I am a PhD student in the Astronomy and Astrophysics group at the University of Warwick and my supervisor is Pier-Emmanuel Tremblay. I work on 3D modelling the helium-dominated atmospheres of white dwarfs.


97% of all stars in our Galaxy will end their lives by blowing off their outer layers and leaving a core remnant, known as a white dwarf, behind. As such, white dwarfs are single-handedly the most important stellar remnants for studies of stellar evolution and given that majority of planet hosting stars will end their lives as white dwarfs, they are crucial for understanding what happens to planetary systems as their host stars die. To better understand white dwarfs and therefore aid the various studies involving white dwarfs, we need to be able to determine their fundamental properties, such as their ages, masses and radii. We can do this by looking at observations of white dwarfs. In order to make sense of what the observations show us we need models that realistically describe what happens in the atmospheres of these stars. This is where my work comes in.

I model the helium-dominated atmospheres of white dwarfs (classified as DB and DBA), which make-up around 20% of all known white dwarfs. Up to now, 1D atmospheric models have been used for DB and DBA studies. However in 1D, the treatment of convection, which occurs in the atmospheres of the majority of white dwarfs, is unphysical. Therefore, an improvement must be made in order to extract more accurate parameters. 3D models are thought to be more accurate as they treat convection from first principles using radiation-hydrodynamics. My work is to analyse the first 3D grid of DB and DBA white dwarf atmosphere models and quantify the differences between these new models and the standard 1D models.

 Animation of convection for a DB model with log(surface gravity) of 7.5 and effective temperature of ~10,000K.Animation showing convection for a DB model with log(surface gravity) = 9 and effective temperature of 34,000K

These animations show radiative flux leaving the top of the simulations for two 3D DB models. On the left, a DB model with surface gravity of 107.5 cm s-² and effective temperature of around 10,000 K is shown. The DB model on the right, has surface gravity of 109 cm s-2 and effective temperature of around 34,000 K. Unlike the model with lower surface gravity and effective temperature, this model has well defined intergranular lanes. These models define the two extremes of the 3D DB grid I analyse.


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Talks and posters