Queen's University Belfast Astronomy Observation and Theory Consolidated Grant 2023-2026

The proposed research at QUB covers a wide range of fundamentally important astrophysics, from studying the evolution and often violent deaths of stars and exotic objects, to analysing the atmospheres of newly discovered alien worlds. Our team has internationally renowned observational and theoretical expertise that lies at the forefront of the proposed activities.

Supernovae create the heavy elements we see in the entire visible Universe. While stars evolve over millions or billions of years, a supernova explosion happens in seconds and the glowing remnant lasts for years. We aim to understand how these explosions happen and how they create the neutron stars, pulsars and black holes in our galaxy. In 2017 a breakthrough discovery was made when the first electromagnetic counterpart to a gravitational wave source was found. Termed a 'kilonova', this was the result of a pair of merging neutron stars and the optical and infrared light arose from the radioactive decay of heavy elements (which we call r-process elements). These elements are heavier than iron and such neutron star mergers may be responsible for all these heavy elements. Our projects will find more of these, and the combination of gravitational waves and electromagnetic signals opens up a new window on the Universe. The thermonuclear supernovae that are used as cosmic yardsticks and led to the Nobel Prize winning discovery of dark energy come from white dwarfs, the incredibly dense remnants of a dead star with a mass greater than that of the sun but the size of the earth. To understand how they explode, we will model their spectra with the most sophisticated 3 dimensional computer models that currently exist.

The heavy elements that are created in supernovae are essential to form planetary systems, and since the Nobel prize-winning discovery of the first planet orbiting a normal star (an exoplanet) we now know of 1000s of alien worlds. Despite their astounding diversity, from hot-Jupiters to super-Earths, we have yet to find a planet that resembles Earth in terms of its size and distance from its parent star due to the tiny signals they produce. With ultra-high precision instruments coming online in the last few years the barrier to success is no longer limited by technology, but by our lack of understanding of the surface activity of stars like our Sun. Our project will aim to understand and mitigate this effect, and carefully test methods to extract the tiny signals we expect with an eye on the future prize of detecting an earth twin. Running parallel to this, we also wish to improve our ability to probe the atmospheres of exoplanets. Our group has a heritage in developing new and increasingly sensitive atmospheric characterisation tools, and we shall apply a technique called Doppler Tomography that demonstrates particular promise. Honing such techniques will allow us to probe smaller planets and search for more subtle signals from previously unseen chemical species.

A critical part of astrophysics is pulling together our detailed knowledge of physics that we can measure on earth to what we can see (through electromagnetic radiation) in the distant Universe. This will be done through computer calculations of model atoms, and laboratory experiments. Our computer codes calculate how electrons are excited in atoms and ensures that astrophysical models identify the elements that cause the spectral lines in supernovae, supermassive black holes, galaxy spectra and stars. Now that we have detected a kilonova we must do the same calculations for the heaviest elements. Meanwhile, novel experiments using powerful lasers can replicate some of the most extreme conditions in the Universe in a controllable and repeatable fashion - something rarely achievable in astronomical observations. Such investigations are key to unlocking a clearer understanding of several exotic astrophysical phenomena, from jets emanating from the cores of active galaxies to Gamma Ray Bursts.