Detection of short-term variability in the Be star ƔCas using SMEI, TESS and the BRITE-Constellation

Be stars are B type stars with Balmer emission from a Keplerian decretion disc. It has long been debated how the decretion discs form and there are currently two main contenders. One contender is binary interactions and the other is combinations of non-radial pulsations. In this talk, I show how we use time series analysis of the Be star ƔCas obtained with SMEI, BRITE and TESS to prove the existence of at least four different stellar oscillations over a period of 17 years. Confirmation of non-radial pulsations in yet another Be star gives weight to the argument that the disc can be formed without the need for a companion