Descrizione del progetto
Cosa succede ai pianeti quando le loro stelle ospiti finiscono il carburante?
Le stelle sono incredibilmente massicce e la maggior parte di quella massa è idrogeno, la cui fusione produce elio e genera energia che viene rilasciata come luce e calore. Le nane bianche sono stelle che hanno «bruciato» tutto il loro idrogeno. Continuano a brillare perché sono molto calde, ma il destino dei loro pianeti non è chiaro. Nel 2021 gli astronomi hanno scoperto un gigante gassoso che orbita attorno a una nana bianca nella nostra galassia. Il progetto WDPlanets, finanziato dall’UE, è sulle tracce di altre nane bianche che ospitano resti di sistemi planetari, utilizzando le osservazioni astrometriche, spettroscopiche e fotometriche di alcuni degli osservatori più avanzati del mondo.
Obiettivo
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.
Campo scientifico
Programma(i)
Argomento(i)
Meccanismo di finanziamento
ERC-ADG - Advanced GrantIstituzione ospitante
CV4 8UW COVENTRY
Regno Unito