Metal-Abundance Peculiarities in the sdOB Star EC11481-2303: A Progress Report

TL;DR

This paper investigates the extreme metal abundances in the hot sdOB star EC11481-2303, revealing unusual spectral features likely caused by intense metal-line blanketing, through advanced NLTE modeling.

Contribution

It provides the first detailed spectral analysis of EC11481-2303 using static and stratified NLTE models, highlighting its peculiar metal-line blanketing effects.

Findings

EC11481-2303 exhibits an extraordinary flat UV continuum.

Spectral analysis suggests extreme metal-line blanketing effects.

Preliminary results support stratified NLTE atmosphere models.

Abstract

Spectral analyses of extreme horizontal branch (EHB) stars indicate a trend to supersolar heavy-metal abundances that is increasing with effective temperature. The sdOB EC11481-2303 is such a star, located at the very hot end of the EHB. In contrast to other sdOB stars, it is exhibiting an extraordinary flat UV continuum. This may be the result of extreme metal-line blanketing. We present preliminary results of a spectral analysis by means of static as well as stratified NLTE model atmospheres.