Credit: Armen Akopian
Astronomical and Imaging Data
| RA: | 16h 27m 40.37s |
| DEC: | -38° 50′ 55.5″ |
| MAG: | 8.99 |
| Diameter: | 8.1′ |
| Const: | Sco |
| OTA | ASA 1000RC |
| Focal Length | 6500mm |
| Camera | FLI PL16803 |
| Site | El Sauce, Chile |
| Sky Quality | Bortle 1 |
Useful Informations
NGC 6139 is a globular cluster located in the constellation Scorpius. It is a massive and aging star cluster, notable for its high stellar density and its location in the inner region of the Galactic halo, close to the center of the Milky Way.
Physical Properties
- Distance: Located approximately 33,000 light-years from Earth. Its distance from the Galactic Center is about 10,000 light-years, which is less than half the Sun’s distance from the center.
- Mass and Age: The cluster has a mass of about 350,000 solar masses and contains a population of stars estimated to be over 10 billion years old.
- Concentration: NGC 6139 is a Shapley-Sawyer Concentration Class II cluster, meaning it has a high central concentration of stars.
Stellar Populations and Metallicity
- Metallicity: While the exact metallicity value varies slightly between studies, NGC 6139 is considered a moderately metal-poor cluster, with a metallicity of approximately -1.68 dex. This is typical for an old globular cluster.
- Multiple Populations: Despite its classification as a fairly standard globular cluster, recent high-resolution spectroscopic studies have revealed that NGC 6139 contains multiple stellar populations. These populations show variations in the abundance of light elements like sodium and oxygen, which is a common characteristic found in many globular clusters.
Kinematics and Origin
- Orbit: NGC 6139 is part of the Milky Way’s population of globular clusters that orbit the Galactic Center. Its close proximity to the Galactic Center means it experiences strong tidal forces, which likely influence its shape and internal dynamics.