Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquarius |
Right ascension | 20h 52m 39.23277s [1] |
Declination | −08° 58′ 59.9499″ [1] |
Apparent magnitude (V) | 4.731 [2] |
Characteristics | |
Spectral type | A3m [3] |
U−B color index | +0.149 [2] |
B−V color index | +0.322 [2] |
Astrometry | |
Radial velocity (Rv) | −9.1 [4] km/s |
Proper motion (μ) |
RA: +45.75
[1]
mas/
yr Dec.: -33.59 [1] mas/ yr |
Parallax (π) | 20.74 ± 0.29 mas [1] |
Distance | 157 ± 2
ly (48.2 ± 0.7 pc) |
Absolute magnitude (MV) | +1.31 [5] |
Orbit [6] | |
Period (P) | 1,566±3 d |
Semi-major axis (a) | ≥ 67.06 Gm (0.4483 AU) |
Eccentricity (e) | 0.23±0.19 |
Periastron epoch (T) | 2,410,497±52 JD |
Semi-amplitude (K1) (primary) | 3.2±0.6 km/s |
Details | |
A | |
Radius | 3.54+0.45 −0.15 [7] R☉ |
Luminosity | 25.6±1.4 [8] L☉ |
Surface gravity (log g) | 3.99 [8] cgs |
Temperature | 6,906+151 −405 [8] K |
Rotational velocity (v sin i) | 53.7 [8] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Mu Aquarii, Latinized from μ Aquarii, is the Bayer designation for a binary star [10] system in the equatorial constellation of Aquarius. It is visible to the naked eye with a combined apparent visual magnitude of 4.7. [2] Based upon parallax measurements, the distance to this system is about 157 light-years (48 parsecs). [1] It is drifting closer to the Sun with a radial velocity of −9.1 km/s. [4]
This star was tentatively identified as a single-lined spectroscopic binary by Helmut A. Abt in 1961. [11] It has an orbital period of 4.29 yr and an eccentricity (ovalness) of 0.23. [6] The pair have been resolved by speckle interferometry, showing an angular separation of 0.06 ″. [12] The visible spectrum matches a stellar classification of A3m, with the 'm' suffix indicating that this is an Am, or chemically peculiar star. [3] The primary has an estimated 3.5 times the Sun's radius and is radiating 26 times the luminosity of the Sun from its photosphere at an effective temperature of 6,906 km/s. [7]
This star together with ν Aquarii is Albulaan /ˌælbjəˈlɑːn/, derived from an Arabic term al-bulaʽān (ألبولعان) meaning "the two swallowers". This star, along with ε Aqr (Albali) and ν Aqr (Albulaan), were al Bulaʽ (البلع), the Swallower. [13] [14] In Chinese, 女宿 (Nǚ Xiù), meaning Girl (asterism) (or Woman), refers to an asterism consisting of μ Aquarii, ε Aquarii, 4 Aquarii, 5 Aquarii and 3 Aquarii. [15] Consequently, the Chinese name for μ Aquarii itself is 女宿二 (Nǚ Xiù èr, English: the Second Star of Girl / Woman.) [16]