Bibcode
Pauldrach, A.; Herrero, A.
Referencia bibliográfica
Astronomy and Astrophysics (ISSN 0004-6361), vol. 199, no. 1-2, June 1988, p. 262-268.
Fecha de publicación:
6
1988
Número de citas
28
Número de citas referidas
24
Descripción
A new technique to calculate multilevel non-LTE continuum formation in
the UV of stellar winds and plane-parallel, static stellar atmospheres
is developed using a local approximate lambda operator similar to those
presented by Werner and Husfeld (1985) and Hamann (1986). In the present
formulation, the iteration of the transfer equation solution is driven
by the relative deviation of the source functions of successive
iteration steps, which stabilizes the convergence. At the same time,
linear equations for the statistical equilibrium are obtained, which
diminishes the computational requirements. The technique has been
applied to photospheric and stellar wind models, where convergence is
reached even under extreme conditions (very large optical thickness and
negligible collisional ionization) for which the usual 'accelerated
lambda iteration' fails. Test calculations are presented for radiative
driven winds of central stars of planetary nebulae close to the
Eddington limit, including extensive model atoms of H, He, C, N, O, Ne,
Mg, Si, and S (see Pauldrach, 1987) and for H and He II in the case of
plane-parallel static photospheres as described by Herrero (1987).