Determining the Origin of the Types of Stars found in Galaxies

我们可见的银河系由数十亿颗恒星和大量的气体和尘埃组成。新的恒星从这些气体和尘埃中形成，而一些老恒星——但只有最大的恒星——在爆炸中死亡。当它们死亡时，它们的物质会混合到形成恒星的储层中。质量较小的恒星，如我们的太阳或更小的恒星，寿命很长，并且永远保持大部分质量。从气体到恒星再到恒星的生命周期取决于形成了多少大恒星和多少小恒星。研究者试图测试一个模型来解释观测到的恒星质量分布。这项研究将测量即将形成新恒星的气体和尘埃。ALMA对数千颗年轻恒星的观测将提供一个大样本，这是精确测量不同恒星大小的相对数量所需要的。将建立一个新的建模框架来预测这些年轻恒星在ALMA眼中的样子。这个项目建立的模型将促进我们对星系和行星系统形成环境的理解。为了进一步促进在天文学方面代表性不足的群体的教育，该项目将包括针对当地中学的外展计划。研究人员将把太阳望远镜带到这些学校，让他们体验白天的天文学。学生对科学的态度将被测量，评估这个项目在多大程度上向他们灌输了他们也能成为科学家的信心。恒星初始质量函数（IMF）是理解恒星种群和星系随时间变化的关键。该项目将测量IMF的诞生阶段，通常被称为核心质量函数（CMF），使用美国国家科学基金会的阿塔卡马大毫米/亚毫米阵列（ALMA）对整个银河系大质量恒星形成区域的观测。该项目将使原始恒星核心的可用样本增加十倍以上。更重要的是，它将对恒星质量的整个动态范围进行采样，从次太阳到目前形成的最大质量的恒星。该项目将基于现有的原恒星演化和辐射转移模型开发一个新的建模框架，将它们整合到一个连贯的工具包中，用于预测ALMA和类似望远镜的观测结果。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.