Descripción del proyecto
Modelización de la formación y la composición del polvo alrededor de estrellas moribundas
En estrellas como el Sol, la última fase de su evolución es la rama asintótica de las gigantes (RAG). A medida que evolucionan a través de esta fase, su temperatura desciende tanto que el polvo empieza a condensarse en una envoltura circunestelar extendida. Hasta el momento, se sabe muy poco sobre la formación, la estructura y la composición química del polvo en los discos RAG. El proyecto financiado con fondos europeos ICEDRAGON desarrollará modelos para estudiar granos de polvo y el efecto de la composición de la fase gaseosa sobre la envoltura circunestelar. El análisis de granos de polvo debería permitir a los astrofísicos vislumbrar el funcionamiento interno violento de los últimos estertores de la envoltura circunestelar alrededor de estrellas moribundas y podría determinar cómo se acumula y procesa el material interestelar para formar planetas nuevos.
Objetivo
In their twilight years, solar-like stars in the asymptotic giant branch (AGB) phase enrich the interstellar medium (ISM) with fresh material (gas and dust) for new stars and planets. AGB stars lose their outer layers to the ISM through a stellar outflow or wind, forming an extended circumstellar envelope (CSE). The wind is thought to be dust-driven, with dust grains forming close to the star. State-of-the-art observations have revealed the composition of the inner CSE, allowing the first identification of gas-phase seeds for dust grains, and the presence of disks around AGB stars. Despite major knowledge gains over the past three decades, it is still not fully understood how dust forms, grows, and drives the stellar wind, limiting our understanding of both stellar evolution and the chemical enrichment of the ISM. Moreover, the structure and chemistry of AGB disks is unknown; if similar to protoplanetary disks, second generation planet formation may be possible therein.
Solving these puzzles requires new and sophisticated models that connect dust formation with chemistry and couple gas and dust chemistry throughout the wind and in the disk. With ‘ICE and Dust Reactions in AGB Gaseous Outflows and disks with Nucleation’ (ICEDRAGON), we will develop the first models that link the chemistry throughout the whole CSE and the first chemical model of an AGB disk. The novel models will allow us to study, for the first time, the organic refractory feedback of dust grains delivered to the ISM and the role of dust formation on the gas-phase chemistry throughout the CSE. This is necessary to deduce the physics behind the wind launching mechanism, that is encoded in the observed composition. The AGB disk model will provide the first answers to the viability of secondary planet formation. The synergy between fellow and host is ideal for this astrochemical (and fundamentally interdisciplinary) project, as it combines their respective expertise in chemical modelling.
Ámbito científico
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Régimen de financiación
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinador
LS2 9JT Leeds
Reino Unido