HR Carinae is a supergiant

Supergiant

Supergiants are among the most massive stars. They occupy the top region of the Hertzsprung-Russell diagram. In the Yerkes spectral classification, supergiants are class Ia or Ib . They typically have bolometric absolute magnitudes between -5 and -12...

, luminous blue variable

Luminous blue variable

Luminous blue variables, also known as S Doradus variables, are very bright, blue, hypergiant variable stars named after S Doradus, the brightest star of the Large Magellanic Cloud. They exhibit long, slow changes in brightness, punctuated by occasional outbursts in brightness during substantial...

 star located in the constellation Carina

Carina (constellation)

Carina is a constellation in the southern sky. Its name is Latin for the keel of a ship, and it was formerly part of the larger constellation of Argo Navis until that constellation was divided in three.-Stars:...

. It is surrounded by a vast nebula of ejected nuclear-processed material because this star has a multiple shell expanding atmosphere. This star is among the most luminous stars in our galaxy. It has very broad emission wings of the Balmer lines, reminiscent from the broad lines observed in the spectra of O and Wolf-Rayet star

Wolf-Rayet star

Wolf–Rayet stars are evolved, massive stars , which are losing mass rapidly by means of a very strong stellar wind, with speeds up to 2000 km/s...

s. A kinematic distance of 5.4 kpc and a bolometric magnitude of -9.4 put HR Car among the most luminous stars of the galaxy.

Brightness variation

HR Carinae undergoes spectral variations apparently correlated with the light variations similarly to other luminous blue variables.

Characteristics

HR Carinae is a lot like Eta Carinae, both luminous blue variables, and both surrounded by ejected material. The only difference is their mass.