EZ Lyn: A Confirmed Period-Bouncer Cataclysmic Variable Below the Period Minimum

Vaidman N.L. Agishev A.T. Khokhlov S.A. Agishev A.T.
December 2025 Multidisciplinary Digital Publishing Institute (MDPI)

Galaxies
2025 #13 Issue 6

We model the short-period cataclysmic variable EZ Lyn with MESA binary evolution and infer its present-day parameters through a staged statistical search. First, we compute a coarse grid of tracks in (Formula presented.) at fixed (Formula presented.) and rank snapshots by a profile likelihood. We then resample the neighbourhood of the minimum to build a refined (Formula presented.) surface. Finally, we sample this surface with an affine-invariant MCMC to obtain posteriors, using a likelihood that treats the one-sided constraint on the donor temperature and the ambiguity of component roles in the binary output. The best-fit snapshot reproduces the observables and identifies EZ Lyn as a period bouncer with a substellar donor. We infer (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.), and (Formula presented.). The instantaneous mass-transfer rate at the best-fit snapshot is (Formula presented.), consistent with the secular range implied by the white-dwarf temperature. Independent checks from the Roche mean-density relation, surface gravities, and the semi-empirical donor sequence support the solution. In population context, EZ Lyn lies in the period-minimum spike and on the low-mass tail of the donor mass–period plane. The classification is robust to modest displacements along the shallow (Formula presented.) valley. We release inlists, tracks, and analysis scripts for reproducibility.

EZ Lyn , MCMC , stellar evolution , variable stars

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Faculty of Physics and Technology, Al-Farabi Kazakh National University, Al-Farabi Ave., 71, Almaty, 050040, Kazakhstan
Fesenkov Astrophysical Institute, Observatory, 23, Almaty, 050020, Kazakhstan

Faculty of Physics and Technology
Fesenkov Astrophysical Institute

10 лет помогаем публиковать статьи Международный издатель

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