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The five-year project has received €3million in funding.

ERC-funded project to explore the origin of diversity in star and planetary systems

One of the University of Exeter’s most distinguished astrophysics researchers has received a significant funding boost from the European Research Council (ERC), it has been announced.

Professor Stefan Kraus, an Associate Professor in Astrophysics, has received a five-year grant from the respected research council through its Consolidator Grants funding scheme.

The award will see Professor Kraus lead an international team to explore the origin of diversity in star and planetary systems. The five-year project has received €3million in funding.

Most stars do not exist alone but are orbited by planets or stellar-mass companions. One of the big open questions is how such systems form and what causes the diversity that is observed in their orbital characteristics.

An intriguing finding has been the discovery of planets orbiting their stars on very close-in orbits that are tilted with respect to the stellar rotation axis. These planets cannot have formed at their observed location, but must have been born further away from the star and then been transported onto the tilted, close-in orbits afterwards. Similarly, also many star-star systems are much too close to have formed in situ.

In the new project, the team lead by Professor Kraus will study the orbital configuration of hundreds of star-star and star-planet systems and apply a novel approach that allows them to measure simultaneously the properties of the stars, their orbits, and the alignment between the orbital axis and the stellar rotation axis.

“We should be able to find out how these systems typically look like at the time of formation and what dynamical interactions happen afterwards,”said Professor Kraus. “Intriguingly, we can study both star-star and star-planet systems with our method and learn what mechanisms are common between star and planet formation, and how they differ.”

To enable these breakthroughs, the team will build an interferometric instrument, named BIFROST, that combines the light from telescopes spread out more than hundred metres apart. This will enable exquisite precision, while, at the same time, enable measurements at unprecedented high spectral resolution.

“Combining the extreme precision achievable with interferometry and high spectral resolution is the key for this project,” said Professor Kraus, “but it will enable also many other innovative application in the future, ranging from studies on the gas around active galactic nuclei to characterisation of exoplanet atmospheres.”

“I am delighted to have the opportunity to take on this ambitious project and to work at the cross section between astrophysics research and cutting-edge technology. It will be exciting to take on this challenge and to work with experts spread over the whole globe and with two of the world’s leading observatories.”

The project will involve observatories both on the northern and southern hemisphere. BIFROST will be installed at the European Southern Observatory’s Very Large Telescope Interferometer facility that observes the southern sky above Chile. In parallel, the team will use Georgia State University’s CHARA array in California and an instrument that has been built as part of a collaboration between the University of Exeter and the University of Michigan.

Date: 9 December 2020

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