Collaborative Research Using High Mass Binaries to Resolve the Mass Discrepancy: Taking Things to the Extreme

AST-0506577菲利普·马赛伊·洛厄尔天文台利用高质量双星解决质量离散的合作研究：将事物带到极限：将实施一个观测计划来确定最大质量恒星的质量。这项工作的动机是从演化模型得出的大质量恒星的质量与根据大气参数计算的质量(即来自巴尔默剖面的表面重力与距离、变红和辐射热星等的组合)的显著差异(两到三个因素)。因此，要么是大质量恒星演化理论的问题(可能没有包括重要的/未知的物理复杂性)，要么是光谱方法的问题(可能使用了不正确的表面重力、光度、距离等)。为了解决这个问题并确定差异的来源，将通过对食双线光谱双星的分析直接测量双星O的质量(特别注意那些周期为3-5天的恒星，因此没有相互作用)。在第一年，将对银河系和麦哲伦星云中的年轻星团和星团进行光度测量，以寻找食双星。候选人的径向速度将在第二年获得。第三年将用来寻找轨道解，并计算光谱和演化质量，以便与结果进行比较。这个项目包括一个重要的外展和本科生研究部分。光度数据(获取北部田野和减少北部和南部目标)将是国家本科生研究观测站的关键项目的一部分。北亚利桑那大学本科生项目和麻省理工学院野外营地将帮助进行光谱观测和轨道解决方案。

AST-0506577Philip MasseyLowell ObservatoryCollaborative Research Using High Mass Binaries to Resolve the MassDiscrepancy: Taking Things to the ExtremeABSTRACTAn observational program will be undertaken to determine the masses of the most massive stars.The work is motivated by significant (factors of two to three) differences in the masses of high massstars derived from evolutionary models compared with those calculated from atmosphericparameters (i.e, surface gravities from Balmer profiles combined with distance, reddening, andbolometric magnitudes). Thus, either problems remain with theories of high mass star evolution(important/unknown physical complications may have not be included), or with the spectroscopicapproach (incorrect surface gravities, luminosities, distances, etc. may be being used). To resolvethe question and ascertain the source of the discrepancy, the masses of binary O stars will bedirectly measured from an analysis of eclipsing double-lined spectroscopic binaries (specialattention will be paid to those with periods 3-5 days which have therefore not interacted). In thefirst year, young associations and clusters in the Milky Way and Magellanic Clouds will bephotometrically surveyed to find eclipsing binaries. Radial velocities for candidates will be obtainedin the second year. The third year will be used to find the orbit solutions, and to calculatespectroscopic and evolutionary masses for comparison with the results.This project includes a significant outreach and undergraduate research component. Thephotometric data (its acquisition for the northern fields and reduction for both northern and southerntargets) will be part of a key project of the National Undergraduate Research Observatory.Undergraduate students in Northern Arizona University Research Experiences for Undergraduatesprogram and MIT field camp will help with the spectroscopic observations and orbit solutions.