  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 21h 09m 35.64888s[1] |
| Declination | –11° 22′ 18.0851″[1] |
| Apparent magnitude (V) | 4.52[2] |
| Characteristics | |
| Spectral type | G8 III[3] |
| U−Bcolor index | +0.66[2] |
| B−Vcolor index | +0.94[2] |
| Astrometry | |
| Radial velocity (Rv) | −11.23[4] km/s |
| Proper motion (μ) | RA: +94.12[1]mas/yr Dec.: −14.62[1]mas/yr |
| Parallax (π) | 20.47±0.21 mas[1] |
| Distance | 159 ± 2 ly (48.9 ± 0.5 pc) |
| Absolute magnitude (MV) | +0.93[5] |
| Details | |
| Mass | 2.35[5] M☉ |
| Radius | 8[4] R☉ |
| Luminosity | 37[4] L☉ |
| Surface gravity (log g) | 2.8[4] cgs |
| Temperature | 4,920[4] K |
| Metallicity [Fe/H] | −0.15[4] dex |
| Rotational velocity (v sin i) | 0.0[4] km/s |
| Age | 708[5] Myr |
| Other designations | |
| 13 Aquarii,BD–11 5538,HD 201381,HIP 104459,HR 8093,SAO 164182[6] | |
| Database references | |
| SIMBAD | data |
Nu Aquarii (ν Aqr, ν Aquarii) is theBayer designation for astar in theequatorialconstellation ofAquarius.
With anapparent visual magnitude of 4.52,[2] Nu Aquarii is visible to the naked eye. Its distance from Earth, as determined fromparallax measurements, is around 159light-years (49parsecs). At an estimated age of 708 million years,[5] it hasevolved into agiant star with aspectrum that matches astellar classification of G8 III.[3] It has than double themass of the Sun[5] and has expanded to eight[4] times theSun's radius. Nu Aquarii is radiating 37-fold[4] theluminosity of the Sun from itsouter atmosphere at aneffective temperature of4,920 K.[4] At this heat, the star is glowing with the yellowish hue of aG-type star.[7]
Together withμ Aquarii, it isAlbulaan/ˌælbjəˈlɑːn/, a name derived from theArabic termal-bulaʽān (ألبولعان), meaning "the two swallowers". This star, along withε Aqr (Albali) andμ Aqr (Albulaan), wereal Bulaʽ (البلع)—the Swallower.[8][9]
InChinese,天壘城 (Tiān Lěi Chéng), meaningCelestial Ramparts, refers to an asterism consisting of ν Aquarii,ξ Aquarii,46 Capricorni,47 Capricorni,λ Capricorni,50 Capricorni,18 Aquarii,29 Capricorni,9 Aquarii,8 Aquarii,14 Aquarii,17 Aquarii and19 Aquarii.[10] Consequently, theChinese name for ν Aquarii itself is天壘城十 (Tiān Lěi Chéng shí, English:the Tenth Star of Celestial Ramparts).[11]
