[70.24] The Effects of Improvements in the Nuclear Reaction Rates on Hydrodynamic Simulations of the Classical Nova Outburst

AAS 207th Meeting, 8-12 January 2006
Session 70 Cataclysmic Variables and Novae
Poster, Tuesday, 9:20am-6:30pm, January 10, 2006, Exhibit Hall

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[70.24] The Effects of Improvements in the Nuclear Reaction Rates on Hydrodynamic Simulations of the Classical Nova Outburst

S. Starrfield (ASU), W. R. Hix (ORNL), C. Iliadis (UNC & TUNL), F. X. Timmes, W. M. Sparks (LANL)

We report on a new series of calculations of the accretion of hydrogen-rich material onto 1.25M_\odot and 1.35M_\odot ONeMg white dwarfs (WD) where we have varied the nuclear reaction library from that used in Politano et al. (ApJ, 448, 807, 1995), through intermediate libraries, to the latest compilation of Iliadis. In addition, we have replaced the nuclear reaction network from that of Weiss & Truran (WT: A&A, 238, 178, 1990) to that of Hix & Thielemann (J. Comp. & Appl. Math., 109, 321 1999). As part of the verification process for the new reaction network, we discovered that the pep reaction (p + e^- +p arrow d + \nu) had been omitted from previous studies. While the energy production from this reaction is unimportant in the Sun, because the density is ~10⁴ gm cm^-3 in our Classical Nova simulations, it increases the rate of energy generation in the pp-chain by 40%. This increase, in turn, has the effect of producing more heating per unit accreted mass so that the thermonuclear runaway occurs earlier with a smaller amount of accreted mass. As a direct result, peak temperatures are lower and the resulting nucleosynthesis differs from previous published studies (c.f., Starrfield et al. MNRAS, 296, 502, 1998) even with no change in the reaction library. Nevertheless, improving the reaction library (and including the pep reaction) does change the quantitative predictions on the amount of ²²Na and ²⁶Al produced by WDs of various mass. We will also show how the peak temperature, peak nuclear luminosity, ejected mass, and light curve are affected by the reaction library. The influence of the addition of the pep reaction to our studies of the evolution of the hot, accreting, white dwarfs in the Super Soft X-ray Binaries will also be presented.

We acknowledge partial support by the NSF, NASA, and DOE under various grants to our respective institutions.

The author(s) of this abstract have provided an email address for comments about the abstract: starrfield@asu.edu

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