New Models of M Dwarf Stars

M矮星的新型号

• 批准号: 0908345
• 负责人: Brian Chaboyer
• 金额: $ 27.99万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908345&HistoricalAwards=false
• 关键词: New; Models; Dwarf; Stars

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Dr. Brian Chaboyer of Dartmouth College will undertake a theoretical investigation of the structure of M dwarfs, which are unevolved stars like the Sun but with less than half its mass. Observations have indicated for some time that theoretical models are unable to correctly predict the mass-radius relation for M dwarfs found in eclipsing binary systems. The observed radii are found to be systematically larger (by about 10%) than that predicted by theoretical models. Recent work has suggested that this is due to increased magnetic activity in these rapidly rotating stars which are tidally locked to their companions. The research will center on the construction of new models of M dwarfs, building upon previous efforts by critically examining the treatment of convection and incorporating the effects of magnetic fields. The physics of the magnetic fields will be included within the stellar structure equations in a phenomenological fashion and the impact of fields of various topologies and field strengths will be studied. Dr. Chaboyer will also explore the effects that various treatments of convection have on the structure and observed properties of low mass stars. This part of the work will incorporate results from recent hydrodynamical calculations of convection. Finally, he will critically examine the color-effective temperature transformations which are used when comparing the models to observations in order to derive an improved calibration.M dwarf stars are the most common type of star in the Milky Way galaxy. Recently, astronomers have realized that the first Earth-mass planets around other stars are likely to be found around M dwarfs. The models generated in this study will be made available to general astronomical community. There will be extensive involvement of both undergraduate and graduate students in all aspects of this research. This will include mentoring of first year undergraduate students who will work on this project through the auspices of the Women in Science Project at Dartmouth College. This program is designed to encourage more Dartmouth women to pursue a career in science, math or engineering through early exposure to hands-on research experiences, role modeling and mentoring. Upper-year undergraduates will also be employed as research assistants. Dr. Chaboyer will also continue his involvement with local K-8 schools and the Monteshire Museum of Science located in Norwich, Vermont, to discuss this research with young learners and the public at large.

该奖项由 2009 年美国复苏和再投资法案（公法 111-5）资助。达特茅斯学院的布赖恩·查博耶将对 M 型矮星的结构进行理论研究，这些矮星是像太阳一样的未演化恒星，但质量还不到太阳的一半。 一段时间以来的观测表明，理论模型无法正确预测食双星系统中 M 矮星的质量半径关系。发现观测到的半径系统地比理论模型预测的半径大（约 10%）。最近的研究表明，这是由于这些快速旋转的恒星的磁活动增加所致，这些恒星被潮汐锁定在其伴星上。该研究将集中于构建 M 矮星的新模型，以先前的努力为基础，严格检查对流的处理并结合磁场的影响。磁场的物理学将以现象学的方式包含在恒星结构方程中，并将研究各种拓扑和场强的场的影响。查博耶博士还将探索各种对流处理对低质量恒星的结构和观测到的特性的影响。这部分工作将纳入最近对流流体动力学计算的结果。最后，他将严格检查颜色有效温度变换，在将模型与观测结果进行比较时使用，以获得改进的校准。M 矮星是银河系中最常见的恒星类型。 最近，天文学家意识到，第一批围绕其他恒星运行的地球质量行星很可能出现在 M 型矮星周围。本研究生成的模型将提供给一般天文学界。 本科生和研究生都将广泛参与这项研究的各个方面。这将包括指导一年级本科生，他们将通过达特茅斯学院女性科学项目的赞助参与该项目。该计划旨在鼓励更多达特茅斯女性通过早期接触实践研究经验、榜样和指导来追求科学、数学或工程领域的职业生涯。高年级本科生也将被聘为研究助理。 Chaboyer 博士还将继续参与当地的 K-8 学校和位于佛蒙特州诺维奇的蒙特郡科学博物馆，与年轻学习者和广大公众讨论这项研究。