New measurements and analysis of the \b{eta} Cephei star V909 Cassiopeiae

TL;DR

This study provides new photometric and spectroscopic data on the ta Cephei star V909 Cassiopeiae, refining its pulsation period and characterizing its physical properties within the OB instability region.

Contribution

It offers the first detailed measurements of V909 Cas's pulsation period, extinction, and luminosity, situating it within the context of ta Cephei variables in the OB association.

Findings

Pulsation period determined as 0.2067798 days.

Interstellar extinction and luminosity measured.

V909 Cas located in the OB instability region.

Abstract

V909 Cas is a little-studied example of a \b{eta} Cep pulsating variable located in the OB association Cas OB8 in the Perseus spiral arm of the Milky Way. Photometric observations in 2016-7 provided 30 new times of pulsation extrema and enabled its mean pulsation period to be determined as 0.2067798(1) d. From spectroscopic observations we determined its interstellar extinction and absolute magnitude and luminosity, and located it with other \b{eta} Cep stars in the OB instability region of the H-R diagram.