Magnetic fields of low mass stars

点击翻译按钮获取中文摘要

Prominences, cool condensations in stellar coronae, are well-studied objects on the sun but less so on stars. These features were first observed on the rapidly rotating star, AB Doradus by Collier-Cameron and Robinson, in the 1980s and were found to be in forced co-rotation at radii considerably larger than would be possible on the sun. The co-rotation of these features signalled their containment by strong magnetic fields at the tops of magnetic loops, making them excellent markers for the stellar magnetic field structure. Observations can only infer, by ZDI, the magnetic field strengths at the stellar surface and there is no known way to extrapolate this up to the stellar corona. A model that can connect prominence formation at a given site around the star with a certain magnetic field structure could be invaluable in providing information on the coronal magnetic field.The relationship between the magnetic field of these stars and the prominence positions means that, with data from observations of these prominence positions and a suitable model, it would be possible to unravel some information about the associated magnetic field structure of these stars. Thus, understanding the formation sites of these features would allow us to better understand the stellar magnetic field, which is important for our understanding of stellar evolution.The ejection of these features can have overwhelming effects on the evolution of orbiting planets and the potential of these planets to harbour life and understanding the ejection of such features from "young suns" could give us insight into the environment in which the Earth evolved.This project aims to build upon previous work where a model was developed for calculating the formation sites of these slingshot prominences, in various magnetic field structures, within the equatorial plane for a cylindrical geometry. Expansion of this model out of the equatorial plane, alongside a model for mapping these modelled formation sites to observational results (and back again) would make the current model more realistic and valuable.