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 250,000 times greater than the Sun (L_☉), and is as well one of the largest stars with a radius more than a thousand times that of the Sun (R_☉).^[8] Older studies frequently calculated higher luminosities and radii.^[6][11] It has an estimated mass loss rate of 5×10⁻⁵ M_☉ per year^[6] and has been once described as a cool hypergiant.^[12] It is surrounded by a dozen early-type stars and a circumstellar nebula which extends 0.12 parsecs (0.39 ly).

HD 143183

HD 143183 (brightest star in the image) as seen from the Rutherfurd Observatory.
Observation data Epoch J2000      Equinox J2000
Constellation	Norma
Right ascension	16h 01m 22.2226s[1]
Declination	−54° 08′ 35.6066″[1]
Apparent magnitude (V)	7.3 - 8.6[2]
Characteristics
Evolutionary stage	Red supergiant
Spectral type	M3 Ia[3]
U−B color index	+0.75[4]
B−V color index	+2.10[4]
Variable type	LB[2]
Astrometry
Radial velocity (Rv)	−39.67±0.66[1] km/s
Proper motion (μ)	RA: −1.1[5] mas/yr Dec.: 13.1[5] mas/yr
Parallax (π)	0.5559±0.1021 mas[1]
Distance	6,850±650[6] ly (2,100±200[6] pc)
Absolute magnitude (MV)	−7.5[7]
Details
Mass	20[6] M☉
Radius	1,261[8] R☉
Luminosity	254,000[8] L☉
Surface gravity (log g)	−0.6[6] cgs
Temperature	3,443–3,605[9] K
Other designations
HD 143183, CD-53 6947, IRAS 15576-5400, 2MASS J16013621-5408356
Database references
SIMBAD	data

A visual band light curve for V558 Normae, plotted from ASAS data^[10]

HD 143183 is catalogued with the variable star designation V558 Normae as its brightness varies irregularly between apparent magnitudes 7.3 and 8.6.^[2]

It is possible that HD 143183 is a spectroscopic binary with an OB+ companion but this is considered doubtful.^[6] HD 143183 lies approximately 1' from the 10th-magnitude O-class bright giant CD-53 6363, the second-brightest star in the cluster.