40 Aquarii
Star in the constellation Aquarius
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40 Aquarii is a star in the equatorial constellation of Aquarius. 40 Aquarii is its Flamsteed designation; it was too faint to be included in the Bright Star Catalogue.[9] The brightness of this star is below the normal limit for visibility with the naked eye, having an apparent visual magnitude of 6.93.[2] Based upon parallax measurements, it is located about 726 light-years (223 parsecs) away from the Sun.[1] It is moving closer to the Earth with a heliocentric radial velocity of -3 km/s.[5] 40 Aquarii is positioned near the ecliptic and thus is subject to lunar occultations.[10]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 13m 26.37997s[1] |
| Declination | −11° 55′ 34.0405″[1] |
| Apparent magnitude (V) | 6.93[2] |
| Characteristics | |
| Spectral type | G5 IV[3] |
| B−V color index | +0.762±0.008[4] |
| Astrometry | |
| Radial velocity (Rv) | −2.9±0.3[5] km/s |
| Proper motion (μ) | RA: +20.95[6] mas/yr Dec.: −20.05[6] mas/yr |
| Parallax (π) | 4.4915±0.0371 mas[1] |
| Distance | 726 ± 6 ly (223 ± 2 pc) |
| Absolute magnitude (MV) | −0.47[4] |
| Details[7] | |
| Radius | 10.07+0.44 −0.21[1] R☉ |
| Luminosity | 154.44[4] L☉ |
| Surface gravity (log g) | 2.69[7] cgs |
| Temperature | 5,355±80[7] K |
| Metallicity [Fe/H] | −0.13[7] dex |
| Age | 100[7] Myr |
| Other designations | |
| 40 Aqr, BD−12°6209, HD 210845, HIP 109720, SAO 164935[8] | |
| Database references | |
| SIMBAD | data |
The stellar classification for 40 Aquarii is G5 IV,[3] matching a G-type, yellow-hued subgiant star that has exhausted the supply of hydrogen at its core and has begun to evolve into a giant. It is around 100[7] million years old with 10[1] times the girth of the Sun. The star is radiating 154[4] times the luminosity of the Sun from its photosphere at an effective temperature of 5,355 K.[7]