OT UMa and 2MASS J09251388+6424488: Two active contact eclipsing binary systems

• Published in: New astronomy 2023-08, Vol.102, p.102038, Article 102038
• Main Authors: Zhang, B., Mei, K.-Y., Zhi, Q.-J., Dong, A.-J., Zhang, X.-D.
• Format: Article
• Language: English
• Subjects: Contact binaries; Eclipsing binary; NSVS 2497620; OT UMa
• ISSN: 1384-1076; 1384-1092
• DOI: 10.1016/j.newast.2023.102038

In this paper, new photometric light curves (LCs) of OT UMa and 2MASS J09251388+6424488 (=NSVS 2497620, hereafter NSVS 2497) in BVRcIc-bands are presented and analyzed by using the 2015 version of the Wilson–Devinney (W–D) code. We found that both of them are active contact eclipsing binaries (CEBs) . At the same time, we estimated masses and radii of OT UMa and NSVS 2497 by using our photometric parameters. Then, we also studied the orbital period changes of them by using the O−C method via collecting all available times of light minimum for the first time, and new linear ephemerides are obtained. Besides, the formation and evolution of these two targets are discussed, and we thought that OT UMa could be undergoing thermal relaxation oscillations. •The new light curves of OT UMa and NSVS 2497620 in B, V, R and I-bands are obtained and analyzed.•We obtained new photometric solutions and analyzed the changes of the orbital period for these two targets.•It is found that both of them are active contact eclipsing binaries.•OT Uma is possible undergoing thermal relaxation oscillations.