A Photometric Study of Two Contact Binaries: CRTS J025408.1+265957 and CRTS J012111.1+272933

We performed new photometric observations for two contact binaries (i.e., CRTS J025408.1+265957 and CRTS J012111.1+272933), which were observed by the 1.0 m telescope at Xingjiang Astronomical Observatory. From our light curves and several survey data, we derived several sets of photometric solutions. We found that CRTS J025408.1+265957 and CRTS J012111.1+272933 were A- and W-type W UMa, respectively. The results imply that the spot migrates or disappears in the two contact binaries, which were identified by chromospheric activity emissions (e.g., H-alpha emission) from LAMOST spectra. From the O-C curves, the orbital periods of the two contact binaries may be increasing, which is interpreted by the mass transfer from the less massive component to the more massive one. With mass transferring, the two contact binaries may evolve from the contact configurations to semi-detached ones as predicted by the theory of thermal relaxation oscillation.

Automated summary

The study conducted new photometric observations and spectroscopic analysis on two contact binaries, indicating that the spots in these binaries may migrate or disappear, and the orbital periods are increasing possibly due to mass transfer leading to evolution towards semi-detached configurations.