A.Y. 2019/2020
Overall hours
Learning objectives
The goal of this course is to provide the students with a general
overview of stellar physics. Starting from the fundamental properties of
stars as inferred from observation (photometry, spectroscopy, parallax,
mass measurements in binary systems), the features of physical stellar
models are introduced. These include the equations of stellar
equilibrium, energy production, stellar evolution. Along the path, some
of the fundamental physical quantities and concepts of astrophysics are
introduced, which will be a basis for the course Astronomy II and for
other courses in the astrophysics curriculum.
Expected learning outcomes
Students at the end of the course are expected to reach the following
1. to correctly use basic quantities and concepts, such as luminosity
and magnitude (relative and absolute), surface brightness, flux density,
effective temperature, luminosity radius, etc.
2. to describe the main properties of a stellar spectrum, continuous
radiation and absorption lines
3. to calculate relative velocities of astrophysical sources from
Doppler effect measurements, and to evaluate the effects of temperature
and pressure from the shape of absorption line profiles
4. to be able to discuss the main properties of the Sun, its structure,
cycle, magnetic activity, the characteristics of the photosphere,
chromosphere, corona
5. to gain familiarity with the mechanisms of nuclear energy production
in stars, including the information of solar interior from
helioseismology and neutrino physics
6. to gain familiarity with the equations of stellar equilibrium, af the
mechanisms of radiative and convective energy transfer in the interior
of stars
7. to be able to discuss stellar evolution for stars of different mass
ranges, including their final stages
8. to be able to discuss the properties of degenerate gas, the nature of
white dwarfs and neutron stars, the conditions for the formation of a
stellar black hole
9. to be able to calculate astronomical distances from observations of
stellar properties, including measurements of trigonometric parallax,
spectroscopic parallax, measurement of Cepheid variables, Supernovae Type Ia
Course syllabus and organization

Single session

Lesson period
First semester
Course syllabus
1) Fundamental properties of stars - Continuum radiation from stars. Brightness. Electromagnetic spectrum. Planck's law. Color indexes. Distance and absolute magnitude. Spectral lines and spectral classes. Origin of spectral lines. Hertzsprung-Russell diagram. Main sequence. Doppler effect. Binaries with circular orbits. Masses and sizes of stars. The Sun as a typical star. Internal structure of the Sun. Photosphere, chromosphere, corona. Solar activity.
2) Stellar structure - Source of stellar energy. Nuclear astrophysics: nucleosynthesis in equilibrium conditions. Proton-proton chain. CNO cycle. The Sun as a main sequence star.
3) Stellar evolution - Evolution of stars of solar mass. Beyond the main sequence. Giant stars. Cepheid variables. Planetary nebulae. The final stages of massive stars. Supernovae and SNe remnants.
4) Telescopes and astronomical instrumentation - Optical telescopes. Effective area, angular resolution. Seeing. Refractive and reflective telescopes. Ground based observatories. Hiubble space telescope. Infrared and sub-mm astronomy. Observations in the microwaves. Radioastronomy. Ground based observations and space missions. Observations in the UV. X-ray astronomy. Gamma-ray astronomy. Space telescopes for high energy observations.
5) The Milky Way - Stellar clusters. Globular and open clusters. Dynamics of clusters. HR diagrm for stellar clusters. Stellar populations. Introduction to the interstellar medium.
6) Extragalactic astronomy and Cosmology - Normal galaxies, classification. Star formation in galaxies. Spiral structure. Dark matter in galaxies.
7) Solar System and extrasolar planets - The Earth-Moon system- Origin and structure of planet Earth. Plate tectonics. Basics of Earth's atmosphere physics. Magnetosphere. Tides. The Moon, origin and structure. Solar system planets. Terrestrial and giant planets: surface, atmosphere, internal structure. Rings and satellites. Minor bodies. Origin of the solar system. Astrobiology. Chemistry of the primordial Earth. Stability of terrestrial environment and biological evolution. Potential for life elsewhere in the solar system and beyond.
These subjects are taken from Unit 1 and 2 of the course of Astronomy for the Degree in Physics.
Prerequisites for admission
Familiarity with the notions of mathematics and physics as offered by the Bachelor Degree of Natural Sciences. Interest in multidisciplinary contents, training in scientific discussion.
Teaching methods
Lectures are carried out using also multimedia material. Exemplifications of the contents, typically taken from contemporary scientific literature, are offered during lectures. The students are regularly solicited to take part in the discussion and to interact during lectures. We also propose an optional activity of field astronomical observation at the telescopes at INAF Brera-Merate.
Teaching Resources
A few reference textbooks are suggested (Marc L. Kutner, "Astronomy: a Physical Perspective", Cambridge Univesity Press, 2003; D. Maoz, "Astrophysics in a nutshell", 2008, Princeton University Press). The lectures utilize slides, which are regularly made available to the students on the course web page, and multimedia material. For some topics, review papers available online are indicated to the students.
Assessment methods and Criteria
The exam consists of a discussion on the topics covered by the course. Starting from a plot, an example or a simple exercise the student will be required to discuss theoretical contents. The final evaluation will take into account the level of critical understanding reached by the student.
FIS/05 - ASTRONOMY AND ASTROPHYSICS - University credits: 6
Lessons: 48 hours
Ask the teacher
Laboratorio di Strumentazione Spaziale, Department of physics (via Celoria 16, Milano)