56 Aquarii

56 Aquarii
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 30m 17.35070s[1]
Declination −14° 35′ 08.6467″[1]
Apparent magnitude (V) 6.36[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type B8 II[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: +35.275[1] mas/yr
Dec.: −33.214[1] mas/yr
Parallax (π)5.0725 ± 0.0758 mas[1]
Distance643 ± 10 ly
(197 ± 3 pc)
Absolute magnitude (MV)−0.05[2]
Details
Mass3.37±0.14[3] M☉
Radius2.8[6] R☉
Luminosity184.5+43.5
−35.2[3] L☉
Temperature11,912+83
−82[3] K
Rotational velocity (v sin i)23[3] km/s
Age292[7] Myr
Other designations
CD−15° 6231, FK5 5985, GC 31428, HD 213236, HIP 111086, HR 8567, SAO 165127[8]
Database references
SIMBADdata

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 5.07 mas,[1] it is located around 643 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]

Houk and Smith-Moore (1978) gave this star a stellar classification of B8 II,[4] matching a B-type bright giant. In contrast, Cowley et al. (1969) found a class of B8 Vs,[10] 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 3.4[3] times the mass of the Sun and about 2.8[6] times the Sun's radius. It is radiating 185[3] times the Sun's luminosity from its photosphere at an effective temperature of 11,912 K.[3]

  1. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b c d e f g h Cite error: The named reference zorec2012 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference houk1978 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference cadars was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Mdzinarishvili2005 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Saffe2011 was invoked but never defined (see the help page).