双星与变星研究组知识库

The period changes of two close binaries, V1107 Cas and AXCas, which are in the same field, were investigated. Their periods both show a long-term decrease. After further analysis, we found that the periods have their respective cyclic oscillations (T-3 = 6.74 +/- 0.24 yr for V1107 Cas and T-3 = 13.8 +/- 0.3 yr for AXCas), which are possibly caused by a third body due to the light-time effect. We also obtained the complete VRcIc light curves for V1107 Cas and analyzed them with the 2010 version of the Wilson-Devinney code. The photometric results reveal that V1107 Cas is a W-type shallow contact (15.2% +/- 1.8%) binary, with a mass-ratio of 1.797 +/- 0.006. The period variation and photometric solution suggest that V1107 Cas is a newly formed contact binary system. Moreover, we estimated the fundamental parameters for V1107 Cas. They are: M-1 = 0.39 +/- 0.01M(circle dot), M-2 = 0.70 +/- 0.03 M-circle dot, R-1 = 0.52 +/- 0.10 R-circle dot, R-2 = 0.68 +/- 0.12 R-circle dot, L-1 = 0.178 +/- 0.108 L-circle dot, and L-2 = 0.196 +/- 0.116 L-circle dot. Then, based on the coplane assumption, we deduced the masses of possible third bodies to be M-3 = 0.091 +/- 0.019 M-circle dot for V1107 Cas and M-3 = 0.325 +/- 0.029 M-circle dot for AXCas. Finally, we inferred the evolutional stage of AXCas, and believe that it is a precontact binary. Thus, the precontact binary AXCas and the shallow contact binary V1107 Cas have adjoining evolutional stages.