Project:	On the mass-radius relation for Sub-Neptunes
Disciplines:	Planetary Science, Astrophysics, Geosciences, Materials Science
Mentor:	Jie Deng, Assistant Professor, (GPS), jie.deng@princeton.edu, Phone: 203-500-6553
Mentor URL:	https://deng.princeton.edu  (opens in new window)
Background:	NOTE: This project is being offered by a non-Caltech mentor and is open only to Caltech students. The project will be conduced at Princeton University in Princeton, New Jersey. Sub-Neptunes are exoplanets with radii between 1.8–3.5 Earth masses on orbits with periods less than 100 days. They are very common and yet their detailed properties are poorly understood. A sub-Neptune is composed of a thick H2-rich atmosphere overlying a massive core (silicate+metal). Due to the blanket effect of the thick atmosphere, sub-Neptunes likely host large magma oceans. As H2 and H2O are highly soluble in magmas, a significant amount of the water and hydrogen may be stored in the magma ocean, which substantially affects the mass-radius relation of the host planet. However, this effect is generally ignored due to the lack of data on the partial molar volume of hydrogen and water in the magma. This project aims to employ the ab initio methods to determine the partial molar volume of hydrogen and water. The results will be used to revise the mass-radius relation for Sub-Neptunes.
Description:	1) Perform density functional theory calculation to derive the partial molar volume for H2 and H2O 2) Model the interiors of sub-Neptune and based on which revise the mass-radius relation
References:	Luo, H., Dorn, C., Deng, J. 2024. The interior as the dominant water reservoir in super-Earths and sub-Neptunes. Nature Astronomy, pp. 1–9.
Student Requirements:	Experience with coding, atomistic simulations, and clusters would be beneficial but not required.
Programs:	This AO can be done under the following programs:   Program    Available To        SURF    Caltech students only  Click on a program name for program info and application requirements.