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A&A Supplement series, Vol. 129, April II 1998, 343-351

Received March 26; accepted October 2, 1997

Legendre expansion of the tex2html_wrap_inline1574 kernel: Influence of high order terms

J.A. Ponstex2html_wrap1602 - J.A. Mirallestex2html_wrap1604 - J.Mtex2html_wrap_inline1576 Ibáñeztex2html_wrap1604

Send offprint request: J.A. Pons,

tex2html_wrap1608  Departament d'Astronomia i Astrofısica, Universitat de Valencia 46100 Burjassot (Valencia), Spain
tex2html_wrap1610  Astronomy program, Department of Physics and Astronomy, SUNY at Stony Brook, Stony Brook, New York 11794, U.S.A.


We calculate the Legendre expansion of the rate of the process tex2html_wrap_inline1580 up to tex2html_wrap_inline1582 order extending previous results of other authors which only consider the tex2html_wrap_inline1584 and tex2html_wrap_inline1586 order terms. Using different closure relations for the moment equations of the radiative transfer equation we discuss the physical implications of taking into account quadratic and cubic terms on the energy deposition outside the neutrinosphere in a simplified model. The main conclusion is that tex2html_wrap_inline1588 order is necessary in the semi-transparent region and gives good results if an appropriate closure relation is used.

keywords: radiation mechanisms: thermal -- radiative transfer -- stars: neutron -- supernovae: general -- nuclear reactions

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