Astronomy:NGC 7492

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Short description: Globular cluster in the constellation Aquarius

Coordinates: Sky map 23h 08m 26.7s, −15° 36′ 39″

NGC 7492
NGC 7492 legacy dr10.jpg
NGC 7492 with legacy surveys
Observation data (J2000 epoch)
ConstellationAquarius
Right ascension 23h 08m 26.7s[1]
Declination−15° 36′ 39″[1]
Distance24,500 kpc (80,000×10^3 ly)[2]
Apparent magnitude (V)11.2
Apparent dimensions (V)4.2
Physical characteristics
Absolute magnitude0.38±0.04[3]
Metallicity[math]\displaystyle{ \begin{smallmatrix}\left[\ce{Fe}/\ce{H}\right]\end{smallmatrix} }[/math] = -1.69[4] dex
Estimated age12 Gyr[2]
Other designationsGCl 125, MWSC 3705
See also: Globular cluster, List of globular clusters

NGC 7492 is a globular cluster[1] in the constellation Aquarius. It was discovered by the astronomer William Herschel on September 20, 1786.[5] It resides in the outskirts of the Milky Way, about 80,000 light-years away, more than twice the distance between the Sun and the center of the galaxy, and is a benchmark member of the outer galactic halo.[6] The cluster is immersed in, but does not kinematically belong to, the Sagittarius Stream.[7]

NGC 7492 possess a tidal tail 3.5 degrees long,[8] embedded into an over-density of stars which may be the remnants of a disrupted dwarf galaxy.[9] The shape of the cluster is flattened rather than spherical, likely due to dynamical interaction with the Milky Way.[10]

References

  1. 1.0 1.1 1.2 "NGC 7492". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+7492. 
  2. 2.0 2.1 Ultraviolet Imaging Telescope (UVIT) observation of the Galactic Globular Cluster NGC 7492
  3. Variable stars in the globular cluster NGC 7492, New discoveries and physical parameter determination
  4. ULTRAVIOLET PROPERTIES OF GALACTIC GLOBULAR CLUSTERS WITH GALEX. II. INTEGRATED COLORS
  5. Seligman, Courtney. "New General Catalogue objects: NGC 7450 - 7499". http://cseligman.com/text/atlas/ngc74a.htm#7492. Retrieved 2021-10-02. 
  6. Koch, Andreas; Xu, Siyi; Rich, R. Michael (2019), "Chemical composition of the outer halo globular cluster Palomar 15", Astronomy & Astrophysics 627: A70, doi:10.1051/0004-6361/201935467, Bibcode2019A&A...627A..70K 
  7. The globular cluster NGC 7492 and the Sagittarius tidal stream: together but unmixed
  8. Navarrete, C.; Belokurov, V.; Koposov, S. E. (2017), "The Discovery of Tidal Tails around the Globular Cluster NGC 7492 with Pan-STARRS1", The Astrophysical Journal 841 (2): L23, doi:10.3847/2041-8213/aa72e1, Bibcode2017ApJ...841L..23N 
  9. Sollima, A.; Martínez Delgado, D.; Muñoz, R. R.; Carballo-Bello, J. A.; Valls-Gabaud, D.; Grebel, E. K.; Santana, F. A.; Côté, P. et al. (2018), "A survey for dwarf galaxy remnants around 14 globular clusters in the outer halo", Monthly Notices of the Royal Astronomical Society 476 (4): 4814–4829, doi:10.1093/mnras/sty539 
  10. MASS SEGREGATION AND TIDAL TAILS OF THE GLOBULAR CLUSTER NGC 7492