Letters of Intent received in 2019

LoI 2021-2090
GA Focus Meeting: Unsolved Problems in Red Giants and Supergiants

Topics

Internal structure and relation to evolution
Nucleosynthesis
Atmospheric and circumstellar structure
Instabilities
Feedback (mass loss)
End products (white dwarfs, neutron stars, black holes; planetary nebulae)
Interaction with stellar and planetary companions
Importance for interstellar chemistry
Diagnostics in nearby and distant galaxies
How to make progress

Rationale

The Sun will become a red giant, yet many fundamental aspects of the structure and evolution of red giants are unknown – convection, mixing, pulsation, mass loss, and the way these processes are affected by rotation and magnetic fields, to name but a few. Many of these problems are shared by more massive red supergiants, with implications for their demise as supernovae. Poor understanding of the timescales of their evolution and their feedback (mechanical, chemical) has consequences also for galactic evolution models and when using either resolved populations of red giants and supergiants or the integrated light of galaxies to infer knowledge of the star formation history.

The IAU Working Group on Red Giants and Supergiants has set itself two objectives: [1] to identify the most important Physics problems pertaining to the evolution of red giants and supergiants and their interaction with their surroundings, and [2] to make suggestions how to make progress in these areas. Before finalising their report, we wish to dedicate a Focus Meeting at the 2021 General Assembly to red giants and supergiants and how gaps in our understanding affect other fields of Astrophysics. We want to take advantage of the forum that the General Assembly provides, to draw in colleagues from other disciplines who would otherwise not have attended a specialist meeting of this kind.

The format we propose for our meeting is as follows: on the first half day we will have contributed talks and a poster viewing session with all of the poster presenters present; on the second half day we will have a few review talks – this session will then end with a panel discussion with the panel composed of the reviewers and the discussion moderated by one of the scientific organising committee members. We will endeavour to obtain a balanced mix of seniority, gender and geographical origin among the presenters and session chairs.

We will post a report on arXiv shortly after the General Assembly and solicit further input from the community before we finalise the Working Group report for the IAU.

We expect to then select a topic we have a reasonable chance of success to solve, to focus on and coordinate in the following triennium. In doing so we also wish to seek out and support new talent who have the promise to make key contributions to this objective.