HD 212771

HD 212771 / Lionrock
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Aquarius
Right ascension 22h 27m 03.072s[1]
Declination −17° 15′ 49.164″[1]
Apparent magnitude (V) 7.6±0.01[2]
Characteristics
Spectral type G8 IV[3]
U−B color index +0.54[4]
B−V color index +0.88[2]
Astrometry
Radial velocity (Rv)14.9±0.03[5] km/s
Proper motion (μ) RA: −85.892 mas/yr[1]
Dec.: −104.042 mas/yr[1]
Parallax (π)8.9648 ± 0.0314 mas[1]
Distance364 ± 1 ly
(111.5 ± 0.4 pc)
Absolute magnitude (MV)2.04[6]
Details[7]
Mass1.42±0.07 M☉
Radius4.44±0.13 R☉
Luminosity11.67±0.57 L☉
Surface gravity (log g)3.263±0.010 cgs
Temperature5,065±75 K
Metallicity [Fe/H]−0.09±0.01[8] dex
Age2.90±0.47 Gyr
Other designations
BD−17°6526, HD 212771, HIP 110813, SAO 165086
Database references
SIMBADdata
Exoplanet Archivedata

HD 212771, also named Lionrock, is a solitary star in the southern zodiac constellation Aquarius. It has an apparent magnitude of 7.60,[2] making it readily visible with binoculars but not the naked eye. Parallax measurements place the object at a distance of 364 light years,[1] and is currently receding with a radial velocity of 15 km/s.[5]

HD 212771 has a stellar classification of G8 IV,[3] indicating that it is a subgiant evolving towards the red giant branch after being an F-type main-sequence star for 1.7 billion years.[8] It has 142% the mass of the Sun and 4.4 times its radius. It radiates at 11.67 solar luminosities from its slightly enlarged photosphere at an effective temperature of 5,065 K,[7] giving it a yellow-hue. Unlike most planetary hosts, HD 212771 is slightly metal deficient, and spins with a projected rotational velocity of about 2 km/s.[8]

  1. ^ a b c d e Cite error: The named reference EDR3 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Houk1988 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Paunzen2022 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Jofré2015 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Campante was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Rhazzi2018 was invoked but never defined (see the help page).