Unravelling the local structure of the Galaxy from young stellar clusters
For more than a century astronomers used the Gould’s Belt model, an expanding ring composed of gas, dust and young stars, to explain the distribution of the most prominent star-forming regions in the Solar neighbourhood. The recent discovery of a wave-shaped gaseous structure, namely the Radcliffe Wave, that extends by more than 2 kpc and encompasses most of the molecular clouds complexes in the Gould’s Belt calls for a revision of the local structure and history of star formation of the Galaxy. Young stellar clusters are the primary laboratories to investigate star and planet formation, thus ideal tracers of galaxy formation and evolution.
Figure 1: 3D representation of the Radcliffe Wave. Blue symbols denote the major molecular cloud complexes of the Solar neighbourhood and red symbols indicate the ones that form the Radcliffe Wave. The Gould’s Belt model is illustrated with the green solid line around the position of the Sun (orange symbol). This figure was extracted from this webpage (see also Alves et al. 2020).
The DYSC project aims to conduct a systematic survey of young clusters in the Galaxy with the ultimate goal of constructing the most complete 7D picture of the Solar neighbourhood. The DYSC project will: (1) deliver a definitive census of the stellar (and substellar) population of young stars that form the Radcliffe Wave and the Local Arm, and potentially discover new stellar groups, (2) investigate the structure, dynamics, evolution and history of star formation of individual young clusters, and (3) connect their properties (spatial distribution, velocity field and age) at a galactic scale.
The final data release of the Gaia space mission combined with the next generation of photometric and spectroscopic surveys (e.g. LSST, SDSS, 2MASS, AllWISE, S-PLUS, Spitzer, 4MOST, WEAVE and others) will constitute the most valuable dataset to study young clusters and re-visit the local cosmography of YSOs with unprecedented accuracy and completeness. The proposed research methodology uses novel and well-proven machine learning methods to fully exploit these precious datasets, extract information and facilitate new discoveries with an interdisciplinary approach. We will:
(i) Measure: distances, radial velocities, spectral types and other atmospheric parameters of young stars and brown dwarfs with unprecedented precision from our own observations using ground-based cutting-edge facilities in a multi-wavelength approach (optical, infrared and radio) to complement and characterize the stellar (and substellar) population in young clusters beyond the sensitivity limit and sky coverage of the upcoming large-scale astronomical surveys.
(ii) Discover: numerous cluster members of known clusters over the entire mass range and potentially new stellar groups that are just awaiting discovery. A complete census of the stellar content, combined with 3D space motions and age estimates will reveal the local structure of the Galaxy and provide clues on its formation process.
(iii) Explain: how star formation propagates in structured clusters, because the formation of stars in one subgroup might induce or affect star formation in the other subgroups. The properties of the star-forming regions targeted in this project will be connected at a galactic scale to provide a complete picture of the Radcliffe Wave and Local Arm, the end of long quest that intrigued astronomers for more than a century to describe the local structure of the Galaxy based on the Gould’s Belt model.