Characterizing the pulsations of the ZZ Ceti star KUV 02464+3239

We present the results on period search and modelling of the cool DAV star KUV 02464+3239. Our observations resolved the multiperiodic pulsational behaviour of the star. In agreement with its position near the red edge of the DAV instability strip, it shows large amplitude, long-period pulsation modes, and has a strongly non-sinusoidal light curve. We determined six frequencies as normal modes and revealed remarkable short-term amplitude variations. A rigorous test was performed for the possible source of amplitude variation: beating of modes, effect of noise, unresolved frequencies or rotational triplets. Among the best-fitting models resulting from a grid search, we selected three that gave l= 1 solutions for the largest amplitude modes. These models had masses of 0.645, 0.650 and 0.680 M⊙. The three ‘favoured’ models have MH between 2.5 × 10−5 and 6.3 × 10−6 M* and give 14.2–14.8 mas seismological parallax. The 0.645 M⊙ (11 400 K) model also matches the spectroscopic log g and Teff within 1σ. We investigated the possibility of mode trapping and concluded that while it can explain high amplitude modes, it is not required.