2026/07/02 by M. Kamenec, Matúš Kamenec, Pavol Gajdoš +7
Physics and Astronomy · Social Sciences · #Astronomy and Astrophysical Research #Educational Leadership and Practices #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/ae87a2
published as The Astronomical Journal, 2026, Volume 172, Number 2, Page 126 · AJ accepted
arxiv created 2026/07/02 · arxiv updated 2026/07/30
We present a new photometric and spectroscopic analysis of detached eclipsing binary IR Cas based on TESS observations, supplementary ground-based photometry in Sloan g^′, r^′, and i^′ filters, and newly obtained radial velocity measurements. The updated orbital and physical parameters of the system were derived using combined light-curve and radial-velocity modeling. The resulting solution indicates that both components are main-sequence stars with masses of approximately 1.32 M\odot and 1.05 M\odot. We investigated in detail the fact, that the TESS light curves exhibit asymmetries near the maxima, which were reproduced by introducing a cool spot that moves on the surface of the secondary component. Long-term analysis of times of minima revealed quasi-periodic variations in the O-C diagram that can be interpreted as a light-time effect due to a possible third body with an orbital period of about 38 years. The positions of both components in the mass-radius diagram agree well with empirical relations for detached main-sequence binaries and do not indicate substantial deviations from standard stellar evolution. Overall, IR Cas appears to be an evolutionarily representative detached eclipsing system with moderate indications of stellar activity.