John Mills

I am a first-year PhD student in the Astronomy and Astrophysics group at the University of Warwick, supervised by Prof Danny Steeghs and Dr Joe Lyman.

Research

I am currently studying the helium nova V445 Puppis. Novae are transient events that result from the ejection of accreted material from the surface of a white dwarf in a binary system, following an episode of thermonuclear runaway burning. V445 Puppis, which erupted in late 2000, is unique amongst Galactic novae due to a total absence of hydrogen in its ejecta, implying an eruption due to runaway helium burning (hence the term helium nova). Such events arise from a close binary system containing a helium star and a white dwarf and so are prime candidates for being the progenitors of Type Ia supernovae, notable for their use as 'standard candles' to measure extragalactic distances. Until recently, the binary has been obscured by a vast amount of dust, preventing any definitive conclusions about its properties. In recent times, however, this dust has started to clear and so I am using imaging, spectroscopic, and photometric observations from a variety of instruments (e.g. NACO/VLT, HST, SALT, TESS) to characterise both the outflow and underlying binary of V445 Puppis.

Teaching

I lead weekly problems classes for first year undergraduate students, focusing on the papers: Classical Mechanics & Special Relativity, Physics Foundations (thermodynamics and waves), Quantum Phenomena, and Electricity & Magnetism.

Previous Experience

I previously completed an MPhys in Physics at the University of Oxford, graduating with first class honours. Whilst here, I joined the Extension to the Investigation on Stellar Population in Relics (E-INSPIRE) team, led by Dr Chiara Spiniello. We built up a statistically large sample of ultra-compact massive galaxies in SDSS with the aim of searching for relic galaxies, which are massive elliptical galaxies that only underwent an initial fast star formation period and did not subsequently merge with other galaxies. Observing these galaxies at low redshifts therefore enables us to shed light on the formation of elliptical galaxies. Together, we published a paper on our findings:

"E-INSPIRE – I. Bridging the gap with the local Universe: stellar population of a statistical sample of ultra-compact massive galaxies at z<0.3", Mills et al. 2025.