I am a 3rd Year PhD Student at the Institute of Astronomy, University of Cambridge, working with Professor Cathie Clarke.
I study protoplanetary discs, where planets form around young stars.
Image of GW Lup: DSHARP survey (Andrews et al., 2018)
Although I originate from Devon, since 2015 I have lived in Cambridge, where I studied Natural Sciences for my BA and MSci degrees, specialising in astrophysics.
I also enjoy doing outreach and public engagement; for several years now I have been part of the committee of Cambridge Hands-On Science (CHaOS), a student-run group which runs hands-on roadshow events in schools and public events around the country.
In what spare time remains, I enjoy heading out into the countryside for long walks, or relaxing with a cryptic crossword.
Contact/LinksTweets by @AndrewSellek
Disc environments evolve through a number of competing processes; my particular interests are on the secular (i.e. long term) evolution, addressing questions such as:
- What is the origin of any winds that are removing material; does photoevaporation affect discs in important ways?
- How long are the resulting protoplanetary disc lifetimes; how is this affected by their surroundings?
- Where does their material end up – on the star, blown away in a wind, or in planets?
Broadly speaking, I tackle these questions in two ways.
– Firstly, by seeking to improve our physical understanding of photoevaporative winds including what heats and cools them, and what controls the structure of these thermal winds.
– Secondly, by investigating how photoevaporative winds compete with other evolutionary processes in the disc such as viscous accretion and radial drift of dust by combining models of these effects in a forward modelling process to try to reproduce trends we see in demographic surveys of protoplanetary discs.
Some recent highlights (as of June 2021) of papers that I have published during my PhD include:
Sellek, Clarke and Booth (2021)
We extend previous self-similar models, considering in particular the effects of temperature gradients, which only make small differences, and elevated wind bases, which are more important. We explain results of hydrodynamics simulations – which generally agree well with our solutions – in terms of space-filling, and consider implications for [Ne II] line profiles.
Sellek, Booth and Clarke (2020)
We consider how the radial drift of dust grains lowers disc masses enough to better explain this correlation, and find that a fairly weak photoevaporative wind is needed to reproduce low accretion rates.