HD 143183
HD 143183 is a red supergiant variable star of spectral type M3Ia in constellation Norma. It is a member of the Norma OB1 association, at a distance of about 2 kiloparsecs. It is one of the most luminous red supergiants with a luminosity over 100,000 times greater than the Sun (), and is as well one of the largest stars with a radius more than a thousand times that of the Sun (). Older studies frequently calculated higher luminosities and radii. It has an estimated mass loss rate of per year and has been once described as a cool hypergiant . It is surrounded by a dozen early-type stars and a circumstellar nebula which extends . HD 143183 is catalogued with the variable star designation V558 Normae as its brightness varies irregularly between apparent magnitudes 7.3 and 8.6. It is possible that HD 143183 is a spectroscopic binary with an OB+ companion but this is considered doubtful. HD 143183 lies approximately 1' from the 10th-magnitude O-class bright giant CD-53 6363, the second-brightest star in the cluster.