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PYU33A03 Stellar and Galactic Structure

Michaelmas Term – 30 lectures/tutorials – 5 credits

This module provides an in-depth view on the physics that govern how stars and galaxies evolve. The universe became a fundamentally different place when the first stars formed about 150 million years after the Big Bang. From this point on, new chemical elements were synthesized, photons were produced on massive scales by nuclear reactions in stars, and galaxies were assembled through collapse and mergers. We will cover the observational quantities that we can measure such as temperature, luminosity, and metallicity. We will derive the fundamental theory that explain the observations of stars and galaxies throughout the history of the universe.

Part I: Stellar Astrophysics
Part II: Galactic and Extragalactic Astrophysics

Learning Outcomes
On successful completion of this module, students should be able to:
· Describe the major stages in the evolution of a star from birth to death
· Explain the Hertzsprung-Russell diagram for stellar populations of different ages
· Manipulate the basic equations for stellar structure and evolution in order to derive elementary results for global stellar properties and timescales
· Derive the basic equations governing the dynamics of the Sun and nearby stars with respect to the Galaxy
· Explain the distribution of stars, gas and dust within galaxies, and describe the properties of the various types of galaxies found in the Universe
· Discuss the evidence for massive black holes at the centres of active galaxies and for Dark Matter in the Universe on a variety of scales

Part I: Stellar Astrophysics
Properties of radiation and their applications to stellar interiors: specific intensity, flux, luminosity, and effective temperature; Stellar opacities: sources, optical depth, Rosseland mean opacity; Stellar structure: hydrostatic equilibrium, mass conservation, equation of state, energy sources and transport; Stellar models: equations of stellar structure and boundary conditions; Stellar evolution: initial mass function, main sequence, hydrogen burning, advanced stages, low mass stellar evolution, high mass stellar evolution; Remnants and Compact Objects: white dwarfs, neutron stars, black holes; Physics of stars in binary systems.

Part II: Galactic and Extragalactic Astrophysics
The basic constituents of galaxies; the properties and dynamics of the Milky Way; the Local Group of galaxies; galaxy types, modern classification, and fundamental properties ; stellar distribution and dynamics in spiral and elliptical galaxies; methods for measuring distances, masses, and luminosities of galaxies, and their limitations; the Virial Theorem applied to galaxies; star-formation histories and chemical evolution of galaxies; dark matter on galactic and extragalactic scales; galaxy clusters; active galaxies and supermassive black holes




Continuous Assessment in Stellar Astrophysics


Continuous Assessment in Galactic and Extragalactic Astrophysics