Course Number: 92023

Course Title: Astrophysics

The course covers both semesters: 2 lectures/week (2 hrs. each)

Lecturer: F. Reale (Associate Prof.)

Prerequisites:

All the courses of the first two years, Astronomy, Structure of matter,

Quantum Mechanics.

Contents:

radiative transfer and stellar atmospheres, detailed studies of the

solar chromosphere and corona, optically thin astrophysical sources,

plasma physics.

Syllabus:

Fundamental of Electromagnetism, radiative transfer, black body

spectrum.

Semi-classical theory of line absorption, Rayleigh-Jeans and Planck

formulations, quantum theory of line absorption, line shapes and line

broadening.

Radiative transfer in stellar atmospheres, source function, growth

curve, convective energy transport in a stellar atmosphere,

Schuster-Schwarzschild model, Milne-Eddington model.

Continuous absorption coefficient: contribution from the neutral and

negatively ionized hydrogen, from negative helium and from the heavier

elements.

Models of stellar photospheres: temperature distribution and

hydrostatic conditions, geometrical depth scale, computation of the

spectrum; effects of the temperature, of the pressure and of the

chemical abundance.

The line absorption coefficient: natural absorption, pressure

broadening, thermal broadening, microturbulence and other broadening

mechanisms, combining absorption coefficients.

Behaviour of spectral lines: behaviour of the line strength, effects of

temperature, pressure and element abundance.

Stellar chemical analysis: scaling laws, curves of growth,

differential analysis and derivation of the abundances.

Primordial elements abundance in the solar system, elements abundance

in stars and nebulae, non-equilibrium conditions.

Solar Chromosphere, small scale and large scale structures, role of

magnetic fields, dynamics of chromosphere.

Solar corona, coronal structuring in closed magnetic loops and open

magnetic structures, scaling laws, diagnostics of coronal temperature

and density, flares.

Optically thin astrophysical X-ray sources, their spectroscopy and

diagnostics.

Fundamentals of plasma physics. Klimontovisch and Vlasov equations,

orbit theory, waves in a plasma, MHD.

Recommended texts:

- G.B. Rybicki e A. P. Lightman, Radiative Processes in Astrophysics ,

New York 1979 (Wiley).

- David F. Gray, The Observation and Analysis of Stellar Photospheres,

New York 1992 (Cambridge University Press)

- C.R. Cowley, The Theory of Stellar Spectra , New York 1970 (Gordon

and Breach).

- A. Dalgarno e D. Layzer (eds.), Spectroscopy of Astrophysical

Plasmas , Cambridge 1987 (Cambridge University Press).

- F.F. Chen, Introduction to Plasma Physics and Controlled Fusion (Vol. 1,

Plasma Physics), New York 1984 (Plenum Press).

- Pallavicini, R., "Spectroscopic Diagnostics of Astrophysical Plasmas"

in

Plasma Astrophysics, C. Chiuderi and G. Einaudi eds., 1996 Springer Verlag

Assessment is by oral examination about the subjects of the course and

about a specific detailed problem assigned to the student at the end of

the course.