Jets from Young Stars and Their Impact on Star Formation

使用世界上最先进的射电望远镜进行观测，将帮助科学家了解像太阳这样的恒星是如何形成的。恒星形成时，来自星际空间的气体和尘埃会盘旋到一个中心物体上（很像水从浴缸的排水管流下）。然而，与此同时，这些新生恒星将超音速气体喷射回太空。天文学家现在才开始了解这个复杂的过程。该提案的首席研究员（PI）将使用先进的计算机模型来展示这一过程的实际工作原理，特别关注非常靠近中央年轻恒星的区域。他将使用两个大型射电天线阵列的观测结果来测试他的模型，一个在智利，另一个在夏威夷。PI将与一名研究生一起完成大部分工作。PI和学生们还共同致力于扩大耶鲁大学莱特纳家庭天文台和天文馆的公众项目和展览。图像和视频将用于教育公众，让他们了解大型射电阵列的天文观测如何帮助我们更好地了解像太阳这样的恒星是如何形成的。本文描述了利用高分辨率ALMA和SMA观测对原恒星周围环境（10-1000 AU尺度）的研究。目标是解决关于大规模组装过程和原恒星反馈对恒星形成的影响的关键问题。分子线观测将与辐射传输模型相结合，以确定原恒星周围气体的速度、温度和密度结构如何演变，以及流入和流出过程如何随时间变化。这些模型不仅包括机械反馈，还包括辐射反馈，以及在原恒星附近的激波中产生的紫外线光子的加热。这些结果将使我们了解分子云核心的恒星形成效率和恒星质量的起源。一名研究生将参与这项为期三年的研究工作。

Observations using some of the world's most modern radio telescopes will be used to help scientists understand how stars like our sun are formed. Stars form as gas and dust from interstellar space spirals down onto a central object (much like water flowing down a bath tub drain). However, at the same time, these baby stars drive supersonic jets of gas back out into space. Astronomers are only now beginning to understand this complex process. The Principal Investigator (PI) on this proposal will use advanced computer models to show how this process actually works, focusing in particular on regions very close to the central young star. He will test his models using observations from two large arrays of radio dishes, one in Chile, the other in Hawaii. The PI will do much of this work with a graduate student. Together, the PI and student also aim to expand programs and exhibitions for the public at Yale's Leitner Family Observatory and Planetarium. Images and videos will be used to educate the public about how astronomical observations from large radio arrays help us better understand how stars, like our Sun, are created.This proposal describes a study of the environment surrounding protostars (on 10-1000 AU scales) using high resolution ALMA and SMA observations. The goal is to address key questions about the mass-assembling process and the impact of protostellar feedback on star formation. Molecular line observations will be combined with radiative transfer models to determine how the velocity, temperature, and density structure of the gas surrounding protostars evolves and how the infall and outflow processes change over time. The models include mechanical feedback but also radiative feedback and heating from ultraviolet photons produced in shocks close to the protostar. The results will inform our understanding of star formation efficiency in molecular cloud cores and the origin of stellar masses. A graduate student will be involved in this research effort throughout its 3-year duration.