In 1911, it was announced thatWilliamina Fleming had discovered the variability and peculiar spectrum of this star, then known as DM −44° 8539.[10] It was given itsvariable star designation, UY Centauri, in 1912.[11] In 1952,S. Gaposchkin listed it as asemiregular variable with a period of 114.6 days and aclass of K5p.[12]K. G. Henize included it in a list of candidateS stars below declination −25°, although noting it showed unusual spectral features.[13] In 1971, UY Cen was named the prototype of SC stars, a rare group with spectra that lie between S- andC-type stars.[14]
This is anevolved star on theasymptotic giant branch that is shedding mass at an estimated rate of1.70×10−7M☉·yr−1.[5] The ratio of carbon to oxygen isotopes in thestellar atmosphere is almost exactly 1.[8] At this stage, it is expected that most of these expelled atoms become locked up in carbon monoxide gas, preventing further dust formation. However, in 2002, this star was observed to undergo a steep decline in luminosity, dropping by two magnitudes. This was interpreted as an episode of circumstellar dust formation. It may be an indication that UY Cen is starting to evolve away from the SC phase.[15]
^abcDucati, J. R. (2002), "Catalogue of Stellar Photometry in Johnson's 11-color system.",VizieR Online Data Catalog, CDS/ADC Collection of Electronic Catalogues,2237,Bibcode:2002yCat.2237....0D.
^abcBorisov, Sviatoslav B.; et al. (May 1, 2023), "New Generation Stellar Spectral Libraries in the Optical and Near-infrared. I. The Recalibrated UVES-POP Library for Stellar Population Synthesis*",The Astrophysical Journal Supplement Series,266 (1): 11,arXiv:2211.09130,Bibcode:2023ApJS..266...11B,doi:10.3847/1538-4365/acc321,ISSN0067-0049.
^Fleming, Williamina; Pickering, Edward C. (September 1911), "Stars Having Peculiar Spectra. 31 New Variable Stars",Harvard College Observatory Circular,167:1–3,Bibcode:1911HarCi.167....1F.
^Steinfadt, Justin D. R.; et al. (September 2005), "A Unique Dust Formation Episode in the SC-Type Star UY Centauri",The Publications of the Astronomical Society of the Pacific,117 (835):950–954,arXiv:astro-ph/0506505,Bibcode:2005PASP..117..950S,doi:10.1086/432848.
