Stochastic light variations in hot stars from wind instability: finding photometric signatures and testing against the TESS data

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F21%3A00118998" target="_blank" >RIV/00216224:14310/21:00118998 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1051/0004-6361/202040148" target="_blank" >https://doi.org/10.1051/0004-6361/202040148</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202040148" target="_blank" >10.1051/0004-6361/202040148</a>

Result language

angličtina

Original language name

Stochastic light variations in hot stars from wind instability: finding photometric signatures and testing against the TESS data

Original language description

Context. Line-driven wind instability is expected to cause small-scale wind inhomogeneities, X-ray emission, and wind line profile variability. The instability can already develop around the sonic point if it is initiated close to the photosphere due to stochastic turbulent motions. In such cases, it may leave its imprint on the light curve as a result of wind blanketing.Aims. We study the photometric signatures of the line-driven wind instability.Methods. We used line-driven wind instability simulations to determine the wind variability close to the star. We applied two types of boundary perturbations: a sinusoidal one that enables us to study in detail the development of the instability and a stochastic one given by a Langevin process that provides a more realistic boundary perturbation. We estimated the photometric variability from the resulting mass-flux variations. The variability was simulated assuming that the wind consists of a large number of independent conical wind sectors. We compared the simulated light curves with TESS light curves of OB stars that show stochastic variability.Results. We find two typical signatures of line-driven wind instability in photometric data: a knee in the power spectrum of magnitude fluctuations, which appears due to engulfment of small-scale structure by larger structures, and a negative skewness of the distribution of fluctuations, which is the result of spatial dominance of rarefied regions. These features endure even when combining the light curves from independent wind sectors.Conclusions. The stochastic photometric variability of OB stars bears certain signatures of the line-driven wind instability. The distribution function of observed photometric data shows negative skewness and the power spectra of a fraction of light curves exhibit a knee. This can be explained as a result of the line-driven wind instability triggered by stochastic base perturbations.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

<a href="/en/project/GA18-05665S" target="_blank" >GA18-05665S: Mass-loss in evolved massive stars</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy and Astrophysics

ISSN

0004-6361

e-ISSN

—

Volume of the periodical

648

Issue of the periodical within the volume

April

Country of publishing house

FR - FRANCE

Number of pages

9

Pages from-to

„A79“

UT code for WoS article

000647070100001

EID of the result in the Scopus database

2-s2.0-85104233564