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PhD projects in Planetary Science for our STFC studentships 2024 are listed below.

• Mars crustal magnetic fields: protection for exploration (Prof. Andrew Coates)
• Multidisciplinary Studies of Comets (Prof. Geraint Jones)

Mars crustal magnetic fields: protection for exploration

Primary Supervisor: Prof. Andrew Coates

The surface of Mars is a harsh environment for robotic and human exploration, with strong temperature differences (0 to 20 °C during the day and -100 to -120 °C at night), ultraviolet radiation which penetrates the thin atmosphere, and a significant radiation environment from galactic and solar energetic particle sources. Mars also has a network of crustal magnetic fields, which are evidence of a past global protective magnetic field. Since the Mars global magnetic field was lost 3.8-4 billion years ago, the atmosphere was gradually lost via solar wind scavenging. The current Mars atmosphere is dominated by CO₂, and the atmospheric pressure varies with time of day and year, but the pressure is overall less than 1% of Earth’s. Also, seasonal dust storms occur at Mars offering some protection. In this project we will study the protection provided by crustal fields, dust and clouds in the atmosphere for potential future exploration, by modelling plasma and radiation effects and comparing with data from Mars Express, Maven and Curiosity. We will also model subsurface effects, relevant for future missions including Mars sample return, Rosalind Franklin and future exploration, building on techniques used by Dartnell…Coates et al., GRL 2007, Regan, Coates et al PSJ 2023, Patel…Coates et al PSJ 2023.
As well as the suggested Mars study, a project on related atmospheric topics, such as negative ions in the vicinity of outer planet moons, would also be possible. One of the surprising discoveries with the Cassini-Huygens mission was of high mass per charge negative ions, indicative of prebiotic chemistry near Titan (Coates et al., 2007, 2009, 2010a, Wellbrock et al., 2013, 2019, Desai et al 2017a, Mihailescu et al., 2020), complemented by high mass positive ions (Haythornthwaite et al., 2021). Water clusters and other negative ions were also found in the Enceladus plume (Coates et al., 2010b), at Rhea (Teolis et al., 2010, Desai et al., 2017b), at Dione (Tokar et al., 2012, Nordheim et al., 2020), and in Saturn’s magnetosphere. Similarly, charged dust was also found in the Enceladus plume with ELS (Jones et al., 2009, Hill et al 2012). These unanticipated measurements were made with the CAPS Electron Spectrometer (ELS), designed for electrons. The measurement technique used the flyby velocity (~km/s) to separate masses of cold ionospheric ions in the spacecraft ram direction. We studied the resolution available via this technique (Nicolaou, Haythornthwaite & Coates, 2022). In addition, negative ions have been detected at comets (Chaizy et al., 1991, Cordiner et al 2013, Burch et al. 2015), and at Mars, and may be present at Venus also. This study would include further data analysis from Cassini-Huygens and other missions in preparation for JUICE reaching the Jupiter system in 2031.

Desired Knowledge and Skills

• Undergraduate/masters in physics or relevant subject
• Strong computational skills

Multidisciplinary Studies of Comets

Primary Supervisor: Prof. Geraint Jones

Comets’ icy nuclei carry invaluable information on the origins of the star systems that they belong to. By studying the gas and dust that they release, we can learn about the composition of these ancient objects, and the nature of solid grains embedded within them. There are several ways to learn about these gas and dust populations liberated from comets. We can remotely observe comets directly from Earth, using imaging and spectroscopic techniques. We can also use data from space missions, such as the upcoming Comet Interceptor, due for launch in 2029. Advances are also being made in the field of exocomets – comets that orbit other stars – with indirect observations of comets being made possible through spectroscopic and photometric observations of other stars. Finally, modelling studies are invaluable in helping us understand the remote and in situ observations that we make.
This project will employ some of the above techniques to learn more about comets within our solar system, and potentially elsewhere. Potential research topics include comet-solar wind interactions, which builds on the ground-breaking work carried out at MSSL since the 1980s through its involvement in comet missions such as Giotto and Rosetta, plus serendipitous tail crossings such as those by Solar Orbiter. Comet Interceptor will involve three spacecraft returning data along parallel paths past the nucleus, giving us a 3D view of solar wind interactions at a comet for the first time. Work is needed to predict the observations that we can expect from these probes.
Other potential topics for the PhD include the study of processes through which comets release gas and dust when heated by the Sun or other star, and the behaviour of that material after it leaves the nucleus. The behaviour of dust grains (e.g. Price et al. 2022; Afghan et al. 2023) and structure and dynamics of ion tails (e.g. Ramanjooloo & Jones 2022) tells us a great deal about the environment surrounding each comet. We may be on the verge of direct images being obtained of exocomets. It would be valuable to constrain the potential behaviour and appearance of comets around other stars, which have different masses, colours, and luminosity to our own Sun (e.g. Strøm et al. 2020).

Ramanjooloo & Jones, JGR, 2022:
Price et al., Icarus 2022:
Afghan et al., Icarus 2023:
Strøm et al. PASP 2020:

Desired Knowledge and Skills

• Undergraduate in astrophysics, planetary science, or a related field.
• Strong computational skills would be a benefit.