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Planetary systems around white dwarfs

Project description

What happens to planets when their host stars run out of fuel?

Stars are incredibly massive, and most of that mass is hydrogen, whose fusion produces helium and generates energy that is released as light and heat. White dwarfs are stars that have ‘burned up’ all their hydrogen. They continue to shine because they are so hot, but the fate of their planets is not clear. In 2021, astronomers discovered a gas giant orbiting a white dwarf in our galaxy. The EU-funded WDPlanets project is hot on the trail of more white dwarfs hosting remnants of planetary systems, making use of the astrometric, spectroscopic and photometric observations from some of the most advanced observatories in the world.

Objective

In the 25 years since the discovery of 51 Peg b, we went from not knowing if the Solar system is a fluke of Nature to realising that it is totally normal for stars to have planets. The common fate of practically all planet hosts is that they will eventually evolve into white dwarfs, the Earth-sized embers that are the evolutionary end-points of most stars. Many of the known planets will survive the post main-sequence evolution of their host stars - in the solar system, this includes Mars, and all planetary bodies beyond it.

Firm evidence for evolved planetary systems at white dwarfs is found in the form of photospheric contamination from the accretion of planetary material, transits caused by clouds of debris, spectroscopic variability from planetesimals on ultra-short period orbits, and one volatile-rich gaseous disc formed from the evaporated atmosphere of a giant planet. These evolved planetary systems provide insight into the formation, structure, evolution, and ultimate fate of planets that are entirely complementary to, and in large parts unattainable by, the analyses of exo-planets orbiting main-sequence stars.

Within this project, we will make use of the astrometric, spectroscopic and photometric observations from Gaia, DESI, WEAVE, SDSS-V and ZTF-II to carry out an ambitious and comprehensive research program of white dwarfs hosting remnants of planetary systems. (1) We will measure the bulk abundances of at least 1000 planetesimals from the spectroscopic analysis of newly discovered white dwarfs that are strongly contaminated by the accretion of planetary material, assembling detailed statistics of the composition of planetary building blocks and/or fragments. (2) We will identify dozens of minor and major planets in close orbits around white dwarfs, and we will characterise their physical and orbital properties. The combined results of both areas of research will greatly improve our understanding of the formation, structure, and evolution of planets.

Host institution

UNIVERSITY OF WARWICK
Net EU contribution
€ 2 535 290,00
Address
KIRBY CORNER ROAD UNIVERSITY HOUSE
CV4 8UW COVENTRY
United Kingdom

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Region
West Midlands (England) West Midlands Coventry
Activity type
Higher or Secondary Education Establishments
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Total cost
€ 2 535 290,00

Beneficiaries (1)