Seminarium: Mass loss of cool luminous stars: A new generation of *3D* stellar wind models

  • Datum: –15.00
  • Plats: https://uu-se.zoom.us/j/64257004440
  • Föreläsare: Bernd Freytag och Arief Ahmad
  • Kontaktperson: Sofia Ramstedt
  • Seminarium

Evolved stars play a crucial role for the cosmic matter cycle and the origin of life. Critical chemical elements, like carbon, are produced inside luminous cool giant stars, transported to the surface by turbulent gas flows, and ejected into interstellar space by massive outflows of gas and dust. The current knowledge of stellar winds is incomplete, and does not allow us to fully understand their effects on the evolution of stars, and how they enrich their surroundings with newly produced elements and cosmic dust.

Observations show evolving complex structures on the stellar surface and in the surrounding dust clouds. Such structures show up in our 3D radiation-hydrodynamics simulations of entire cool giants performed with the CO5BOLD code. The dynamics are governed by small surface granules, global convection cells, stochastically excited waves, and radial fundamental-mode pulsations. The latter are extremely important for the formation of dust and thus the driving of winds of cool giants. We will present results from the analysis of the self-consistently excited pulsations for a variety of stellar models. Later in the project, a parametrized description of the radial pulsations of the 3D models will be used as inner boundary condition for 1D DARWIN models.

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We will run with the following setup:
- The zoom meeting will open at 13.45 so that you can log on and try it out.
- Participants should mute their microphones unless they have a question.
- Questions are allowed during the talk. Just raise your hand in the zoom app.
- After the talk has finished, unmute for applause.
- If possible, keep your video on during the full seminar so that the speaker gets visual feedback while talking.
- Questions after the talk will be administered as follows; raise your hand in the app and Sofia will chair and give the word.

-Finally, after the talk and question sessions are finished, the meeting will remain open for an informal ”bring-your-own-fika” if you want to hang around and chat with your colleagues and the speaker.