Initiation of Convection in Novae Precursors

L. Jonathan Dursi, University of Chicago

Classical Novae result from the explosive thermonuclear burning of material accreted from a companion star onto the surface of a white dwarf. Observed abundances and explosion energies estimated from observations indicate that there must be significant mixing of the heavier material of the white dwarf (C/O) into the lighter accreted material (H/He). Accordingly, nova models must incorporate a mechanism that will dredge up the heavier white dwarf material, and fluid motions from an early convection phase is one proposed mechanism. We present results from two-dimensional simulations of classical nova precursor models that demonstrate the beginning of a convective phase during the ‘simmering’ of a Nova precursor. We use a new hydrostatic equilibrium hydrodynamics module recently developed for the adaptive-mesh code FLASH. The two-dimensional models are based on the one-dimensional models of Ami Glasner (Glasner et al. 1997), and were evolved with FLASH from a pre-convective state to the onset of convection. In addition, we present the details of the hydrostatic equilibrium module and the hydrostatic boundary conditions used in the simulations. This research has been supported by the U.S. Department of Energy under Grant No. B341495 to the ASCI Flash Center at the University of Chicago.

Abstract Author(s): Dursi, L. J.; Calder, A. C.; Ricker, P. M.; Truran, J. W.; Zingale, M.; Fryxell, B.; Olson, K.; Rosner, R.; Timmes, F. X.; Tufo, H.; MacNeice, P.