56 Aquarii
Star in the constellation Aquarius
From Wikipedia, the free encyclopedia
56 Aquarii, abbreviated 56 Aqr, is a star in the constellation of Aquarius. 56 Aquarii is its Flamsteed designation. It is a sixth magnitude star, having an apparent visual magnitude of 6.36,[2] and thus is a challenge to view with the naked eye. Based upon an annual parallax shift of 5.01 mas, it is located around 653 light years from the Earth. At that distance, the visual magnitude is diminished by an extinction of 0.12 due to interstellar dust.[7] The star is moving closer with a heliocentric radial velocity of −28 km/s.[5] It is a candidate runaway star showing a transverse peculiar velocity of 213.87 km/s.[9]
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 30m 17.35101s[1] |
| Declination | −14° 35′ 08.6373″[1] |
| Apparent magnitude (V) | 6.36[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | B8 Vs[4] |
| B−V color index | −0.047±0.007[2] |
| Astrometry | |
| Radial velocity (Rv) | −27.6±1.2[5] km/s |
| Proper motion (μ) | RA: +34.997 mas/yr[1] Dec.: −33.804 mas/yr[1] |
| Parallax (π) | 4.9951±0.0533 mas[1] |
| Distance | 653 ± 7 ly (200 ± 2 pc) |
| Absolute magnitude (MV) | −0.05[2] |
| Details[1] | |
| Mass | 3.579±0.044 M☉ |
| Radius | 3.21±0.07 R☉ |
| Luminosity | 229±5 L☉ |
| Surface gravity (log g) | 3.869+0.007 −0.008 cgs |
| Temperature | 12,520+48 −53.5 K |
| Metallicity [Fe/H] | −0.35±0.32[6] dex |
| Rotational velocity (v sin i) | 23[3] km/s |
| Age | 292[7] Myr |
| Other designations | |
| 56 Aqr, CD−15°6231, FK5 5985, GC 31428, HD 213236, HIP 111086, HR 8567, SAO 165127[8] | |
| Database references | |
| SIMBAD | data |
Houk and Smith-Moore (1978) gave this star a stellar classification of B8 II,[10] matching a B-type bright giant. In contrast, Cowley et al. (1969) found a class of B8 Vs,[4] corresponding to a B-type main-sequence star with narrow ("sharp") absorption lines due to a relatively low projected rotation. Zorec and Royer (2012) modeled it as a dwarf star that is 67% of the way through its main sequence lifespan. It is a chemically peculiar mercury-manganese star, showing abnormally strong absorption lines of mercury and magnesium with weak lines of helium.[11] The star has 3.6 times the mass of the Sun and about 3.2 times the Sun's radius. It is radiating 230 times the Sun's luminosity from its photosphere at an effective temperature of 12,500 K.[1]