Thesis Topic: The role of magnetic fields in the intermediate-mass star formation process
Thesis Supervisor: Markus SchУЖller
Abstract
Spectropolarimetric observations of Herbig Ae/Be stars indicate that magnetic fields are important ingredients of intermediate mass star formation. To properly understand the physics involved in the intermediate mass star formation process, it is particularly important to know the origin of the magnetic fields in these stars. However, current theories are not able to present a consistent scenario of how the magnetic fields in Herbig Ae/Be stars are generated or how these fields interact with the circumstellar environment, presenting a combination of disk, wind, accretion, and jets. Understanding the interaction between the central stars, their magnetic fields, and protoplanetary disks is crucial to reconstruct the Solar System's history, and to account for the diversity of exoplanetary systems.
The PhD project aims at a pioneering study of the disk-magnetosphere interaction in detail. Observational constraints on magnetic field models will be placed by inferring the relative contributions of vertical and azimuthal magnetic field components. Using observations with ESO instruments, the Stokes V profiles of the observed Zeeman signatures in photospheric lines as well as various wind and accretion diagnostic lines will be modeled. Furthermore, the study of the magnetic field structure will be combined with the determination of chemical composition and surface element distribution to constrain theories on star formation and magnetospheric accretion.