Determining the Origin of the Types of Stars found in Galaxies

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Our visible Galaxy consists of billions of stars and vast amounts of gas, and dust. New stars form from this gas and dust, and some old stars - but only the biggest - die in explosions. When they die, their matter gets mixed back into the star-forming reservoir. The less-massive stars, those like our Sun and smaller, live a very long time and keep most of their mass forever. The lifecycle from gas to stars and back depends on how many big and how many small stars are formed. The investigator seeks to test a model to explain the observed distribution of masses of stars. This investigation will measure the gas and dust that is just about to form new stars. ALMA observations of thousands of young stars will provide a large sample, which is needed to accurately measure the relative numbers of different star sizes. A new modeling framework will be built to predict what these young stars will look like to ALMA. The models this project builds will advance our understanding of galaxies and the formation environments of planetary systems.To further advance the education of groups under-represented in astronomy, this project will involve an outreach program targeted at local middle schools. The investigators will bring solar telescopes to these schools to give a daytime astronomy experience. Students' attitudes toward science will be measured, assessing the degree to which this project instilled in them the confidence that they too can be scientists.The stellar initial mass function (IMF) is key to understanding stellar populations and galaxy changes over time. This project will measure the natal phase of the IMF, often referred to as the core mass function (CMF), using the NSF’s Atacama Large Millimeters/submillimeter Array (ALMA) observations of massive star forming regions throughout the Galaxy. The project will increase the available sample of proto-stellar cores by more than a factor of ten. More importantly, it will sample the full dynamic range of star masses, from sub-solar to the most massive that are forming at present. The project will develop a new modeling framework based on existing proto-stellar evolution and radiative transfer models, bringing them together in a coherent toolkit for predicting observables for ALMA and similar telescopes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.