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Forming cosmic dust in low- and high-mass, evolved stars

English title Forming cosmic dust in low- and high-mass, evolved stars
Applicant Cherchneff-Parrinello Isabelle
Number 149190
Funding scheme Project funding (Div. I-III)
Research institution Departement Physik Universität Basel
Institution of higher education University of Basel - BS
Main discipline Astronomy, Astrophysics and Space Sciences
Start/End 01.02.2014 - 31.01.2015
Approved amount 59'220.00
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Keywords (6)

Dust; AGB stars; Molecules; Early universe; Supergiants; Clusters

Lay Summary (French)

Lead
Les étoiles géantes rouges sont caractérisées par des des zones au dessus de la surface de l'étoile denses et propices à la formation de grains de poussière. Ces étoiles sont les principaux fournisseurs en poussière des galaxies. Elles forment des grains oxygénés (silices) selon leur degré d'évolution. Malgré leur importance dans le budget de la poussière cosmique de notre univers local ou lointain, la formation des poussières oxygénées n'est pas comprise.
Lay summary

Contenu et objectifs du travail de recherche

Notre principal objectif est de contribuer à une meilleure compréhension des procédés de formation de la poussière et des molécules dans les géantes rouges oxygénées. Plus précisément, nous souhaitons (i) modéliser la zone de formation des poussières sujette au passage de chocs périodiques, (ii) identifier la composition chimique des grains formés, (iii) quantifier la masse de poussière produite par ces étoiles. Nous chercherons finalement à estimer la contribution des géantes rouges oxygénées  dans le budget de la poussière cosmique localement et dans l’univers lointain.

Contexte scientifique et social du projet de recherche

Notre travail générera des informations inédites et essentielles quant à l’étude des géantes rouges. Ces informations seront testées par des programmes d’observation avec les plus récentes infrastructures astronomiques comme l’interféromètre millimétrique ALMA. Il génèrera également des informations pour un public de non-experts sur la poussière cosmique et l’origine des molécules complexes, un sujet directement lie à l’origine de la vie dans l’univers.

 

Direct link to Lay Summary Last update: 17.01.2014

Responsible applicant and co-applicants

Employees

Collaboration

Group / person Country
Types of collaboration
Chemistry Department/University of Barcelona Spain (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Chemistry Department/University of Leeds Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Why Galaxies care of AGB stars III Talk given at a conference Dust formation in AGB stars 28.07.2014 Vienna, Austria Cherchneff-Parrinello Isabelle; Gobrecht David Leon;


Associated projects

Number Title Start Funding scheme
132616 Dust synthesis in evolved stellar winds: a local diagnostic for the identification of dust providers in the early universe 01.02.2011 Project funding (Div. I-III)
128950 CoDustMas: Cosmic Dust Grains as a Diagnostic for Massive Stars 01.09.2010 Project funding (special)
132616 Dust synthesis in evolved stellar winds: a local diagnostic for the identification of dust providers in the early universe 01.02.2011 Project funding (Div. I-III)

Abstract

This proposal aims to study the dust formation processes in the wind of low- and high-mass, evolved stars to gain knowledge on the way cosmic dust is formed and processed in our local and far universe. The proposal focuses on understanding how oxygen-rich and carbon dust is produced in these environments. The nucleation stage of dust formation is described using a novel approach based on chemical kinetic and the inclusion of dust nanoclusters. Nucleation is coupled to the dust condensation phase described by various formalisms. For carbon dust, the aims are twofold: (1) description of carbon dust formation including the synthesis of polycyclic aromatic hydrocarbons (PAHs) and grapheme in hydrogen-rich environments such as carbon stars; (2) model of the carbon dust production routes that include fullerene and carbon cages in hydrogen-poor and hot environments such as Wolf- Rayet massive binaries. The oxygen-rich dust study will focus on the formation of metal oxides (e.g., alumina Al2O3 and spinel Mg2Al2O4), silica and silicate dust in O-rich, evolved stellar environments such as Mira stars and supergiants. The broad objectives are: (1) characterize the dust chemical composition and derive dust mass yields in these objects; (2) study the wind acceleration mechanism in the dust formation zone of Mira and supergiant stars; (3) identify a population of nanoclusters that survive the nucleation and condensation of dust and may be responsible for still unidentified bands observed in these stars; and (4) assess the contribution of AGB stars and massive stars like supergiants and Wolf-Rayet stars to the dust budget of the local and far universe. These research lines are entirely new, novel, and timely as observational data of AGB and supergiant stars from the Herschel telescope are continuously released, and these stellar objects are ALMA key targets. The proposal will thus provide the astronomical community with new, crucial, and topical predictions on dust, molecules, and large clusters in these evolved stellar objects, and assess their impact on the dust budget of local and primeval galaxies. To achieve the objectives of this ambitious programme, we ask for 2 PhD student positions, equivalent to a total budget amounting to 334’800 CHF for the 3-year length of the project.The proposal is connected to the current study of dust synthesis in O-rich Mira stars (SNF project 200021_132616). The first year of one of the requested PhD positions corresponds to the 4rth year PhD extension for David Gobrecht, currently employed under the project 200021_132616.
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