PI: Felix Sainsbury-Martinez
The exo/astrochemistry group at the University of Leeds has been using Dirac HPC resources to study planet formation on multiple scales, from protoplanetary discs to planetary atmospheres, with a focus on the role that ices play. As of February 2026, we have two papers under-review with ApJ and two papers being prepared for submission.
The first submitted paper (Ahmad et al 2026) performs quantum mechanical simulations of the binding of complex organic molecules onto amorphous solid water ice typical of the ices found in the midplanes of protoplanetary discs. This work used the Binding Energy Evaluation Platform (BEEP, Bovolenta et al 2022) on DIAL3 to self-consistently calculate binding energies methanol and its photochemically derived species and found broad binding energy distributions that reflect the heterogeneity of amorphous solid water ices. They found that the inclusion of self-consistently calculated binding energies into an astrochemical model led to an increase in the predicted abundance of radicals which are key reactants in the formation of complex organic molecules.
Hydrogen escape rates in the months following the impact of a pure-water-ice comet with a tidally-locked and Earth-analogue atmosphere. Here we can see the delay in transport of water to the day-side (substellar) upwelling as well as the reduced efficiency of vertical transport on the Earth.
The second paper (Sainsbury-Martinez et al 2026) ran the Community Earth System Model on DIAL3 to study the transport of cometary impact delivered water in the atmospheres of Earth-like exoplanets. They focused on the vertical advection of water and other hydrogen bearing molecules (such as OH, a photochemical derivative of water) through the tropopause. On the Earth, the tropopause acts as a key control valve in setting the atmospheric escape rate of Hydrogen. Here, they found that the strong winds that drive a global circulation on tidally-locked worlds (worlds in which the same side always faces the host star) can drive cometary water aloft, even when an impact occurs far away from the day-side upwelling. Their results suggest that a not-insignificant fraction of the impact delivered hydrogen should escape in the first 5-10 years following a massive cometary impact.
As a follow up to this work, we are currently exploring the role of cometary ices as a source of volatiles, specifically oxygen, on younger terrestrial atmospheres with a lower initial oxygen content. In particular, we are interested in studying if a single or multiple impacts can deliver enough oxygen to change the global oxygenation state of the atmosphere. In turn we are also studying the effects that this atmospheric oxygenation has on the climate state since molecular oxygen and ozone are key components in setting the radiative balance of an Earth-like atmosphere.
Finally, a paper exploring the impact of wind-driven accretion on the evolution of volatiles in protoplanetary discs is almost ready for submission. Results show that winds initially accelerate the depletion of volatiles, but over time start to act counter to other depletion mechanisms centred around dust settling.