文章基本信息

标题：An X-ray view of HD 166734, a massive supergiant system
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作者：Yaël Nazé ; Eric Gosset ; Laurent Mahy 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2017
卷号：607
页码：1-10
DOI：10.1051/0004-6361/201630303
语种：English
出版社：EDP Sciences
摘要：The X-ray emission of the O+O binary HD 166734 was monitored using Swift and XMM-Newton observatories, leading to the discovery of phase-locked variations. The presence of an f line in the He-like triplets further supports a wind-wind collision as the main source of the X-rays in HD 166734. While temperature and absorption do not vary significantly along the orbit, the X-ray emission strength varies by one order of magnitude, with a long minimum state (Δ(φ) ~ 0.1) occurring after a steep decrease. The flux at minimum is compatible with the intrinsic emission of the O-stars in the system, suggesting a possible disappearance of colliding wind emission. While this minimum cannot be explained by eclipse or occultation effects, a shock collapse may occur at periastron in view of the wind properties. Afterwards, the recovery is long, with an X-ray flux proportional to the separation d (in hard band) or to d2 (in soft band). This is incompatible with an adiabatic nature for the collision (which would instead lead to FX ∝ 1 /d), but could be reconciled with a radiative character of the collision, though predicted temperatures are lower and more variable than in observations. An increase in flux around φ ~ 0.65 and the global asymmetry of the light curve remain unexplained, however.
关键词：enstars: early-typestars: winds, outflowsX-rays: starsstars: individual: HD 166734