  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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−Bcolor index | −0.561[2] |
| B−Vcolor 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 |
Psi2 Aquarii,Latinized from ψ2 Aquarii, is theBayer designation for a star in theequatorialconstellation ofAquarius. It is visible to the naked eye with anapparent visual magnitude of 4.4.[2] Based uponparallax measurements made during theHipparcos mission, the distance to this star is roughly 400light-years (120parsecs).[1]
This is aB-type main sequence star with astellar classification of B5 Vn.[3] The 'n' suffix indicates that theabsorption lines in thespectrum are being broadened byDoppler shift from the star's rapid rotation rate. Theprojected rotational velocity of the star is 341 km/s.[8] Psi2 Aquarii is 4.6[7] times as large as the Sun with aneffective temperature of 15,212 K[7] in itsouter envelope.
It is aλ Eridani variable, orperiodic Be star, with a pulsation cycle lasting 1.073 days.[4] The amplitude of the variation is 0.024 in magnitude.[11]
