InterCat seminar

Speaker:
Jose Angel Martin-Gago, Instituto de Ciencia de Materiales de Madrid-CSIC, Spain

Title: 
Unveiling the Nature of the carbonaceous species formed in the circumstellar environments of evolved stars by vacuum technology

Abstract:
Evolved starsare a factory of chemical complexity, gas and dust, which contribute to thebuilding blocks of planets and life. However, the dust and gas formation processes remainpoorly understood. Different laboratory techniques are used to produce analogs of cosmicdust being based the majority of them on uncontrolled combustion or plasma decompositionof molecular precursors in conditions far removed from those in star photospheres.We have designed and built an unprecedented ultra-high vacuum machine, called STARDUST,combining gas aggregation sources with in-situ advanced surface science characterizationtechniques (as STM, XPS or IRAS) and mass spectroscopy [1]. We show that astrochemicalproblems can be successfully addressed and understood using surface sciencemethodologies.This combination opens the door to the investigation and modelling of processes related todust particles and its interaction with the gas in different regions of the universe.Different model systems will be presented. In the first analogues of cosmic dust are analysedto conclude that evolved stars do not form aromatics or fullerenes but aliphatic material madeup by bottom-up coalescence[2]. In the second example we propose a new route for theformation of polycyclic aromatic hydrocarbons produced by etching of graphene on the SiCgrains in a top-down process[3].References[1] L. Martinez, Sci Rep. 8 (2018) 7250. / G Santoro, Review of Scientific Instruments 91 (2020), 124101[2] L. Martinez, Nature Astronomy, 4 (2020), 97-105 /MAccolla, The Astrophysical Journal 906 (2021),44[3] Merino P., et al. Nature Communications 5, (2014), 3054