Physical Nature and Orbital Behavior of the Eclipsing System UZ Leonis

摘要: New CCD photometric observations of UZ Leo were obtained between February 2012 and April 2013, on 2017. Its physical properties derived from detailed analyses our light curves existing radial velocities. The results indicate that this system is a totally-eclipsing A-subtype overcontact binary with both high fill-out factor 76 \% third source contributing 12 in the $B$ bandpass, 10 $V$, 7 $R$. residuals theoretical models are satisfactorily fitted by adopting magnetic cool spot more massive primary star. Including measurements, total 172 eclipse times used for ephemeris computations. We found orbital period has varied due to periodic oscillation superposed an upward parabolic variation. observed increase at rate $+3.49 \times 10^{-7}$ d yr$^{-1}$ can be plausibly explained some combination non-conservative mass transfer secondary component angular momentum loss braking. semi-amplitude about 139 yrs 0.0225 d, respectively, which interpreted as light-time effect $M_3 \sin i_3$ = 0.30 M$_\odot$. Because lights 7$-$12 circumbinary object very overluminous its mass, it would possibly match white dwarf, rather than M-type main sequence.