IRC + 10 216 revisited. Pt. 1 The circumstellar dust shell

A spherically symmetric dust radiative transfer code is used to model the circumstellar dust shell around IRC +10 216. Compared to numerous previous models a much larger body of observational data is used as constraints; the spectral energy distribution between 0.5 and 60000 #mu#m. 2-4 #mu#m and 8-23 #mu#m spectra, optical, farinfrared and centimeter sizes and interferometric visibility curves between 1.6 and 11.2 #mu#m are used to constrain the model. The most important result is that in order to fit the visibility curve at 2.2 #mu#m and the size of the shell in the optical, scattering coefficient on grain size allows one to derive a mean grain size of 0.16 #+-# 0.01 #mu#m. (orig.)Available from TIB Hannover: RR 4697(960) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman