Professor Bill Chaplin

Bill's research interests are focused on the study of the Sun and other Sun-like stars, with a particular interest in using asteroseismology to characterize newly discovered exoplanet systems with Sun-like hosts. He has leadership positions in Kepler/K2, TESS and PLATO, and is the principal-investigator on the BiSON project.

Dr Guy R. Davies

Guy is a lecturer at the University of Birmingham and he is interested in researching the nature of the Sun, stars that are a little bit like the Sun, and stars that are much more evolved than the Sun. He is interested in the evolution of stars and how the rotation, magnetism, and mass loss of stars evolves with time.  Guy uses observations of the oscillations of the Sun and the stars to learn about stellar evolution and to characterise the fundamental properties of stars.  The use of oscillations can be particularly valuable when studying stars that host extrasolar planets.  Guy is also involved with the daily operations of the BiSON project.

Professor Yvonne Elsworth FRS

Yvonne has previously been the head of the group and is now part-time and fully engaged with research. There are two primary strands to her research. The first is in helioseismology - the study of the interior of the Sun through the sound waves that propagate there. Associated with this is a strong interest in the instrumentation that enables the observations i.e., BiSON. The second strand is measurement of asteroseismic parameters and their use in the determination of the internal structure of red giants stars as key tracers of the structure of the galaxy. Yvonne is a Fellow of the Royal Society and currently vice-president of the Royal Astronomical Society.

In January 2020 Yvonne received the RAS Gold Medal. This is the highest award in the Society's gift, awarded for her achievements in helioseismology.

Dr Annelies Mortier

After spending time studying and doing research in Gent (BE), Leiden (NL), Porto (PT), St Andrews (UK), and Cambridge (UK), Annelies is now an Assistant Professor at the University of Birmingham. Annelies is an observational astronomer playing with stars and exoplanets. She works on the detection and characterisation of (small) exoplanets, currently mostly using the HARPS-N spectrograph and preparing to use the HARPS3 spectrograph. She studies the link between planetary and stellar parameters, focusing mainly on chemical composition. Annelies also studies the Sun-as-a-star to understand the processes behind stellar variability and their effect on radial velocity.

Professor Amaury Triaud - Head of Group

A regular visitor to observatories in the Atacama desert, Amaury is the discoverer of over one hundred exoplanets. His observations focus on planetary systems that are different compared to our own, either by the type of planets that compose those systems, by their architectures, or because of the type of star(s) they orbit. As part of the SPECULOOS collaboration, he now searches for planets the same size and the same temperature as the Earth and aims to find out if life emerged elsewhere in the Universe. The first such examples were found in the TRAPPIST-1 system.

In January 2020 Amaury received the Fowler award from the Royal Astronomical Society, and was named a finalist in the Blavatnik awards. Both recognise the important work done by young researchers across all of the physical sciences and engineering.

Postdoctoral researchers

Dr Rachel Howe

Rachel's main interests are the changes in the properties of solar oscillation modes in response to solar activity and the changes in the Sun's interior rotation over the solar cycle - in particular the pattern of migrating faster and slower flows known as the torsional oscillation. She is also interested in helioseismology using different observables such as the UV observations from SDO/AIA.

Dr Martin Nielsen

Martin works on preparations for the ESA PLATO Mission, in particular the design, development and testing of "peak bagging" algorithms for extracting estimates of individual oscillation frequencies from PLATO data. This work involves use of machine-learning algorithms and hierarchical Bayesian models. Martin also works on analysing data from NASA's TESS spacecraft, and studying the rotation of stars similar to the Sun.

Dr Lalitha Sairam

Lalitha has worked extensively on both ground-based and space-based observations to understand the underlying physics of stellar atmospheres and their effects on orbiting exoplanets. Her focus areas include understanding stellar magnetic activity at the bottom of the main sequence. She also works on employing the computationally tractable probabilistic data analysis methods such as Gaussian processes to mitigate the effects of stellar activity on the planetary radial velocity signal. As part of the Solar & Stellar Physics group, Lalitha will be developing an analytical method to accurately measure the radial velocity of the double-line binaries.

Dr Daniel Sebastian

Daniel’s fascination with the field of exoplanets motivated him to focus on the planetary population of different types of stars. Planets in different environments offer perfect laboratories to answer the gripping questions of how planet form, how stable are they and, even, the composition of their atmospheres. On the upper mass-end, using radial velocity techniques, his research focusses on close-in massive companions and planets of intermediate-mass stars within the CoRoT space mission. On the lower mass end, Daniel is focussed of the transit detection of Earth sized planets orbiting ultracool stars. Here, he has been involved in the target selection of the SPECULOOS project, a photometric survey, which aims to understand the population and parameters of close-in terrestrial planets within a 40pc range. Circumbinary planets are a rare laboratory to study the formation mechanisms of Exoplanets. As part of the BEBOP project, he joined the search for these exotic worlds orbiting binary stars. Furthermore, he is well-versed in observational techniques and robotic astronomy. Here, he is quite involved in the technical development of the SPECULOOS survey, comprised of a global network of 1m robotic telescopes.

Technical Staff

Dr Steven J. Hale CSci

Steven leads the operation and development of the international Birmingham Solar Oscillations Network (BiSON), a global network of automated robotic solar telescopes funded by the Science and Technology Facilities Council.  His research interests are instrumentation and electronics, and high-resolution optical spectroscopy techniques.

PhD Students

Thomas Baycroft

Tom's research focusses on searching for and characterising circumbinary planets.  To do this he uses radial velocity measurements obtained using the HARPS instrument in la Silla (Chile) and the SOPHIE instrument at the Observatoire d'Haute Provence (France), among others. Few such planets have been discovered to date, despite a large proportion of stars being in binary or multiple systems.  Discovering more of them is important to better understand the difference in formation and evolution of planets around binary stars compared to single stars.

Tom's other interests include the SPECULOOS project, searching for habitable planets around cool stars, and his Masters research, which was in modelling dust and gas in debris discs.

Yasmin Davis

Yasmin’s research is focussed on establishing well defined parameters for M dwarf stars by applying methods used for exoplanet detection to binary star systems. M dwarf stars could be excellent candidates for finding planets within the habitable zone, due to their lower temperatures compared to solar type stars. This results in a habitable zone that is closer to the star, and therefore a transiting planet would produce a deeper signal in a light curve.

By having a better understanding of low-mass stars we hope to be able to detect exoplanets around them and accurately characterise them. This is achieved using radial velocity data, from instruments such as the HARPS spectrograph in Chile, alongside transit photometry.

Georgina Dransfield

Georgina is predominantly interested in exoplanets and how we can group them together. Classification of objects like stars, planets and moons allow us to make predictions about how they were formed and what they are made of. Georgina is looking at where exoplanets fit in with populations of well-studied objects in order to learn more about the atmospheres of exoplanets. This is particularly interesting, as better techniques to determine whether or not a planet has, for example, water in its atmosphere will allow us to spot potential candidates for sustaining life.

Alix Violet Freckelton

Alix started work in the group as an undergraduate, developing a pipeline to determine stellar parameters from their spectra for her Masters’ project. She now uses spectra from HARPS, SOPHIE, HERMES, and FIES to study both stellar parameters and radial velocities for bright dwarf stars. Alix also likes to work with TESS light curves - particularly those of eclipsing binaries. Timing variations of the eclipses in such a system can indicate the presence of a third body - be this a third star, or even better, an orbiting planet. All this work is assisted by her cat Bruce, who loves sitting on laptops.

Emily Hatt

Emily previously worked in the group as an undergraduate investigating asteroseismic modelling with individual mode frequencies. Continuing in asteroseismology, she has moved her focus to data analysis, where she is currently working on automating methods of detecting stellar oscillations from spectra. She will use these to determine the current asteroseismic yield of the TESS mission, which she will compare to the initial predictions made. This is important to either reinforce or review the methods used to predict detectability for future missions. It will also lead into the second line of questioning, the impact of magnetic activity on stellar oscillations, which was purposefully neglected from the initial predictions. Exploiting the high quality asteroseismic data from the Kepler and TESS missions, she will use the interaction of the oscillations and activity to study the near surface magnetic flux in a host of F, G and K-type stars. Here she hopes to constrain the behaviour of such as a function of various stellar properties.

Alexander Lyttle

Alex is using machine learning with stellar models to speed up the inference of fundamental stellar parameters. Using asteroseismology from NASA’s Kepler and TESS missions with astrometry from ESA’s Gaia mission, he hopes to develop robust statistical methods to determine how helium abundance varies in the Milky Way. His other research interests include probing the physics of stellar interiors using asteroseismology and contributing to open source software in astronomy. One such software is the python package PBjam which, for example, he uses to measure the oscillation modes of exoplanet host stars and subgiants.

Walter Van Rossem

Walter's primary research interest lies in stellar modelling and asteroseismology. Combining these two he is looking for asteroseismic signatures for stellar mergers using MESA and GYRE for stars a bit more massive than the Sun.

Owen Scutt

Owen’s Master’s research focussed on characterising dark matter substructure in gravitational lens galaxies using convolutional neural networks. For his PhD project, Owen is currently working with the University’s asteroseismology group, using machine learning for rapid inference of stellar model parameters from grids of stellar models. In the future, he aims to work with the exoplanets group to apply this machine learning interpolation method to grids of exoplanet atmospheres. He hopes this will create finer grids of exoplanet atmosphere models which take into account the 3D shape of exoplanets, aiding in the creation of continuous exoplanet spectra from observational data, potentially from the James Webb Space Telescope. Outside of his research, Owen regularly visits the peak district for walks and runs (and to visit his three cats!).

Emma Willett

Emma Started working in the group during her Master’s project, during which she investigated the helium abundance in red clump stars. She is now working on asterochronometry – a project to measure the ages of stars more precisely and accurately using data from asteroseismology and other sources. These ages are important for many fields within astrophysics. For example, we can use them for galactic archaeology to understand the formation and evolution of the Milky Way and to study systems of planets around other stars.

Artist in Collaboration

Caroline Devine

Administrative Staff

Louise Barden

Louise works as the secretarial support for the Solar & Stellar Physics research group. She started at the University in September 2018, moving to the role after 9 years working as an office administrator at a primary school in Worcestershire.

Louise helps the team organise conferences, meetings as well as taking on all the daily office tasks to enable the team to concentrate on their research activities, such as booking travel etc. In addition, Louise often instigates whole group social events such as quizzes and group meals and often brings yummy baked items into the office (for eating at coffee break time!)

Outside work, Louise lives out in the Worcestershire sticks with her hubby, two children grown up (but, yet to leave home), and a lively, ball obsessed, (nearly) 15-year-old rescued spaniel cross called Jake. She likes going for early morning walks with Jake, gardening, baking and, also enjoys looking at the sky and stars at night – as she said in her interview for the role, “there are no streetlights where I live!”