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

Empirical evidence for the involvement of nonradial pulsations (NRP's) in themass loss from Be stars ranges from (i) a singular case (\object{$\mu$ Cen}) ofrepetitive mass ejections triggered by multi-mode beating to (ii) severalphotometric reports about enormous numbers of pulsation modes popping up duringoutbursts and on to (iii) effective single-mode pulsators.  The BRITE Constellation of nanosatellites was used to obtain mmag photometryof the Be stars $\eta$ and \object{$\mu$ Cen}.  In the low-inclination star \object{$\mu$ Cen}, light pollution by variableamounts of near-stellar matter prevented any new insights into the variabilityand other properties of the central star. In the equator-on star \object{$\eta$Cen}, BRITE photometry and {\sc Heros} echelle spectroscopy from the 1990sreveal an intricate clockwork of star-disk interactions. The mass transfer ismodulated with the frequency difference of two NRP modes and an amplitude threetimes as large as the amplitude sum of the two NRP modes. This process feeds ahigh-amplitude circumstellar activity running with the incoherent and slightlylower so-called \v{S}tefl frequency. The mass loss-modulation cycles aretightly coupled to variations in the value of the \v{S}tefl frequency and inits amplitude, albeit with strongly drifting phase differences.  The observations are well described by the decomposition of the mass lossinto a pulsation-related engine in the star and a viscosity-dominated engine inthe circumstellar disk. Arguments are developed that large-scalegas-circulation flows occur at the interface. The propagation rates of theseeddies manifest themselves as \v{S}tefl frequencies. Bursts in power spectraduring mass-loss events can be understood as the noise inherent to these gasflows.

Short-term variability and mass loss in Be stars I. BRITE satellite photometry of $\eta$ and $\mu$ Centauri