Chromium, Nickel and Iron as clues to the formation histories of exoplanetary bodies
<p>We are now entering an era of rocky exoplanet detection. To determine whether an exoplanet is &#8216;Earth-like&#8217;, 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&#8217;s subsequent evolution and habitability.</p><p>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.</p><p>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&#8217;s size.</p><p>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.</p>