In this paper we presented the extension of our grid of dwarf model atmospheres to giant stars. The models were computed using spherical symmetry, including spherical radiative transfer. We discuss the results of the calculations. We have calculated a small number of NLTE models and verified the conclusions of : In the considered range of effective temperatures, NLTE effects do not alter the structure of the atmospheres significantly but they can change the profiles of individual lines. NLTE should therefore be considered in abundances analyses. Our grid has been used successfully in evolutionary models of Cepheids . We provide the model structures and spectra through the WWW and anonymous FTP for general use, see http://dilbert.physast.uga.edu/yeti or ftp://calvin.physast.uga.edu/pub/NG-giant. In the next version of the grid we will use improved molecular line opacities as well as dust opacities for low effective temperatures. In addition, stellar winds models are needed for those models that are unstable against radiation pressure, which occurs at both high and low effective temperatures.
This work was supported in part by the CNRS and by NSF grant AST-9720704, NASA ATP grant NAG 5-3018 and LTSA grant NAG 5-3619 to the University of Georgia, and NASA LTSA grant NAG5-3435 and NASA EPSCoR grant NCCS-168 to Wichita State University. This work was also supported in part by NSF grants AST-9417242, AST-9731450, and NASA grant NAG5-3505; an IBM SUR grant to the University of Oklahoma. Some of the calculations presented in this paper were performed on the IBM SP2 and the SGI Origin 2000 of the UGA UCNS and on the IBM SP of the San Diego Supercomputer Center (SDSC), with support from the National Science Foundation, and on the Cray T3E of the NERSC with support from the DoE. We thank all these institutions for a generous allocation of computer time.
. We provide the model structures and spectra through the WWW and anonymous FTP for general use, see http://dilbert.physast.uga.edu/yeti or ftp://calvin.physast.uga.edu/pub/NG-giant. In the next version of the grid we will use improved molecular line opacities as well as dust opacities for low effective temperatures. In addition, stellar winds models are needed for those models that are unstable against radiation pressure, which occurs at both high and low effective temperatures.
This work was supported in part by the CNRS and by NSF grant AST-9720704, NASA ATP grant NAG 5-3018 and LTSA grant NAG 5-3619 to the University of Georgia, and NASA LTSA grant NAG5-3435 and NASA EPSCoR grant NCCS-168 to Wichita State University. This work was also supported in part by NSF grants AST-9417242, AST-9731450, and NASA grant NAG5-3505; an IBM SUR grant to the University of Oklahoma. Some of the calculations presented in this paper were performed on the IBM SP2 and the SGI Origin 2000 of the UGA UCNS and on the IBM SP of the San Diego Supercomputer Center (SDSC), with support from the National Science Foundation, and on the Cray T3E of the NERSC with support from the DoE. We thank all these institutions for a generous allocation of computer time.