UZ Pyxidis (HD 75021) is a semiregular variable star in the constellation Pyxis. It is located about 3,600 light-years (1,100 parsecs) away from the Earth.
UZ Pyxidis lies directly between α and γ Pyxidis. It has a common proper motion companion, HD 75022, less than 2' away but the two are not listed in double star catalogues.
UZ Pyxidis is a carbon star. These types of stars are known for having large amounts of carbon in their atmospheres, forming carbon compounds that make the star appear strikingly red. It was first recognised as having an unusual spectrum in 1893. Under the Morgan–Keenan classification of carbon stars, UZ Pyxidis' spectral type is C55; if it were a normal giant star, this would correspond to a spectral type of about K5. It is also unusual in that it has very strong isotopic bands of C2 and CN.
There were hints that the star is variable as early as the late 19th century, and its variability was firmly estabilished by Olin J. Eggen in 1972. The variable star designation UZ Pyxidis was assigned in 1978. UZ Pyxidis is classified as a semiregular variable with a dominant period of 159.6 days. It varies in brightness between magnitude 6.99 and 7.63.
References
Eggen, O. J. (1972). "The classification of intrinsic variable stars. I. The red variables of type N". Astrophysical Journal. 174: 45. Bibcode:1972ApJ...174...45E. doi:10.1086/151467. /wiki/Bibcode_(identifier) ↩
Fleming, W. P. (1893). "Stars having peculiar spectra". Astronomy and Astro-Physics. 12: 546. Bibcode:1893AstAp..12..546F. /wiki/Bibcode_(identifier) ↩
Keenan, P. C.; Morgan, W. W. (1941). "The Classification of the Red Carbon Stars". The Astrophysical Journal. 94: 501. Bibcode:1941ApJ....94..501K. doi:10.1086/144356. /wiki/The_Astrophysical_Journal ↩
Keenan, P. C. (1993). "Revised MK Spectral Classification of the Red Carbon Stars". Publications of the Astronomical Society of the Pacific. 105: 905. Bibcode:1993PASP..105..905K. doi:10.1086/133252. https://doi.org/10.1086%2F133252 ↩
Fleming, W. P. (1893). "Stars having peculiar spectra". Astronomy and Astro-Physics. 12: 546–547. Bibcode:1893AstAp..12..546F. Retrieved 21 December 2024. https://babel.hathitrust.org/cgi/pt?id=njp.32101045541982&seq=630 ↩
Eggen, O. J. (1972). "The classification of intrinsic variable stars. II. The red variables of S and related types". Astrophysical Journal. 177: 489. Bibcode:1972ApJ...177..489E. doi:10.1086/151725. https://doi.org/10.1086%2F151725 ↩
Eggen, O. J. (1972). "The classification of intrinsic variable stars. I. The red variables of type N". Astrophysical Journal. 174: 45. Bibcode:1972ApJ...174...45E. doi:10.1086/151467. /wiki/Bibcode_(identifier) ↩
Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (1978). "63rd Name-List of Variable Stars". Information Bulletin on Variable Stars. 1414: 1. Bibcode:1978IBVS.1414....1K. /wiki/Bibcode_(identifier) ↩
Otero, Sebastian Alberto (15 April 2012). "VSX: Detail for UZ Pyx". The International Variable Star Index. American Association of Variable Star Observers. Retrieved 18 January 2017. https://www.aavso.org/vsx/index.php?view=detail.top&oid=27220 ↩