Stark broadening of Zr iv spectral lines in the atmospheres of chemically peculiar stars

Abstract

Stark widths for 18 Zr Iv spectral lines have been calculated by using the modified semiempirical method. The obtained results have been used to investigate the influence of Stark broadening on the spectra of atmospheres of chemically peculiar stars of A spectral type and hydrogen-rich DA and helium-rich DB white dwarfs. Our results have been used also to test possibility to predict new data using some approximate methods developed on the basis on regularities and systematic trends.

Regularities and Systematic Trends on Zr IV Stark Widths

“…In Tables 1 and 2, calculated Stark widths of 18 Zr IV lines made by different estimation methods mentioned above are compared to previous MSE calculations of Stark FWHM Majlinger et al [5]. All results presented in Tables 1 and 2 are calculated for a temperature of 10,000 K and electron density of 10 23 m −3 .…”

“…First we will estimate Stark widths with the simple formula of Cowley [7] which is often in use by some modern authors in original or modified form (see, for example, Killian et al [11], Ziegler et al [12] and Przybilla et al [13]) and which has recently used by our team for comparison with MSE calculated values of Stark widths of Lu III spectral lines too, see Majlinger et al [14]. In Majlinger et al [5] we derived it from the Griem [10] semiempirical formula at low temperature limit and added the contribution to the width of the lower energy level. In such a case, the difference between original formula of Cowley and the modified formula in [5] is for a factor 2/3 3/2 plus the contribution of the lower energy level.…”

“…In Majlinger et al [5] we derived it from the Griem [10] semiempirical formula at low temperature limit and added the contribution to the width of the lower energy level. In such a case, the difference between original formula of Cowley and the modified formula in [5] is for a factor 2/3 3/2 plus the contribution of the lower energy level. Here, we want to test the original formula of Cowley.…”

“…Such quick estimates of Stark-broadening parameters may be based on different regularities and systematic trends among the Stark widths of atomic spectral lines (see e.g., [4]). We focus on present work on searching regularities and systematic trends of Stark widths for 18 Zr IV spectral lines calculated in [5] by modified semiempirical approach (MSE-Dimitrijević & Konjević [6]). This study has two directions.…”

Stark Broadening of Cr III Spectral Lines: DO White Dwarfs

“…Chromium in various ionization stages from Cr I to Cr VI has been observed and in the spectra of white dwarfs, where the Stark broadening is often the dominant broadening mechanism in wide layers of the atmosphere [19][20][21][22][23][24][25][26][27]. For example, Cr I has been found by Gianninas et al [28] in an extremely low mass white dwarf in the SDSS J074511.56+194926.5 binary system and by Dufour et al [29] in the spectrum of DZ white dwarf G165-7; Cr II spectral lines were identified by Klein et al [30] in the spectrum of white dwarf GD 40, observed on the Keck I telescope at Mauna Kea Observatory; and, for example, Cr V and Cr VI by Rauch et al [31] in the spectrum of the white dwarf central star of Sh 2-216.…”