Project VeSElkA: abundance analysis of chemical species in HD 41076 and HD 148330

Abstract

A new semi-automatic approach is employed to carry out the abundance analysis of highresolution spectra of HD 41076 and HD 148330 obtained recently with the spectropolarimetre ESPaDOnS at the CFHT. This approach allows to prepare in a semi-automatic mode the input data for the modified ZEEMAN2 code and to analyse several hundreds of line profiles in sequence during a single run. It also provides more information on abundance distribution for each chemical element at the deeper atmospheric layers. Our analysis of the Balmer profiles observed in the spectra of HD 41076 and HD 148330 has resulted in the estimates of their effective temperature, gravity, metallicity and radial velocity. The respective models of stellar atmosphere have been calculated with the code PHOENIX and used to carry out abundance analysis employing the modified ZEEMAN2 code. The analysis shows a deficit of the C, N, F, Mg, Ca, Ti, V, Cu, Y, Mo, Sm and Gd, and overabundance of Cr, Mn, Fe, Co, Ni, Sr, Zr, Ba, Ce, Nd and Dy in the stellar atmosphere of HD 41076. In the atmosphere of HD 148330, the C, N and Mo appear to be underabundant, while the Ne, Na, Al, Si, P, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Sr, Y, Zr, Ba, Ce, Pr, Nd, Sm, Eu, Gd and Dy are overabundant. We also have found signatures of vertical abundance stratification of Fe, Ti, Cr and Mn in HD 41076, and of Fe, Ti, V, Cr, Mn, Y, Zr, Ce, Nd, Sm and Gd in HD 148330.

Project VeSElkA: results of abundance analysis for HD 53929 and HD 63975

“…A preliminary analysis of these three parameters allows us to decide which lines are well fitted and which ones may be misidentified or are blends due to a significant contribution from other ions. The ZEEMAN2 code allows to estimate the optical depth τ l at which the core of a spectral line is formed (Khalack et al 2007(Khalack et al , 2017. For each analysed line profile the code determines the abundance of studied element and the optical depth τ l of the line core formation.…”

“…We present these graphs only for chemical species for which we have obtained abundance estimates from the analysis of at least 10 line profiles. The procedure of the determination of the optical depth of line core formation is described in details in Khalack et al (2007Khalack et al ( , 2017. The dashed line shows the level of the solar abundance of the studied chemical element.…”

The 10.5 year rotation period of the strongly magnetic rapidly oscillating Ap star HD 166473

“…These spectra were reduced using the dedicated software package Libre-ESpRIT (Donati et al 1997), which yields both the Stokes I spectrum and the Stokes V circular polarisation spectrum. The Stokes I spectra were normalised using the same procedure as in Khalack et al (2017); -one spectrum recorded with the Ultraviolet and Visible Echelle Spectrograph (UVES) fed by Unit Telescope 2 (UT2) of the ESO Very Large Telescope (VLT), retrieved from the ESO Archive; -and eight spectra recorded with the High Accuracy Radial velocity Planet Searcher (HARPS) fed by the ESO 3.6-m telescope, retrieved from the ESO Archive. One of these spectra was obtained with the polarimetric mode of HARPS (HARPSpol; Piskunov et al 2011) and is further discussed in Sect.…”

Rotational and pulsational variability in the TESS light curve of HD 27463

“…Specifically, in this study we use the grids of synthetic fluxes 6 simulated by Husser et al (2013) for models with different metallicities and abundances of the α-elements (O, Ne, Mg, Si, S, Ar, Ca, and Ti) employing version 16 7 of the PHOENIX code (Hauschildt & Baron 1999). These grids were computed with a spectral resolution of R = 500 000, which we reduced to R = 50 000 during their transformation to the format read by the FITSB2 code (Khalack et al 2017). This latter resolution is close to the spectral resolution of FEROS (see Section 2).…”