NGC 6284

NGC 6284
NGC 6284 as seen through the Hubble Space Telescope
Observation data (J2000 epoch)
ClassIX
ConstellationOphiuchus
Right ascension17h 04m 28.747s[1]
Declination−24° 45′ 51.22″[1]
Distance43,000 ly[2] (13,200 pc[2])
Apparent magnitude (V)7.43[1]
Apparent dimensions (V)6.2' × 6.2'[3]
Physical characteristics
Metallicity = -1.26[4] dex
Estimated age13.3~ billion years
Other designationsGCl 53, 2MASX J17042874-2445512[1]
See also: Globular cluster, List of globular clusters

NGC 6284 is a globular cluster located in the constellation Ophiuchus. It is designated as IX in the galaxy morphological classification scheme and was discovered by the German-born British astronomer William Herschel on 22 May 1784. Its distance had previously been estimated at 49,900 light years from Earth,[5][3][6][7][8] but this was revised in 2023 to around 43,000 light years.[2] This same study, based on high-resolution Hubble Space Telescope optical observations, produced the first high-quality colour-magnitude diagram (CMD) of NGC 6284, extending down to about six magnitudes below its main sequence turn-off. The new observations moved its centre of gravity by 1.5–3 arcseconds from previous values, and its density profile showed a steep central cusp, suggesting that NGC 6284 is a post-core collapse (PCC) cluster.

The nearby metal-poor star HD 194598 [es] may be a recent runaway from NGC 6284.[9]

  1. ^ a b c d "NGC 6284". SIMBAD. Centre de données astronomiques de Strasbourg.
  2. ^ a b c "Globular cluster NGC 6284 inspected by astronomers".
  3. ^ a b "Revised NGC Data for NGC 6284". Seds. Retrieved 3 October 2015.
  4. ^ William E. Harris. "Catalog of Parameters for Milky Way Globular Clusters". Retrieved 3 February 2017.
  5. ^ "Object No. 1 - NGC 6284". NASA/IPAC extragalactic database. NASA/IPAC. Retrieved 3 October 2015.
  6. ^ "NGC 6284 (= GCL 53)". cseligman. Retrieved 3 October 2015.
  7. ^ "NGC 6284". Seds. Retrieved 3 October 2015.
  8. ^ "The globular cluster NGC 6284". In-the-sky. Retrieved 3 October 2015.
  9. ^ Şahin, Timur; Bilir, Selçuk (2020), "On the Origin of Metal-poor Stars in the Solar Neighborhood", The Astrophysical Journal, 899 (1): 41, arXiv:2007.08514, Bibcode:2020ApJ...899...41S, doi:10.3847/1538-4357/aba2d2, S2CID 220545932