The peculiar abundance pattern of the new Hg-Mn star HD 30085

TL;DR

This study analyzes the star HD 30085, revealing unusual overabundances of s-process elements Sr, Y, Zr, and an inverted abundance pattern, indicating complex atmospheric processes like radiative diffusion.

Contribution

It provides the first detailed spectral analysis of HD 30085 showing its peculiar abundance pattern and suggests physical processes responsible for these anomalies.

Findings

Strong lines of Sr II, Y II, Zr II detected

Large overabundances of s-process elements found

Inverted abundance pattern compared to solar system

Abstract

Using high-dispersion, high-quality spectra of HD 30085 obtained with the echelle spectrograph SOPHIE at Observatoire de Haute Provence, we show that this star contains strong lines of the s-process elements Sr II, Y II and Zr II. Line syntheses of the lines yield large overabundances of Sr, Y, Zr which are characteristic of HgMn stars. The Sr-Y-Zr triad of abundances is inverted in HD 30085 compared to that in our solar system. The violation of the odd-even rule suggests that physical processes such as radiative diffusion, chemical fractionation and others must be at work in the atmosphere of HD 30085, and that the atmosphere is stable enough to sustain them.