| Issue |
A&A
Volume 686, June 2024
|
|
|---|---|---|
| Article Number | A152 | |
| Number of page(s) | 11 | |
| Section | Stellar atmospheres | |
| DOI | https://doi.org/10.1051/0004-6361/202348721 | |
| Published online | 07 June 2024 | |
Phase-resolved XMM-Newton observations of the massive post-RLOF system HD 149404*
1
Space sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège,
Allée du 6 Août, 19c, Bât. B5c,
4000
Liège,
Belgium
e-mail: g.rauw@uliege.be
2
Department of Physics, KTH Royal Institute of Technology, The Oskar Klein Centre, AlbaNova,
106 91
Stockholm,
Sweden
Received:
23
November
2023
Accepted:
4
March
2024
Context. We investigated the X-ray emission of HD 149404, a 9.81-day period O-star binary in a post-Roche lobe overflow evolutionary stage. X-ray emission of O-star binaries consists of the intrinsic emission of the individual O stars and a putative additional component arising from the wind-wind interaction.
Aims. Phase-locked variations in the X-ray spectra can be used to probe the properties of the stellar winds of such systems.
Methods. XMM–Newton observations of HD 149404 collected at two conjunction phases and a quadrature phase were analysed. X-ray spectra were extracted and flux variations as a function of orbital phase were inferred. The flux ratios were analysed with models considering various origins for the X-ray emission.
Results. The highest and lowest X-ray fluxes are observed at conjunction phases respectively with the primary and secondary star in front. The flux variations are nearly grey with only marginal energy dependence. None of the models accounting for photoelectric absorption by homogeneous stellar winds perfectly reproduces the observed variations. Whilst the overall X-ray luminosity is consistent with a pure intrinsic emission, the best formal agreement with the observed variations is obtained with a model assuming pure windwind collision X-ray emission.
Conclusions. The lack of significant energy-dependence of the opacity most likely hints at the presence of optically thick clumps in the winds of HD149404.
Key words: binaries: close / stars: early-type / stars: individual: HD 149404 / X-rays: stars
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.