The Low Mass End of the Mass Function in OB Associations with Small and Medium Astronomical Research Telescopes System (SMARTS)

被称为OB星群的恒星群是热的、大质量的O星和B星的诞生地。它们是恒星形成的化石区域，保留了在其中形成的所有恒星的完整记录。所有在这样的OB群中形成的低质量恒星仍然存在，通常没有被遮挡，并且处于它们的最后质量。这些恒星的诞生时间相同，质量非常低的恒星和次恒星质量的物体仍然足够明亮，可以很容易地观察到。由于大多数低质量恒星都是在OB星群中形成的，这些区域提供了我们银河系中低质量恒星形成的代表性观点。观测工作调查了几个问题：低质量恒星是在猎户座OB1b星群中原位形成的，它们的发展被大质量恒星阻止了，还是它们作为未完成的胚胎被多体引力相互作用从星群中弹出？恒星旋转周期的分布是怎样的？恒星在200万年到1000万年之间（这个年龄间隔目前还没有得到很好的采样）是如何旋转起来的？新的观测结果将为附近年轻OB群样本中的恒星提供一套统一的质量分布函数，因此我们可能会问，初始质量函数的低质量端有多普遍？更广泛的影响：该项目有助于石溪大学的本科生和研究生天文学项目，以及当地的推广工作。通过中小型天文研究望远镜系统联盟提供的大量保证观测时间允许合格本科生的研究提案获得用于本科课程的数据。为此，将雇用两名本科生数据助理，该项目将为其他人提供研究机会。这项支持也将加强与本地中学的联系。在过去的十年里，每年大约有2名高中生被指导参加科学展览项目。保证的观察时间将为这些学生提供更广泛的选择，以规划，提出，减少和分析他们选择的项目数据。

AST 0307454PI WalterGroups of stars known as OB associations are the birthplaces of the hot and massive O and B stars. They are fossil star formation regions, retaining a complete record of all the stars that formed therein. All the low mass stars that formed in such an OB association are still present, generally unobscured, and are at their final masses. The stars have the same times of birth, and the very low mass stars and substellar mass objects are still sufficiently bright to be easily observable. Since most low mass stars form in OB associations, these regions provide a representative view of low mass star formation in our Galaxy. The observational effort investigates several questions: Are the low mass stars formed in-situ in the Orion OB1b association, with their development arrested by the massive stars, or are they ejected from the association by multi-body gravitational interactions as underdone embryos? What is the distribution of stellar rotation periods, and how do the stars spin up at ages between two and ten million years, an age interval currently not well sampled? New observations will provide a uniform set of mass distribution functions for the stars in a sample of young nearby OB associations, and so we may ask how universal is the low mass end of the initial mass function?Broader Impact: This project contributes to both undergraduate and graduate astronomy programs at Stony Brook, as well as to local outreach efforts. Large amounts of guaranteed observation time through the Small and Medium Astronomical Research Telescopes System consortium allows research proposals from qualified undergraduates to obtain data for use in the undergraduate courses. To that end, two undergraduate data aides will be employed, and the project will offer research opportunities to others. This support will also enhance outreach to local secondary schools. About 2 high school students per year have been supervised over the past decade for science fair projects. The guaranteed observing time will afford these students a wider range of options for planning, proposing, reducing, and analyzing data on projects of their choosing.