Sumários

Degenerate remnants of stars (part I)

4 Maio 2020, 13:00 • Israel Matute

End stages of stars include cores composed of degenerate matter.

Eq. of state for a degenerate gas:

  • electron degenerate pressure due to Pauli’s exclusion principle.

  • Polytrope models for the relativistic and non-relativistic cases.

Properties and classification of white dwarfs (WD).
The particular case of Sirius B.

Introduction and discussion of due reports (grade weight 30%)

30 Abril 2020, 15:00 • Israel Matute

These lecture hours were used to introduce and assign to each student the reports to present before the end of the semester (May 30th), namely:

  • Computational exercise using the STATSTAR code. Testing on students anaconda-python

  • Essay on a specific topic for each student. Description of length & detail of it.

Details of such reports can be found in the moodle page of the course.


Stellar Evolution (III)

30 Abril 2020, 14:00 • Israel Matute

Evolution of intermediate-mass stars (~5 M☉)

  • Helium and hydrogen burning in shells

  • (small) Helium flashes in shells

  • White dwarf and Planetary Nebulae phase


Evolution of the most massive stars

  • Similar evolution to intermediate stars but at a much higher temporal pace.

  • Most massive stars end up with an iron core and continuous layers burning the less heavy elements: Silicon, Oxygen, Neon, carbon, He, and H.

  • Depending on whether the final core mass reaches the Chandrasekhar limit different end scenarios are described: neutron star, Type-II supernova or black-holes.

  • These stars lose a large fraction of their mass before the end-stage. Large enrichment of ISM. Examples described in class.

Stellar evolution (II)

28 Abril 2020, 13:00 • Israel Matute

  Evolution of low-mass stars (~1 M☉)

  • Formation of a degenerate Helium nucleus (ashes) and the Helium flash

  • Stable burning of Helium into Carbon and Oxygen

  • Helium and hydrogen burning in shells

  • (Small) Helium flashes in shells

  • White dwarf and Planetary Nebulae phase

Evolution of intermediate-mass stars (~5 M☉) (part I)

  • No degenerate Helium nuclei and therefore no Helium flash

  • Stable burning of Helium into Carbon and Oxygen

Stellar Evolution (I)

27 Abril 2020, 13:00 • Israel Matute

Evolving the equations of stellar structure with time. The factors that drive stellar evolution:

  • Why low, intermediate and high-mass stars have different evolution

  • Stellar evolution in the HR diagram

  • Examples of evolutionary tracks at all masses

  • Examples of changing conditions in the interiors of the stars with time