Magnetohydrodynamics in hot Jupiters
Lead Research Organisation:
Newcastle University
Department Name: Mathematics and Statistics
Abstract
The field of exoplanet research is relatively young with the first exoplanet orbiting a main-sequence star discovered in 1995. "Hot Jupiters" (Jupiter sized planets orbiting
close to their host stars) were the earliest discoveries and are the best characterized exoplanets due to their favorable observing conditions. They are also substantially
different than the giant planets in our own solar system. For both of these reasons, hot Jupiters are an ideal test bed for theories of dynamical processes in gas spheres.
Two of the most fundamental and long standing observational mysteries associated with these objects are: 1) How did hot Jupiters get to their current close positions
(i.e. how did they form)? and 2) Why are they so big? In this project we will be focusing on the second of these two problems.
Recent observations of hot Jupiters indicate that these objects are often substantially larger than standard evolutionary theory predicts. The inflated radii can only be explained by an injection of heat into the planetary interior, which halts gravitational contraction as the planet evolves. One of the leading theories is that Ohmic
heating, due to the dissipation of electric currents, may cause this inflation. This project will use numerical simulations of the magnetohydrodynamic (MHD) equations in both cartesian and spherical geometry to quantify Ohmic dissipation under a variety of parameters typical of the observed hot Jupiters. More specifically, this project will investigate the effect of a fully temperature dependent magnetic diffusivity on the wind structure, magnetic field geometry and Ohmic dissipation within the atmosphere.
The theories developed in this project will be incorporated into planetary evolution models and compared to observations of hot Jupiters. Such observations are already in abundance, but will multiply rapidly with current and future space missions dedicated. Additionally, our simulations will also inform on atmospheric dynamics, atmospheric loss rates and planetary spin down.
close to their host stars) were the earliest discoveries and are the best characterized exoplanets due to their favorable observing conditions. They are also substantially
different than the giant planets in our own solar system. For both of these reasons, hot Jupiters are an ideal test bed for theories of dynamical processes in gas spheres.
Two of the most fundamental and long standing observational mysteries associated with these objects are: 1) How did hot Jupiters get to their current close positions
(i.e. how did they form)? and 2) Why are they so big? In this project we will be focusing on the second of these two problems.
Recent observations of hot Jupiters indicate that these objects are often substantially larger than standard evolutionary theory predicts. The inflated radii can only be explained by an injection of heat into the planetary interior, which halts gravitational contraction as the planet evolves. One of the leading theories is that Ohmic
heating, due to the dissipation of electric currents, may cause this inflation. This project will use numerical simulations of the magnetohydrodynamic (MHD) equations in both cartesian and spherical geometry to quantify Ohmic dissipation under a variety of parameters typical of the observed hot Jupiters. More specifically, this project will investigate the effect of a fully temperature dependent magnetic diffusivity on the wind structure, magnetic field geometry and Ohmic dissipation within the atmosphere.
The theories developed in this project will be incorporated into planetary evolution models and compared to observations of hot Jupiters. Such observations are already in abundance, but will multiply rapidly with current and future space missions dedicated. Additionally, our simulations will also inform on atmospheric dynamics, atmospheric loss rates and planetary spin down.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| ST/N504191/1 | 01/10/2015 | 30/09/2020 | |||
| 1775865 | Studentship | ST/N504191/1 | 01/10/2016 | 28/02/2020 | Alex Hindle |