Gliese 221

Gliese 221
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Orion
Right ascension 05h 53m 00.285s[1]
Declination −05° 59′ 41.44″[1]
Apparent magnitude (V) 9.70[2]
Characteristics
Spectral type K7V/M0V[3]
B−V color index 1.321±0.001[2]
Astrometry
Radial velocity (Rv)+22.9±0.4[1] km/s
Proper motion (μ) RA: −1.170 mas/yr[1]
Dec.: −346.762 mas/yr[1]
Parallax (π)49.2485 ± 0.0185 mas[1]
Distance66.23 ± 0.02 ly
(20.305 ± 0.008 pc)
Absolute magnitude (MV)8.154±0.077[4]
Details
Mass0.72±0.21[5] M
Radius0.613±0.064[4] R
Luminosity0.095±0.01[5] L
Surface gravity (log g)4.74±0.02[5] cgs
Temperature4,324±100[5] K
Metallicity [Fe/H]−0.34±0.08[5] dex
Age4.4±4[5] Gyr
Other designations
BD−06 1339, GJ 221, HIP 27803, PPM 188554, LTT 2396, 2MASS J05530028-0559410,[6] Gaia EDR3 3022099969137163904
Database references
SIMBADdata
Exoplanet Archivedata

Gliese 221 (GJ 221), also known as BD-06 1339, is a star with an exoplanetary companion in the equatorial constellation of Orion. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 9.70[2] and an absolute magnitude of 8.15.[4] Using parallax measurements, the distance to this system can be estimated as 66.2 light-years. It is receding from the Sun with a radial velocity of +23 km/s.[1] This is a high proper motion star, traversing the celestial sphere at an angular rate of 0.333·yr−1.[7]

This is a late K-type or early M-type main-sequence star with a stellar classification of K7V/M0V.[3] It has 72% of the mass and 61% of the radius of the Sun.[5] The star is roughly 4.4[5] billion years old and is depleted in heavy elements, containing just 46% of solar abundance of iron.[5] It is an active star and the level of chromospheric activity has been found to vary significantly over time.[3] The star is radiating 10%[5] of the luminosity of the Sun from its photosphere at an effective temperature of 4,324 K.[5]

  1. ^ a b c d e f Cite error: The named reference EDR3 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Lo_Curto_et_al_2013 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Houdebine_et_al_2016 was invoked but never defined (see the help page).
  5. ^ a b c d e f g h i j k Cite error: The named reference Sousa2018 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Luyten1995 was invoked but never defined (see the help page).