V528 Carinae has an apparent visual magnitude that varies between about 6.3 and 6.8. When it is near its maximum brightness, it is very faintly visible to the naked eye under ideal observing conditions. It is a distant star but the exact distance is uncertain. The Hipparcos satellite gives a negative annual parallax and is not helpful,[8] while the Gaia Data Release 3 parallax of 0.45 mas implies a distance of around 7,200 light years (2,200 parsecs).[1] Assuming membership of the Carina OB2 membership would give a distance of about 1,830 parsecs.[9]
V528 Carinae is a red supergiant of spectral type M2 Ib with an effective temperature of 3,700 K. It has a radius of 700 solar radii.[5] In the visible spectrum, its luminosity is 11,900 times higher than the Sun,[11] but the bolometric luminosity considering all wavelengths reaches around 81,000 L☉.[5] It loses mass at 0.5×10−9M☉ per year.[12]
It was found to be a variable star when the Hipparcos data was analyzed, and for that reason it was given its variable star designation in 1999.[13] It is classified as a slow irregular variable whose prototype is TZ Cassiopeiae.[6]
^ abSamus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
^Josselin, E.; Blommaert, J. A. D. L.; Groenewegen, M. A. T.; Omont, A.; Li, F. L. (2000). "Observational investigation of mass loss of M supergiants". Astronomy and Astrophysics. 357: 225. Bibcode:2000A&A...357..225J.
^Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. (January 1999). "The 74th Special Name-list of Variable Stars"(PDF). Information Bulletin on Variable Stars. 4659: 1–27. Bibcode:1999IBVS.4659....1K. Retrieved 11 January 2025.