Is Shedir Variable?

TL;DR

This study uses high-precision space-based and Hipparcos data to investigate whether alpha Cassiopeiae is variable, concluding it shows no significant variability over three years.

Contribution

The paper provides the first detailed analysis with modern high-precision data confirming alpha Cassiopeiae's non-variability.

Findings

No significant variability detected in 3 years of SMEI data.

Hipparcos data also shows no variability.

Alpha Cassiopeiae is likely not a variable star.

Abstract

Before the age of modern photographic and CCD observations alpha Cassiopeiae was labelled as a variable star, though this variability has not been seen with modern instrumentation. We present an analysis of 3 years of high precision space-based photometric measurements of the suspected variable star alpha Cassiopeiae, obtained by the broad band Solar Mass Ejection Imager (SMEI) instrument on board the Coriolis satellite. Over the 3 years of observations the star appears to not show any significant variability. Also, data from the Hipparcos epoch photometry annex shows no significant variability.