Star formation and molecular cloud structure at low metallicity

在像银河系这样的星系中，新的恒星不断地形成。星系开始时主要由氢原子组成，但恒星内部的核聚变会产生更重的原子。这些原子，如碳和氧，是由垂死的恒星喷出的，改变了恒星之间空间的化学成分。这个过程再次开始，形成新的巨大气体云，这些气体云变得足够冷和稠密，以至于原子结合在一起形成分子。新的分子云开始形成下一代的恒星。这些来自第一代恒星的重原子被分子云包围，吸收来自附近恒星的紫外线。这种吸收有助于保护脆弱的分子不被分解，从而再次改变云的化学性质。研究人员试图通过比较银河系与附近矮不规则星系的化学过程来了解这些化学过程。与银河系这样的螺旋星系相比，这些小星系的重原子要少得多。结果，这些矮星系分子云的外部部分被破坏，留下比螺旋星系更小的分子云。研究者正在研究微小矮星系中分子云的结构。研究人员试图了解由于分子丰度的差异对矮星系中恒星形成的影响。恒星正在矮星系中形成，研究人员计划进行更多的观测，以了解这些星系中气体的性质。这些问题的答案将帮助我们了解早期宇宙中恒星的形成，在重原子形成之前。这位研究者领导着洛厄尔天文台美洲原住民天文学拓展项目，该项目将天文学家与纳瓦霍和霍皮民族的4 -8年级教师配对。该项目每三年举办一次教师研讨会，向教师介绍课堂活动，提高他们对天文学的理解。合作者创建了文化响应课程，使土著学生将自己视为科学家，并解决了部落和教育标准。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。

New stars are continuously forming in galaxies like the Milky Way. Galaxies begin as mostly hydrogen atoms, but nuclear fusion inside of stars produces heavier atoms. These atoms, like carbon and oxygen, are spewed out by dying stars, changing the chemistry of the space between the stars. The process begins again with the formation of new giant clouds of gas, which become cold and dense enough that atoms bond together to form molecules. New molecular clouds begin to form the next generations of stars. These heavy atoms from the first generation of stars are caught up in a molecular cloud and absorb ultraviolet light from nearby stars. The absorption helps to protect the fragile molecules from being broken apart, again changing the chemistry of the clouds. The investigator seeks to understand these chemical processes by comparison of the Milky Way to the chemistry in nearby dwarf irregular galaxies. These small galaxies have much less of the heavy atoms compared to spiral galaxies like the Milky Way. As a result, the outer parts of molecular clouds in those dwarf galaxies are destroyed, leaving smaller molecular clouds than are found in spiral galaxies. The investigator is studying the structure of molecular clouds in tiny dwarf galaxies. The investigator seeks to understand the consequences on star formation in dwarf galaxies due to the differences in molecular abundance. Stars are forming in dwarf galaxies, and the investigator plans additional observations to understand the nature of the gas in these galaxies. The answers to these questions will help us to understand star formation in the early universe, before heavy atoms were formed. The investigator leads the Lowell Observatory Native American Astronomy Outreach Program, which pairs astronomers with 4th-8th grade teachers in the Navajo and Hopi Nations. The program holds tri-annual teacher workshops that introduce teachers to classroom activities enhancing their understanding of astronomy. The collaborators create culturally responsive curriculum that enables Native students to see themselves as scientists and addresses the tribal and educational standards.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.