CFHT UM2025 - Presentation Details
Abstract Details
Title: Launching into the next era of hot star magnetism studies with Wenaokeao
Presenter: Alexandre David-Uraz
Abstract:
20 years of observations with ESPaDOnS, and more recently with SPIRou, have crucially contributed to our understanding of magnetism in hot stars with radiative envelopes. Through a series of surveys and more targeted investigations, the basic properties of surface magnetic fields in the upper HR diagram have been established: their overall incidence (roughly 10%), and their general structure and strengths (mostly large-scale dipoles, of order kG). In parallel, theoretical studies have highlighted the crucial interplay between magnetism, internal structure and pulsations, rotation, and for the highest-mass stars, winds, thus highlighting the importance of these fields when considering stellar evolution and the end products of hot stars. As is usually the case however, this major breakthrough ultimately brought forth more questions than answers, notably: why do only a small fraction of hot stars form these large-scale detectable fields, how do their fields evolve throughout various evolution stages, how does magnetism impact internal stellar structure, and do seemingly “non-magnetic” stars host weak, small-scale fields on their surfaces? Currently, several spectropolarimetric space mission concepts (in both the ultraviolet and optical) are being developed, e.g., Polstar, CASSTOR, and Arago, with plans to incorporate spectropolarimetric capabilities (POLLUX) on NASA’s next flagship mission (HWO). In this talk, I will discuss the key role that Wenaokeao can play in launching the field into this exciting new era, fostering transformative synergies with other spectropolarimetric instruments and thus cementing CFHT’s legacy in uniquely shaping our understanding of magnetism in the upper HR diagram.