Psi2 Aquarii
Star in the constellation Aquarius
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Psi2 Aquarii, Latinized from ψ2 Aquarii, is the Bayer designation for a star in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of 4.4.[2] Based upon parallax measurements made during the Hipparcos mission, the distance to this star is roughly 400 light-years (120 parsecs).[1]
  | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 23h 17m 54.21372s[1] |
| Declination | −09° 10′ 57.0675″[1] |
| Apparent magnitude (V) | 4.403[2] |
| Characteristics | |
| Spectral type | B5 Vn[3] |
| U−B color index | −0.561[2] |
| B−V color index | −0.146[2] |
| Variable type | λ Eri[4] |
| Astrometry | |
| Radial velocity (Rv) | −6[5] km/s |
| Proper motion (μ) | RA: +17.13[1] mas/yr Dec.: −11.70[1] mas/yr |
| Parallax (π) | 8.12±0.38 mas[1] |
| Distance | 400 ± 20 ly (123 ± 6 pc) |
| Absolute magnitude (MV) | −1.04[6] |
| Details | |
| Radius | 4.6[7] R☉ |
| Luminosity | 565[6] L☉ |
| Temperature | 15,212 ± 288[7] K |
| Rotational velocity (v sin i) | 341[8] km/s |
| Other designations | |
| ψ2 Aqr, 93 Aquarii, BD−09°6160, HD 219688, HIP 115033, HR 8858, SAO 146620.[9] | |
| Database references | |
| SIMBAD | data |
This is a B-type main sequence star with a stellar classification of B5 Vn.[3] The 'n' suffix indicates that the absorption lines in the spectrum are being broadened by Doppler shift from the star's rapid rotation rate. The projected rotational velocity of the star is 341 km/s.[8] Psi2 Aquarii is 4.6[7] times as large as the Sun with an effective temperature of 15,212 K[7] in its outer envelope.
It is a λ Eridani variable, or periodic Be star, with a pulsation cycle lasting 1.073 days.[4] The amplitude of the variation is 0.024 in magnitude.[11]