Volume 315 - The Golden Age of Cataclysmic Variables and Related Objects IV (GOLDEN 2017) - Classical Novae, Recurrent Novae and Nova-Like Stars
Hydrodynamic Simulations of Classical Novae: Accretion onto CO White Dwarfs as SN Ia Progenitors
S. Starrfield,* M. Bose, C. Iliadis, W.R. Hix, R.M. Wagner, C.E. Woodward, J. Jose, M. Hernanz
*corresponding author
Full text: pdf
Pre-published on: 2018 April 10
Published on: 2018 September 13
Abstract
We report on our continuing studies of Classical Nova explosions by following the evolution of thermonuclear runaways (TNRs) on carbon-oxygen (CO) white dwarfs (WDs). We have varied both the mass of the WD and the composition of the accreted material. Rather than assuming that the material has mixed from the beginning, we now rely on the results of the
multidimensional (multi-D) studies of mixing as a consequence of the TNRs in WDs that accreted only Solar matter. The multi-D studies find that mixing with the core occurs after the TNR is well underway and reach enrichment levels in agreement with observations of the ejecta abundances. We report on 3 studies in this paper. First, simulations in which we accrete only Solar matter with NOVA (our 1-D, fully implicit, hydro code). Second, we use MESA for similar studies in which we accrete only Solar material and compare the results. Third, we accrete Solar matter until the TNR is initiated and then switch the composition in the accreted layers to a mixed composition: either 25\% core and 75\% Solar or 50\% core and 50\% Solar. The amount of accreted material is inversely proportional to the initial $^{12}$C abundance. Thus, accreting Solar material results in more material to fuel the outburst - much larger than in the earlier studies where mixed materials were used from the beginning. We tabulate the amount of ejected gases, their velocities, and abundances. We predict the amount of ${^7}$Li and $^{7}$Be produced and ejected by the explosion and compare our predictions to our Large Binocular Telescope (LBT) high dispersion spectra which determined the abundance of $^7$Li in nova V5668 Sgr. Finally, many of these simulations eject significantly less mass than accreted and, therefore, the WD is growing in mass toward the Chandrasekhar Limit.
DOI: https://doi.org/10.22323/1.315.0066
Open Access