UNC-CH Physics and Astronomy Colloquium

João Alves, Universität Wien

“The rise of the Milky Way”

Most of what we know about star and planet formation has been obtained from spatial 2D observations of the local Galactic neighborhood (d < 1 kpc), collected over the last 70 years. During this time we have established a series of ground truths developed around a poorly understood structure called the Gould’s Belt. In this framework, we use Orion as the template for massive star formation and Taurus for low-mass star formation, but we do not know how giant molecular clouds form nor why different clouds have different star formation yields. We embrace supersonic turbulence as a fundamental pillar of the star formation process, but have not identified its source; We have organized groups of young stars as either bound clusters or associations but do not know how they disperse to build up the Galactic field. In this talk, I will report on our ongoing exploration of the Gaia data in the local neighborhood. We found a new arrangement of the dense gas that alone rules out the existence of the Gould’s Belt. We have found in the local neighborhood the tidal tails to open clusters and what is likely to be the long, stretched remnants of old clusters and associations. Although still mostly unexplored, Gaia data is beginning to radically change our view of the Local Neighborhood, and with it, our understanding of star formation and the structure of the Galactic disk.