General Astrophysics 1

A.Y. 2024/2025
6
Max ECTS
42
Overall hours
SSD
FIS/05
Language
Italian
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 General Astrophysics 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
capabilities:
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
Single course

This course can be attended as a single course.

Course syllabus and organization

Single session

Lesson period
First semester
Course syllabus
1) Fundamental properties of stars
- Continuous radiation from stars. Luminosity. Electromagnetic spectrum. Planck's law. Color indices. Distances and absolute magnitudes.
- Spectral lines in stars. Spectral types. Formation of spectral lines. Hertzsprung-Russell diagram.
- Binary stars and stellar masses. Doppler effect in circular orbits. Elliptical orbits. Stellar masses and radii.
- The Sun as a typical star. Fundamental structure. Elements of radiative transfer theory. Photosphere, Chromosphere, Corona. Solar activity.

2) Stellar energy and structure
- Energy in stars. Sources of stellar energy. Nuclear astrophysics: formation of elements. Proton-proton chain. Carbon cycle. Heavy elements.
- Stellar structure and models. Hydrostatic equilibrium. Equations of stellar equilibrium. Radiative and convective energy transport. Cosmic abundances. Stellar models. Solar model. Helioseismology. Solar neutrinos.

3) Stellar evolution
- Evolution of solar-mass stars. Beyond the main sequence. Giants. Cepheid variables. Planetary nebulae. Degenerate gas. White dwarfs.
- The final stage of massive stars. Supernovae and SN remnants. Neutron stars. Pulsars. Schwarzschild radius, black holes.
- Gravitational waves: multi-messenger astronomy.
- Evolution of compact binaries. Compact systems with a white dwarf. Binary systems with neutron stars, with a black hole. Examples of compact systems.
- The distance scale: From trigonometric parallax to SN Ia.
Prerequisites for admission
It is assumed that the "Laurea Triennale" in Physics has been completed, or an equivalent background.
Teaching methods
Lectures on theory with examples and exercises. Attendance is highly recommended.
Teaching Resources
The teaching materials used (slides, articles) are made available to students on the Ariel site after each lesson. Several textbooks are recommended for the different parts of the course.
Assessment methods and Criteria
The examination is an oral interview. A critical understanding of the topics covered is required, including the ability to discuss situations not directly presented in class within a guided dialogue.
FIS/05 - ASTRONOMY AND ASTROPHYSICS - University credits: 6
Lessons: 42 hours
Educational website(s)
Professor(s)
Reception:
Ask the teacher
Laboratorio di Strumentazione Spaziale, Department of physics (via Celoria 16, Milano)