Back in 2020 astronomers on Earth were puzzled by a mysterious dimming of the famous red giant star. After some years of a closer look at Betelgeuse they recently found out it was a binary system after all, with a companion star now named Siwarha, orbiting the big star with a period of around 2000 days and leaving a wake behind its path within the atmosphere.
The radius of the orbit is only 2.3 times the radius of Betelgeuse, placing Siwarha extremely deep into the chromosphere of the supergiant. Can you imagine the hellish of a ride that must be? It's so wild that while speeding through so close to its parent star, it changes the distribution of plasma and other materials in such a way that we on Earth have detected spectral shifts correlated to when Siwarha is interacting with the extended atmosphere that is directly facing us.
More specifically blueshifts, meaning mass from Betelgeuse is being ejected towards our direction, either caused by its companion directly or some internal processes most likely also triggered or exaggerated by it. You can read more about this on this recent paper:
https://arxiv.org/pdf/2601.00470