The ion-atom absorption processes as one of the factors of the influence on the sunspot opacity

Abstract

As a continuation of the previous investigations of the symmetric and strongly non-symmetric ion-atom absorption processes in the far-UV region within the models of the quiet Sun photosphere, these processes are studied here within a model of the sunspot. Here, we mean the absorption processes in the H(1s)+H+ and H(1s) + X + collisions and the processes of the photodissociation of the H+2 and HX+ molecular ions, where X is one of the metal atoms: X = Na, Ca, Mg, Si and Al. Obtained results show that the influence of the considered ion-atom absorption processes on the opacity of sunspots in the considered spectral region (110 ≰ λ ≠ 230 nm) is not less and in some parts even larger than the influence of the referent electron-atom processes. In such a way, it is shown that the considered ion-atom absorption processes should be included ab initio in the corresponding models of sunspots of solar-type and near-solar-type stars. Apart from that, the spectral characteristics of the considered nonsymmetric ion-atom absorption processes (including here the case X = Li), which can be used in some further applications, have been determined and presented within this work. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.