IX Carinae

IX Carinae (IX Car) is a red supergiant and pulsating variable star of spectral type M2Iab in the constellation Carina. It is a member of the Carina OB1 association along the Carina Nebula.

IX Carinae is a semiregular variable star, but its properties are poorly-defined. Different sources give its brightness range as magnitude 7.2 to 8.5. or 6.87 to 7.9. The International Variable Star Index finds a period of approximately 384 days from ASAS-3 and visual observations, but also gives a possible period of 108 days. Another analysis finds a primary period of $0.9$ and a longer secondary period of $3,660$.

The physical characteristics of IX Carinae are also only known approximately, partly because of an uncertain distance. The effective temperature is around $408 days$, while its bolometric luminosity is between and. It is one of the largest stars with a radius of approximately 600 solar radius. If placed at the center of the Solar System, it would extend close to the orbit of the outer asteroid belt.

IX Carinae has been listed as a candidate supernova close enough to Earth that pre-collapse neutrinos could be detected, allowing for observations of the star to be made from before the supernova explosion.