NGC 5822
Open cluster in the constellation Lupus
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NGC 5822 is an open cluster of stars in the southern constellation of Lupus.[7] It was discovered by English Astronomer John Herschel on July 3, 1836,[2] and lies close to another cluster, NGC 5823, which suggests there may be a physical association.[8][9]
| NGC 5822 | |
|---|---|
NGC 5822 (taken from Stellarium) | |
| Observation data (J2000 epoch) | |
| Right ascension | 15h 4m 21.(2)s[1] |
| Declination | −54° 23′ 5(8)″[1] |
| Distance | 2,682 ly (822.3 pc)[1] |
| Apparent magnitude (V) | 6.5[2] |
| Physical characteristics | |
| Mass | ~1.7×103[3] M☉ |
| Radius | 26.1 ± 1.3 ly (8.0 ± 0.4 pc)[4] |
| Estimated age | 900±100 Myr[5] |
| Other designations | NGC 5822, Cr 289, ESO 176-SC 009[6] |
| Associations | |
| Constellation | Lupus |
NGC 5822 is an intermediate age cluster, estimated at around 900 million years old, and it is located nearby[3] at a distance of 2,700 light years.[1] The Trumpler class of this cluster is III 2m.[9] It is richly populated[5] with half the cluster members lying within an angular radius of 22.1′.[1] The cluster is considered low mass at ~1,700 times the mass of the Sun.[3] It has a core radius of 1.1±0.1 pc and a limiting radius of 8.0±0.4 pc.[4]
Measuring the abundances of a set of F-type stars that are probable members demonstrates the cluster metallicity is very similar to the Sun.[5] It displays an extended main sequence turnoff on the Hertzsprung–Russell diagram, most likely due to differences in stellar rotation.[3] Two barium stars have been identified in NGC 5822, making it only the second cluster shown to host these objects as of 2013.[10]
Gallery
Map showing the location of NGC 5822
