Stellar Astrophysics in the Era of Gaia, Spectroscopic, and Asteroseismic Surveys

31 May - 25 June 2021

Maria Bergemann, Daniel Huber, Saskia Hekker, Amanda Karakas, Rolf Kudritzki

This MIAPP program will focus on theoretical and observational challenges in the broad area of Stellar Astrophysics.

Over the past decade, the astronomical community has invested enormous efforts to exploit major ground- and space-based facilities. The advent of stellar spectroscopic surveys, such as Gaia-ESO, GALAH, and APOGEE, paved the way for the large-scale analysis of the chemical compositions of millions of stars. Time-domain photometry missions, such as CoRoT, Kepler, and TESS, allowed detailed characterization of the interior structure of stars by asteroseismic techniques. Interferometric observations with VLTI and CHARA provide new information about stellar diameters and the circumstellar environment. With Gaia, stellar luminosities and radii of millions of stars can now be derived. The upcoming facilities and surveys, such as SDSS-V, 4MOST, PLATO, LSST, and JWST will revolutionize the field with unique time-domain information, and an increase in sample size by orders of magnitude.

The main challenge is to combine the large amount of high-quality observations into a general coherent picture of the fundamental parameters of stars and to position them within the context of theoretical stellar structure and stellar evolution. The MIAPP program will assess the state-of-the-art in the field and develop concepts for new strategies and models to move towards the percent-level precision and accuracy in diagnostics of stellar structure.

The program will bring together specialists in stellar astrophysics, theorists as well as observers, who work on related and complementary aspects of stellar physics. In particular, we will focus on the following questions:

  1. What are the key unknowns in our understanding of stellar structure and evolution?
  2. How do we combine the information from various types of surveys (asteroseismic, spectroscopic, interferometric, astrometric) to learn about stellar physics?
  3. How accurately and precisely can we determine fundamental stellar parameters?
  4. Can we reduce our dependence on calibrations to observations, to make stellar models more predictive?
  5. What new theoretical approaches could be used in conjunction with the data to advance stellar modelling?
  6. What are the key discrete observational tests of theory?

This program will open numerous new opportunities for synergies and collaboration, from the knowledge transfer on radiative transfer and hydrodynamics (stellar atmospheres, stellar evolution models), to developing new methods of pattern recognition in observations (spectroscopy, asteroseismology), identifying the ways to implement complex physical processes, such as multi-scale dynamics, into the models, and relating these developments to other astrophysical disciplines, where stellar parameters and stellar models are used.