Credit: Armen Akopian
Astronomical and Imaging Data
| RA: | 17h 31m 54.99s |
| DEC: | -67° 02′ 54.0″ |
| MAG: | 7.73 |
| Diameter: | 15′ |
| Const: | Ara |
| OTA | ASA 20N |
| Focal Length | 1900mm |
| Camera | FLI PL16803 |
| Site | El Sauce, Chile |
| Sky Quality | Bortle 1 |
Useful Informations
NGC 6362 is a globular cluster located in the constellation Ara. It is a scientifically important object because it’s one of the least massive globular clusters known to contain multiple stellar populations, challenging previous theories about the minimum mass required for such a phenomenon.
Physical Characteristics
- Distance: Located about 24,800 light-years from Earth.
- Apparent Magnitude: With an apparent magnitude of 7.73, it is a faint but resolvable target for medium-sized amateur telescopes.
- Concentration: NGC 6362 has a Shapley-Sawyer Concentration Class X, indicating a very low central concentration of stars, making it a “loose” cluster.
- Mass and Age: It has an estimated mass of approximately 50,000 solar masses, making it one of the least massive globulars. Its age is estimated to be around 13.57 billion years.
Stellar Populations and Metallicity
- Multiple Generations: Unlike what was once thought, NGC 6362 contains at least two distinct stellar populations that have different chemical compositions. A key finding is that the ratio of these populations is almost equal, which is unusual as most globular clusters are dominated by a “second generation” of stars.
- Chemical Properties: The stars in NGC 6362 show variations in light elements like sodium but have a consistent iron abundance, with a metallicity of around -1.07 dex. The presence of these multiple populations at such a low mass suggests that the processes that create them can happen in smaller systems than previously believed.
Dynamics and Origin
- Tidal Disruption: The cluster’s loose structure and the fact that its two stellar populations are spatially mixed suggest that it has undergone significant mass loss (up to 80% of its original mass) due to long-term tidal interactions with the Milky Way.
- Blue Stragglers: NGC 6362 is known to have a significant population of blue stragglers, which are stars that appear younger and bluer than their neighbors. They are thought to form from stellar collisions or mass transfer between binary stars, a process more common in the dense environment of a globular cluster.