Betelgeuse: Long Secondary Period, a Fundamental Mode and Overtones

Abstract

Betelgeuse is the brightest Red Supergiant (RSG) in the sky and thus has been studied over decades. Photometrically, a funda-<br> mental pulsation mode (FM) at a period P ≈400 d and a long, secondary period (LSP) with still disputed origin at P ≈2400 d have<br> been found. The Leibniz Institute for Astrophysics Potsdam (AIP) monitors Betelgeuse almost nightly since more than a decade<br> with its robotic spectroscopic telescope STELLA, collecting R≈55000 spectra covering wavelength ranges from 390-860 nm.<br> This proceeding reports about radial-velocity data, periods found within and their connection to photometric measurements.