Massive stars are those with initial masses on the main sequence above about 8 solar masses, leading to core-collapse (or pair-instability) supernovae. They dominate the ecology of the Universe as "cosmic engines" via their extreme output in radiation and particles - not only as supernovae, but also during their entire lifetimes - with far-reaching consequences.
Although the existence of magnetic fields in massive stars is no longer in question, our knowledge of the basic statistical properties of massive star magnetic fields is seriously incomplete. There is a troubling deficit in our knowledge of the scope of the influence of fields on massive star evolution, and almost no empirical basis for how fields modify mass loss. This proposal represents a consensus effort by an international team of recognized researchers who have compiled a strategic sample of sources to address these outstanding issues.
The basic aim of this Large Program is to exploit the unique characteristics of ESPaDOnS obtain critical missing information about the poorly-studied magnetic properties of these important stars, to confront current models and to guide theory. The general scientific objectives are: 1. To identify and model the physical processes responsible for the generation of magnetic fields in massive stars; 2. To observe and model the detailed interaction between magnetic fields and massive star winds; 3. To investigate the role of the magnetic field in modifying the rotational evolution of massive stars; 4. To investigate the impact of magnetic fields on massive star evolution, and the evolution of the fields themselves. In particular we will explore the connection between magnetic fields of nondegenerate massive stars and those of neutron stars, with consequential constraints on stellar evolution, supernova astrophysics and gamma-ray bursts.