English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Among the most spectacular variable stars are the Luminous Blue Variables(LBVs), which can show three types of variability. The LBV phase of evolutionis poorly understood, and the driving mechanisms for the variability are notknown. The most common type of variability, the S Dor instability, occurs ontimescales of tens of years. During an S Dor outburst, the visual magnitude ofthe star increases, while the bolometric magnitude stays approximatelyconstant. In this work, we investigate pulsation as a possible trigger for theS Dor type outbursts. We calculate the pulsations of envelope models using anonlinear hydrodynamics code including a time-dependent convection treatment.We initialize the pulsation in the hydrodynamic model based on linearnon-adiabatic calculations. Pulsation properties for a full grid of models from20 to 85 M$_{\odot}$ were calculated, and in this paper we focus on the fewmodels that show either long-period pulsations or outburst-like behaviour, withphotospheric radial velocities reaching 70-80 km/s. At the present time, ourmodels cannot follow mass loss, so once the outburst event begins, oursimulations are terminated. Our results show that pulsations alone are not ableto drive enough surface expansion to eject the outer layers. However, theoutbursts and long-period pulsations discussed here produce large variations ineffective temperature and luminosity, which are expected to produce largevariations in the radiatively driven mass-loss rates.

Pulsations as a Driver for LBV Variability