Credit: Aldo Zanetti
Astronomical and Imaging Data
| RA: | 18h 53m 04.30s |
| DEC: | -08° 42′ 22.0″ |
| MAG: | 8.10 |
| Diameter: | 9.8′ |
| Const: | Sct |
| OTA | RC 12″ |
| Focal Length | 2432 |
| Camera | PlayerOne Poseidon M |
| Site | Central Italy |
| Sky Quality | Bortle 4 |
Useful Informations
NGC 6712 is a globular cluster located in the constellation Scutum, approximately 26,400 light-years away from Earth. It’s a scientifically interesting object because its properties, like metallicity and structure, are indicative of a cluster that has been significantly affected by the tidal forces of the Milky Way.
Physical and Chemical Properties
- Age and Metallicity: NGC 6712 is an ancient stellar system, with an estimated age of about 12 billion years. While this is consistent with most globular clusters, its metallicity is unusually high for its type, with an iron abundance ([Fe/H]≈−0.94 dex) that is higher than the average for globulars. This characteristic, combined with its location near the galactic disk, suggests it may have formed from a more chemically enriched gas cloud than typical halo clusters or could be an “immigrant” from a now-disrupted dwarf galaxy.
- Structure and Classification: The cluster is classified as Shapley-Sawyer Concentration Class IX, which denotes a loose, low-density structure. This lack of a high central concentration is likely a result of its orbit, which brings it close to the galactic center and disk, causing it to lose stars to tidal stripping. It’s considered a “tidally disrupted” cluster, having lost a significant portion of its original mass.
Notable Features and Scientific Significance
NGC 6712’s unique properties make it a valuable target for research.
- Black Widow Pulsar: It is home to a unique “black widow” pulsar, PSR J1853-0842A. This binary system consists of a rapidly spinning pulsar and a low-mass companion star. The pulsar’s intense radiation is “evaporating” the companion star, hence the name.
- Tidal Disruption: Evidence of its tidal disruption is a primary focus of study. Astronomers have found that the cluster has lost its fainter, low-mass stars, leaving behind a population of more massive stars. This provides a direct case study of how globular clusters lose mass and evolve under the gravitational influence of a host galaxy’s disk and bulge.
- Variable Star Population: The cluster has a rich population of variable stars, particularly RR Lyrae stars. Studying these stars provides important data for determining the cluster’s distance, age, and chemical composition, as well as for understanding the physical processes of stellar pulsation.