DPhil in Atmospheric Oceanic and Planetary Physics
University of Oxford, United Kingdom
October 2022 — Early 2026
Currently in my final year of the DPhil programme in atmospheric physics, supervised by Ray Pierrehumbert and co-supervised by Tim Lichtenberg.
I research the coupled interior-atmosphere evolution of rocky (exo)planets, aiming to understand how the physics of these systems shapes their evolution through delicate feedback processes. This research takes the form of numerical modelling, which is then compared to telescope observations.
MPhys in Physics
University of Exeter, United Kingdom
September 2018 — July 2022
Four-year integrated MPhys Physics programme completed with a 1st (final grade of 85%).
Modules included: astrophysics, electromagnetism, analytical dynamics, thermodynamics, scientific programming, and extensive partnered lab work.
My dissertation project was published in MNRAS as Nicholls et al. (2023).
A sub-Neptunian origin of the super-Earth L 98-59 d
Nicholls, Lichtenberg, Chatterjee, Guimond, Pierrehumbert (2025d)
In preparation
Following our previous paper, we study the evolution of the super-Earth L 98-59 d from its formation up to the present day. Including atmospheric escape alongside a real-gas atmosphere structure model, we are able to reproduce JWST and HST observations of this planet's hybrid H2-H2S atmosphere.
These models indicate a sub-Neptune origin for this planet, and highlight the need for radiative-convective atmosphere calculations.
AGNI: A radiative-convective model for lava planet atmospheres
Nicholls, Pierrehumbert, Lichtenberg (2025c)
In review at JOSS
Accurate models for the atmospheres of lava planets are critical for understanding their evolution and present states.
We present a new radiative-convective model for lava planet atmospheres. This model is designed to be flexible and accurate, allowing for rapid exploration of parameter spaces while including a suite of physical processes.
Self-limited tidal heating and prolonged magma oceans in the L 98-59 system
Nicholls, Guimond, Hay, Chatterjee, Lichtenberg, Pierrehumbert (2025b)
In review at MNRAS
Observations of L 98-59 indicate that it hosts three planets with large orbital eccentricities. We calculate the tidal heating within these planets self-consistently with outgassing and atmospheric energy transport.
A robust feedback between tidal heating, radiative cooling, and mantle rheology leads to self-regulation of tidal heating. Tidal heating may allow them remain molten for a long time, and raises the potential for 'tidally supported worlds'.
Convective shutdown in the atmospheres of lava worlds
Nicholls, Pierrehumbert, Lichtenberg, Soucasse, Smeets (2025a)
Published in MNRAS, 10.1093/mnras/stae2772
Using a new radiative-convective atmosphere model 'AGNI', we found that atmospheres on permanent lava worlds can be convectively stable.
Absorption features of CO2 and SO2 within emission spectra are associated with mantle redox state. Presented at UKPF Meeting 2025.
Magma Ocean Evolution at Arbitrary Redox State
Nicholls, Lichtenberg, Bower, Pierrehumbert (2024)
Published in JGR (Planets), 10.1029/2024JE008576
With a new interior-atmosphere modelling framework 'PROTEUS', we simulated the evolution and cooling of primordial terrestrial magma oceans.
The greenhouse effect of outgassed atmospheres exerts significant control over magma ocean cooling and crystallisation. Presented at EGU 2024.
Distinguishing Oceans of Water from Magma on Mini-Neptune K2-18b
Shorttle, Jordan, Nicholls, Lichtenberg, Bower (2024)
Published in ApJ Letters, 10.3847/2041-8213/ad206e
JWST observations of the sub-Neptune K2-18 b have indicated the presence of CO2 and absence of NH3 in its atmosphere.
We used models of atmospheric chemistry to assess whether these observations are consistent with an underlying magma ocean, as an alternative to the 'hycean' hypothesis.
Self-Consistent Modelling of Flares and Gas Giants
Nicholls, Hebrard, Venot, Drummond, Evans (2023)
Published in MNRAS, 10.1093/mnras/stad1734
Using a radiative-convective photochemical kinetics model, we found that flares induce observable features in the spectra of sufficiently cool gas giants orbiting M-stars.
Presented at Exoclimes VI.
Reviewer for academic journal
Winter 2024 — Spring 2025
I have been a reviewer for the Planetary Science Journal, providing feedback on articles concerning atmospheric energy transport in exoplanet atmospheres.
Co-supervision of two undergraduate BSc projects
Spring 2025 — Ongoing, Groningen
Co-supervision of two undergraduate astronomy students. Projects currently in progress.
Co-supervision of undergraduate BSc project
Spring — Summer (2024), Groningen
This project aimed to test the robustnest of the canonical runaway greenhouse effect, considering different secondary atmosphere compositions. A paper derived from their thesis work is currently in-review at ApJ.
I guided the student through the research project, including the use of computer simulations and statistical analysis, and provided feedback and assessment of their dissertation at the end of the project.
Undergraduate lab teaching
Academic years 2023 — 2025, Oxford
Demonstrating electromagnetism lab experiments to undergraduate students at Oxford. The experiments involve calculating various physical constants, and demonstrating known relationships such as Faraday’s Law. Demonstrating in labs has taught me several skills, particularly on providing instructions and constructive feedback.
Primary school outreach programme
Autumn 2022, Oxford
I visited two primary schools to engage Year 5 children with workshops on general physics. Introduced a class of 30 to broader concepts, and then worked with groups to conduct small experiments.
Summer research project
June 2020 — August 2020, Exeter
Using proprietary FDTD software and open source data science libraries, I optimised photonic crystal cavities for the desired characteristics. My code was later applied to other photonic systems by the research group at Exeter.
Internship at Plessey Semiconductors Ltd
June 2019 — August 2019
I was involved with the development of gallium nitride micro-LED display technology with the process engineering group. This included operation of plasma etch tools, as well as developing novel methods for colour conversion using quantum dots.