Modelling stellar coronal magnetic fields

Abstract

Our understanding of the structure and dynamics of stellar coronae has changed dramatically with the availability of surface maps of both star spots and also magnetic field vectors. Magnetic field extrapolations from these surface maps reveal surprising coronal structures for stars whose masses and hence internal structures and dynamo modes may be very different from that of the Sun. Crucial factors are the fraction of open magnetic flux (which determines the spin-down rate for the star as it ages) and the location and plasma density of closed-field regions, which determine the X-ray and radio emission properties. There has been recent progress in modelling stellar coronae, in particular the relative contributions of the field detected in the bright surface regions and the field that may be hidden in the dark star spots. For the Sun, the relationship between the field in the spots and the large scale field is well studied over the solar cycle. It appears, however, that other stars can show a very different relationship.

6pages, 4 figures

References in corpus (12)

• Simulations of dynamo action in fully convective stars
• Large-scale magnetic topologies of early M dwarfs
• Magnetic field generation in fully convective rotating spheres
• Magnetospheric accretion on the T Tauri star BP Tauri
• Magnetic fields and accretion flows on the classical T Tauri star V2129 Oph
• Simulations of core convection in rotating A-type stars: Magnetic dynamo action
• Surface magnetic fields on two accreting T Tauri stars: CV Cha and CR Cha
• Mass Accretion onto T Tauri Stars
• The non-dipolar magnetic fields of accreting T Tauri stars
• Rotationally Modulated X-ray Emission from T Tauri Stars
• Modelling stellar coronae from surface magnetograms: the role of missing magnetic flux
• Coronal structure of the cTTS V2129 Oph