Stellar Substructure in the Milky Way across Time
May 3 - 7, 2027
ESO Santiago, Chile
Conference Rationale and Topics:
Stars typically do not form in isolation but in clusters out of the collapsing gas cores within a giant molecular cloud. Most clusters are quickly disrupted by a combination of galactic tides, passing massive objects, and the density fluctuations produced, for example, by spiral arms. On a larger scale, galaxies may accrete stars and clusters from other systems. All these processes result is a rich array of stellar substructure across many different scales, ranging from star-forming complexes like those in the Sco-Cen association, to dynamically disrupted star clusters in the Galactic disk, bulge, and halo, to tidal streams from accreted galaxies, to the still bound open clusters, globular clusters and dwarf galaxies around the Milky Way.
While decades of research has focused primarily on bound systems due to their observability, the introduction of precision astrometry from the Gaia space mission has allowed for a quantum leap in the study of stellar populations and the dynamic history of the Galaxy. Critically, ground-based spectroscopic surveys such as Gaia-ESO, SDSS, LAMOST, etc., provide the necessary complementary data for understanding these structures: radial velocities that complete the six-dimensional phase space information of these stars, and detailed elemental abundances to determine their chemical consistency. Upcoming surveys such as 4MOST, SDSS-V, WEAVE, and MOONS will only keep increasing the database available.
These data have allowed different research groups from around the world to approach stellar substructure with a new lens, making remarkable discoveries along the way, such as the existence of tidal tails and extra-tidal stars around previously known star clusters, the recognition that previously detected open clusters have a common origin, the discovery of apparently large numbers of stream-like groups of stars of common origins in the Galactic disk, or the identification of the remnants of accretion and merger events experienced by the Milky Way throughout its history, and that these themselves brought in star clusters.
While research groups tend to focus on one type of substructure, the data and analysis tools tend to be similar. This conference is to connect research groups working on different aspects of stellar substructure, with the goal of spreading different analysis techniques and tools, as well as to bring together theorists and observers working on the formation and evolution of stellar substructure of all scales in the Milky Way.
Key topics of the conference:
- Birth, evolution, and disruption of stellar substructures of various scales
- Observations of Milky Way stellar substructure
- Chemical and dynamical analyses of Milky Way stellar substructures and populations
- Dating of stellar populations
- Assembly of the Milky Way through its components (bulge, disks and halo)
- Halo assembly: halo stars, globular clusters, accreted satellites, nearby dwarf galaxies
- Bulge stellar substructures: field and globular cluster populations
- Dwarf Galaxies in the Local Group
- Extra-galactic stellar substructure
- Cosmological Perspective
- Current and future surveys
E-mail:mw-substructure2027@eso.org
The conference will take place at ESO Chile, Alonso de Cordova 3107, Vitacura, Santiago.
