NGC 265 is an open cluster of stars in the southern constellation of Tucana. It is located in the Small Magellanic Cloud, a nearby dwarf galaxy. The cluster was discovered by English astronomer John Herschel on April 11, 1834. J. L. E. Dreyer described it as, “faint, pretty small, round”, and added it as the 265th entry in his New General Catalogue.
This cluster has an angular core radius of 18″ and a physical radius of approximately 47 ly. It has a combined 4,200 times the mass of the Sun and is around 250 million years old. The metallicity of the cluster – what astronomers term the abundance of elements with higher atomic number than helium – is at around −0.62, or only 24% of that in the Sun. The turn-off mass for the cluster, when a star of that mass begins to evolve off the main sequence into a giant, is about 4.0 to 4.5 M☉.
- Sulentic, Jack W.; et al. (1973). The revised new catalogue of nonstellar astronomical objects. Tucson: University of Arizona Press. Bibcode:1973rncn.book…..S. See the VizierVII/1B/catalog entry for NGC 265.
- “Magellanic gemstone in the southern sky [NGC 265]“. Space Telescope Website. Retrieved 2009-03-02.
- Nayak, P. K.; et al. (September 2018). “Star clusters in the Magellanic Clouds. II. Age-dating, classification, and spatio-temporal distribution of the SMC clusters”. Astronomy & Astrophysics. 616: 24. arXiv:1804.00635. Bibcode:2018A&A…616A.187N. doi:10.1051/0004-6361/201732227. A187.
- Piatti, Andrés E.; et al. (May 2007). “Young star clusters immersed in intermediate-age fields in the Small Magellanic Cloud”. Monthly Notices of the Royal Astronomical Society. 377 (1): 300–316. Bibcode:2007MNRAS.377..300P. doi:10.1111/j.1365-2966.2007.11604.x.
- “NGC 265”. SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-04-17.
- Seligman, Courtney. “NGC Objects: NGC 2600 – 2649”. Celestial Atlas. Retrieved 2020-09-06.
- Chiosi, E.; Vallenari, A. (April 2007). “Three clusters of the SMC from ACS/WFC HST archive data: NGC 265, K 29 and NGC 290 and their field population”. Astronomy and Astrophysics. 466 (1): 165–179. arXiv:astro-ph/0702281. Bibcode:2007A&A…466..165C. doi:10.1051/0004-6361:20066834.