Variability of Galactic blue supergiants observed with TESS

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00619830" target="_blank" >RIV/67985815:_____/25:00619830 - isvavai.cz</a>

Result on the web

<a href="https://hdl.handle.net/11104/0366483" target="_blank" >https://hdl.handle.net/11104/0366483</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202452360" target="_blank" >10.1051/0004-6361/202452360</a>

Result language

angličtina

Original language name

Variability of Galactic blue supergiants observed with TESS

Original language description

Blue supergiants (BSGs) span phases between the main sequence and the late stages of massive stars, which makes them valuable for assessing the physics that drives stars across diverse evolutionary channels. Aims. By exploring correlations between the parameters of BSGs and their variability properties, we aim to improve the constraints on models of the evolved star structure and on the physics of post-main-sequence evolution. Methods. We conducted a variability study of 41 BSGs with known spectroscopic parameters in the Galaxy using high-precision photometry from the Transiting Exoplanet Survey Satellite. Stellar luminosities were calculated from the fit of multiband photometry and using the latest distance estimates from Gaia. We described the time domain of the stars by means of three statistical measures and extracted prominent frequencies via an iterative pre-whitening process. We also investigated the debated stochastic low-frequency (SLF) variability, which manifests itself in all amplitude spectra. Results. We report a positive correlation between the amplitude of photometric variability and the stellar luminosity. For log (L/L-circle dot) less than or similar to 5, stars display frequencies that match the rotational one, suggesting that variability is driven by surface spots and/or features embedded in the wind. For log (L/L-circle dot) greater than or similar to 5, variables of the alpha Cygni class manifest themselves via their diverse and/or time-variant photometric properties and their systematically lower frequencies. Moreover, we report a positive correlation between the SLF variability amplitude and the effective temperature, which indicates that the stellar age plays an influential role in the emergence of the background signal beyond the main sequence. A positive, though weak, correlation is also observed between the intrinsic brightness and the SLF variability amplitude, similar to the findings in the Large Magellanic Cloud, which suggests an excitation mechanism that depends only mildly on metallicity. Exceptionally, the alpha Cygni variables display a suppressed SLF variability that points to the interior changes that the evolving stars undergo.

Czech name

—

Czech description

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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

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

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

Name of the periodical

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

697

Issue of the periodical within the volume

May

Country of publishing house

FR - FRANCE

Number of pages

19

Pages from-to

A152

UT code for WoS article

001488693800007

EID of the result in the Scopus database

2-s2.0-105005485445