Magnetism, rotation and accretion in Herbig Ae-Be stars

TL;DR

This paper reviews high-precision observations of Herbig Ae-Be stars, revealing new insights into their magnetic fields, accretion processes, and rotational evolution during the pre-main sequence phase.

Contribution

It provides new observational evidence on the origin and evolution of magnetic fields and accretion in intermediate-mass pre-main sequence stars.

Findings

Magnetic fields are strong and organized in Herbig Ae-Be stars.

Magnetic fields influence spectroscopic activity and accretion processes.

Factors affecting rotational angular momentum are identified.

Abstract

Studies of stellar magnetism at the pre-main sequence phase can provide important new insights into the detailed physics of the late stages of star formation, and into the observed properties of main sequence stars. This is especially true at intermediate stellar masses, where magnetic fields are strong and globally organised, and therefore most amenable to direct study. This talk reviews recent high-precision ESPaDOnS observations of pre-main sequence Herbig Ae-Be stars, which are yielding qualitatively new information about intermediate-mass stars: the origin and evolution of their magnetic fields, the role of magnetic fields in generating their spectroscopic activity and in mediating accretion in their late formative stages, and the factors influencing their rotational angular momentum.