On the influence of Stark broadening on Si I lines in stellar atmospheres

¹ Astronomical Observatory, Volgina 7, 11160 Belgrade 74, Serbia
² Isaac Newton Institute of Chile, Yugoslavia Branch
³ Institute of Astronomy, Russian Academy of Science, Pyatnitskaya 48, 119017 Moscow, Russia
⁴ Institute for Astronomy, University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria
⁵ Tavrian National University, Yaltinskaya 4, 330000 Simferopol, Crimea, Ukraine

Corresponding author: M. S. Dimitrijević, mdimitrijevic@aob.bg.ac.yu

Received: 12 November 2002
Accepted: 27 March 2003

Abstract

We study the influence of Stark broadening and stratification effects on Si i lines in the rapidly oscillating (roAp) star 10 Aql, where the Si i 6142.48 Åand 6155.13 Ålines are asymmetrical and shifted. First we have calculated Stark broadening parameters using the semiclassical perturbation method for three Si i lines: 5950.2 Å, 6142.48 Åand 6155.13 Å. We revised the synthetic spectrum calculation code taking into account both Stark width and shift for these lines. From the comparison of our calculations with the observations we found that Stark broadening + the stratification effect can explain asymmetry of the Si i 6142.48 Å and 6155.13 Å lines in the atmospere of roAp star 10 Aql.