Theoretical Models of Binary Star and Brown Dwarf Formation

PI将提高对双星、棕矮星和亚棕矮星形成的理解。发现与主序星频率至少相等的主序星伴星，要求双星形成发生在恒星演化的主序星前阶段，即在原恒星坍缩阶段。虽然与太阳质量恒星伴星的棕矮星似乎很少，但已知的自由漂浮的棕矮星数量很大，而且还在不断增长。褐矮星双星是很常见的，一些亚褐矮星可能已经被发现，其质量范围通常与气态巨行星有关。据推测，双星是由原恒星坍缩过程中的碎片形成的，这一过程可能导致质量越来越小的原恒星的形成。该项目将通过分子云核心坍缩的详细模型，进一步发展原恒星碎裂理论。这些模型将有助于我们更好地理解双星和多星的形成，以及新形成的原恒星碎片的最小质量。这项工作的更广泛影响集中在PI通过与记者的频繁互动、公开演讲、帮助博物馆举办展览和为流行杂志撰写文章，努力向公众传达科学发现的激动人心之处。作为NSF REU项目的一部分，PI还指导本科生。

Boss, AlanAST 0305913The PI will improve the understanding of the formation of binary, brown dwarf, and sub-brown dwarf stars. The discovery of companions to pre-main sequence stars with a frequency at least equal to that of main sequence stars requires that binary star formation occur prior to the pre-main-sequence phase of stellar evolution, i.e., during the protostellar collapse phase. While brown dwarf companions to solar-mass stars appear to be rare, the number of known free-floating brown dwarf stars is large and growing. Brown dwarf binaries are common, and several sub-brown dwarfs may have been discovered with masses in the range generally associated with gas giant planets. Binary stars are hypothesized to form by fragmentation during protostellar collapse, a process that can lead to the formation of increasingly smaller mass protostars. This project will further develop the theory of protostellar fragmentation, through detailed models of the collapse of molecular cloud cores. The models will result in an improved understanding of binary and multiple star formation, as well as of the minimum mass of a newly-formed protostellar fragment.The broader impact of this work centers on the PI's efforts to communicate the excitement of scientific discoveries to the public, through frequent interactions with journalists, giving public lectures, helping museums with exhibits, and writing articles for popular magazines. The PI also mentors undergraduate students as a part of an NSF REU program.