Sumários

Stellar evolution in Star cluster + Star-formation (part I)

12 Maio 2020, 13:00 • Israel Matute

Role of Stellar clusters in Stellar Evolution

  • Information provided by Stellar clusters

  • Isochrones

  • Fitting isochrones to HR diagrams: Jupyter-notebook exercise.

Star Formation

  • Where star formation occurs: The ISM

  • Properties of the ISM

    • Composition of the ISM

    • Physical states in the ISM

  • The equilibrium state of the densest clumps (Bok globules)

Variable stars and Binary systems (II)

11 Maio 2020, 13:00 • Israel Matute

Lecture dedicated to the description of binary systems.

Binary systems - types of binary systems.
Equipotential surfaces and the Roche lobes.
The evolutionary path of binary systems: cataclysmic, novas/recurrent-novas, and type-I supernovae.
A detailed description of type-Ia supernovae and their use in cosmology for distance measurements.

Questions/problems on computational assignment + initial exercises of Series #5

7 Maio 2020, 15:00 • Israel Matute

A large fraction of this lab time was dedicated to solving questions and computational problems that the students had found while running the stellar structure code STASTAR for the computational assignment. Several masses for stars were tested as examples of how to look for stable solutions. Further insight is given on the kind of plots and representations to use for the assignment report.


During the final part of this lab time, we started to look into the initial questions posted In the exercises series #5. 

Variable stars and binary evolution

7 Maio 2020, 14:00 • Israel Matute

This lecture looks into special cases of evolution and not-so-rare systems.


Description and details of stars that vary their luminosity with time.
Classification of such stars through the light curves, i.e. 
Cepheid stars and their Period-Luminosity relation.
The use of Cepheids as standard candles for distance measurements.
Physical mechanisms for stellar variability: Pulsation and the Eddington thermodynamic engine.
The kappa-mechanism for star pulsation.
Example of regular (Mira) and semi-regular (Betelguese) variable stars.


Degenerate remnants of stars (part II)

5 Maio 2020, 13:00 • Israel Matute

Conditions for degeneracy: Fermi energy

Comparison of degeneracy conditions for a solar-type star like the Sun and for Sirius B.
The mass-volume relation for white dwarf
The mass limit supported by degenerate gas pressure: the Chandrasekhar limit
The cooling timescale of white dwarfs

Neutron stars: when the core exceeds the Chandrasekhar limit
The mass-volume relation for neutron stars
Description of the conditions in the interior of these stars. Large uncertainties due to lack of conditions to reproduce physical conditions at the interior of such dense stars.
High rotating neutron stars: Pulsars

Black-holes: when neutron stars exceed the Chandrasekhar limit for neutron degeneracy pressure.