Stellar winds from nearby AGB stars with ALMA

  • Date: –15:00
  • Location: Ångströmlaboratoriet, Lägerhyddsvägen 1 Hjorter's room (Å73101)
  • Lecturer: Miora Andriantsaralaza and Sofia Ramstedt
  • Organiser: Division of Astronomy and Space Physics, Department of Physics and Astronomy
  • Contact person: Sofia Ramstedt
  • Seminarium

4 month seminar.

Winds from evolved stars are of fundamental importance for modern astrophysics as they are the means of replenishing the Universe with newly formed elements and dust. The most reliable wind parameters are derived from observations of CO line emission in combination with detailed radiative transfer modelling. These measurements are used as constraints for radiation hydrodynamics wind models, e.g. DARWIN. However, the uncertainties related to the measured values are too large to guide further improvements of the wind models and therefore need to be reduced. One issue we can address observationally is the poorly constrained size of the CO envelopes. In the DEATHSTAR project, the CO envelopes of close to 200 stars are spatially resolved with interferometry observations with ALMA and PdB/NOEMA. Another source of uncertainty is the validity of the assumption of spherical symmetry used in both theoretical models to study wind mechanisms, and in radiative transfer models used to interpret observations. With the tools we have developed for 3D analysis (of arbitrary geometries and kinematics), we can now quantify the impact this assumption has on the measured parameters for different reasonable deviations from isotropy. In this seminar, we will present current results from the DEATHSTAR project and the plan for Mioras PhD project within the DEATHSTAR collaboration.