The Origin of Massive Stars (ORMAS)

High-mass stars, although less common than Sun-like stars, have a profound impact on their galaxies. These stars end their lives in supernova explosions, creating heavy elements necessary for life, creating turbulence, and even causing large-scale movements known as galactic fountains. The ORMAS project team will investigate two critical questions: How do high-mass stars form? and What determines their mass? ORMAS will use advanced supercomputer simulations to explore supernova-induced turbulence, which might compress interstellar gas enough to form these stars. ORMAS also aims to reduce the environmental impact of computational science by developing energy-efficient computing strategies and promoting carbon-neutral data centers through outreach and education. The goal of the ORMAS project is to achieve a comprehensive understanding of the origin of massive stars and to derive a general model of their mass function. Because stellar luminosity, chemical yields, and mechanical feedbacks are non-linear functions of stellar mass, massive stars have a disproportional impact on galaxy evolution. The growth of a massive star is a problem involving turbulent mass transport through a wide range of dynamically coupled scales. ORMAS will take advantage of recent advances in task-based asynchronous computing (the new DISPATCH code) to address this problem with computational models covering 9 orders of magnitude in spatial scales, from 0.1 AU to 250 pc, simulating the formation and evolution of realistic stellar clusters, including stellar outflows and photo-ionization regions, under a self-consistent, large-scale turbulent driving by supernovae. Through a detailed analysis of the interactions between the stellar feedback mechanisms and the turbulent mass transport during the growth of a massive star, ORMAS will identify the basic ingredients for a new model of the stellar mass function. ORMAS's legacy will also include large catalogs of synthetic observations of star-forming regions and young stellar clusters with up to a million stars. 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.