Light variations due to the line-driven wind instability and wind blanketing in O stars
- A small fraction of the radiative flux emitted by hot stars is absorbed by their winds and redistributed towards longer wavelengths. This effect, which leads also to the heating of the stellar photosphere, is termed wind blanketing. For stars with variable winds, the effect of wind blanketing may lead to the photometric variability. We have studied the consequences of line driven wind instability and wind blanketing for the light variability of O stars. We combined the results of wind hydrodynamic simulations and of global wind models to predict the light variability of hot stars due to the wind blanketing and instability. The wind instability causes stochastic light variability with amplitude of the order of tens of millimagnitudes and a typical timescale of the order of hours for spatially coherent wind structure. The amplitude is of the order of millimagnitudes when assuming that the wind consists of large number of independent concentric cones. The variability with such amplitude is observable using present space borneA small fraction of the radiative flux emitted by hot stars is absorbed by their winds and redistributed towards longer wavelengths. This effect, which leads also to the heating of the stellar photosphere, is termed wind blanketing. For stars with variable winds, the effect of wind blanketing may lead to the photometric variability. We have studied the consequences of line driven wind instability and wind blanketing for the light variability of O stars. We combined the results of wind hydrodynamic simulations and of global wind models to predict the light variability of hot stars due to the wind blanketing and instability. The wind instability causes stochastic light variability with amplitude of the order of tens of millimagnitudes and a typical timescale of the order of hours for spatially coherent wind structure. The amplitude is of the order of millimagnitudes when assuming that the wind consists of large number of independent concentric cones. The variability with such amplitude is observable using present space borne photometers. We show that the simulated light curve is similar to the light curves of O stars obtained using BRITE and CoRoT satellites.…
Author details: | Jiri Krticka, Achim FeldmeierORCiDGND |
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DOI: | https://doi.org/10.1051/0004-6361/201731614 |
ISSN: | 1432-0746 |
Title of parent work (English): | Astronomy and astrophysics : an international weekly journal |
Publisher: | EDP Sciences |
Place of publishing: | Les Ulis |
Publication type: | Article |
Language: | English |
Year of first publication: | 2018 |
Publication year: | 2018 |
Release date: | 2021/09/24 |
Tag: | hydrodynamics; stars: early-type; stars: mass-loss; stars: variables: general; stars: winds, outflows |
Volume: | 617 |
Number of pages: | 7 |
Funding institution: | Austrian Research Promotion Agency (FFG); University of Vienna; Technical University of Graz; Canadian Space Agency (CSA); University of Toronto Institute for Aerospace Studies (UTIAS); Foundation for Polish Science & Technology (FNiTP MNiSW); National Science Centre (NCN); [GACR 16-01116S] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
Peer review: | Referiert |
Publishing method: | Open Access / Bronze Open-Access |