Characterising the outbursting mechanisms of centaur 29P/Schwassmann-Wachmann 1 by engaging schools in the research process

Stoddard-Jones, Ioan Cai 2026. Characterising the outbursting mechanisms of centaur 29P/Schwassmann-Wachmann 1 by engaging schools in the research process. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

The underlying mechanisms responsible for the frequent and violent outbursts of 29P/Schwassmann–Wachmann 1 (29P/SW1) are still poorly understood. This thesis characterises the photometric behaviour of 29P/SW1 during these outbursts using data obtained in part by school students in Wales as part of the Comet Chasers STEM educational outreach programme. Images collected through a global robotic telescope network, Las Cumbres Observatory, between May 2016 and July 2025 were processed using a Python pipeline to consistently measure the magnitude of 29P/SW1. An average of 15.3+/-1.0 outbursts per year with DELTAm>0.2 mag were identified and classified as major, moderate, or minor. The number of outbursts in each category varies significantly between apparitions. Overall, 29P was found to be brighter than its quiescent level for more than 80% of the time. The mean colour indices were g'-r'=0.49 mag and r'-i'=0.29 mag. These indices vary slightly during the surge phase of an outburst, with changes of DELTA(g'-r')=-0.25+/-0.30 mag and DELTA(r'-i')=-0.01+/-0.08 mag. A mean photometric decay rate of 0.10+/-0.10 mag/d was measured, with higher‑intensity outbursts exhibiting faster decay. Ejecta expansion velocities were estimated as v_dust<0.1 km/s and v_gas~0.4 km/s. Students participating in Comet Chasers reported high levels of engagement with the practical, student‑led research activities. Introducing young learners to active scientific research shows strong potential for encouraging interest in STEM subjects: space was identified as a particularly popular topic among 8 to 11‑year‑olds, with over 20% expressing interest in pursuing a STEM‑related career in the future. These findings contribute to a deeper understanding of 29P/SW1’s unusually active behaviour while demonstrating the scientific value and educational benefits of involving school students directly in contemporary astronomical research.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Physical, Chemical & Environmental Sciences Schools > Physics and Astronomy
Subjects:	Q Science > QC Physics
Date of First Compliant Deposit:	23 September 2026
Last Modified:	30 Sep 2026 14:19
URI:	https://orca.cardiff.ac.uk/id/eprint/189773

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