NGC 6284
Globular cluster in the constellation Ophiuchus
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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.
| NGC 6284 | |
|---|---|
NGC 6284 as seen through the Hubble Space Telescope | |
| Observation data (J2000 epoch) | |
| Class | IX |
| Constellation | Ophiuchus |
| Right ascension | 17h 04m 28.747s[1] |
| Declination | −24° 45′ 51.22″[1] |
| Distance | 43,000 ly[2] (13,200 pc[2]) |
| Apparent magnitude (V) | 7.43[1] |
| Apparent dimensions (V) | 6.2' × 6.2'[3] |
| Physical characteristics | |
| Metallicity | [Fe/H] = −1.26[4] dex |
| Estimated age | 13.3~ billion years |
| Other designations | GCl 53, 2MASX J17042874-2445512[1] |
The nearby metal-poor star HD 194598 may be a recent runaway from NGC 6284.[9]
