CFHT UM2025 - Presentation Details
Abstract Details
Title: Revisiting the Doubly-Magnetic Massive Binary epsilon Lupi: A Detailed Spectropolarimetric and Photometric Variability Study
Presenter: Ayan Biswas
Abstract:
The doubly-magnetic close B-star binary epsilon Lupi has a unique orbital configuration where the component stars behave like anti-aligned dipoles pointing almost pole-on towards earth. Recently, off-periastron radio enhancements were detected from the system, which was expected to be a consequence of relative motion of the component magnetospheres. However, without knowledge of the stars' rotation periods and magnetic field maps, it remains impossible to characterize energy release due to the winding of their coupled fields. In this study, we present detailed spectropolarimetric and photometric observations of epsilon Lupi to investigate its variability. Abundance analysis from ESPaDOnS spectra shows a common abundance pattern, confirming the near-twin nature of the components. Longitudinal magnetic field measurements from ESPaDOnS data show minimal temporal variation. We provide the best estimates of the system’s stellar and magnetospheric parameters based on polarimetric and photometric data. The TESS light curve, spanning two years, exhibits a stable periodogram with newly identified significant frequencies. We explore their origin through spectroscopic variability of Si lines and investigate the potential presence of beta-Cephei pulsations.