Credit: Jim Fordice
Astronomical and Imaging Data
| RA: | 18h 03m 36.40s |
| DEC: | -26° 04′ 21.0″ |
| MAG: | 14.9 |
| Diameter: | 1.5′ |
| Const: | Sgr |
| OTA | Planewave CDK24 |
| Focal Length | 3962mm |
| Camera | QHY 600M |
| Site | Río Hurtado, Chile |
| Sky Quality | Bortle 1 |
Useful Informations
Terzan 10 is a globular cluster belonging to the Milky Way galaxy, notable for its proximity to the Galactic Center and the extreme challenges its observation presents due to heavy obscuration. It is a critical object for understanding the most internal stellar structures of our galaxy.
Location and Obscuration
Terzan 10 is located in the direction of the constellation Sagittarius, lying very close to the Galactic Plane.
- Inner Galaxy Object: Its low Galactic latitude and angular proximity to the Galactic Center confirm it as a member of the Galactic Bulge or the innermost part of the Galactic Halo. It has an estimated distance from the Sun of approximately 5.8 kpc (about nineteen thousand light years).
- Extreme Extinction: The cluster is one of the most highly reddened and obscured globular clusters known. It suffers from an extremely high level of interstellar extinction caused by the dense dust and gas clouds in the Milky Way’s disc, which lie along the line of sight to the Galactic Center. This heavy obscuration makes it practically invisible at visual wavelengths. The color excess E(B-V), a measure of reddening, is very high, often cited around 2.4, necessitating the use of near infrared photometry for effective study.
Stellar Characteristics
As a globular cluster, Terzan 10 is an ancient system of gravitationally bound stars.
- Age and Metallicity: It is considered an old cluster, consistent with the ages of most other Galactic globular clusters. Its stellar population is typically classified as metal-poor, with iron abundance ([Fe/H]) estimated to be around -0.0 or -1.6 on the logarithmic scale, suggesting it formed early in the galaxy’s history from relatively unenriched material.
- Structural and Dynamic Properties: Terzan 10 is generally described as a less concentrated cluster compared to many other inner galaxy globular clusters, with a relatively low concentration parameter. This suggests a less centrally condensed structure, although this measurement can be highly uncertain due to the extreme crowding and variable extinction effects in the inner galaxy.
- Scientific Importance: Studies of Terzan 10 and other highly obscured Terzan clusters rely heavily on infrared surveys, such as the VISTA Variables in the Via Lactea (VVV) survey, to penetrate the dust and analyze the stellar populations, including variable stars like RR Lyrae, which are crucial for accurately determining the cluster’s distance and extinction properties.