Description AG Carinae

aavso light curve of luminous blue variable ag car 1 jan 1940 23 nov 2010. brighter , down fainter.

the star surrounded nebula of ejected material @ 0.4–1.2pc star. nebula contains around 15 m☉, lost star around 10,000 years ago. there 8.8pc wide empty cavity in interstellar medium around star, presumably cleared fast winds earlier in star s life.

ag carinae apparently in transitional phase between massive class o blue supergiant , wolf–rayet star, highly unstable , suffers erratic pulsations, occasional larger outbursts, , rare massive eruptions. spectral type varies between wn11 @ visual minimum , hypergiant @ maximum. @ visual minimum star 65 r☉ , 20,000–24,000k, while @ maximum on 400 r☉ , 8,000k. temperature varies @ different minima.

one study calculated bolometric luminosity of ag carinae decreases during s doradus outbursts, unlike lbvs remain @ approximately constant luminosity. luminosity drops around 1.5 million l☉ @ visual minimum around 1 million l☉ @ visual maximum, possibly due energy required expand considerable fraction of star.

evolutionary models of star suggest had low rotation rate of life, current observations show rapid rotation.

models of lbv progenitors of type iib supernovae list ag carinae matching final stellar spectrum prior core collapse, although models stars 20 25 times mass of sun while ag carinae thought considerably larger. initial mass of star have been around 100 m☉ , thought 55-70 m☉.