Asteroseismology of the ZZ Ceti star KUV 11370+4222

Abstract

KUV 11370+4222 is a ZZ Ceti star discovered in 1996, which has not been observed since then. We performed observations for KUV 11370+4222 in 2010 January. From the Fourier transform spectrum of the light curves, ten independent modes are detected. We searched for the best-fitting model by using the observed periods to match the model periods and get it with the total mass of 0.625 ${\rm M_{\odot}}$, the effective temperature of 10950 K, and the helium mass fraction and hydrogen mass fraction of $10^{-2.2}$ and $10^{-4.0}$, respectively. We have found a triplet of frequency split by rotation, which are $l=1$ modes. Using the frequency shifts we estimate a rotation period of $5.56\pm0.08$ h. Besides it, another $l=1$ mode is identified. The other observed periods are identified as $l=2$ modes. At last we investigated the property of the mode trapping.