Omega2 Aquarii, Latinised from ω2 Aquarii, is the Bayer designation for a triple star[9] system in the equatorial constellation of Aquarius. It can be seen with the naked eye, having an apparent visual magnitude of 4.49.[2] The approximate distance to this star, 149 light-years (46 parsecs), is known from parallax measurements taken during the Hipparcos mission.[1]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquarius |
Right ascension | 23h 42m 43.34473s[1] |
Declination | −14° 32′ 41.6523″[1] |
Apparent magnitude (V) | 4.49[2] |
Characteristics | |
Spectral type | B9 V[3] |
U−B color index | −0.12[2] |
B−V color index | −0.04[2] |
Astrometry | |
Radial velocity (Rv) | +3[4] km/s |
Proper motion (μ) | RA: +99.28[1] mas/yr Dec.: −66.32[1] mas/yr |
Parallax (π) | 21.96 ± 0.26 mas[1] |
Distance | 149 ± 2 ly (45.5 ± 0.5 pc) |
Absolute magnitude (MV) | +1.20[5] |
Details | |
Radius | 1.94 ± 0.06[6] R☉ |
Luminosity | 37[5] L☉ |
Surface gravity (log g) | 4.22 ± 0.03[6] cgs |
Temperature | 10,504 ± 91[6] K |
Rotational velocity (v sin i) | 148[7] km/s |
Other designations | |
Database references | |
SIMBAD | data |
The primary component of this system is a massive, B-type main-sequence star with a stellar classification of B9 V.[3] This star has nearly double the radius of the Sun[6] and is spinning rapidly with a projected rotational velocity of 148 km/s.[7] The outer atmosphere has an effective temperature of 10,504 K,[6] giving it the blue-white hue of a B-type star.[10]
There is a close orbiting stellar companion of unknown type, with a third component at an angular separation of 5.7 arcseconds. The latter is a K-type main-sequence star with a visual magnitude of 9.5.[9] This system is among the 100 strongest stellar X-ray sources within 163 light-years (50 parsecs) of the Sun. It is emitting an X-ray luminosity of 1.2 × 1030 erg s−1.[11]