We presented a low-precision spectrum for HI Leo,Transiting Exoplanet Survey Satellite data for V523 Cas,and new photometry for both K-type contact binaries.Comparing their light curves on different observing dates,we...We presented a low-precision spectrum for HI Leo,Transiting Exoplanet Survey Satellite data for V523 Cas,and new photometry for both K-type contact binaries.Comparing their light curves on different observing dates,we found small intrinsic variabilities,such as variable amplitudes for HI Leo and the varying heights around the second maxima for V523 Cas.By the Wilson-Devinney Code,we deduced six photometric solutions.The dark spot of V523 Cas may appear on the surface of the more massive component on BJD 2458768,while it disappears on BJD 2458779.Our results indicate that the two binaries are W-type shallow-contact binaries(f≤10%).From the eclipse timing residuals,we found that the orbital periods may continuously increase,accompanied by one to two light-time effects due to additional bodies.The modulated periods and semi-amplitudes are P_(3)=25.8(±1.0)yr and A_(3)=0_·^(d)0066(6)for HI Leo,P_(3)=-14.8(±2.0)yr and A_(3)=0_·^(d)0448(12),P_(4)=18.89(±0.14)yr and A4=0_·^(d)0025(2)for V523 Cas,respectively.The orbital period secularly increases at a rate of dP/dt=2.86(±0.11)×10^(-7)day yr^(-1)for HI Leo and dP/dt=3.45(±0.07)×10^(-8)day yr^(-1)for V523 Cas,which may be attributed to mass transfer from the secondary to the primary.With mass transferring,the shallow-contact binaries,HI Leo and V523 Cas,will evolve into the broken-contact configurations.展开更多
We presented new CCD photometry for two contact binaries,V724 And and QR Com,which were observed during the 2020–2022 observing seasons.By using the Wilson–Devinney method,the photometric solutions were deduced from...We presented new CCD photometry for two contact binaries,V724 And and QR Com,which were observed during the 2020–2022 observing seasons.By using the Wilson–Devinney method,the photometric solutions were deduced from new observed data and TESS ones.Their asymmetric light curves were modeled by a dark spot on the more massive component.Results indicate that the starspot may immigrate or disappear on the surface of the active component.From the TESS observations of QR Com,it is discovered that the difference between light maxima exhibits a 29.5 day oscillation,which implies the continuous evolution of spot feathers on the timescale of several weeks.Their mass ratio and fill-out factor are q=2.308 and f=11.55% for V724 And,and q=0.624 and f=12.77% for QR Com,respectively.From the(O-C)curve,the orbital period secularly decrease at a rate of d P/dt=-1.66×10^(-7)day yr^(-1)for V724 And and d P/dt=-3.98×10^(-7)day yr^(-1)for QR Com,which was interpreted by mass transfer from the more massive component to the less massive one.With period decreasing,this kind of shallow-contact binaries,V724 And and QR Com,will evolve into the deep-contact configurations.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11873003)。
文摘We presented a low-precision spectrum for HI Leo,Transiting Exoplanet Survey Satellite data for V523 Cas,and new photometry for both K-type contact binaries.Comparing their light curves on different observing dates,we found small intrinsic variabilities,such as variable amplitudes for HI Leo and the varying heights around the second maxima for V523 Cas.By the Wilson-Devinney Code,we deduced six photometric solutions.The dark spot of V523 Cas may appear on the surface of the more massive component on BJD 2458768,while it disappears on BJD 2458779.Our results indicate that the two binaries are W-type shallow-contact binaries(f≤10%).From the eclipse timing residuals,we found that the orbital periods may continuously increase,accompanied by one to two light-time effects due to additional bodies.The modulated periods and semi-amplitudes are P_(3)=25.8(±1.0)yr and A_(3)=0_·^(d)0066(6)for HI Leo,P_(3)=-14.8(±2.0)yr and A_(3)=0_·^(d)0448(12),P_(4)=18.89(±0.14)yr and A4=0_·^(d)0025(2)for V523 Cas,respectively.The orbital period secularly increases at a rate of dP/dt=2.86(±0.11)×10^(-7)day yr^(-1)for HI Leo and dP/dt=3.45(±0.07)×10^(-8)day yr^(-1)for V523 Cas,which may be attributed to mass transfer from the secondary to the primary.With mass transferring,the shallow-contact binaries,HI Leo and V523 Cas,will evolve into the broken-contact configurations.
基金partly supported by the National Natural Science Foundation of China(No.11873003)the Open Project Program of the Key Laboratory of Optical Astronomy of NAOC。
文摘We presented new CCD photometry for two contact binaries,V724 And and QR Com,which were observed during the 2020–2022 observing seasons.By using the Wilson–Devinney method,the photometric solutions were deduced from new observed data and TESS ones.Their asymmetric light curves were modeled by a dark spot on the more massive component.Results indicate that the starspot may immigrate or disappear on the surface of the active component.From the TESS observations of QR Com,it is discovered that the difference between light maxima exhibits a 29.5 day oscillation,which implies the continuous evolution of spot feathers on the timescale of several weeks.Their mass ratio and fill-out factor are q=2.308 and f=11.55% for V724 And,and q=0.624 and f=12.77% for QR Com,respectively.From the(O-C)curve,the orbital period secularly decrease at a rate of d P/dt=-1.66×10^(-7)day yr^(-1)for V724 And and d P/dt=-3.98×10^(-7)day yr^(-1)for QR Com,which was interpreted by mass transfer from the more massive component to the less massive one.With period decreasing,this kind of shallow-contact binaries,V724 And and QR Com,will evolve into the deep-contact configurations.
