Gliese 221
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 and an absolute magnitude of 8.15. 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. This is a high proper motion star, traversing the celestial sphere at an angular rate of 0.333″·yr−1.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 53m 00.285s |
| Declination | −05° 59′ 41.44″ |
| Apparent magnitude (V) | 9.70 |
| Characteristics | |
| Spectral type | K7V/M0V |
| B−V color index | 1.321±0.001 |
| Astrometry | |
| Radial velocity (Rv) | +22.9±0.4 km/s |
| Proper motion (μ) | RA: −1.170 mas/yr Dec.: −346.762 mas/yr |
| Parallax (π) | 49.2485 ± 0.0185 mas |
| Distance | 66.23 ± 0.02 ly (20.305 ± 0.008 pc) |
| Absolute magnitude (MV) | 8.154±0.077 |
| Details | |
| Mass | 0.72±0.21 M☉ |
| Radius | 0.613±0.064 R☉ |
| Luminosity | 0.095±0.01 L☉ |
| Surface gravity (log g) | 4.74±0.02 cgs |
| Temperature | 4,324±100 K |
| Metallicity [Fe/H] | −0.34±0.08 dex |
| Age | 4.4±4 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is a late K-type or early M-type main-sequence star with a stellar classification of K7V/M0V. It has 72% of the mass and 61% of the radius of the Sun. The star is roughly 4.4 billion years old and is depleted in heavy elements, containing just 46% of solar abundance of iron. It is an active star and the level of chromospheric activity has been found to vary significantly over time. The star is radiating 10% of the luminosity of the Sun from its photosphere at an effective temperature of 4,324 K.