Letters of Intent received in 2017

LoI 2019-1985
Asteroseismology for Galactic Archaeology

Date: 4 November 2019 to 8 November 2019
Location: Saint-Malo, France
Contact: Benoit Mosser (benoit.mosser@obspm.fr)
Coordinating division: Division G Stars and Stellar Physics
Co-Chairs of SOC: Sofia Feltzing (Lund Observatory)
Benoit Mosser (Observatoire de Paris)
Annie Robin (Institut Utinam, OSU Theta Franche-Comté-Bourgogne)
Victor Silva-Aguirre (Aarhus University)
Chair of LOC: Kevin Belkacem (Observatoire de Paris)

 

Topics

- The Milky Way as we know it
- Characterizing resolved stellar populations
- Asteroseismology of red giant stars
- Large scale surveys and their impact in Galactic Archaeology

 

Rationale

Low-mass stars now benefit from new insights from the thorough study of their oscillation spectra carried out by the space missions CoRoT and Kepler. Among them, red giants play a special role: they not only benefit from their bright magnitudes, so that plenty of light curves were recorded for seismology, but they also exhibit modes that directly probe their innermost regions. It is therefore possible to derive relevant estimates of their stellar masses and radii using the asteroseismic scaling relations, which complemented with the ability of distinguishing between red giants burning helium in the core and those still only burning hydrogen in a shell opens the window towards precise age determinations. The space missions CoRoT and Kepler hence permitted to unravel the structure and evolution of low-mass red giant stars; K2, following Kepler, continues this task in various Galactic fields across the ecliptic plane, as TESS will soon do for bright stars all over the sky.

Such a wealth of seismic information allows the development of a novel approach for investigating stellar populations in the Milky Way based on the detection of oscillations in thousands of red giants stars spread across the Galaxy. A key piece of this new Galactic puzzle comes from the possibility of determining precise ages of red giants stars by coupling asteroseismic information with observations from large scale spectroscopic, photometric, and astrometric surveys. The synergy between these fields will bring new light to our Galactic past by unraveling the key processes that shaped the Milky Way throughout its lifetime into what it is today.

By 2019, the CoRoT and Kepler asteroseismic data will be extended by the various surveys carried out by the K2 and TESS mission. Moreover, we shall have access to astrometric solutions and stellar parameters from the Gaia mission for all these targets. Ground-based follow-up efforts such as the Gaia-ESO survey, APOGEE, LAMOST, and GALAH have been specifically targeting red giants with asteroseismic detections and will produce the new benchmark sets of properties in stellar populations that chemo-dynamical models will use to calibrate the ingredients included in their simulations of our Galaxy. Going beyond the solar neighborhood using accurately characterized stellar samples, which are truly representative of populations across the Milky Way, will produce the next revolution in the field of galaxy formation. This synergy of information of ageing stars will undoubtedly strengthen our understanding of the physics and the evolution of red giants, and add a new dimension for dating chemodynamical investigations of the Galaxy.