Below is a list of available DPhil projects for Planetary and Exoplanetary Physics. If you are interested in any of the following research areas, please contact the relevant supervisor directly as they will be happy to have a dialogue with you. Please note that additional exoplanet projects are available as a DPhil in Astrophysics (exoplanets and stellar physics).

Some projects may be filled as applications are reviewed, so we particularly encourage any candidates considering an application after the January deadline to contact prospective supervisors about available project options.

 

Studying the Moon’s water and composition from Lunar Trailblazer

Neil Bowles
Project ref: AOPP/NB/1/2024

The Lunar trailblazer spacecraft is due to launch in Spring 2024 carrying two instruments to lunar orbit to map temperature, composition and variation in small amounts of water on the Moon.  One of the instruments is the Lunar Thermal Mapper, a  multispectral thermal imager built here in Oxford Physics.  This project will look at the data returned by the mission and work with our laboratory spectroscopy facilities to map surface composition, study the evolution of the lunar water spectral signature and the temperatures of the lunar surface to help us understand how the Moon formed and evolved and plan for future human and robotic exploration.

This project will involve the joining our existing team to work on the analysis of data from space instrumentation built in the department.  A first degree in physics/astrophysics/Earth Sciences or an engineering related discipline is required.

Preparing for Comet Interceptor

Neil Bowles
Project ref: AOPP/NB/2/2024

Working with colleagues in  Finland, France and the US, Oxford Physics are leading the development of the multi and hyper spectral imager for the European Space Agency’s Comet Interceptor mission due for launch in 2029.  Our instrument is called MIRMIS and will remotely map the temperature and composition of the comet’s nucleus and coma.  As part of  the instrument team you will be working on the test and calibration of our instrument and connecting the performance testing science analysis to feed into the instrument operations.

This project will involve the joining our existing team to work on the development and testing of equipment for testing space instrumentation, including the optical instrumentation.  A first degree in physics/astrophysics or an engineering related discipline is required.

Testing the Ariel Exoplanet space telescope

Neil Bowles
Project ref: AOPP/NB/3/2024

Oxford Physics are part of the international team helping to develop ESA's ARIEL Exoplanet space telescope due for launch in the late 2020s. ARIEL is a 1 m class telescope that will be located at the 2nd Earth-Sun Lagrange point to carry out the first detailed transit spectroscopy survey of more than 1000 exoplanetary atmospheres. Our group, supported by the UK Space Agency, are working on the optical ground test equipment to ensure that ARIEL can meet its strict stability requirements that will allow the mission once launched to untangle the signal of a planet’s atmosphere from that of its host star. We are looking for a student to join our team to work on the design, test and development of ARIEL’s optical ground test equipment. The student will then link the performance we can measure on the ground will to ARIEL’s predicted ability to characterise the atmospheres of planets around other stars.

This project will involve the joining our existing team to work on the development and testing of equipment for testing space instrumentation, including the optical instrumentation.  A first degree in physics/astrophysics or an engineering related discipline is required.

Exploring asteroids in the thermal infrared using OSRIS-REx

Neil Bowles
Project ref: AOPP/NB/4/2024

Using data from meteorites and OSIRIS-Rex to map asteroid composition and how that feeds into Solar System evolution.  Oxford Physics are part of the OSIRIS-REx sample analysis team and we are interested in connecting laboratory measurements now being made on the sample returned from asteroid Bennu to the observations made during the orbital reconnaissance phase of the mission.  This project will work with our infrared spectroscopy laboratory to measure samples from meteorites, analogue materials and potentially samples returned by OSIRIS-REx to connect lab scale measurements to the larger areas measured on Bennu and apply them to observations of other asteroids being made in the thermal infrared by ground and space based telescopes.

Exploring the surfaces of Saturn’s icy satellites

Carly Howett
Project ref: AOPP/CH/1/2024

Saturn’s icy satellites are diverse and remain enigmatic, despite years of study by NASA’s Cassini mission. The satellites vary in colour, size, and activity. Some, like Mimas, are long dead and show the scars from years of impactor bombardment. While others, like Mimas’ neighbour Enceladus, have active plumes that send ice and dust into space. Understanding the surface of these targets is crucial in understand their role in the Saturn-system, how they interact with Saturn’s rings, high-energy particles, impacting populations, and even whether they could even host life.

Enceladus’ geysers erupt from four fractures that span its south polar region. The resulting plume escapes the moon, forming a ring around Saturn called the E-ring. Exactly why and how the plumes are formed is unknown, but the eruptive material is thought to come from a liquid water ocean, held beneath Enceladus’ icy surface. Whether this ocean supports life is arguably one of the greatest current mysteries of our solar system.

The high-energy electrons that orbit Saturn bombard the surface of Mimas, Tethys and Dione. This bombardment damages their water-ice surfaces, effectively gluing grains in the surface together, which stops it from cooling down at night as much as their surroundings. This surface alteration also changes its colour, making it appear more blue. How this bombardment alters with electron energy, surface depth, and whether such alteration could be occurring elsewhere in the solar system is still poorly understood.

Cassini studied the Saturn system from 2004 until 2017, during which time a wealth of data was obtained on Saturn’s icy satellites. I am seeking one DPhil (PhD) student to continue my work in analysing Cassini’s Composite Infrared Spectrometer (CIRS) data, specifically to analyse eclipse observations made of Saturn’s icy satellites. Eclipse observations are powerful because they allow the very surface (top few mm) of an icy world to be probed. This region is otherwise difficult to study, but yet vital to understanding everything that happens beneath it. Eclipse observations were made of most of Saturn’s icy moons, so could inform on how Enceladus’ plume recoats its surface, and how the very near surface of Mimas/Tethys/Dione is altered by electron bombardment.

The study of icy worlds has a strong future. The upcoming NASA mission “Europa Clipper” will launch in 2024 to study Jupiter’s icy world Europa, and NASA’s Lucy mission launches in late 2021 to study Jupiter’s Trojan asteroids. As a Co-I on both of these missions future opportunities exist for expanding into these targets. The successful candidate would be joining a well-established planetary science group, which is actively involved with many planetary missions and astronomy. International collaborations are include working with other modelling groups located in the USA and Switzerland.

The work will be computationally intensive, using programming languages like IDL and python, so a physics/computing/mathematics background is preferred, and a first degree in Physics, Mathematics or a related discipline is required.

Observations of Jupiter’s atmosphere in support of the NASA Juno mission

Patrick Irwin
Project ref: AOPP/PGJI/1/2024

The NASA Juno mission arrived at Jupiter in July 2016 and entered into a series of elliptical polar orbits designed to probe Jupiter’s interior structure through measurement of its gravity and magnetic fields and remote sensing of its deep atmosphere. Juno’s highly elliptical orbit minimises the damaging effects of Jupiter’s extremely harsh radiation belts, but means that its UV, visible and near-IR observations are mostly of Jupiter’s poles, while microwave observations using the MWR instrument are mostly confined to narrow north-south swaths during ‘perijove’ (closest approach) passes that lack the global spatial context necessary to interpret them properly. Hence, a global campaign is under way to provide Earth-based observational support for Juno, in which our group is closely involved making observations with the MUSE (Multi Unit Spectroscopic Explorer) instrument at ESO’s Very Large Telescope (VLT) in Chile. The MUSE instrument measures spectral ‘cubes’ in which each pixel of its 300x300-pixel field of view is a complete spectrum covering 480 to 930 nm. These ‘cubes’ allow us to map the spatial distribution of the clouds and colouring agents (called chromophores), and determine spatial variations of ammonia abundance and cloud top levels. While other instruments can provide partial coverage of these wavelengths (usually as images in discrete spectral filters), only MUSE provides the unique combination of spatial and spectral coverage, making it a very powerful tool for studying clouds in giant planet atmospheres. 

Existing MUSE observations have already been used to model Jupiter’s atmosphere (e.g., https://ora.ox.ac.uk/objects/uuid:a5856d5a-eba1-487b-82c5-0a31761ff218, https://arxiv.org/pdf/1912.00918.pdf), but Jupiter’s atmosphere is continually evolving and the Juno mission is set to operate for several more years. Hence, continuing observations and analysis are vital. At longer wavelengths, instruments such as VLT/VISIR provide thermal mapping that can be used to determine the vertical and spatial distribution of temperature and gaseous abundances. A set of MUSE observations was made within a few minutes of a set of VISIR observations in 2018, which have never been co-analysed and provide a golden opportunity to link visible cloud features with thermal anomalies. In addition to these ground-based observations, NASA’s James Webb Space Telescope (JWST), launched successfully in 2021, has already made several observations of the gas giants over a very wide wavelength range that could be co-analysed as part of this project. The project could also be extended to MUSE observations of Saturn.

In summary, in this project the student will analyse existing VLT/MUSE observations of Jupiter and participate in proposing and reducing further measurements. The student will analyse these observations with our world-leading NEMESIS radiative transfer code (https://nemesiscode.github.io), and will thus also gain a deep insight into observational analysis, radiative transfer modelling, and gain a deep understanding of the atmospheric circulation on these worlds.

This project will be computationally intensive using Fortran, IDL, python and others, so a physics/computing/mathematics degree is preferred.

Interior-atmosphere coupling of hot gas giant exoplanets

Thaddeus Komacek
Project ref: AOPP/TDK/1/2024

Hot Jupiters are the best characterized class of exoplanet, yet significant mysteries remain concerning the chemistry and dynamics of their atmospheres and the evolution of their interiors. In order to improve our understanding of hot Jupiters, in this project we will more self-consistently model the inherent coupling between the interiors and 3D atmospheres of hot Jupiters. This will both elucidate how the inhomogeneous atmospheres of hot Jupiters act as a boundary to regulate the interior cooling rate, as well as whether atmospheric heat transport can serve to transport heat from the atmosphere to the interior of the planet and aid in the explanation of the large ``inflated’’ radii of many hot Jupiters. To do so, we will conduct a suite of MESA interior evolution models with a compressible core and deposited heating, as well as drive 3D atmospheric general circulation models using the SPARC/MITgcm with boundary conditions from this evolution model. We will post-process our results using the PICASO radiative transfer framework in order to aid in the interpretation of JWST and ground-based high resolution spectroscopic observations.  

One DPhil (PhD) student is sought for this project on interior-atmosphere coupling of hot Jupiters. I am open to modifications and/or extensions to the project to study other aspects of hot Jupiter atmospheric circulation and evolution, including the impact of clouds, thermochemistry, and/or magnetism on atmospheric dynamics and observable properties as well as the potential for specific heating mechanisms (e.g., Ohmic dissipation, thermal tides) to explain hot Jupiter radius (re)-inflation. This DPhil student will work in collaboration with members of my group, outside collaborators who are experts in interior evolution modeling, and the SPARC/MITgcm hot Jupiter userbase more broadly. As part of this project, the student will work to advance and modernize the SPARC/MITgcm modeling framework. I am also open to support students who would prefer to define their own research direction in the area of exoplanet atmospheric dynamics, climate, and/or internal evolution.

This work will require a thorough understanding of fluid dynamics and radiative transfer, which require a solid background in mechanics, electricity and magnetism, thermodynamics, and quantum mechanics, as well as the mathematical methods of physics. As a result, a degree in physics, mathematics, geophysical sciences, astronomy, or a related discipline is required. This project will be computationally intensive, with coding in Fortran (MESA, MITgcm), Python (PICASO, post-processing and analysis), and MATLAB (MITgcm). A keen familiarity with computer programming is required, while prior experience with Fortran, Python, and MATLAB is desirable but not required.

Exoplanet climate dynamics

Raymond Pierrehumbert
Project ref: AOPP/RTP/1/2024

The newly discovered exoplanets present possibilities for a diverse range of climate situations not encountered in our own solar system. The demands of this new subject challenge the limits of current modelling capabilities, and while they involve the same underlying physical components as are familiar from the Solar systems, these components are present in novel combinations. This project involves a range of modeling and theoretical activities aimed at understanding the new climates. There is a particular emphasis on identifying potentially observable consequences of various exoplanet climate phenomena. I am seeking up to two DPhil (PhD) students for work in the general area of exoplanet climate modeling, with a particular emphasis on smaller planets (super-Earth size and below) which can have a more rich diversity of atmospheric compositions than the hydrogen-dominated gas giants, and offer a range of additional phenomena associated with the possibility of a condensed rocky, icy or liquid surface. In all of our work, there is an emphasis on maintaining an appropriate balance between theoretical work or idealized modeling aimed at elucidating fundamental principles, and work with more comprehensive general circulation models.

Two DPhil (PhD) students are sought for exoclimate projects in one or more of the following general areas: (1) Atmospheric escape and implications for habitability of M-star planets, (2) Baroclinic instability on tide-locked slowly rotating planets (3) Exchange of volatiles between planetary interiors and atmospheres, including effects of magma oceans on atmospheres and implications of the deep carbon cycle and CO2 outgassing on the outer edge of the habitable zone. (4) Transient phenomena in exoplanet atmospheres, their use in constraining planetary characteristics, and prospects for detection with future observational programs. (5) Spatially inhomogeneous chemistry of planetary atmospheres driven by mixing due to idealized large scale flow. In addition to these specific project areas, I am open to suggestions from students who wish to take the initiative in defining their own research direction within the general area of exoplanet climate and climate evolution.

There are also possibilities for DPhil students to work in collaboration with the ERC EXOCONDENSE project on topics related to effect of condensible substances on exoplanet climate dynamics, and on generalised moist convection in planetary atmospheres. Further information on EXOCONDENSE is available here. Topics of interest include both generalized moist convection and its parameterization and condensation effects (including clouds) in planetary scale dynamics. Further information on EXOCONDENSE can be found at the EXOCONDENSE project page.

These projects require a thorough understanding of fundamental physics, including thermodynamics, mechanics and electromagnetic radiation, as well as a facility with analysis of mathematical models. Familiarity with physical chemistry is also desirable. Hence, a first degree in Physics, Mathematics or a related discipline is required. The projects involve considerable use of computational techniques, so basic familiarity with numerical analysis and familiarity with programming techniques in some computer language is required. The main programming languages used are Python and Fortran, but prior experience with these specific languages, while desirable, is not required.