Sumários

Star-formation (V)

21 Maio 2020, 14:00 • Israel Matute

Star Formation & Evolution - A large view

This last theoretical lecture touched on topics that link all the concepts described during the course with a wider view on the evolution of galaxies and the universe itself. This is a brief list of topics discussed:

  • Understanding galaxy spectra.

  • Stellar population and the initial mass function (IMF). 

  • Star Formation Rate (SFR) and its efficiency along with the history of the Universe.

  • SFR and the accretion into SuperMassive Black Holes (SMBHs).

  • Stellar Population Models (SPMs): a comprehensive description of mass assembly on galaxies, their stellar ages, and metallicities through detailed modeling of their optical/near-IR spectra and multiwavelength properties.

Star-formation (IV)

19 Maio 2020, 13:00 • Israel Matute

Angular Momentum & Protostellar emission:

  • Pre main-sequence evolution for the most massive and the smallest (brown dwarf) stars. 
  • Pre main-sequence taxonomy: T Tauri stars, Herbig Ae/Be, and disk emission.
  • The effect of Rotation. Conservation fo the angular momentum:

    • Disk formation & emission. Proto-planetary disks;

    • Jet emission & bipolar fluxes;

    • Examples: HH30, IRAS 04302+2247,  HK Tau/c, Orion 114-426.

  • Protostellar continuum emission

    • Classes of Young Stellar Objects;

    • The evolution of the continuum emission.

Star-formation (III)

18 Maio 2020, 13:00 • Israel Matute

From the Hayashi line to the ZAMS

  • Protostar formation when adiabatic core reached. The role of the opacity generated by H-.

  • The Hayashi track. Protostar evolution into the Hayashi line and the constraints imposed by convection:

    • Marks a completely convective limit (stability/No-stability)

  • Detailed follow-up of the processes that drive the 1 M☉ star evolution from the Hayashi line to the Zero-Age-Main-Sequence (ZAMS)

Discussion and solving of Exercises Series #5.

14 Maio 2020, 15:00 • Israel Matute

This lab time was dedicated to continuing the discussion on the first set of questions in the 5th series of exercises: “Things to think about”. These questions helped the students get a better insight into concepts discussed during lectures while providing further insight into the physics that drive them.


Star-formation (II)

14 Maio 2020, 14:00 • Israel Matute

Gravitational collapse of dense cores.

  • Gravitational collapse of cores - Virial Theorem

    • Jeans Mass/Radius equations and examples based on actual conditions for the collapsing clouds.

    • Bonnor-Ebert Mass

  • Fragmentation during collapse

    • Conditions for max. Fragmentation: Isothermal vs Adiabatic and discussion on what other important physical processes could be important but initially neglected, e.g. magnetic fields and rotation.

    • Discussed that more detailed models set a limit for max fragmentation on  0.01 M⊙.