Globular Cluster NGC 7006

NGC 7006
NGC 7006: Globular cluster NGC 7006 with multiple background galaxies; 500 mm Cassegrain 5800 mm f/11.4; SBIG STL11K; 60+15+15+15 min LRGB; Bernese Highlands; © 2005 Radek Chromik

History

The globular cluster NGC 7006 was discovered on August 21, 1784 by the English-based German astronomer Wilhelm Herschel and confirmed on October 11, 1825 by his son John. John Louis Emil Dreyer, who revised Herschel's «General Catalogue», described it in his 1888 «New General Catalogue of Nebulae and Clusters of Stars» as follows: «bright, rather large, round, increasing in brightness towards the centre». [313]

Physical Properties

NGC 7006
NGC 7006: Image taken with the Hubble Space Telescope [323]

The globular cluster is located about 40 kpc (about 130'000 light-years) from the galactic center in the halo, the outer region of the Milky Way. The distance to Earth is about 135'000 light years, about five times the distance from the Sun to the center of the Milky Way. The halo is a roughly spherical region around the Milky Way composed of dark matter, gas, and loosely distributed globular star clusters. Like most globular clusters, NGC 7006 has a very eccentric orbit, suggesting that it evolved independently of the Milky Way and was later captured. The metal abundance of NGC 7006 is comparable to that of globular clusters M 13 and M 3. The age is estimated at 12.25 ± 0.75 billion years. [323, 324]

In roughly the same viewing direction as globular cluster NGC 7006 are a number of much more distant, faint galaxies. These are shown in Fig. 1. The brightest of these are identified on the overlay: PGC 65907, PGC 1501723, PGC 65908, PGC 1500528, PGC 65935.

«Revised New General Catalogue and Index Catalogue» Dr. Wolfgang Steinicke, 2021 [277]
DesignationNGC 7006
TypeGCL (I)
Right Ascension21h 01m 29.5s
Declination+16° 11' 17"
Diameter3.60 arcmin
Visual magnitude10.6 mag
Dreyer DescriptionB, pL, R, gbM
IdentificationGCL 119

Finder Chart

The globular cluster NGC 7006 is located in the constellation Delphinus (Dolphin). The best observation time is May to October.

Chart NGC 7006
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

References

149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
313«A New General Catalogue of Nebulae and Clusters of Stars, being the Catalogue of the late Sir John F.W. Herschel, Bart., revised, corrected, and enlarged» Dreyer, J. L. E. (1888); Memoirs of the Royal Astronomical Society. 49: 1–237; Bibcode:1888MmRAS..49....1D
323A remote outpost of the Milky Way; esahubble.org/images/potw1137a (2021-05-02)
324«Globular clusters in the outer Galactic halo: new HST/ACS imaging of 6 globular clusters and the Galactic globular cluster age-metallicity relation» Aaron Dotter (STScI), Ata Sarajedini (UF), Jay Anderson (STScI); arXiv:1106.4307; DOI:10.1088/0004-637X/738/1/74