Betelgeuse -- A Century and more of Variation

Christopher Lloyd

Published 2020-06-27Version 1

The mean light curve of Betelgeuse is constructed from the visual data in BAA VSS and AAVSO archives. Period analysis reveals clusters of periods around 2000 and 400 days but these are swamped by the long-term trends. No identifiable periods emerge but the feature near 400 days is the most persistent and survives even when the range of variation is low. Herschel's data from 1836-40 and early data from the BAA VSS around 1900 show a range of V {\raise.3ex\hbox{\boldmath${\scriptstyle\sim}$}} 0 -- 1, so the star was brighter and more active than recently. Historically it shows a wide range of behaviour.