Omega2 Aquarii

For other stars with this Bayer designation, see ω Aquarii.
Omega2 Aquarii
Location of ω2 Aquarii (circled)
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]
Distance149 ± 2 ly
(45.5 ± 0.5 pc)
Absolute magnitude (MV)+1.20[5]
Details
Radius1.94 ± 0.06[6] R☉
Luminosity37[5] L☉
Surface gravity (log g)4.22 ± 0.03[6] cgs
Temperature10,504 ± 91[6] K
Rotational velocity (v sin i)148[7] km/s
Other designations
ω2 Aqr, 105 Aquarii, BD–15 6476, FK5 894, GJ 9836, HD 222661, HIP 116971, HR 8988, SAO 165842[8]
Database references
SIMBADdata

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]

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]

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  2. ^ a b c d Cite error: The named reference aass34_1 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1978 was invoked but never defined (see the help page).
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  5. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference aj129_3_1642 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference aaa463_2_671 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference mnras389_2_869 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference aj126_4_1996 was invoked but never defined (see the help page).