Description du projet
Qu’arrive-t-il aux planètes lorsque leurs étoiles hôtes manquent de carburant?
Les étoiles sont incroyablement massives et la majeure partie de cette masse est constituée d’hydrogène, dont la fusion produit de l’hélium et génère de l’énergie qui est libérée sous forme de lumière et de chaleur. Les naines blanches sont des étoiles qui ont «brûlé» tout leur hydrogène. Elles continuent de briller, car elles sont chaudes, mais le sort des planètes de leur système n’est pas clair. En 2021, des astronomes ont découvert une géante gazeuse en orbite autour d’une naine blanche dans notre galaxie. Le projet WDPlanets, financé par l’UE, pistera d’autres naines blanches hébergeant des restes de systèmes planétaires en utilisant les observations astrométriques, spectroscopiques et photométriques de certains des observatoires les plus avancés au monde.
Objectif
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.
Champ scientifique
Programme(s)
Thème(s)
Régime de financement
ERC-ADG - Advanced GrantInstitution d’accueil
CV4 8UW COVENTRY
Royaume-Uni