Caught in the Act: Observations of the Double-mode RR Lyrae V338 Boo During the Disappearance of a Pulsation Mode

TL;DR

This study reports the disappearance and reappearance of a pulsation mode in the double-mode RR Lyrae star V338 Boo, observed through TESS and AAVSO data, providing insights into pulsation mode dynamics and the Blazhko effect.

Contribution

It presents new observational evidence of mode disappearance and dominance shifts in V338 Boo, advancing understanding of RR Lyrae pulsation behavior.

Findings

First overtone mode disappeared during TESS observations

Mode reappeared and became dominant after TESS data

Potential link to solving the Blazhko effect

Abstract

New results on the behavior of the double-mode RR Lyrae V338 Boo are presented. The Transiting Exoplanet Survey Satellite (TESS) observed this star again in 2022, and an observing campaign of the American Association of Variable Star Observers (AAVSO) was completed after the TESS observations as a follow-up. We find that the first overtone pulsation mode in this star completely disappears during the TESS observing window. This mode reappears at the end of the TESS observations, and the AAVSO observing campaign shows that in the months that followed, the first overtone mode was not only present, but was the dominant mode of pulsation. This star, and potentially others like it, could hold the key to finally solving the mystery of the Blazhko effect in RR Lyrae.