HD 102776

This article is about j centauri and is not to be confused with J Centauri, i Centauri, l Centauri, or ι Centauri.

HD 102776, also known by its Bayer designation j Centauri, is a suspected astrometric binary^[10] star system in the southern constellation of Centaurus. It has a blue-white hue and is faintly visible to the naked eye with a typical apparent visual magnitude of 4.30.^[2] The distance to this star is approximately 710 light years based on parallax,^[3] and it is drifting further away with a radial velocity of ~29 km/s.^[2] It is a member of the Lower Centaurus Crux subgroup of the Sco OB2 association.^[11] HD 102776 has a relatively large peculiar velocity of 31.1 km/s and is a candidate runaway star that was ejected from its association, most likely by a supernova explosion.^[12]

HD 102776

A light curve for HD 102776, plotted from Hipparcos data[1]
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Centaurus[2]
Right ascension	11h 49m 41.06733s[3]
Declination	−63° 47′ 18.5007″[3]
Apparent magnitude (V)	4.30[2] (+4.30 - 4.39)[4]
Characteristics
Evolutionary stage	main sequence[3]
Spectral type	B3V[5]
U−B color index	−0.59
B−V color index	−0.15
Variable type	γ Cas[4]
Astrometry
Radial velocity (Rv)	+29.0±4.1[2] km/s
Proper motion (μ)	RA: −22.022[3] mas/yr Dec.: +2.755[3] mas/yr
Parallax (π)	4.5957±0.3290 mas[3]
Distance	710 ± 50 ly (220 ± 20 pc)
Absolute magnitude (MV)	−1.98[2]
Details
Mass	5.955 M☉[6] 7.2±0.1[7] M☉
Radius	5.00±0.10[8] R☉
Luminosity	1,342[2] L☉
Surface gravity (log g)	3.20±0.03[8] cgs
Temperature	20,000±200[8] K
Rotational velocity (v sin i)	200±4[8] km/s
Age	31.6±0.6[7] Myr
Other designations
j Cen, NSV 5357, CPD−63°1988, FK5 2944, GC 16201, HD 102776, HIP 57669, HR 4537, SAO 251602[9]
Database references
SIMBAD	data

The stellar classification of the visible component is B3V,^[5] matching a B-type main-sequence star. It is around 32^[7] million years old and is spinning rapidly with estimates of its projected rotational velocity ranging from 200^[8] up to 270 km/s, giving it an equatorial bulge that is up to 11% larger than the polar radius.^[13] This is a Be star showing emission features in its Balmer lines due to a circumstellar disk of decreated gas.^[14] It is classified as a suspected Gamma Cassiopeiae type variable star with a visual magnitude varying from +4.30 down to +4.39.^[4]