Heavy ions and ices for astrophysics

Séminaire IPAG de Philippe Boduch (CIMAP), jeudi 6 juillet 2017 à 11h00, IPAG seminar room

Since 2008, a CIMAP-GANIL team has studied irradiation of ice of astrophysical interest with swift heavy ions. These ices are mainly composed of simple molecules such as H2O, CO, CO2, NH3 ... Ices are ubiquitous in space. They are present on comets, satellites of certain planets (Jovian moons for example) and on the grains the dense clouds in ISM. These ices can be irradiated in space by UV photons, stellar winds or cosmic rays. Proton and UV irradiations have been the subject of numerous studies. With heavy ions, only a few studies have been carried out at low energy. It seemed therefore important to simulate in the laboratory the interactions between fast heavy ions and the ice present in space in order to understand the role of cosmic rays in the evolution of these ices. These ions deposit locally a very large amount of energy. They can then generate unobservable effects with lighter particles like UV photons or protons. In this framework, I will present the study of simple ice and mixtures at 15 K irradiated by heavy ions produced at GANIL facilties (Grand Accélérateur National d’Ions Lourds, Caen, France). The effects of irradiation are analyzed in situ by photon spectroscopy (infrared (FTIR) and UV-Visible domain). The results presented at this seminar will deal with the effects induced on the structure of the ice, the chemical modifications and the role of the implantation. Outlooks will also be discussed, notably on the use of a novel ultra-vacuum device IGLIAS financed by the ANR as well as work on more complex molecules (Heterocyclic Aromatic Molecules (HAM), for example).