Importance of collisions with charged particles for stellar UV line shapes: $\ion{Cd}{iii}$

Abstract

Abstract. Stark broadening parameters, widths and shifts, for 84 spectral lines of doubly-ionized cadmium (Cd ) have been calculated using the modified semi-empirical approach (MSE). Calculated spectral lines belong to the transitions 4d 9 5s-4d 9 5p and 4d 9 5p-4d 9 5d. Widths and shifts of the spectral lines are given for temperature range of 5000 K-60 000 K and an electron density of 10 23 m −3 . The influence of collisions with charged particles on Cd  UV stellar lines along the HR diagram is discussed. Compared to the Doppler broadening, the influence of the Stark broadening mechanism is more important for deeper atmospheric layers and for larger values of log g. Stark broadening does not depend on turbulent velocity for the considered stellar model of a standard main sequence hot star of A0 spectral type. The influence of the Stark widths for standard models of DA and DB white dwarfs is also discussed.

Modified semiempirical electron width calculations of singly-ionized oxygen spectral lines

“…Stark broadening in a strongly correlated plasma has been considered recently by Ben Chaouacha et al (2004). The other criteria for the applicability of the modified semiempirical approach have been dicussed in detail in Milovanović et al (2004).…”

Stark broadening of B iv spectral lines

“…Lanz et al (1988); Popović et al (1999a); Popović et al (1999b); Popović et al (2001a,b); Tankosić, Popović & Dimitrijević (2003); Simić et al (2005a,b)). In white dwarfs, especially Stark broadening is the dominant collisional line broadening mechanism in all important layers of the atmosphere (Popović et al 1999b;Tankosić, Popović & Dimitrijević 2003;Milovanović et al 2004;Simić et al 2006;Dimitrijević et al 2011;Dufour et al 2011;Larbi-Terzi et al 2012;Simić, Dimitrijević & Sahal-Bréchot 2013;Simić, Dimitrijević & Popović 2014). The theory of Stark broadening is well applied, especially for accurate spectroscopic diagnostics and modelling.…”

“…This broadening mechanism may be of interest and for the main sequence stars, especialy for A type and late B type (Lanz et al 1988;Popović et al 1999a;Popović et al 1999b;Popović et al 2001a,b;Dimitrijević et al 2003a,b;Tankosić, Popović & Dimitrijević 2003;Dimitrijević et al 2004;Milovanović et al 2004;Dimitrijević et al 2005;Simić et al 2005a,b;Simić, Dimitrijević & Kovačević 2009;Simić, Dimitrijević & Sahal-Bréchot 2013;Simić, Dimitrijević & Popović 2014).…”

On the stark broadening of Ar VII spectral lines

“…An important topic where Stark broadening data are needed are astrophysical plasmas (Beauchamp et al, 1997;Dimitrijević & Sahal-Bréchot, 2014b ), in particular at mospheres of white dwarfs, pre white dwarf stars, and post AGB (Asymptotic Giant Branch) stars (Tankosić et al, 2003;Milovanović et al, 2004;Simić et al, 2006;Dufour et al, 2011). Additionally, since for temperatures higher than around 10 000 K hydrogen is mainly ionized, Stark broadening is, in such a case, the principal pressure broadening mechanism (Griem, 1974).…”