The demystification of classical Be stars through space photometry
Abstract
All optical high-cadence space photometers have observed Be stars and achieved some of their most prominent results with them. Single-object highlights from five different satellites are selected to delineate the progress made for Be stars. Multi-mode nonradial pulsation (NRP) is the most universal photometric signature of Be stars, and variations on timescales from days to years can be traced back to them. Nested multi-instance NRP frequency differences explain regularly repeating outbursts of Be stars, which probably are the building blocks of the formation process of the gaseous disks around Be stars. During outbursts, frequency spectra can differ drastically from those at quiescence. Observations by TESS of hundreds of Be stars may (i) pulsationally distinguish Be stars from the also rapidly rotating but diskless Bn stars and (ii) discriminate between different evolutionary paths towards Be stars. Conceivably, the angular-momentum loss incurred by pulsation-driven outbursts enables Be stars to escape rotational rupture. This process may also govern the selection of frequency differences involved in the mass loss.
- Publication:
-
Stars and their Variability Observed from Space
- Pub Date:
- 2020
- Bibcode:
- 2020svos.conf...35B
- Keywords:
-
- Stars: emission-line;
- Be;
- Stars: oscillations;
- Stars: mass loss;
- Stars: individual: ζ Oph;
- αEri;
- HD 49330;
- KIC 11971405;
- 25 Ori