Credit: Armen Akopian
Astronomical and Imaging Data
| RA: | 15h 03m 58.63s |
| DEC: | -33° 04′ 05.6″ |
| MAG: | 9.09 |
| Diameter: | 7.2′ |
| Const: | Lup |
| OTA | ASA 1000RC |
| Focal Length | 6500mm |
| Camera | FLI PL16803 |
| Site | El Sauce, Chile |
| Sky Quality | Bortle 1 |
Useful Informations
NGC 5824 is a globular cluster located in the constellation Lupus. It is a highly condensed and luminous cluster in the outer galactic halo, known for its great distance from the Galactic Center and its complex stellar population.
Physical Characteristics
- Distance: NGC 5824 is exceptionally distant, located approximately 104,400 light-years from Earth and about 83,000 light-years from the Galactic Center.
- Mass and Age: It’s a massive cluster with an estimated mass of about 7.5×105 solar masses and is considered a very old object, with an age of around 12.8 billion years.
- Concentration: On the Shapley–Sawyer Concentration Scale, it is a Class I cluster, indicating a very high central stellar density. This makes it challenging to resolve its core stars with smaller telescopes.
Stellar Populations and Origin
Like many of the most massive globular clusters, NGC 5824 is not a “simple” stellar population with a single generation of stars.
- Multiple Generations: Spectroscopic studies have shown an intrinsic spread in the abundances of light elements (like magnesium and sodium) among its stars. There is also some evidence for variations in iron content, which is a rare characteristic for a globular cluster.
- Tidal Tails and Accretion: NGC 5824 is associated with the Cetus Stream, a vast stellar stream believed to be the tidally disrupted remnant of a dwarf galaxy. This association, along with the cluster’s high luminosity and complex chemical composition, has led astronomers to hypothesize that NGC 5824 may be the former nuclear star cluster of that now-disrupted dwarf galaxy, which was later captured by the Milky Way.
- Oosterhoff Type II: NGC 5824 is classified as an Oosterhoff Type II globular cluster, a classification based on the long pulsation periods of its RR Lyrae variable stars. This type is generally associated with very metal-poor clusters.