ASTROPHYSICS

Academic Year 2019/2020 - 3° Year
Teaching Staff: Valerio PIRRONELLO
Credit Value: 6
Scientific field: FIS/05 - Astronomy and astrophysics
Taught classes: 35 hours
Exercise: 15 hours
Term / Semester:

Learning Objectives

This course is devoted to give a fairly deep panoramic view of the phenomena occurring in our Universe.

Particular attention will be given to the description of the physical mechanisms that explain the occurrence of such phenomena.

Due to the intrinsic interdisciplinary nature of Astrophysics, when necessary, some concepts will be introduced in heuristic way; such consepts will be treated in depth subsequently in other courses.

The approach used during the course will be both observalional and theoretical.


Course Structure

The structure of the course consists in lectures addressed in the classroom.

It is programmed to perform one or more visits of the students to the Station the Stellar Stations of the Catania Astrophysical Observatory.


Detailed Course Content

1 – Introduction

Metodology of scientific investigation in Astrophysics – Distance ladder and units – Instrumentation – Astronomical coordinates.

 

2 – The stars

Fundamental quantities - Magnitude systems – Spectral classes – The Hertzprung-Russell diagram.

– Stellar Atmospheres

Radiation transport – Temperature versus depth – Line formation – Boltzmann and Saha equations* – Einstein's coefficients – Mechanisms of line widening – Abundance analysis.

– Internal Structure

Equations of the internal structure of stars – Mass-Luminosity relation – Nuclear Fusion – Energy transport – Schwarzschild's criterion for convection.

– Stellar Evolution

Pre- and post-sequence stellar evolution – Pulsating stars – Planetary nebulae, novae and supernovae – Degenerate Fermi-gas* - White dwarfs, neutron stars and black holes.

 

3 – The Sun: a main sequence star

Atmosphere: photosphere, cromosphere, corona – Convection zone – Differential rotation – Magnetic Fields – Alfvèn's theorem* - Solar activity (sunspots, facolae, prominences, flares) - The neutrino problem.

 

4 – The interstellar medium

Interstellar clouds – Gas and dust – Chemistry in the gas phase and on the surface of dust grains – The Virial theorem* - Jeans criterion for gravitational collapse and star formation.

 

5 – Our Galaxy

Morfology and dynamics – Globular and open clusters – Stellar populations – The galactic nucleus – Dark matter – Cosmic rays.

 

6 – External galaxies

Hubble's morphological classification – Physical properties and formation processes of elliptical and disk galaxies – Cluster and supercluster of galaxies – Quasars and the other Active Galactic Nuclei (AGN).

 

7 – Cosmology

Observational evidences: Hubble's Law of the espanding Universe, the Cosmic Background – Cosmologic principle - Newtonian Cosmology - Friedmann's equation - Fluid equation – Inflation and primordial fluctuations – Radiation dominated and matter dominated Universe – Cosmological models - Dark matter and dark energy - The cosmological constant - Thermal history of the Universe.

 

N.B.: The detailed quantitative description of subjects marked with * may be omitted.


Textbook Information

G.B. Rybicki & A.P. Lightman: Radiative processes in Astrophysics, Wiley-VCH, New York (2004)

H. Karttunen et al.: Fundamental Astronomy, 5th ed, Springer Verlag, Berlin (2007)

B.W. Carroll & D.A. Ostlie: An Introduction to Modern Astrophysics 2nd ed, Cambridge University Press, Cambridge (2007)