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.^[16] 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.^[2] 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.^[5]

ConstellationLeo

Right ascension10^h 35^m 02.15893^s[1]

Declination+08° 39′ 01.5434″^[1]

Apparentmagnitude(V)5.66 - 5.75^[2]

Quick facts Constellation, Right ascension ...

TX Leonis

Location of TX Leonis (circled in red)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Leo
Right ascension	10h 35m 02.15893s[1]
Declination	+08° 39′ 01.5434″[1]
Apparent magnitude (V)	5.66 - 5.75[2]
Characteristics
Spectral type	A2V[3]
B−V color index	0.059[4]
Variable type	Algol/detached[2][5]
Astrometry
Proper motion (μ)	RA: −52.68±0.73[1] mas/yr Dec.: −4.23±0.46[1] mas/yr
Parallax (π)	7.61±0.67 mas[1]
Distance	430 ± 40 ly (130 ± 10 pc)
Absolute magnitude (MV)	0.458[4]
Orbit
Period (P)	2.4450566 d[6]
Eccentricity (e)	0.060±0.010[7]
Inclination (i)	66.8[6]°
Argument of periastron (ω) (secondary)	295.9±9[6]°
Argument of periastron (ω) (primary)	[7]°
Details
TX Leonis Aa
Mass	2.75±0.12[8] M☉
Radius	3.49±0.16[8] R☉
Luminosity	73[9] L☉
Temperature	8,616[10] K
Rotational velocity (v sin i)	15[11] km/s
TX Leonis Ab
Mass	1.05±0.05[8] M☉
Radius	2.10±0.09[8] R☉
Luminosity	6.0[9] L☉
Temperature	6,266[9] K
Age	850[12] Myr
B
Mass	1.75[13] M☉
Surface gravity (log g)	4.24[10] cgs
Temperature	6,338[10] K
Metallicity [Fe/H]	−0.24[10] dex
Other designations
49 Leonis, BD+09 2374, HD 91636, HIP 51802, HR 4148, SAO 118380[14]
Database references
SIMBAD	data

Close

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).^[17][18] 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.^[13]

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,^[6] although newer estimates give the luminosities as 83 L_☉ and 6 L_☉ respectively.^[9]