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 600 light years based on parallax, 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]
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Centaurus |
Right ascension | 11h 49m 41.05745s[1] |
Declination | −63° 47′ 18.4299″[1] |
Apparent magnitude (V) | 4.30[2] (+4.30 - 4.39)[3] |
Characteristics | |
Spectral type | B3V[4] |
U−B color index | −0.59 |
B−V color index | −0.15 |
Variable type | γ Cas[3] |
Astrometry | |
Radial velocity (Rv) | +29.0±4.1[2] km/s |
Proper motion (μ) | RA: -20.76 ± 0.56[5] mas/yr Dec.: 4.30 ± 0.48[5] mas/yr |
Parallax (π) | 5.4391 ± 0.4369 mas[1] |
Distance | 600 ± 50 ly (180 ± 10 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 | |
Database references | |
SIMBAD | data |
The stellar classification of the visible component is B3V,[4] 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, 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.[3]