Stellar bonfires on Bonfire Night from Dr Justyn Campbell-White who gave us a talk about the accretion disks of stars and his work interpreting their spectra. Really interesting stuff and a good demonstration of the software he wrote for the task, STAR MELT.

Alan Pickup also gave us a very comprehensive guide to the night sky in November.

You can find out more about Justyn’s work and software on his University of Dundee webpages. You can also try out the STAR MELT Jupyter Notebook there too.

This was our second physical meeting back after lockdown and the first with a speaker actually at the Augustine United Church. We had a good ASE crowd and it was great to chat to people again, some of whom I’ve never met in person before.

Mark Phillips

Low- and intermediate-mass stars acquire most of their mass in the protostellar phase, but accretion continues into the pre-main-sequence phase via a disk for a few million years. Accretion is a fundamentally important process, affecting disk stability/evolution, stellar rotation/activity, and planet formation/migration. The main observational challenge is probing the sub-au scales of the innermost disk, not yet possible for most of these stars, even via interferometry. Such young stars, however, possess a wealth of high-energy emission lines, revealing the nature of these accretion-related processes.

During my current position at the University of Dundee, I have developed the Python package, STAR-MELT, to automatically extract, identify, and fit emission lines, directly from the input spectral data. These lines can then be used to investigate the accretion activity and its temporal variability, allowing us to tomographically map the structures and inner disk of the stars.

In this talk, I will present an overview of our analysis method and the STAR-MELT package, along with results from our recently published paper that features analyses of three YSOs. We find that even with similar stellar parameters, the accretion processes and the final stages of star formation can be vastly different in terms of stability and nature.