Acoustic wave energy fluxes for late-type stars
II. Nonsolar metallicities
P. Ulmschneider 1,
J. Theurer 1,
Z.E. Musielak 2,3,1 and
R. Kurucz 4
Received 17 November 1998 / Accepted 16 April 1999
Using the Lighthill-Stein theory with modifications described by Musielak et al. (1994), the acoustic wave energy fluxes were computed for late-type stars with the solar metal abundance (population I stars) by Ulmschneider et al. (1996). We now extend these computations to stars with considerably lower metal content (population II stars with 1/10 to 1/1000 of solar metallicity) and find that the acoustic fluxes calculated for stars of different spectral types and different luminosities are affected differently by the metallicity. It is found that the Hertzsprung-Russel diagram can be subdivided into three domains (labeled I, II and III) representing a different dependence of the generated acoustic fluxes on the stellar metal abundance. For the high stars of domain I there is no dependence of the generated acoustic fluxes on metallicity. In domain III are stars with low . Here the generated acoustic fluxes are lowered roughly by an order of magnitude for every decrease of the metal content by an order of magnitude. Finally, domain II represents the transition between the other two domains and the generated acoustic fluxes strongly depend on . The boundaries between the domains I and II, and II and III can be defined by simple relationships between stellar effective temperatures and gravities.
Key words: convection hydrodynamics turbulence waves stars: chromospheres stars: Hertzsprung Russel (HR) and C-M diagrams
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© European Southern Observatory (ESO) 1999
Online publication: June 18, 1999