On the extreme period change of the RR Lyrae variable BE Dor

BE Dor is a 15th magnitude first-overtone RR Lyrae variable star in the foreground of the Large Magellanic Cloud, located at about 8.7+/-3.3 kpc from the Sun. Previous investigations have revealed a cyclic period modulation with a period of 8 yr that is associated with a very stable light curve shape. To review and update our knowledge of the seemingly pure phase modulation, we collected all photometric data from the literature and extracted the light curves from all TESS Full Frame Image observations of the star. We extend the time base of earlier studies with another ~10 yrs, supplemented with new spectroscopic observations, and uncover further hints on the true physical nature of this intriguing pulsating star.