Dynamical Distance, RR Lyrae Absolute Magnitude, and Age of the Globular Cluster NGC 6266", The Astronomical Journal, 142 (5): 4, Bibcode:2011AJ....142..163M, doi:10.1088/0004-6256/142/5/163, 163.
  13. ^ a b c Beccari, G.; et al. (May 2006), "The Dynamical State and Blue Straggler Population of the Globular Cluster NGC 6266 (M62)", The Astronomical Journal, 131 (5): 2551–2560, arXiv:astro-ph/0601187, Bibcode:2006AJ....131.2551B, doi:10.1086/500643.
  14. ^ Baumgardt, H.; Hilker, M. (August 2018), "A catalogue of masses, structural parameters, and velocity dispersion profiles of 112 Milky Way globular clusters", Monthly Notices of the Royal Astronomical Society, 478 (2): 1520–1557, arXiv:1804.08359, Bibcode:2018MNRAS.478.1520B, doi:10.1093/mnras/sty1057.
  15. ^ Contreras, R.; et al. (December 2010), "Time-series Photometry of Globular Clusters: M62 (NGC 6266), the Most RR Lyrae-rich Globular Cluster in the Galaxy?", The Astronomical Journal, 140 (6): 1766–1786, arXiv:1009.4206, Bibcode:2010AJ....140.1766C, doi:10.1088/0004-6256/140/6/1766
  16. ^ Cocozza, G.; et al. (June 2008), "A Puzzling Millisecond Pulsar Companion in NGC 6266", The Astrophysical Journal Letters, 679 (2): L105, arXiv:0804.3574, Bibcode:2008ApJ...679L.105C, doi:10.1086/589557.

External links

Coordinates: Sky map 17h 01m 12.60s, −30° 06′ 44.5″

Green Bank Telescope

The Robert C. Byrd Green Bank Telescope (GBT) in Green Bank, West Virginia, US is the world's largest fully steerable radio telescope. The Green Bank site was part of the National Radio Astronomy Observatory (NRAO) until September 30, 2016. Since October 1, 2016, the telescope has been operated by the newly separated Green Bank Observatory. The telescope honors the name of the late Senator Robert C. Byrd who represented West Virginia and who pushed the funding of the telescope through Congress.

The Green Bank Telescope operates at meter to millimeter wavelengths. Its 100-meter diameter collecting area, unblocked aperture, and good surface accuracy provide superb sensitivity across the telescope's full 0.1–116 GHz operating range. The GBT is fully steerable, and 85% of the entire local celestial hemisphere is accessible. It is used for astronomy about 6500 hours every year, with 2000–3000 hours per year going to high-frequency science. Part of the scientific strength of the GBT is its flexibility and ease of use, allowing for rapid response to new scientific ideas. It is scheduled dynamically to match project needs to the available weather. The GBT is also readily reconfigured with new and experimental hardware. The high-sensitivity mapping capability of the GBT makes it a necessary complement to the Atacama Large Millimeter Array, the Expanded Very Large Array, the Very Long Baseline Array, and other high-angular resolution interferometers. Facilities of the Green Bank Observatory are also used for other scientific research, for many programs in education and public outreach, and for training students and teachers.

The telescope began regular science operations in 2001, making it one of the newest astronomical facilities of the US National Science Foundation. It was constructed following the collapse of a previous telescope at Green Bank, a 90.44 m paraboloid erected in 1962. The previous telescope collapsed on 15 November 1988 due to the sudden loss of a gusset plate in the box girder assembly, which was a key component for the structural integrity of the telescope.

List of NGC objects (6001–7000)

This is a list of NGC objects 6001–7000 from the New General Catalogue (NGC). The astronomical catalogue is composed mainly of star clusters, nebulae, and galaxies. Other objects in the catalogue can be found in the other subpages of the list of NGC objects.

The constellation information in these tables is taken from The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer, which was accessed using the "VizieR Service". Galaxy types are identified using the NASA/IPAC Extragalactic Database. The other data of these tables are from the SIMBAD Astronomical Database unless otherwise stated.

M62

M62 or M-62 may refer to:

M62 motorway, a motorway in England.

M-62 (Michigan highway), a state highway in Michigan.

M62 locomotive, a Soviet heavy freight diesel locomotive.

BMW M62, a 1994 automobile engine.

Messier 62, a globular cluster in the constellation Ophiuchus.

Shvetsov ASh-62, an aircraft engine produced in the Soviet Union.

M62 (camouflage), a Finnish military camouflage pattern of the year 1962 uniform.

Messier object

The Messier objects are a set of 110 astronomical objects cataloged by the French astronomer Charles Messier in his Catalogue des Nébuleuses et des Amas d'Étoiles ("Catalogue of Nebulae and Star Clusters").

Because Messier was interested in finding only comets, he created a list of non-comet objects that frustrated his hunt for them. The compilation of this list, in collaboration with his assistant Pierre Méchain, is known as the Messier catalogue. This catalogue of objects is one of the most famous lists of astronomical objects, and many Messier objects are still referenced by their Messier number.

The catalogue includes some astronomical objects that can be observed from Earth's Northern Hemisphere such as deep-sky objects, a characteristic which makes the Messier objects extremely popular targets for amateur astronomers.A preliminary version first appeared in the Memoirs of the French Academy of Sciences in 1771,

and the last item was added in 1966 by Kenneth Glyn Jones, based on Messier's observations.

The first version of Messier's catalogue contained 45 objects and was published in 1774 in the journal of the French Academy of Sciences in Paris. In addition to his own discoveries, this version included objects previously observed by other astronomers, with only 17 of the 45 objects being Messier's.

By 1780 the catalogue had increased to 80 objects. The final version of the catalogue containing 103 objects was published in 1781 in the Connaissance des Temps for the year 1784.

However, due to what was thought for a long time to be the incorrect addition of Messier 102, the total number remained 102. Other astronomers, using side notes in Messier's texts, eventually filled out the list up to 110 objects.The catalogue consists of a diverse range of astronomical objects, ranging from star clusters and nebulae to galaxies. For example, Messier 1 is a supernova remnant, known as the Crab Nebula, and the great spiral Andromeda Galaxy is M31. Many further inclusions followed in the next century when the first addition came from Nicolas Camille Flammarion in 1921, who added Messier 104 after finding Messier's side note in his 1781 edition exemplar of the catalogue. M105 to M107 were added by Helen Sawyer Hogg in 1947, M108 and M109 by Owen Gingerich in 1960, and M110 by Kenneth Glyn Jones in 1967.

Timeline of epochs in cosmology

The timeline of cosmological epochs outlines the formation and subsequent evolution of the Universe from the Big Bang (13.799 ± 0.021 billion years ago) to the present day. An epoch is a moment in time from which nature or situations change to such a degree that it marks the beginning of a new era or age.

Times on this list are measured from the moment of the Big Bang.

List
See also

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