Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquarius |
Right ascension | 22h 20m 11.91830s [1] |
Declination | –07° 49′ 15.9742″ [1] |
Apparent magnitude (V) | +5.34 [2] |
Characteristics | |
Spectral type | B8 IIIp Mn:Hg: [3] |
U−B color index | –0.358 [2] |
B−V color index | –0.057 [2] |
Astrometry | |
Radial velocity (Rv) | –9 [4] km/s |
Proper motion (μ) |
RA: +13.201
[1]
mas/
yr Dec.: +0.030 [1] mas/ yr |
Parallax (π) | 3.7483 ± 0.1608 mas [1] |
Distance | 870 ± 40
ly (270 ± 10 pc) |
Absolute magnitude (MV) | −1.78 [5] |
Orbit [6] | |
Period (P) | 220.41±0.10 d |
Periastron epoch (T) | 2,418,548.7±7.4 JD |
Semi-amplitude (K1) (primary) | 18.66±2.75 km/s |
Details | |
A | |
Mass | 5.00±0.22 [7] M☉ |
Luminosity | 1,035 [7] L☉ |
Temperature | 12,593 [8] K |
Rotational velocity (v sin i) | 65 [3] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Rho Aquarii, Latinized from ρ Aquarii, is the Bayer designation for a binary star [8] system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of +5.34. [2] Based upon parallax measurements, this star is at a distance of roughly 870 light-years (270 parsecs) from Earth. [1] It is drifting closer with a radial velocity of –9 km/s. [4] The proximity of this star to the ecliptic means it is subject to lunar occultations. [10]
This is a single-lined spectroscopic binary, with the presence of a companion being revealed by Doppler shifts in the spectrum. [8] An initial orbital solution for the data gives an orbital period of 220.4 days. [6] The primary is a giant star with a stellar classification of B8 IIIp Mn:Hg:. [3] It is a candidate mercury-manganese star, showing a surfeit of these elements in the spectrum. [8] With five times the Sun's mass, this star is radiating 1,035 [7] times as much luminosity from its outer atmosphere at an effective temperature of 12,593 K. [8] This heat gives it the blue-white hue of a B-type star. [11] The companion may be a variable star. [12]