TX Leonis
TX Leonis, also known by its Flamsteed designation 49 Leonis, is a triple star system that includes an eclipsing binary, located in the constellation Leo. It was discovered to be a variable star, showing eclipses, by Ernst-Joachim Meyer in 1933. The apparent magnitude of TX Leonis ranges between 5.66 and 5.75, making it faintly visible to the naked eye for an observer located well outside of urban areas. The star's brightness drops by 0.09 and 0.03 magnitudes during the primary and secondary eclipses respectively, and neither the primary nor the secondary eclipse is total.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Leo |
| Right ascension | 10h 35m 02.15893s |
| Declination | +08° 39′ 01.5434″ |
| Apparent magnitude (V) | 5.66 - 5.75 |
| Characteristics | |
| Spectral type | A2V |
| B−V color index | 0.059 |
| Variable type | Algol/detached |
| Astrometry | |
| Proper motion (μ) | RA: −52.68±0.73 mas/yr Dec.: −4.23±0.46 mas/yr |
| Parallax (π) | 7.61 ± 0.67 mas |
| Distance | 430 ± 40 ly (130 ± 10 pc) |
| Absolute magnitude (MV) | 0.458 |
| Orbit | |
| Period (P) | 2.4450566 d |
| Eccentricity (e) | 0.060±0.010 |
| Inclination (i) | 66.8° |
| Argument of periastron (ω) (secondary) | 295.9±9° |
| Argument of periastron (ω) (primary) | ° |
| Details | |
| TX Leonis Aa | |
| Mass | 2.75±0.12 M☉ |
| Radius | 3.49±0.16 R☉ |
| Luminosity | 73 L☉ |
| Temperature | 8,616 K |
| Rotational velocity (v sin i) | 15 km/s |
| TX Leonis Ab | |
| Mass | 1.05±0.05 M☉ |
| Radius | 2.10±0.09 R☉ |
| Luminosity | 6.0 L☉ |
| Temperature | 6,266 K |
| Age | 850 Myr |
| B | |
| Mass | 1.75 M☉ |
| Surface gravity (log g) | 4.24 cgs |
| Temperature | 6,338 K |
| Metallicity [Fe/H] | −0.24 dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
TX Leonis is a triple star, consisting of magnitude 8.1 star (component B) separated by 2 arc seconds from the brighter eclipsing pair (components Aa and Ab). Although orbital motion has not been detected, the companion shares a common proper motion with the primary star and is at approximately the same distance.
Both stars comprising the eclipsing binary are main sequence stars. Of those two stars, star Aa has been assumed to be 8 times more luminous than star Ab, although newer estimates give the luminosities as 83 L☉ and 6 L☉ respectively.