Geometrical Constraints on the Hot Spot in Beta Lyrae

TL;DR

This study analyzes six years of spectropolarimetric data of Beta Lyrae to investigate the hot spot on its accretion disk, revealing a potential direct evidence for the hot spot through polarization discrepancies.

Contribution

It provides the first direct evidence of a hot spot on Beta Lyrae's accretion disk using long-term spectropolarimetric observations.

Findings

Discrepancy of 0.245 days between light and polarization minima

Evidence supporting the existence of an accretion hot spot

Long-term spectropolarimetric data characterizing polarized light curves

Abstract

We present results from six years of recalibrated and new spectropolarimetric data taken with the University of Wisconsin's Half-Wave Spectropolarimeter (HPOL) and six years of new data taken with the photoelastic modulating polarimeter (PEMP) at the Flower and Cook Observatory. Combining these data with polarimetric data from the literature allows us to characterize the intrinsic BVRI polarized light curves. A repeatable discrepancy of 0.245 days (approximately 6 hours) between the secondary minima in the total light curve and the polarization curve in the V band, with similar behavior in the other bands, may represent the first direct evidence for an accretion hot spot on the disk edge.