Infrared eruptive variability of young stars – Dr Calum Morris

This talk, part of the UH Centre for Astrophysics Research (CAR) 2023-2024 seminar series, was presented by Dr Calum Morris (UH) on work from his PhD.

Date: 13 March 2024

Investigations into the Infrared-Selected Variable Stars

Abstract: The diversity seen in the infrared variable sky is vast, and understudied when compared to variability in the optical regime. Utilising near-infrared (NIR) colours and amplitudes can be a powerful tool in the classification of the various members of this population, made easier in combination with spectroscopy. Understanding the demographics of NIR variables is key when considering pre-main sequence stellar evolution, because high-amplitude variability in YSOs can trace eruptive behaviour, which in turn is crucial in understanding the 'protostellar luminosity spread problem'. Within my thesis (and work since) I have examined and attempted to classify high-amplitude variability in NIR stellar populations, with a focus on candidate YSOs with the intention of understanding the types and prevalence of eruptive variability. Additionally I worked on classifications for high amplitude non-YSOs to better understand the feature space for variable stars in the NIR, this included a novel cataclysmic variable which features a more complete accretion disk than others of it's class. That object will act as a precursor to finding more of these stars within the upcoming PRIMVS catalogue of Miller et al.

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