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

philip MasseyLowell天文台利用大质量双星解决质量差异的合作研究：把事情推到极端【摘要】将进行一项观测计划，以确定最大质量恒星的质量。这项工作的动机是由进化模型得出的高质量恒星的质量与由大气参数（即巴尔默剖面的表面重力与距离、变红和辐射等相结合）计算出来的质量有显著（2到3个因素）差异。因此，大质量恒星演化理论（可能没有包括重要的/未知的物理复杂性）或光谱方法（可能使用了不正确的表面重力、光度、距离等）仍然存在问题。为了解决这个问题并确定差异的来源，双星O的质量将直接通过对双星双星的分析来测量（特别注意那些周期为3-5天的双星，因为它们没有相互作用）。在第一年，银河系和麦哲伦星云中的年轻星团和星团将进行光度测量，以发现食双星。候选者的径向速度将在第二年得到。第三年将用于寻找轨道解，并计算光谱质量和进化质量，以便与结果进行比较。该项目包括重要的外展和本科生研究组成部分。该测光数据将作为国家本科生科研观测站重点项目的一部分（采集北部地区的测光数据，减少北部和南部的测光数据）。北亚利桑那大学本科生研究经验项目和麻省理工学院野外营地的本科生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.