Stellar astrophysics II

• advanced knowledge of astrophysical concepts in description of stellar structure and astrophysical plasma

Enrollment into the current study year. Completed exam in Stellar Astrophysics I.
For the exchange students, meeting of the course prerequisites will be checked by the Study committee of the school.

Basic assumptions in stellar description, timescales, hydrostatic equilibrium, virial theorem, energy production, transport and conservation.

roperties of matter in stars: equations of state (ideal gas, photon gas, mixture of ideal and photon gases, denegerate matter, matter at high temperatures). Atomic levels, Saha equation, ionization degree, depression of continuum.

ates of nuclear reactions in stars.

• Mechanisms of energy transfer in stars:
  radiation, convection and condition for convection, conduction.

adiative energy transfer:
ss absorption coefficient, Rosseland mean, dependence of the opacity on temperature, Thomson scattering, Kramers' law.

Radiative transfer equation and examples of solution. Optical depth, transport in local thermodynamical equilibrium approximation, formation and properties of spectral lines in stellar atmospheres, broadening of spectral lines due to temperature, uncertainty principle, collisions; equivalent width of lines, curve of growth.
quations of stellar structure and boundary conditions: Euler and Lagrange description; local thermodynamical equilibrium; local and global energy conservation; effective temperature, examples of stellar structure equations solutions: UV plane, homologous models, polytropic models and degenerate matter, mass limits. Stability of stars.

• Stellar evolution after the main sequence: Hayashi line, helium ignition, final states: white dwarfs, neutron stars and black holes.

• Stellar rotation: von Zeipel theorem and influence of rotation on a star;

asics of plasma astrophysics: basic description and equations: the continuity equation, equation of motion, energy equation, induction equation.

lfven theorem on frozen flux, Sunspots and Solar magnetic field.

The students will learn:

• description of stellar structure and processes
• plasma astrophysics

• A.R. Choudhuri: Astrophysics for Physicists, Cambridge University Press 2010. E-version
• D. Prialnik: An Introduction to the Theory of Stellar Structure and Evolution, Cambridge University Press 2010. Catalogue E-version
• R. Kippenhahn, A. Weigert, A. Weiss: Stellar Structure and Evolution, Spinger, 2012. E-version

Homework, written tests, writen exam al exam

Prof. dr. Andreja Gomboc se raziskovalno največ ukvarja s plimskim raztrganjem zvezd v bližini masivnih črnih lukenj, izbruhi sevanja gama in dogodki gravitacijskih valov. Je članica več mednarodnih kolaboracij, med njimi Gaia in Rubin LSST. Doslej je objavila več kot 130 znanstvenih člankov v mednarodnih referiranih revijah. Je avtorica učbenika Osnove astronomije izdane pri založbi UNG leta 2025.

Prof. Dr. Andreja Gomboc main filed of research are tidal distruption of stars by massive black holes, gamma-ray bursts, and gravitational wave events. She is a member of seveal international astrophysical collaborations, e.g. Gaia, Rubin LSST. She has published more than 130 scientific papers in international refereed journals. She is the author of the textbook Astronomy Fundamentals, published in 2025 by UNG Press.

Izbrane objave /selected publications:

1. G. Ghirlanda et al (incl. A. Gomboc). HERMES: Gamma-ray burst and gravitational wave counterpart hunter. Astronomy & Astrophysics, 689, id.A175, 2024.

2. Gaia Collaboration (incl. A. Gomboc). Discovery of a dormant 33 solar-mass black hole in pre- release Gaia astrometry. Astronomy & Astrophysics, 686, id.L2, 2024.

3. T. Jankovič, C. Bonnerot, A. Gomboc. Spin-induced offset stream self-crossing shocks in tidal disruption events. Monthly Notices of the Royal Astronomical Society, 529, 1, 2024.

4. K. Bučar Bricman, S. Van Velzen, M. Nicholl, A. Gomboc. Rubin Observatory's Survey Strategy Performance for Tidal Disruption Events. The Astrophysical Journal Supplement Series, 268, 1, 2023.

5. T. Jankovič, A. Gomboc. The Mass Fallback Rate of the Debris in Relativistic Stellar Tidal Disruption Events. The Astrophysical Journal, 946, 1, 2023.

6. K.M. Hambleton et al (incl. A. Gomboc). Rubin Observatory LSST Transients and Variable Stars Roadmap. Publications of the Astronomical Society of the Pacific, 135, 1052, 2023.
7. K. Bricman, A. Gomboc. The Prospects of Observing Tidal Disruption Events with the Large Synoptic Survey Telescope. The Astrophysical Journal, 890, 1, 2020.
8. S. Covino et al. (incl. A. Gomboc). The unpolarized macronova associated with the gravitational wave event GW 170817. Nature Astronomy, 1: 791-794, 2017.