SPACE PHYSICS

This course intends to present to students the state of the art of observational, theoretical and experimental research about some of the most relevant processes of interaction among the solid and gasseous components among themselves and with the radiation field in the Interstellar Medium; special attention will be focused on the processes of formation and destruction of some molecular species that play a fundamental role into helping the gravitational collapse and hence regulating the formation rate of stars.

Special attention will be also devoted to laboratory simulations of processes taking place in the Interstellar medium, that in recent years allowed to put on a firm galilean ground the whole matter.

A detailed fluid dynamic description of the generation and propagation of shock waves in the Interstellar and Circumstellar Medium will be tackled on a quantitative ground to investigate the interaction between stars and the Interstellar medium.

1 – The Interstellar Medium (ISM)

Observational evidences of the presence of the ISM – Distribution of the ISM in the Galaxy – Multiphase strutture of the ISM – Dense and molecular clouds – Diffuse clouds – Intercloud Medium – Coronal gas – Cooling and heating processes in clouds.

2 – Interstellar Gas

Observational evidences – Composition – Atomic and molecular components – The most important species: H, H₂, H₂O, CO, CO₂ ecc. – Polyciclic Aromatic Hydrocarbons (PAHs) – Fullerens.

3 – Interstellar Dust

Observational evidences of the presence of interstellar dust grains – Abundance of dust – Composition – Size distribution of interstellar grains – Morphology – Icy mantles on grains - Importance of the presence of dust – Formation sites of interstellar grains.

4 – Molecule formation in the gas phase

Taxonomy of gas phase reactions according to their rate constants - Dissociation processes induced by UV photons in the diffuse medium and by energetic particles in the dense one – Numerical modeling of the chemical enrichment of clouds.

5 – Gas-dust interaction

Physisorption and chemisorption - Mobility of adsorbed species - Dust grains as catalysts – Mechanisms of heterogeneous catalysis - Experimental techniques of investigation of reactions catalyzed on grain surfaces - Main results.

6 – Interaction between cosmic rays and interstellar dust grains

Short description of cosmic rays – Propagation inside the Heliosphere – Interaction of fas ions with solids – Experimental techniques for the investigation of physico-chemical processes induced by cosmic rays.

7 – Interaction among stars and the ISM

Stroemgren spheres – Generation and propagation of shock waves in the ISM. A case study.

1. A.G.G.M. Tielens: The Physics and Chemistry of the Interstellar Medium, Cambridge Acad Press (2005)

2. D.C.B. Whittet: Dust in the Galactic Environment, 2nd ed., IOP, London (2002)

3. V. Pirronello, J. Krelowski, G. Manicò (eds): Solid State Astrochemistry, Kluwer, Dordrecht (2003)