The stellar astrophysics group studies the formation of stars and their planetary systems, the properties of stars, and how stars effect their environments.
We pursue observational programmes in the X-ray, ultraviolet, optical, infrared, mm and radio bands using ground-based (e.g. JCMT, eMerlin) and space-borne observatories (Kepler, Herschel, XMM-Newton).
By combining photometric, spectroscopic and imaging observations we unravel the interactions between the stars and their environments, and the processes within the stars themselves.
We additionally pursue theoretical and computational studies of how Sun-like stars form in collapsing clouds, and how low-mass stars, brown dwarfs and planets form in protostellar discs. Finally, we also investigate the evolution of massive stars and supernovae.
Asteroseismology is the study of oscillations and pulsations in a star using a collection of observational techniques.
These pulsations provide a unique view into the interiors of stars. Professor Donald Kurtz and Dr Daniel Holdsworth apply the techniques of Asteroseismology to see beneath the surfaces of the stars, a place Sir Arthur Eddington thought was “less accessible to scientific investigation than any other region of the Universe”.
Professor Kurtz is co-author of the fundamental textbook, Asteroseismology (Springer Publishers, 2010, 866 pages). Both Prof. Kurtz and Dr Holdsworth are members of the large international consortia, KASC (Kepler Asteroseismic Science Consortium) and TASC (TESS Asteroseismic Science Consortium).
Star formation and exoplanets
Stars form within the cores of cold, dense clouds of interstellar gas and dust. When gravity dominates over turbulent, thermal, and magnetic support, the cores of these clouds collapse to form stars.
The stellar masses range from a few times the mass of Jupiter, the largest planet in our Solar System, up to a few hundred times the mass of our Sun.
We investigate the initial conditions of star formation using observations from ground-based (e.g. JCMT, PdBI, ALMA) and space-borne observatories (e.g.Herschel), and radiative transfer modelling.
We also explore the physics of protoplanetary discs that relate to the formation of giant exoplanets, brown dwarfs and low-mass stars, and develop novel computational hydrodynamics and radiative transfer methods.
Massive stars and supernovae
Supernovae are bright, cosmic explosions which often outshine their host galaxy. Over recent years dedicated surveys have identified a variety of different supernova classifications, leading to what is now known as the “supernova zoo”.
In order to identify the star that exploded, the progenitor star, we use existing imaging from telescope archives to try and match the position of the supernova with a specific star, however this direct-detection method has not proved as effective and the source of many of these cosmic explosions is still unknown.
We can investigate the environments of supernova and massive-star, since massive stars have very short lifetimes they should not move very far from where they are born and so if they are indeed progenitors of supernova then the properties of each environment should be the same.
Also, by undertaking narrow-band imaging surveys we can build up a catalogue of evolved massive stars, thought to be the progenitor of at least 2 different supernova subtypes which can then be referred to for any future supernovae which will provide us direct confirmation of this massive star-supernova connection.