I am a first year PhD student in the Astronomy and Astrophysics group at the University of Warwick, supervised by Prof. Tom Marsh. My research primarily focuses on double-white-dwarf binary stars. White dwarfs mark the endpoint of stellar evolution for intermediate-mass main-sequence stars, and will inevitably be the final stage of evolution for the Sun. However, the presence of a binary companion can majorly alter the evolution away from that of an isolated star. With two white-dwarf stars together as a binary, over time significant angular momentum can be lost from the system through the means of gravitational wave radiation, to the point where the stars spiral closer and closer together and hence radiate gravitational waves stronger.
I investigate systems exhibiting this effect using observational data to explore some of the final stages of stellar evolution close to the point of collision, where the orbital decay can be used to gain ultra-precise characterisation of system masses. Furthermore, for the most compact of systems, I strive to investigate the impact of mass transfer, tidal effects, and the potential presence of third bodies. By doing this, my research has an immediate implication to understand type 1a supernovae, where the merger of a double white dwarf binary is a leading candidate to explain such an event.
A second part of my research is to exploit state-of-the-art wide-field surveys such as Gaia to identify promising double white dwarf binary candidates. After finding systems, I will lead photometric and spectroscopic observations to firstly confirm the type of system and to then investigate those that are most interesting. Also, I will perform large population analyses of the double white dwarf systems with predictions for the number that will be detectable with the Laser Interferometer Space Antenna (LISA) mission, set to launch in 2034.
All of this is to better understand stellar evolutionary tracks and the evolution of the Milky Way and distant galaxies, as well as binary star interactions. Also, some of the strongest gravitational wave emitting systems that I am investigating will be used as verification binaries to optimise the scientific performance of LISA.
J. Munday et al. “The post-common-envelope binary central star of the planetary nebula ETHOS 1Link opens in a new window”. In: Monthly Notices of the Royal Astronomical Society 498.4 (Sept. 2020), pp. 6005–6012. doi: 10.1093/mnras/staa2753. arXiv: 2009.03577Link opens in a new window [astro-ph.SR]
A. Pastorello et al. “Forbidden hugs in pandemic times. I. Luminous red nova AT 2019zhd, a new merger in M 31Link opens in a new window”. In: Astronomy and Astrophysics 646, A119 (Feb. 2021), A119. doi: 10 . 1051 / 0004 - 6361 / 202039952. arXiv: 2011.10588Link opens in a new window [astro-ph.SR]
D. Jones et al. “The post-common-envelope binary central star of the planetary nebula PN G283.7-05.1. A possible post-red-giant-branch planetary nebula central starLink opens in a new window”. In: Astronomy and Astrophysics 642, A108 (Oct. 2020), A108. doi: 10.1051/0004-6361/202038778. arXiv: 2007.08960Link opens in a new window [astro-ph.SR]
Prior to Warwick, I studied at the University of Surrey and a Master's research year with the Instituto de Astrofisica de Canarias (IAC) in La Palma, Canary Islands. There I researched binary central stars of planetary nebulae, which are the immediate result of a mass transfer phase which engulfs the central stars and is abruptly ejected. I characterised and analysed the systems ETHOS 1Link opens in a new window and Ou 5, with key results of very massive and hot primary stars in both cases compared to the investigated sample of binary central planetary nebulae. Also, the work of ETHOS 1 verified a binary-nebula inclination relation and a lack of inflation of the companion main sequence star, while the study of Ou 5 indicates a younger primary star (a pre-white dwarf post-nebula ejection) evolutionary path, ejecting the nebula during a post-RGB evolutionary state opposed to the dominant post-AGB pathway. The motivation for these investigations again revolved about classifying stellar evolutionary tracks for intermediate-mass stars, except at a much earlier stage of a binary's lifetime to a double white dwarf binary.
I often perform observations on telescopes around the world. I have been fortunate enough to spend nights using the WFC and IDS instruments at the Isaac Newton Telescope (INT) and ALFOSC at the Nordic Optical Telescope (NOT), La Palma. I have also observed remotely from England with ULTRASPEC, mounted on the Thai National Observatory (TNO). During the time of my PhD, I will observe with HiPERCAM and ULTRACAM currently based in La Palma and Chile.
I teach an undergraduate astronomy experiment in 2nd year labs where students calibrate spectra of the Sun using basic telescope equipment and CCDs to derive its radial velocity and temperature.