Globular Cluster NGC 288

NGC 288
NGC 288: Image taken with the Hubble Space Telescope [368]

History

The globular cluster NGC 288 was first sighted on October 27, 1785 by the German-British astronomer Wilhelm Herschel with its 18.7 inch reflector. The cluster is a very loose association with a Shapley – Sawyer concentration class of X. [196, 277]

Physical Properties

Like most globular clusters, NGC 288 is in an elliptical orbit around the galactic center, from which it is currently at a distance of 12 kpc (approx. 39'000 light years). The distance to us is only 8.5 kpc (approx. 27'000 light years). This orbit takes him through the galactic bulge and every time he passes it he loses stars. This creates a tidal tail on both sides of the cluster, which, however, due to the orbit and the position of the cluster in the apocenter, can hardly be made out from the earth. [369, 370, 371]

The different colors and brightnesses of the stars that can be seen in Fig. 1 tell the story of how they developed differently within the cluster. The many weaker points of light are normal stars with low mass, which fuse hydrogen to helium in the same way as our sun does. The brighter stars are divided into two classes: The yellow are red giants, which are in a later stage of their life and are now bigger, cooler and brighter. The bright blue stars are even more massive stars and are powered inside by the fusion of helium. Stars in a globular cluster all form at about the same time from the same gas cloud and are usually very old: 10 to 12 billion years. It is assumed that the stars in less dense clusters can develop differently. [368]

«Revised New General Catalogue and Index Catalogue» Dr. Wolfgang Steinicke, 2021 [277]
DesignationNGC 288
TypeGCL (X)
Right Ascension00h 52m 45.5s
Declination-26° 35' 51"
Diameter13.00 arcmin
Visual magnitude8.1 mag
Dreyer Descriptionglobular, B, L, lE, st 12…16
IdentificationESO 474-SC37, GCL 2

Finder Chart

The globular cluster NGC 288 is located in the constellation Sculptor, about 2 ° southeast of the well-known Silver Dollar (NGC 253). Due to its southern location of -26.5° declination, it is only clearly visible in Central Europe from September to November.

Chart NGC 288
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
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
368Family of stars breaking up; esahubble.org/images/potw1111a (2021-05-30)
369«The globular cluster NGC 288» Alcaino, G.; Astronomy and Astrophysics, Suppl. Ser., Vol. 21, p. 15 (1975); Bibcode:1975A&AS...21...15A
370«On the extended stellar structure around NGC 288» Andrés E. Piatti; Monthly Notices of the Royal Astronomical Society, Volume 473, Issue 1, January 2018, Pages 492–497; DOI:10.1093/mnras/stx2471
371«Rediscovering the tidal tails of NGC 288 with Gaia DR2» Kaderali, Shaziana; Hunt, Jason A. S.; Webb, Jeremy J.; Price-Jones, Natalie; Carlberg, Raymond; Monthly Notices of the Royal Astronomical Society: Letters, Volume 484, Issue 1, p.L114-L118; March 2019; arXiv:1809.04108; DOI:10.1093/mnrasl/slz015