高能暂现源 · 每日文献综述

Hydrogen atmosphere white dwarf KUV03442+0719 was first reported as a pulsator by Gianninas et al. in 2006. Follow up campaigns by Su et al. (2014) revealed more periods. Some spectroscopic results suggest that KUV03442+0719 has a slightly below average mass and an effective temperature of 11000 K. But Gaia data (parallax and magnitude) suggest that it may be a low mass white dwarf. Such an object would have a helium core. We perform the asteroseismic fitting of KUV03442+0719, modeling it both as a carbon/oxygen normal mass white dwarf, and a helium core, low mass white dwarf. To perform the study, we perfom a grid search with WDEC models, refined by simplex minimization of the best fits. Both analyses result in best fit models that are comparable in terms of quality of fit. More pulsation data would be required to allow us to distinguish between the two scenarios. We present and constrast our results with expectations from stellar evolution. We also provide analytic formulae for a temperature dependent mass-radius relationship for helium core white dwarfs.