STFC Studentship Projects

Two STFC Research Studentship Opportunities in Planetary Physics, University of Oxford

Closing date: noon on 16th July.

Applications are invited for two Doctoral (DPhil) studentships in Atmospheric, Oceanic & Planetary Physics, funded by the STFC for up to 3.5 years. The two DPhil studentships will start in October 2020 and are based in the Department of Physics, with supervision from Professor Neil Bowles, and from Professor Pat Irwin. Please see below for list of available projects.

STFC training grant eligibility conditions apply for the award of these studentships. The STFC funding provides full maintenance stipend (starting at £15,285 in 2020-21) plus course fees for applicants with Home Fees status, or Fees Only support for applicants with EU Fees Status.

Available projects.

Exploring clouds and gaseous abundances in the atmospheres of Uranus and Neptune

(Supervisor: Prof Pat Irwin, Reference code: AOPP/STFC/PGJI/1/2020)

Uranus and Neptune, known as the “Ice Giants” are amongst the most mysterious and poorly understood planets in our solar system. The spatial resolution of ground-based telescopes has been transformed in the last 20 years by the development of adaptive optics and the activity of Uranus’s atmosphere has been seen to increase dramatically through its equinox in 2007, while Neptune’s atmosphere shows enormous changes in cloud activity. In this project, the student will use spatially-resolved spectral observations of Uranus and Neptune made with the Gemini-North (Hawaii) and VLT (Chile) to determine the vertical and horizontal distribution of cloud and gaseous abundances in these atmospheres and compare these with thermal infrared spatially-resolved observations with VLT, Subaru and Spitzer. The goal of the project is to build a self-consistent picture of the circulation and cloud-forming processes at work on the ice giants during a period of rapid change, paving the way for future atmospheric studies by ground-based telescopes and also the James Webb Space Telescope, due for launch, hopefully, in 2021.

Additional details are provided further down this webpage.

Ground-based observations of Jupiter (and Saturn) in support of the NASA Juno mission

(Supervisor: Prof Pat Irwin, Reference code: AOPP/STFC/PGJI/2/2020)

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 and 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 are mostly confined to narrow north-south swaths during closest approach passes. 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 instrument at ESO’s Very Large Telescope (VLT) in Chile, which is a spatially-resolved spectrometer that allows us to map the vertical and horizontal distribution of the clouds, colouring agents and ammonia abundance in Jupiter’s atmosphere. In this project, the student will analyse existing MUSE observations, participate in proposing and reducing further measurements, and compare the observations with other datasets, including thermal emission observations to gain insights into the planet’s atmospheric circulation. As with Project A, this will again paving the way for future atmospheric studies by ground-based telescopes and also the James Webb Space Telescope, due for launch, hopefully, in 2021.

Additional details are provided further down this webpage.

Testing the ARIEL Exoplanet space observatory

(Supervisor: Prof Neil Bowles, Reference: AOPP/STFC/NEB/1/2020)

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.

Space instrumentation for exploring the Moon and a comet in the thermal infrared as part of NASA’s Lunar Trailblazer and ESA’s Comet Interceptor missions.

(Supervisor: Prof Neil Bowles, Reference code: AOPP/STFC/NEB/2/2020)

Understanding the surface characteristics of the Moon and comets through measurements in the thermal infrared provides important information on their geology and evolutionary history. Our group here in Oxford Physics has a long history in developing space-based thermal infrared cameras and spectrometers and we are providing two similar instruments for NASA’s Lunar Trailblazer and ESA’s Comet Interceptor missions.

Lunar Trailblazer is a NASA SIMPLEX small satellite mission to the Moon that is due to launch in 2024 with two instruments, a near-infrared spectrometer (called HVM3) from NASA/JPL and the Lunar Thermal Mapper from Oxford Physics. The Lunar Thermal Mapper (LTM) has a similar design to the thermal infrared module that is part of the multispectral camera, called MIRMIS, on ESA’s Comet Interceptor mission so the student will have the unique opportunity to become involved in both missions.

The student will join our Lunar Trailblazer and Comet Interceptor teams. The project will involve working on the science, calibration and test of the LTM breadboard instrument that supports both missions, as well as the opportunity to work with existing data sets from missions such as NASA’s Lunar Reconnaissance Orbiter and ESA’s Rosetta mission to comet 67P. The student should have a good first degree in a Physics/Engineering or Earth Sciences with a strong interest in space instrumentation.

Please address informal enquiries about these projects to Professor Neil Bowles (https://www2.physics.ox.ac.uk/contacts/people/bowles ) and/or Professor Pat Irwin (https://www2.physics.ox.ac.uk/contacts/people/irwin ).

Candidate Requirements

In addition to project-specific requirements noted above, candidates are also expected to meet the graduate admissions criteria. For full details on entry requirements see:

https://www.ox.ac.uk/admissions/graduate/courses/dphil-atmospheric-ocean...

STFC training grant eligibility conditions apply for the award of these studentships and only applicants with Home fees status are eligible for full funding.

Application Procedure

Candidates must submit a graduate application form. Details of the application procedure are available on the course page of the University website:

https://www.ox.ac.uk/admissions/graduate/courses/dphil-atmospheric-ocean...

Applications must arrive by noon on July 16th, 2020. Please note that applicants can apply to be considered for one or more of the projects. Please state the project reference codes of any of the above projects you wish to apply to in your application form. For further details of the application process, send an email to the AOPP Graduate team. .

Further details on projects

Further details: Exploring clouds and gaseous abundances in the atmospheres of Uranus and Neptune

Supervisor: Patrick Irwin (AOPP)
Project ref: AOPP/STFC/PGJI/1/2020

Uranus and Neptune, known as the “Ice Giants” are amongst the most mysterious and poorly understood planets in our solar system. The poles of Uranus are tipped over by an extraordinary 98º (compared with an obliquity of 23.5º for the Earth) leading to enormous annual variations in solar forcing, with the poles annually receiving more sunlight per unit area than the equator! In contrast, Neptune’s obliquity of 29º appears much less anomalous. The Voyager 2 fly-bys in 1986 and 1989 provided our only close-up views of these worlds and revealed that Uranus is in almost perfect radiative balance with the Sun, while Neptune emits thermally more than 2.5 times the solar radiation it receives! Perhaps as a result of this imbalance, the atmospheric circulation of Uranus was found to be rather quiescent, while that of Neptune was extraordinarily dynamic and active.

More than a quarter of a century later, the spatial resolution of ground-based telescopes has been transformed by the development of adaptive optics. The activity of Uranus’s atmosphere has been seen to increase dramatically through its equinox in 2007, while Neptune’s atmosphere shows enormous changes in cloud activity. We have been monitoring and these developments with an extensive programme of near-infrared ground-based observations at the Gemini-North Telescope in Hawai’i and ESO’s Very Large Telescope in Chile. Near infrared reflectance spectroscopy enables us to determine the vertical and horizontal distribution of cloud and gaseous abundances in these atmospheres, using our world-leading NEMESIS retrieval code. Recent highlights include the first positive detection of hydrogen sulphide in the atmosphere of Uranus, probable detection in Neptune’s atmosphere and the first ground-based detection of methane variability in Neptune’s atmosphere.

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Figure 1. Uranus (left) and Neptune (right) as observed by the Hubble Space Telescope in 2018. The development of a polar ‘cap’ on Uranus can be seen, which is expected to thicken in the coming years, while a new dark spot can be seen towards the top left of the Neptune image.

As Uranus advances towards its northern summer solstice in 2030, its north pole is swinging towards the Sun and we are starting to see the development of a polar ‘cap’ of haze (Fig. 1). Meanwhile, Neptune has seen the appearance of several mysterious dark spots (similar to the Great Dark Spot seen in 1989 by Voyager 2) whose structure is almost entirely unknown. Continuing visible and near-infrared observations offer an opportunity to better constrain and thus better understand such atmospheric features. At longer wavelengths, in the thermal infrared spatially-resolved observations with VLT/VISIR, Subaru and NASA’s Spitzer Space Telescope have allowed a better understanding of temperature variations and upper atmospheric composition.

The aim of this project is to develop our ground-based visible and near-infrared observing programme and combine these new observations with existing thermal infrared determinations to build a self-consistent picture of the circulation and cloud-forming processes at work on the ice giants during a period of rapid change. This work will help pave the way for future atmospheric studies by ground-based telescopes and also the James Webb Space Telescope, due for launch in 2021. Further in the future, the Ice Giants are being seen as a key future target for planetary space missions with concepts being studied by both NASA and ESA. The successful candidate would be joining a well-established planetary data analysis group that is actively involved in observational astronomy and planetary missions (e.g., the recently completed Cassini mission at Saturn).

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

Further details: Ground-based observations of Jupiter (and Saturn) in support of the NASA Juno mission

Supervisor: Patrick Irwin (AOPP)
Project ref: AOPP/STFC/PGJI/2/2020

The clouds of the Solar System’s Gas Giants (Jupiter and Saturn) are amongst the most beautiful and complex phenomena displayed by the planets. Their spatial distribution reveals the forces and energy exchange mechanisms (e.g., moist convection) shaping the banded appearance of the planetary weather layers; their vertical structure tells us about the composition and cloud microphysics; and their colour reveals the chemical alteration of aerosols in a giant planet atmosphere. While most clouds are white, the clouds of Jupiter and Saturn are coloured with various hues of yellow and red, but the nature of these colours, or ‘chromophores,’ has yet to be determined, and remains an enduring mystery.

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Figure 1. NASA/Juno’s orbit insertion trajectory and early orbits showing very close perijove passes necessary to probe Jupiter’s gravity field (to determine internal structure), and also avoid radiation damage from Jupiter’s intense radiation belts.

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Figure 2. Left: Colour-composite MUSE image constructed from data recorded on 9th April 2018 (101.C-0097), with the GRS clearly visible. Right: False-colour image, where red is 630 nm (weak atmospheric absorption), green is 490 nm (sensitive to blue-absorbing ‘chromophores’, and blue is 890 nm (strong methane absorption, sensitive only to high level hazes).

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 (Fig. 1) 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 closely involved making observations with the MUSE instrument at ESO’s Very Large Telescope (VLT) in Chile. The MUSE (Multi Unit Spectroscopic Explorer) instrument provides an unprecedented opportunity to study the clouds, dynamics and composition of the giant planet atmospheres at a spatial and spectral resolution never before possible. MUSE measures spectral ‘cubes’ in which each pixel of the 300 x 300 field of view is a complete spectrum covering the range spectral 480 to 930 nm (Fig. 2). These ‘cubes’ allow us to map the spatial distribution of the clouds and colouring agents, estimate cloud top levels and determine spatial variations of ammonia abundance. While other ground-based and space-based instruments can provide partial coverage of these wavelengths (usually as images in discrete filters), only MUSE provides the unique combination of spatial and spectral coverage, which makes it a very powerful tool for studying clouds in giant planet atmospheres.

Analysis of existing MUSE observations has been used to model the distribution of cloud, chromophores and ammonia in Jupiter’s atmosphere (https://ora.ox.ac.uk/objects/uuid:a5856d5a-eba1-487b-82c5-0a31761ff218, https://ora.ox.ac.uk/objects/uuid:3ab6381e-3cdf-4975-b255-9f3077ede8b8), but Jupiter’s atmosphere continues to develop and the Juno mission is set to observe for several more years. Hence, continuing observations are vital and more are planned or remain waiting to be processed. 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 on one night in 2018 and provides a golden opportunity to link cloud features to observed thermal anomalies. We envision that our VLT/MUSE programme could extend to further observations of Saturn also to compare and contrast these two worlds. In addition to these ground-based facilities, NASA’s James Webb Space Telescope (JWST), scheduled for launch in 2021, is planned to make many observations of the gas giants over a wide wavelength range that will need to be understood and interpreted.

The successful candidate would be joining a well-established planetary data analysis group that is actively involved in observational astronomy and planetary missions (e.g., the recently completed Cassini mission at Saturn). In this project, the student will analyse existing VLT/MUSE Jupiter observations and participate in proposing and reducing further measurements, gaining excellent experience in telescopic observational data analysis and gaining a deep insight into the atmospheric circulation and cloud formation on these worlds. The spectral cubes will be analysed with our sophisticated multiple-scattering radiative transfer model, NEMESIS. Given the timeline, it is possible that the student may also analyse JWST observations.

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