https://doi.org/10.1140/epjp/s13360-026-07411-3
Regular Article
First photometric study of the contact binaries ZTF J181921.1 + 523627 and LINEAR_9406163
1
Department of Astronomy, National Research Institute of Astronomy and Geophysics, 17211, Helwan, Cairo, Egypt
2
Physics Department, College of Science, Northern Border University, Arar, Saudi Arabia
3
Department of Management Information System, College of Business and Economic, Qassim University, 51452, Buraidah, Qassim, Saudi Arabia
a
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Received:
29
January
2025
Accepted:
5
February
2026
Published online:
25
February
2026
Abstract
This paper presents the first light curve solutions for the contact binaries ZTF J181921.1+523,627 (J181921) and LINEAR_9406163 (LINEAR94) using the Wilson–Devinney code. The light curve solutions indicate that the two systems are contact binaries with EW subtype, where the secondary components fill their lobes with fill-out factor f = 0.44 for the system J181921 and 0.38 for the system LINEAR94, respectively. For the two systems, we calculated new ephemeris based on our time of minima, and the orbital period variations were investigated using our new periods of minima and epochs from all available data. We computed the physical parameters using two approaches. We adopted the final physical parameters from the second approach: for J181921, the primary and secondary components were found to have masses of 0.79 M⊙ and 0.27 M⊙, respectively, with corresponding radii of 0.81 R⊙ and 0.51 R⊙, and luminosities of 0.44 L⊙ and 0.14 L⊙. Similarly, LINEAR94 exhibited masses of 0.82 M⊙ and 0.35 M⊙ for its primary and secondary stars, along with radii of 0.81 R⊙ and 0.54 R⊙, and luminosities of 0.49 L⊙ and 0.21 L⊙. Both systems were classified as over-contact binaries within the W UMa type, characterized by significant energy and mass exchange between components.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
