[74.10] Further Studies of Accretion onto Hot, Massive, White Dwarfs: The Growth to the Chandrasekhar Limit

AAS 204th Meeting, June 2004
Session 74 Stellar Leftovers
Poster, Thursday, June 3, 2004, 9:20am-4:00pm, Ballroom

[74.10] Further Studies of Accretion onto Hot, Massive, White Dwarfs: The Growth to the Chandrasekhar Limit

S. Starrfield (ASU), F. X. Timmes (LANL), W. R. Hix (ORNL), E. M. Sion (Villanova), W. M. Sparks (LANL), S. Dwyer (ASU)

We report on further studies of accretion (Solar Composition material) at a variety of rates onto hot, massive white dwarfs (WDs: Starrfield et al. 2003, Atlanta Meeting, poster 45.10). Our initial models are 1.0~M_\odot, 1.25~M_\odot, and 1.35~M_\odot WDs with luminosities of 30~L_\odot. We have now run evolutionary sequences with mass accretion rates varying from 1.6\times10^-10 M_\odot yr^-1 to 3.5\times10^-7 M_\odot yr^-1 and, in all cases, the WDs grow in mass to near the Chandrasekhar Limit. We use the 1D, hydrodynamic computer code as described in Starrfield et al. (APJS, 127,485, 2000) and have updated the nuclear reaction network, since the calculations reported at Atlanta, to that found at {\tt www.cococubed.com/code_pages/net_hhe.shtml}. This network combines the pp + hot cno + rp breakout network used previously with an alpha-chain that runs to ⁵⁶Ni. This will allow us to report on whether or not elements such as Si, S, and Ca are produced in the outer layers during the evolution to explosion so that they do not have to be produced by the explosion. We will also report on simulations done with a lower metallicity for the accreting material - characteristic of that of the LMC. S. Starrfield acknowledges support from NSF and NASA grants to ASU, FXT is supported by the National Security Fellow program at Los Alamos National Laboratory, WRH is partially supported by the National Science Foundation under contracts PHY-0244783 and AST-9877130 and by the Department of Energy, through the Scientific Discovery through Advanced Computing Program. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. EMS is supported by NASA ADP grant NAG5-11182.

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

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