James Jackman, Arizona State University

Bridging the gap between the white-light and UV flaring behaviour of low-mass stars

Abstract: Stellar flares are explosive phenomena that release radiation across the entire electromagnetic spectrum. The far-UV emission from flares can dissociate atmospheric species and exacerbate atmospheric erosion. Yet, the near-UV flux may be necessary for the emergence of life on rocky planets around low-mass stars such as TRAPPIST-1. A detailed knowledge of the UV energies and rates of flares is therefore essential for our understanding of the habitability of M dwarf systems. However, measurements of UV flare rates can require expensive campaigns with space-based instruments, limiting such measurements to individual active stars. To get around this, habitability studies instead often use UV rates based on extrapolations from white-light studies with TESS. Despite their use in contemporary habitability studies, such extrapolations are untested and as such their accuracy remains unconstrained. To this end, we have combined TESS white-light and archival GALEX UV photometry for main sequence M dwarfs from TESS cycles 1 to 3 to test the UV predictions of habitability studies. We will show how white-light flare studies underestimate the UV rates of flares, what this tells us about the UV properties of flares from low-mass stars, and the impact our results have on our current understanding of the UV environments and habitability of terrestrial exoplanets around low-mass stars.

Bio: James did his PhD at the University of Warwick in the UK, where he worked with Peter Wheatley on studying white-light flares from K, M and L stars with the Next Generation Transit Survey (NGTS). After finishing his PhD in spring 2020, he started a postdoctoral research position with Evgenya Shkolnik at Arizona State University, where he’s been working on the UV properties of flares using GALEX, Swift and HST data, and how they compare to the predictions of flare models calibrated using TESS data.

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12:00 – 12:30pm

Josh Borrow (MKI)

Using the Engaging Cluster

Abstract: In this talk, I will discuss how to get set up on the Engaging cluster, and how to use MKI’s new (and old) nodes. This will include:

– Running python scripts
– How to use the batch system to run jobs
– Using the ‘module’ system to select versions of compilers and libraries
– What disks are available and how to get your data onto the cluster
– Compiling and running C/C++/Fortran programs that need to use multiple nodes.

This talk is ideal for graduate students and postdocs who would like to move from using notebooks to using the batch system. I will also discuss some of the intricacies of the new (AMD Zen2) nodes.

As we have had a last-minute cancellation, we’ll use the second slot in BBL on Monday to discuss the use of the MIT Engaging cluster.