Asteroseismology of WD J004917.14-252556.81, the Most Massive Pulsating White Dwarf
O. Caliskan, M. Uzundag, M. Kilic, F. C. Geronimo, A. Moss, A. H. Corsico, S. G. Parsons, I. Pelisoli, G. Jewett, A. Rebassa-Mansergas, A. J. Brown, V. K. Dhillon, P. Bergeron
arXiv:2505.17177v1 Announce Type: new
Abstract: We present extensive follow-up time-series photometry of WD J0049$-$2525, the most massive pulsating white dwarf currently known with $T_{rm eff} = 13, 020,{rm K}$ and $log{it g} = 9.34$ cm s$^{-2}$. The discovery observations detected only two significant pulsation modes. Here, we report the detection of 13 significant pulsation modes ranging from 170 to 258 s based on 11 nights of observations with the New Technology Telescope, Gemini, and Apache Point Observatory telescopes. We use these 13 modes to perform asteroseismology and find that the best-fitting models (under the assumption of an ONe core composition) have $M_{star} approx 1.29~M_odot$, surface hydrogen layer mass of $log(M_{rm H}/M_{star}) lesssim -7.5$, and a crystallized core fraction of $>99%$. An analysis of the period spacing also strongly suggests a very high mass. The asteroseismic distance derived is in good agreement with the distance provided by Gaia. We also find tentative evidence of a rotation period of 0.3 or 0.67 d. This analysis provides the first look at the interior of a $sim 1.3~M_{odot}$ white dwarf.arXiv:2505.17177v1 Announce Type: new
Abstract: We present extensive follow-up time-series photometry of WD J0049$-$2525, the most massive pulsating white dwarf currently known with $T_{rm eff} = 13, 020,{rm K}$ and $log{it g} = 9.34$ cm s$^{-2}$. The discovery observations detected only two significant pulsation modes. Here, we report the detection of 13 significant pulsation modes ranging from 170 to 258 s based on 11 nights of observations with the New Technology Telescope, Gemini, and Apache Point Observatory telescopes. We use these 13 modes to perform asteroseismology and find that the best-fitting models (under the assumption of an ONe core composition) have $M_{star} approx 1.29~M_odot$, surface hydrogen layer mass of $log(M_{rm H}/M_{star}) lesssim -7.5$, and a crystallized core fraction of $>99%$. An analysis of the period spacing also strongly suggests a very high mass. The asteroseismic distance derived is in good agreement with the distance provided by Gaia. We also find tentative evidence of a rotation period of 0.3 or 0.67 d. This analysis provides the first look at the interior of a $sim 1.3~M_{odot}$ white dwarf.