111 Tauri
111 Tauri is a wide binary star system in the constellation Taurus. It is located at a distance of 48 light years from the Sun. Primary component A is a main sequence star with a stellar classification of F8V. The secondary component B (Gliese 201) is a K-type main sequence star. The primary is larger and more luminous than the Sun, with about 130% of the Sun's radius and 185% of the Sun's luminosity. The apparent magnitude of 5.0 indicates it is a faint star that can be viewed by the naked eye under good, dark-sky conditions.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Taurus |
| Right ascension | 05h 24m 25.46328s |
| Declination | +17° 23′ 00.7264″ |
| Apparent magnitude (V) | 5.0 |
| Characteristics | |
| A | |
| Spectral type | F8 V |
| U−B color index | −0.05 |
| B−V color index | 0.544 |
| Variable type | BY Dra |
| B | |
| Spectral type | K5 V |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +37.8 km/s |
| Proper motion (μ) | RA: +250.585 mas/yr Dec.: −7.156 mas/yr |
| Parallax (π) | 68.5908 ± 0.1040 mas |
| Distance | 47.55 ± 0.07 ly (14.58 ± 0.02 pc) |
| Absolute magnitude (MV) | 3.49 ± 0.06 |
| Details | |
| 111 Tau A | |
| Mass | 1.08 M☉ |
| Radius | 1.67 ± 0.06 R☉ |
| Luminosity | 1.845 L☉ |
| Surface gravity (log g) | 4.24 cgs |
| Temperature | 6,015 K |
| Metallicity [Fe/H] | −0.14 dex |
| Rotation | 3.503±0.006 d |
| Rotational velocity (v sin i) | 16.0 km/s |
| Age | 20–50 Myr |
| Other designations | |
| 111 Tau A: Gl 202, HR 1780, BD+17°920, HD 35296, SAO 94526, HIP 25278, V1119 Tau | |
| 111 Tau B: Gl 201, BD+17°917, HD 35171, SAO 94513, HIP 25220 | |
| Database references | |
| SIMBAD | A |
| B | |
The metallicity of the primary star, which measures the proportion of elements other than hydrogen and helium, is similar to the Sun. Estimates of [Fe/H], which is the logarithm of the ratio of iron to hydrogen as compared to the Sun, range from a low of −0.14 to a high of 0.05. This star shows an unusually high content of lithium, which remains unexplained. Age estimates for this star range from 3.6 to 3.76 billion years. however the most recent age determination indicates a very young star with an age of 20 to 50 million years. It is a prominent X-ray source.
This star is rotating relatively rapidly, completing a rotation along the equator every 3.5 days as compared to 25 days for the Sun. It is also undergoing differential rotation in which the rotation velocity varies by latitude. 111 Tauri is a BY Draconis variable, and has been given the variable star designation V1119 Tauri.
This star was examined for an excess of infrared emission that could indicate it has a circumstellar debris disk of dust, but no significant excess was observed. The space velocity components of this star are [U, V, W] = [−36.94, −14.63, 7.63] km/s. It is a member of the Hyades stellar kinematic group of co-moving stars.