Short-term variability and mass loss in Be stars. I. BRITE satellite photometry of η and μ Centauri
Abstract
Context. Empirical evidence for the involvement of nonradial pulsations (NRPs) in the mass loss from Be stars ranges from (I) a singular case (
Aims: The purpose of this study is to develop a more detailed empirical description of the star-to-disk mass transfer and to check the hypothesis that spates of transient nonradial pulsation modes accompany and even drive mass-loss episodes.
Methods: The BRITE Constellation of nanosatellites was used to obtain mmag photometry of the Be stars η and
Results: In the low-inclination star
Conclusions: The observations are well described by the decomposition of the mass loss into a pulsation-related engine in the star and a viscosity-dominated engine in the circumstellar disk. Arguments are developed that large-scale gas-circulation flows occur at the interface. The propagation rates of these eddies manifest themselves as Štefl frequencies. Bursts in power spectra during mass-loss events can be understood as the noise inherent to these gas flows.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- April 2016
- DOI:
- 10.1051/0004-6361/201528026
- arXiv:
- arXiv:1602.01744
- Bibcode:
- 2016A&A...588A..56B
- Keywords:
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- circumstellar matter;
- stars: emission-line;
- Be;
- stars: mass-loss;
- stars: oscillations;
- stars: individual:ηCentauri;
- stars: individual:μCentauri;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Recommended for publication in Astronomy &