My main field of interest is astrobiology, the search for life in space, and I am especially interested in
how life might be discovered on distant exoplanets, by looking at so-called biosignatures in the atmospheres of the planets.
In my current research at the Centre for ExoLife Sciences (CELS) at UCPH,
we would like to study how known types metabolism ("breathing" of life) affects the atsmopheres of exoplanets.
When life forms are breathing, they change the atsmopheres around them and thereby disturbs the chemical equilibrium that would otherwise be in the atmosphere.
This creates a chemical disequilibrium, which might be one of our most promising biosignatures, since it is not specific for life on Earth, and can therefore
allow us to discover life that is very different from what we know from our own planet.
In our research, we are simulating exoplanet atmospheres on the computer, using a combination between our current atmosphere model, MARCS, and a newly added disequilibrium chemistry code, KROME.
When these computer simulations are up and running (hopefully in the very near future) we will implement known types of metabolism into our disequilibirum code,
so we can observe their effects on the simulated atmospheres.
Selection of previous work
We have found a correlation between the shape of planetary orbits (eccentricity)
and the number of planets (multiplicity) in exoplanet systems, such that larger systems have more
circular orbits. This is true for all studied planet types, such as Hot Jupiters (HJ), Cold
Jupiters (CJ) and Super Earths (SE).
In my current research I use an atomizer to introduce SiO2 particles into an atmosphere
chamber. Similarly to the environment in the upper atmosphere, the particles in the chamber are
radiated with UV and gamma radiation, which will affect their tendency to aggregate and
form cloud droplets.
Atmosphere models can be used to simulate the chemical and physical processes taking place
in an atmosphere, and thereby predict the structure of the atmosphere based on e.g. the chemical
composition and type of host star. This is an example of how different molecules are distributed
throughout the atmosphere of the exoplanet HATS-6b according to an atmosphere model.
PhD - Exoplanet atmospheres in high-energy radiative environments
In my PhD I was looking at how the radiative environment of a planet affects the chemistry and cloud formation of its
atmosphere. We did this in two ways: 1) We did experiments with clouds in an atmosphere chamber, to look
at how cloud particles behave under gamma radiation. This is important because clouds can have a huge effect on our observations
of atmospheres as well as the climate of the planet, and understanding the cloud formation is therefore important to understand
the planet. 2) We did computer simulations of exoplanet atmospheres to model how different types of high-energy
radiation affect the chemistry of an atmosphere. This is important because exoplanets are found in many different environments
around different host stars and in different parts of the galaxy, which alters the radiation that reaches the planet. We know that
radiation can change the atmospheric chemistry, and that these changes can in some cases look like biosignatures. In order to
recognize biosignatures, we therefore need to understand the environment of the planets we are looking at.
Nanna Bach-Møller, Christiane Helling, Uffe G. Jørgensen, and Martin B. Enghoff -
"Aggregation and Charging of Mineral Cloud Particles under High-energy Irradiation."
The Astrophysical Journal, Volume 962 (2024), 87
Nanna Bach-Møller, and Uffe G. Jørgensen -
"Orbital eccentricity–multiplicity correlation for planetary systems and comparison to the Solar system."
Monthly Notices of the Royal Astronomical Society 500.1 (2021): 1313-1322.
Sven Kiefer1, Nanna Bach-Møller, Dominic Samra, David A. Lewis, Aaron D. Schneider, Flavia Amadio, Helena Lecoq-Molinos, Ludmila Carone,
Leen Decin, Uffe G. Jørgensen, and Christiane Helling -
"Under the magnifying glass: A combined 3D model applied to cloudy warm Saturn-type exoplanets around M dwarfs."
Astronomy & Astrophysics 692, A222 (2024).
