Doppler imaging of young solar-type stars using the ANU 2.3 m Siding Spring Telescope

Doppler imaging of young solar-type stars using the ANU 2.3 m Siding Spring Telescope

The study of surface activity on young solar-type stars provides an opportunity to improve understanding of stellar dynamos and indirectly gain insight into early solar evolution. Doppler Imaging (DI) can be used to map stellar surface activity, and utilises rotation-induced Doppler-broadening of spectral lines to calculate the surface distribution of a fundamental parameter such as temperature.
DI requires high-resolution spectroscopic observations distributed over one or more stellar rotation periods. To date only a limited number of single young solar analogues have been observed using this technique. Observations of many stars at various evolutionary states and with varying physical parameters are necessary to comprehensively constrain stellar dynamo models. These observations require long-term access to a telescope with a high-resolution echelle spectrograph to undertake multiple epoch studies of stellar activity.

This project has used the ANU 2.3 metre telescope to test Doppler imaging with two active young stars, AB Doradus (AB Dor) and HIP43720, with the HIP43720 observations contemporaneous with the Anglo-Australian Telescope (AAT) observations.

Analysis of the AB Dor mapping and comparison of the 2.3 metre and AAT results for HIP43720 indicates that the ANU 2.3 metre telescope with its high resolution echelle spectrograph is capable of undertaking scientifically useful Doppler Imaging for stellar dynamo surveys.