NGC 6934
| NGC 6934 | |
|---|---|
NGC 6934 by Hubble Space Telescope; 3.5′ view | |
| Observation data (J2000 epoch) | |
| Class | VIII |
| Constellation | Delphinus |
| Right ascension | 20h 34m 11.37s |
| Declination | +07° 24′ 16.1″ |
| Distance | 52 kly (16 kpc) |
| Apparent magnitude (V) | 8.83 |
| Apparent dimensions (V) | 1.20′ |
| Physical characteristics | |
| Absolute magnitude | −7.65 |
| Mass | 2.95×105 M☉ |
| Metallicity | = –1.47 dex |
| Other designations | Caldwell 47, NGC 6934 |
![{\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}}](./4c0821bd80891e071c08e7c7ee8e022baedf522c.svg)
NGC 6934 (also known as Caldwell 47) is a globular cluster of stars in the northern constellation of Delphinus, about 52 kilolight-years distant from the Sun. It was discovered by the German-born astronomer William Herschel on 24 September 1785. The cluster is following a highly eccentric orbit (with an eccentricity of 0.81) through the Milky Way along an orbital plane that is inclined by 73° to the galactic plane. It may share a common dynamic origin with NGC 5466. As of 2018, it has been poorly studied.
This appears to be a Oosterhoff type I cluster with an intermediate metallicity. It has an Shapley–Sawyer Concentration Class of VIII, with a core radius of 15″ and a half-light radius of 36″. The estimated mass is 295,000 times the mass of the Sun. The cluster displays photometric anomalies, with a split subgiant branch on the HR diagram. Searches for variable stars have discovered 85 in the cluster field, of which 79 are of the RR Lyrae class and one is a SX Phe variable. There is some evidence for a tidal tail.