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NGC 5466

NGC 5466
NGC 5466 by Hubble Space Telescope; 3.5′ view
Observation data (J2000 epoch)
ClassXII[1]
ConstellationBoötes
Right ascension14h 05m 27.29s[2]
Declination+28° 32′ 04.0″[2]
Distance4.91 ± 0.12 kpc (16.0 ± 0.4 kly)[3]
Apparent magnitude (V)9.2[4]
Apparent dimensions (V)9.0′[4]
Physical characteristics
Absolute magnitude−6.98[3]
Mass1.79×105[5] M☉
Tidal radius238.0 ly (72.98 pc)[3]
VHB16.47
Metallicity = –1.95±0.02[6] dex
Estimated age12.15±0.11 Gyr[6]
Notable featuresTidal stream
Other designationsNGC 5466, C 1403+287, GCl 27, GC 3776, h 1746, H 6[7]
See also: Globular cluster, List of globular clusters

NGC 5466 is a globular cluster of stars in the constellation Boötes. It was discovered by German-British astronomer William Herschel on May 17, 1784, and catalogued as H VI.9.[8] This large, dim cluster has an apparent visual magnitude of 9.2 and spans an angular size of 9.0′.[4] It is relatively distant from the Sun,[3] about 52 thousand light-years (16.0 kpc) away,[3][9] and 53 thousand light-years (16.3 kpc) from the Galactic Center.[10]

Observations

The Shapley–Sawyer Concentration Class of NGC 5466 is XII.[1] This is a loose cluster with an unusually low central density compared to other globulars with similar luminosity.[11] It is located at a high galactic latitude and thus displays negligible reddening from interstellar dust.[11] The cluster has a core radius of 1.43′±0.10′ and a half-light radius of 2.3′±0.07′. The King tidal radius is 238.0 ly (72.98 pc).[3]

Observation of the distribution of stars in the cluster shows the impact of mass segregation, with heavier objects sinking toward the center. This is a dynamically young cluster that is just starting to evolve.[12] An isochrone fit to the cluster yields an age estimate of 12.15±0.11 billion years.[6] Other age estimates range from 12.2±0.9 to 13.57 Gyr, depending on the method.[9][13] It has an extremely low metallicity.[6]

In 2006, a long tidal stream was detected stretching from this cluster,[14] perhaps reaching as far as 45° to 60° across the sky.[15][16] It has a combined mass estimated as 4.0×103 M☉.[3] The width dispersion of the stream is 1.31°±0.24°, corresponding to a physical width of 1,200 ± 220 ly (367 ± 67 pc) at the distance of the cluster.[3] The presence of a tidal tail suggests the cluster has been strongly disrupted due to gravitational interactions with the Milky Way galaxy.[11] At some point, this stream may have been tidally disrupted by the Large Magellanic Cloud.[16]

A total of 97 blue straggler stars have been identified in this cluster, which show a mild central peak in distribution.[17] In 2019, it was reported that a candidate hot white dwarf had been discovered orbiting a blue straggler star in the outskirts of NGC 5466. This was the second such pair discovered in a globular cluster.[18] Three short period eclipsing binaries have been found along with six SX Phoenicis variables.[19][20] This was the first globular where a blue straggler eclipsing variable was found.[12] The cluster is host to the brightest-known anomalous Cepheid variable, designated V19.[21][22]

  • The location of NGC 5466 (circled in red)
    The location of NGC 5466 (circled in red)
  • NGC 5466 imaged with a 32-inch telescope
    NGC 5466 imaged with a 32-inch telescope

See also

References

  1. ^ 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.
  2. ^ 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.
  3. ^ a b c d e f g h Jensen, Jaclyn; et al. (October 2021), "Uncovering fossils of the distant Milky Way with UNIONS: NGC 5466 and its stellar stream", Monthly Notices of the Royal Astronomical Society, 507 (2): 1923–1936, arXiv:2108.04340, Bibcode:2021MNRAS.507.1923J, doi:10.1093/mnras/stab2325.
  4. ^ a b c Thompson, Robert Bruce; Thompson, Barbara (2007), Illustrated Guide to Astronomical Wonders: From Novice to Master Observer, DIY science, O'Reilly Media, Inc., p. 104, ISBN 9780596526856.
  5. ^ 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, S2CID 118649860.
  6. ^ a b c d Gontcharov, G. A.; et al. (June 2024), "Isochrone Fitting of Galactic Globular Clusters—VI. High-latitude Clusters NGC 5024 (M53), NGC 5053, NGC 5272 (M3), NGC 5466, and NGC 7099 (M30)", Research in Astronomy and Astrophysics, 24 (6), id .065014, arXiv:2404.14797, Bibcode:2024RAA....24f5014G, doi:10.1088/1674-4527/ad420f.
  7. ^ "NGC 5466", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2025-03-15.
  8. ^ Steinicke, Wolfgang (2021), Wiliam Herschel: Discoverer of the Deep Sky, Books on Demand, p. 149, ISBN 9783754397374.
  9. ^ a b Arellano Ferro, A.; et al. (2008), "CCD photometry of the globular cluster NGC 5466. RR Lyrae light-curve decomposition and the distance scale", Monthly Notices of the Royal Astronomical Society, 384 (4): 1444–1458, arXiv:0711.4027, Bibcode:2008MNRAS.384.1444A, doi:10.1111/j.1365-2966.2007.12760.x, S2CID 17346022.
  10. ^ Lux, H.; Read, J. I.; Lake, G.; Johnston, K. V. (July 2012), "NGC 5466: a unique probe of the Galactic halo shape", Monthly Notices of the Royal Astronomical Society: Letters, 424 (1): L16 – L20, arXiv:1204.5771, Bibcode:2012MNRAS.424L..16L, doi:10.1111/j.1745-3933.2012.01276.x.
  11. ^ a b c Fekadu, Nassissie; et al. (2007), "Photometry of the Globular Cluster NGC 5466: Red Giants and Blue Stragglers", The Astrophysical Journal, 663 (1): 277–295, arXiv:astro-ph/0602602, Bibcode:2007ApJ...663..277F, doi:10.1086/518637, S2CID 2600674.
  12. ^ a b Beccari, G.; et al. (December 2015), "Deep Multi-telescope Photometry of NGC 5466. II. The Radial Behavior of the Mass Function Slope", The Astrophysical Journal, 814 (2), id. 144, arXiv:1511.00829, Bibcode:2015ApJ...814..144B, doi:10.1088/0004-637X/814/2/144.
  13. ^ 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.
  14. ^ Belokurov, V.; et al. (2006), "The discovery of tidal tails around the globular cluster NGC 5466", The Astrophysical Journal, 637 (1): L29 – L32, arXiv:astro-ph/0511767, Bibcode:2006ApJ...637L..29B, doi:10.1086/500362, S2CID 125827556.
  15. ^ Grillmair, C. J.; Johnson, R. (2006), "The detection of a 45° tidal stream associated with the globular cluster NGC 5466", The Astrophysical Journal, 639 (1): L17 – L20, arXiv:astro-ph/0602602, Bibcode:2006ApJ...639L..17G, doi:10.1086/501439, S2CID 17925570.
  16. ^ a b Yang, Yong; et al. (June 2022), "Revisit NGC 5466 tidal stream with Gaia, SDSS/SEGUE, and LAMOST", Monthly Notices of the Royal Astronomical Society, 513 (1): 853–863, arXiv:2203.13414, Bibcode:2022MNRAS.513..853Y, doi:10.1093/mnras/stac860.
  17. ^ Beccari, G.; et al. (October 2013), "Deep Multi-telescope Photometry of NGC 5466. I. Blue Stragglers and Binary Systems", The Astrophysical Journal, 776 (1), id. 60, arXiv:1308.5810, Bibcode:2013ApJ...776...60B, doi:10.1088/0004-637X/776/1/60.
  18. ^ Sahu, Snehalata; et al. (May 2019), "Detection of a White Dwarf Companion to a Blue Straggler Star in the Outskirts of Globular Cluster NGC 5466 with the Ultraviolet Imaging Telescope (UVIT)", The Astrophysical Journal, 876 (1), id. 34, arXiv:1903.08212, Bibcode:2019ApJ...876...34S, doi:10.3847/1538-4357/ab11d0.
  19. ^ Mateo, Mario; et al. (1990), "Blue stragglers as remnants of stellar mergers: the discovery of short-period eclipsing binaries in globular cluster NGC 5466", The Astrophysical Journal, 100: 469–484, Bibcode:1990AJ....100..469M, doi:10.1086/115530.
  20. ^ Jeon, Young-Beom; et al. (2004), "SX Phoenicis stars in the globular cluster NGC 5466", The Astronomical Journal, 128 (1): 287–299, arXiv:astro-ph/0404069, Bibcode:2004AJ....128..287J, doi:10.1086/421735, S2CID 17310076.
  21. ^ McCarthy, James K.; Nemec, James M. (1997), "The chemical composition and period change rate of the anomalous cepheid V19 in NGC 5466", The Astrophysical Journal, 482 (1): 203–229, Bibcode:1997ApJ...482..203M, doi:10.1086/304118.
  22. ^ Zinn, R.; King, C. R. (1982), "The mass of the anomalous Cepheid in the globular cluster NGC 5466", The Astrophysical Journal, 262: 700–708, Bibcode:1982ApJ...262..700Z, doi:10.1086/160462.

Further reading

  • Rojas López, V.; et al. (2006), Infante, L.; Rubio, M. (eds.), "Physical parameters of RR Lyrae stars in the globular cluster NGC 5466: The Oosterhoff dichotomy", XI IAU Regional Latin American Meeting of Astronomy, Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias), vol. 26, p. 49, Bibcode:2006RMxAC..26...49R.
  • Buonanno, R.; et al. (1985), "The giant, asymptotic and horizontal branches of globular clusters. II. Photographic of the metal-poor clusters M 15, M 92 and NGC 5466", Astronomy & Astrophysics, 145: 97–117, Bibcode:1985A&A...145...97B.
  • R., Buonanno; et al. (1984), "Positions, magnitudes and colors for stars in the globular cluster NGC 5466", Astronomy & Astrophysics, 56: 79–86, Bibcode:1984A&AS...56...79B.
  • Brosche, P.; Geffert, M. (1983), "Membership of above horizontal branch stars in the globular cluster NGC 5466", Astronomy & Astrophysics, 127: 415–416, Bibcode:1983A&A...127..415B.


Quelle: https://en.wikipedia.org/wiki/NGC_5466
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