Proceedings of the International Astronomical Union

Table of Contents - 2010 - Volume 6, Symposium S272 (Active OB stars: structure, evolution, mass loss, and critical limits)  

Contributed Papers

The surprising X-ray emission of Oe stars

Yael Nazéa1, Gregor Rauwa1 and Asif ud-Doulaa2

a1 FNRS-ULg, Dept AGO, Allée du 6 Août 17, Bât B5C, B4000-Liège, Belgium, email: naze@astro.ulg.ac.be

a2 Penn State Worthington Scranton, 120 Ridge View Drive, Dunmore, PA 18512, USA

Abstract

Oe stars are thought to represent an extension of the Be phenomenon to higher temperatures. Dedicated XMM observations of HD 155806 revealed a surprising X-ray spectrum: soft character, absence of overluminosity, broad X-ray lines. These properties are fully compatible with the wind-shock model, which usually explains the X-rays from “normal”, single O-type stars. In contrast, some other Oe/Be stars display a completely different behaviour at high energies.

Keywords

  • X-rays: stars;
  • stars: early-type;
  • stars: individual (HD 155806);
  • stars: emission-line;
  • Be