Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquarius |
Right ascension | 23h 01m 23.64174s [1] |
Declination | −07° 03′ 40.1556″ [1] |
Apparent magnitude (V) | 6.23 [2] |
Characteristics | |
Spectral type | K5 III [3] |
B−V color index | 1.418±0.005 [2] |
Astrometry | |
Radial velocity (Rv) | +1.59±0.14 [1] km/s |
Proper motion (μ) |
RA: −16.221±0.139
[1]
mas/
yr Dec.: −7.911±0.087 [1] mas/ yr |
Parallax (π) | 7.2372 ± 0.0691 mas [1] |
Distance | 451 ± 4
ly (138 ± 1 pc) |
Absolute magnitude (MV) | 0.34 [2] |
Details | |
Radius | 18.02+1.36 −2.45 [1] R☉ |
Luminosity | 102.3+1.3 −0.6 [1] L☉ |
Temperature | 4,324+329 −154 [1] K |
Other designations | |
Database references | |
SIMBAD | data |
81 Aquarii is a star in the constellation of Aquarius. It has an orange hue and is barely visible to the naked eye with an apparent visual magnitude of 6.23. [2] 81 Aquarii is its Flamsteed designation. The star is located at a distance of approximately 451 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +1.6 km/s. [1] It is positioned near the ecliptic and thus is subject to lunar occultations. [5]
This is an aging giant star with a stellar classification of K5 III, [3] indicating it has exhausted the supply of hydrogen at its core then cooled and expanded off the main sequence. The stellar spectrum displays strong lines of cyanogen. [6] It presently has 18 times the radius of the Sun and is radiating 102 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,324 K. [1]