[P-AE22] Exoplanets

[PAE22-P04] Exploring Super-Earth Surfaces: Albedo of Near-Airless Magma Ocean Planets and Topography

*Yuichi Ito¹, Darius Modirrousta-Galian^2,3, Giuseppina Micela² (1. University College London, 2.INAF - Osservatorio Astronomico di Palermo, 3.University of Palermo)

Keywords:Exoplanet , Rocky planet, Magma ocean

We propose an analytic function for the bond albedo of an airless or near-airless magma ocean planet (AMOP). We generated multiple 1D fractal surfaces with varying compositions unto which we individually bombarded 10,000 light rays. Using an approximate form of the Fresnel equations we measured how much of the incident light was reflected. Having repeated this algorithm on varying surface roughnesses we find the albedo as a function of the Hurst exponent, the geochemical composition of the magma, and the wavelength. As a proof of concept, we used our model on Kepler-10 b to demonstrate the applicability of our approach. We present the albedos of different lava compositions and multiple tests that can be applied to observational data in order to determine their characteristics. Currently, there is a strong degeneracy in the surface composition of AMOPS due to the large uncertainties in their measured albedos. In spite of this, when applied to Kepler-10 b we show that the high albedo could be caused by a moderately wavy ocean that is rich in oxidised metallic species such as FeO, Fe2O3, Fe3O4. This would imply that Kepler-10 b is a coreless or near-coreless body.