Research Fellow - University of Southampton

Welcome! I am a research fellow at the Astronomy group of the University of Southampton. My research interests are modeling the atmosphere and climate of exoplanets, focusing on radiative, convective, and dynamical processes happening around the inner edge of the habitable zone.

Research interests

The fields of Planetary Science and Astrobiology are relatively new in the wider umbrella of space sciences, and have been rapidly growing since the first exoplanet was discovered in 1992. Humanity’s interests beyond Earth include not only fundamental questions about the fabric of the Universe, the formation of galaxies, or the evolution of black holes, but also older questions that largely motivate the push of governments, space agencies, and private companies towards space exploration. Until very recently, answering the immemorial question “Are we alone in the Universe?” has always been a matter of theoretical work and abstract considerations. However now, for the first time in History, we are beginning to develop the technological tools that will allow us to finally put these hypotheses and abstractions to the test. The field of Astrobiology has begun with Astronomy, but evolved to include increasingly more fields in Climate Science, Chemistry, Geology, Biology and many others.

I specialize in the radiative, convective, and dynamical processes that drive the evolution of planetary climates through time, including long-term climate feedbacks that control habitability loss and gain. Ultimately, I seek to understand the main factors that can cause planets to enter and exit temperate, habitable states, not only for our general understanding of exoplanets and the theoretical evolutionary paths they can take, but also for our understanding of the long-term climate trajectory of the Earth. I outline below a few key areas of my research.

Climate dynamics

Runaway greenhouse climate transitions

Water-rich rocky planets within the inner edge of their habitable zones are expected to undergo extreme, 'runaway' greenhouse effects that force their climate into a transient hothouse state culminating into a hot, uninhabitable, and desiccated surface. The transition from this transient runaway greenhouse effect to a post-runaway state involves many radiative and convective processes that have major implications for their present-day climate, atmospheric composition, and observable features.
The habitability prospects of this post-runaway state are also dependent on factors including the initial water inventory of the planet. The more water the planet has accreted and stored in its surface reservoir, the more vulnerable its habitability will be, due to the powerful greenhouse effect of water vapor. Could a planet recondense its water vapor into surface water oceans before losing it all to space? This is an open question that depends on many factors.
The question of whether the Earth is susceptible to a moist greenhouse or runaway greenhouse climate transition has also been studied; however the answer is still unclear, partly due to the same processes that make climate change on Earth difficult to predict, clouds chief among them.

greenhouse
Atmospheric physics / Geophysics

Magma ocean planets and non-dilute atmospheres

Condensation and evaporation are key atmospheric processes impacting the thermal profile of atmospheres. When the mixing ratio of a condensible species is larger than ~10%, the atmosphere is said to be non-dilute. Condensation of non-dilute condensible components can change the surface pressure of the planet significantly and potentially have strange effects never seen in the Earth system.
Additionally, in certain evolutionary scenarios and thermodynamical conditions, multiple species can undergo phase changes simultaneously, which has first-order effects on the temperature structure of the atmosphere. One such scenario is the early stages of a planet's evolution, just after its formation. It then has a global magma ocean that cycles volatiles between the mantle and the atmosphere, including condensible volatiles such as water vapor, carbon dioxide, and silicate vapors that can potentially condense simultaneously. The gases overlying magma oceans can also be subject to supercritical conditions, whose effects on atmospheres are poorly understood.

silicate vapors
Climate change and habitability

Impact of cloud feedbacks on the habitability of rocky planets and the Earth

The current largest uncertainty regarding the course that the climate of the Earth will take in the future comes from the chaotic nature and complexity of clouds at both large and small scales. Clouds of various compositions and radiative properties are expected to form on exoplanets, and depending on the context, can be a first-order determinant on whether a given planet can maintain a temperate habitable climate or will tip towards a stable hothouse or snowball climate state.
The radiative effects of high and low clouds can also change the picture we get from three-dimensional clear-sky simulations and dramatically hamper our ability to detect biosignatures. These considerations make it an important endeavor to improve our current cloud models and couple them to exoplanet general circulation models to offer us the opportunity to test and validate Earth climate models outside their nominal range as well as improving our understanding of more exotic exoplanet feedbacks.

clouds
Astronomy

Remote detection of habitability and life

The various observatories currently in operation are unable to characterize Earth-like planets in their habitable zones. First, more than 95% of them do not transit, making the most successful detection method used to date, transmission spectroscopy, ineffective. Second, such planets are so small, cold, and far away from their host stars that to detect and characterize them with sufficient accuracy requires technological specifications that have never been deployed. Upcoming observatories such as the Large Interferometer for Exoplanets (LIFE) and the Planetary Camera & Spectrograph on the Extremely Large Telescope (ELT-PCS) as expected to achieve these requirements. Precursor science is needed to explore the potential of these efforts to detect vast numbers of non-transiting exoplanets and possible signs of habitability and life.

red sun

Image Credits

Shutterstock
@Даниил Хогоев, Creative Commons CC0
NASA/JPL-Caltech