HD 93205, or V560 Carinae, is a binary stellar system, in the Carina Nebula (NGC 3372) in the constellation Carina. It consists of two massive O-stars that revolve around each other in 6 days.
The more massive member of the pair is an O3.5 main sequence star. The spectrum shows some ionised nitrogen and helium emission lines, indicating some mixing of fusion products to the surface and a strong stellar wind. The mass calculated from apsidal motion of the orbits is 40 to 60 M☉. This is somewhat lower than expected from evolutionary modelling of a star with its observed parameters.[6]
The less massive member is an O8 main sequence star of approximately 20 M☉.[7] It moves in its orbit at a speed of over 300 km/s and is considered to be a relativistic binary, which causes the apses of the orbit to change in a predictable way.[5]
In 1985, Arnout van Genderen et al. reported that the star appeared to be "variable in brightness".[9] Eleonora A. Antokhina et al. confirmed the star's variability in the year 2000, and presented an extensive analysis of the light curve.[7] The star was given its variable star designation, V560 Carinae, in 2001.[10] The closeness of the two stars causes them to become deformed, and this means that the observed brightness of the system varies slightly every six days during its orbit. The total amplitude of the variation is only 0.02 magnitudes.[4]
^ abcDucati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
^ 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.