Asteroseismology of DAV star EC14012-1446, mode identification and model fittings

Yanhui Chen, Yan Li

Published 2014-07-11Version 1

EC14012-1446 was observed by Handler et al. in April 2004, June 2004, May 2005, and April 2007, and by Provencal et al. in 2008. We review the observations together and obtain 34 independent frequencies. According to the frequency splitting and the asymptotic period spacing law, we identify 6 $l$=1 modes, 4 $l$=2 modes, 5 $l$=3 modes, 10 $l$=1 or 2 modes. Grids of white dwarf models are generated by WDEC with H, He, C, O diffusion in a four-parameter space. The core compositions are directly from white dwarf models generated by MESA. The best-fitting model has $M_{*}$=0.710\,$M_{\odot}$, $T_{\rm eff}$=12200\,K, log($M_{\rm He}/M_{*}$)=-2.5, log($M_{\rm H}/M_{*}$)=-7.0, log\,$g$=8.261, and $\phi$=3.185\,s. There are 4, 2, and 1 modes identified as trapped in H envelope for observed $l$=1, 2, and 3 modes, respectively. Trapped modes jump the queue of uniform period spacing.