Upsilon1 Centauri

Upsilon¹ Centauri, Latinized from υ¹ Centauri, is a single^[8] star in the southern constellation of Centaurus. It has a blue-white hue and is visible to the naked eye with an apparent visual magnitude of +3.87.^[2] The distance to this object is approximately 427 light years based on parallax,^[1] and is receding with a radial velocity of +9 km/s.^[4] It is a member of the Lower Centaurus Crux group of the Scorpius–Centaurus association.^[2]

For other stars with this Bayer designation, see υ Centauri.

υ¹ Centauri

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Centaurus
Right ascension	13h 58m 40.75s[1]
Declination	−44° 48′ 12.9″[1]
Apparent magnitude (V)	+3.87[2]
Characteristics
Spectral type	B2 IV/V[3]
B−V color index	−0.208±0.011[2]
Astrometry
Radial velocity (Rv)	+9.2±1.4[4] km/s
Proper motion (μ)	RA: −27.51±0.15[1] mas/yr Dec.: −22.44±0.13[1] mas/yr
Parallax (π)	7.63±0.16 mas[1]
Distance	427 ± 9 ly (131 ± 3 pc)
Absolute magnitude (MV)	−1.72[2]
Details
Mass	7.9±0.1[5] M☉
Radius	3.74±0.34[6] R☉
Luminosity	1,884[2] L☉
Surface gravity (log g)	4.15±0.07[6] cgs
Temperature	21,411±377[6] K
Rotational velocity (v sin i)	124[4] km/s
Age	13.0±2.0[5] Myr
Other designations
υ1 Cen, CD−44°9010, FK5 3112, HD 121790, HIP 68282, HR 5249, SAO 224585[7]
Database references
SIMBAD	data

The stellar classification of this object is B2 IV/V,^[2] matching a massive B-type star with a luminosity class displaying mixed traits of a main sequence and a subgiant star. It is 13^[5] million years old and is spinning with a projected rotational velocity of 124 km/s.^[4] The star has 7.9^[5] times the mass of the Sun and 3.7^[6] times the Sun's radius. It is radiating 1,884^[2] times the luminosity of the Sun from its photosphere at an effective temperature of 21,411 K.^[6]