16 Aquarii

16 Aquarii
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 21h 21m 04.31919s[1]
Declination −04° 33′ 36.4532″[1]
Apparent magnitude (V) 5.869[2]
Characteristics
Spectral type G7 III[3]
B−V color index 0.912±0.001[4]
Astrometry
Radial velocity (Rv)−6.0±2.9[5] km/s
Proper motion (μ) RA: −9.86[6] mas/yr
Dec.: +11.22[6] mas/yr
Parallax (π)9.5319 ± 0.1192 mas[1]
Distance342 ± 4 ly
(105 ± 1 pc)
Absolute magnitude (MV)1.08[4]
Details[7]
Mass2.34±0.13 M☉
Radius7.86±0.26 R☉
Luminosity37.4±2.3 L☉
Surface gravity (log g)3.03±0.04 cgs
Temperature5,096±35 K
Metallicity [Fe/H]0.01±0.10 dex
Rotational velocity (v sin i)1.79[8] km/s
Age740±130 Myr
Other designations
BD−05° 5524, HD 203222, HIP 105412, HR 8160, SAO 145317[9]
Database references
SIMBADdata

16 Aquarii, abbreviated 16 Aqr, is a star in the constellation of Aquarius. 16 Aquarii is the Flamsteed designation. It is a faint star, just visible to the naked eye, with an apparent visual magnitude of 5.869.[2] Based upon an annual parallax shift of 9.5 mas,[1] it is located about 342 light years away. It is moving closer to the Earth with a heliocentric radial velocity of −6 km/s,[5] and is predicted to come within 220 light-years in 6.8 million years.[4]

At the estimated age of 740 million years, this is an aging giant star currently on the red giant branch[7] with a stellar classification of G7 III.[3] This indicates it has exhausted the supply of hydrogen at its core and is generating energy via hydrogen fusion along a shell surrounding a hot core of inert helium. The star has 2.3 times the mass of the Sun and has expanded to 8 times the Sun's radius. It is radiating 37 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,096 K.[7]

  1. ^ a b c d Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Soubiran2016 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Houk1999 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Anderson2012 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 vanLeeuwen2007 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference reffert2015 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference hekker2007 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).