Sur l'origine du spectre continu des comètes

In: Bulletin de la Classe des sciences, Volume 45, Issue 1, p. 218-238

Abstract

The possible sources of the continuous (solar) spectrum of comets are discussed. Four mechanisms are considered :
1) diffuse reflection by the solid nucleus (Lambert's Law) ;
2) scattering by molecules (Rayleigh) ;
3) scattering by small solid particles (Mie) ;
4) scattering by free electrons (Thomson).
It was found that the solar continuum of comets is due in most cases to scattering by small solid particles.
An attempt has also been made to determine the continuous spectrum of comet Arend-Roland by photographic spectrophotometry.