EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Chromium, Nickel and Iron as clues to the formation histories of exoplanetary bodies

Andrew Buchan1, Amy Bonsor1, Oliver Shorttle1, Jon Wade2, and John Harrison1
Andrew Buchan et al.
  • 1Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK
  • 2Department of Earth Sciences, South Parks Road, Oxford, OX1 3AN, UK

We are now entering an era of rocky exoplanet detection. To determine whether an exoplanet is ‘Earth-like’, we must estimate not only its mass, radius and insolation, but also its geological composition. These geological constraints have wide ranging implications, not least for a planet’s subsequent evolution and habitability.

Polluted white dwarfs which have accreted fragments of planetary material provide a unique opportunity to probe exoplanetary interiors. We can also learn about their formation histories, including the geological process of core-mantle differentiation.

Cr, Ni and Fe behave differently during differentiation, depending on the conditions under which it occurs. This alters the Cr/Fe and Ni/Fe ratios in the core and mantle of differentiated bodies. The pressure inside the body is a key parameter, and depends on the body’s size.

In our work, we present a novel approach for modelling this behaviour and use it to gain crucial insight into the sizes of exoplanetary bodies which pollute white dwarfs.

How to cite: Buchan, A., Bonsor, A., Shorttle, O., Wade, J., and Harrison, J.: Chromium, Nickel and Iron as clues to the formation histories of exoplanetary bodies, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12909,, 2021.

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