Iota Leonis
 Location of ι Leonis (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Leo |
| Right ascension | 11h 23m 55.45273s |
| Declination | +10° 31′ 46.2195″ |
| Apparent magnitude (V) | 4.00 |
| Characteristics | |
| Spectral type | F4 IV |
| U−B color index | +1.420 |
| B−V color index | +0.456 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | −10.3 km/s |
| Proper motion (μ) |
RA: +141.45 mas/yr Dec.: −79.14 mas/yr |
| Parallax (π) | 41.26 ± 1.16mas |
| Distance | 79 ± 2 ly (24.2 ± 0.7 pc) |
| Orbit | |
| Primary | ι Leo A |
| Companion | ι Leo B |
| Period (P) | 186 yr |
| Semi-major axis (a) | 1.91″ |
| Eccentricity (e) | 0.53 |
| Inclination (i) | 128° |
| Longitude of the node (Ω) | 235° |
| Periastron epoch (T) | B 1948.8 |
|
Argument of periastron (ω) (secondary) |
325° |
| Details | |
| Mass | 1.62−1.70 M☉ |
| Radius | 2.1 R☉ |
| Luminosity | 11.5 L☉ |
| Surface gravity (log g) | 3.98 cgs |
| Temperature | 6,739 K |
| Metallicity [Fe/H] | 0.06 dex |
| Rotational velocity (v sin i) | 16 km/s |
| Age | 1.7 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Iota Leonis (ι Leonis, abbreviated to ι Leo), is a triple star system in the constellation Leo. The system is fairly close, at only 79 light-years (24.2 parsecs) away, based on its parallax. The system has a combined apparent magnitude of 4.00 making it faintly visible to the naked eye.
Iota Leonis has a spectral type of F3IV. It is a spectroscopic binary, which means it is a binary star with components that are too close together to be able to resolve individually through a telescope. In this case, light from only the primary star can be detected, and it is considered single-lined.
The third component in the star system is designated Iota Leonis B. It orbits the central pair almost every 200 years, and with its perihelion passage in 1948, the separation between the two is steadily growing. Iota Leonis B has a mass approximately 8% greater than that of the Sun. It is a G-type main-sequence star, like the Sun.
In Chinese, 太微右垣 (Tài Wēi Yòu Yuán), meaning Right Wall of Supreme Palace Enclosure, refers to an asterism consisting of ι Leonis, β Virginis, σ Leonis, θ Leonis and δ Leonis. Consequently, ι Leonis itself is known as 太微右垣三 (Tài Wēi Zuǒ Yuán sān, English: the Third Star of Right Wall of Supreme Palace Enclosure.), representing 西次將 (Xīcìjiāng), meaning The Second Western General. 西次將 (Xīcìjiāng), spelled Tsze Tseang by R.H. Allen, means "the Second General"
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