Spectral Classification of Algol C

Megan G. Frank, David G. Whelan, Jessica C. Junginger

Published 2022-05-12Version 1

The spectral classification of Algol C, the third star in the Algol triple system, has long been a matter of some uncertainty. There is good reason to suspect that it should be a metallic-line A-type star, and one study in particular showed that this was so, but further studies have cast doubt on that assessment. We utilized a simple spectral subtraction method between spectra taken in and out of primary eclipse to reveal the light of Algol C in the absence of the light from the brightest star. Our resultant spectrum is well-matched to an F1 V spectroscopic standard and shows no evidence of metallic-line spectral anomalies. We note that this classification matches recent abundance determinations for this source.