中国科学院云南天文台机构知识库

New multi-color photometry of the eclipsing binary UU Leo, acquired from 2010 to 2013, was carried out by using the 60-cm and 85-cm telescopes at the Xinglong station, which is administered by National Astronomical Observatories, Chinese Academy of Sciences. With the updated Wilson-Devinney code, the photometric solution was derived from BV R light curves. The results imply that UU Leo is a semi-detached Algol-type binary, with a mass ratio of q = 0.100 (+/- 0.002). The change in orbital period was reanalyzed based on all available eclipsing times. The O - C curve could be described by an upward parabola superimposed on a quasi-sinusoidal curve. The period and semi-amplitudes are P-mod = 54.5 (+/- 1.1) yr and A = 0.0273(d) (+/- 0.0015(d)), which may be attributed to the light-time effect via the presence of an invisible third body. The long-term period increases at a rate of dP/d t = +4.64(+/- 0.14) x 10(-7) d yr(-1), which may be interpreted by the conserved mass being transferred from the secondary to the primary. With mass being transferred, the low-mass Algol-type binary UU Leo may evolve into a binary system with a main sequence star and a helium white dwarf.