HD 221420

HD 221420
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Octans
Right ascension 23h 33m 19.5789s[1]
Declination −77° 23′ 07.194″[1]
Apparent magnitude (V) 5.81±0.01[2]
Characteristics
Spectral type G2 IV-V[3]
U−B color index +0.31[4]
B−V color index +0.68[4]
Astrometry
Radial velocity (Rv)26.48±0.02[5] km/s
Proper motion (μ) RA: +16.306 mas/yr[1]
Dec.: +0.736 mas/yr[1]
Parallax (π)32.1023 ± 0.0325 mas[1]
Distance101.6 ± 0.1 ly
(31.15 ± 0.03 pc)
Absolute magnitude (MV)+3.33[6]
Details
Mass1.35±0.01[7] M☉
Radius1.95±0.01[7] R☉
Luminosity4.01±1[8] L☉
Surface gravity (log g)4.03±0.03[7] cgs
Temperature5,830±44[9] K
Metallicity [Fe/H]+0.34±0.07[10] dex
Rotational velocity (v sin i)2.8±0.5[11] km/s
Age3.65±0.23[7] Gyr
Other designations
83 G. Octantis, CPD−78°1473, FK5 3887, GC 32742, GJ 4340, HD 221420, HIP 116250, HR 8935, SAO 258154[12][13]
Database references
SIMBADdata
Exoplanet Archivedata

HD 221420 (HR 8935; Gliese 4340) is a likely binary star system[7] in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.81, allowing it to be faintly seen with the naked eye. The object is relatively close at a distance of 102 light years but is receding with a heliocentric radial velocity of 26.5 km/s.

HD 221420 has a stellar classification of G2 IV-V,[3] indicating a solar analogue with a luminosity class intermediate between a subgiant and a main sequence star. The object is also extremely chromospherically inactive.[3] It has a comparable mass to the Sun and a diameter of 1.95 R☉.[7] It shines with a luminosity of 4 L☉[8] from its photosphere at an effective temperature of 5,830 K,[9] giving a yellow glow. HD 221420 is younger than the Sun at 3.65 billion years.[7] Despite this, the star is already beginning to evolve off the main sequence. Like most planetary hosts, HD 221420 has a metallicity over twice of that of the Sun[7] and spins modestly with a projected rotational velocity 2.8 km/s.[11]

There is a mid-M-dwarf star with a similar proper motion and parallax to HD 221420, which is likely gravitationally bound to it. The two stars are separated by 698 arcseconds, corresponding to a distance of 21,756 AU.[7]

  1. ^ a b c d Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Gray2006 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  5. ^ 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 c d e f g h i Cite error: The named reference Venner2021 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Kane2019 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Li2021 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Valenti2005 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).