U.S.-Netherlands Cooperative Research on Hydrodynamic Modelsof the Shaping of Planetary Nebulae

美国-荷兰关于行星状星云形成的流体动力学模型的合作研究

• 批准号: 8714186
• 负责人: Bruce Balick
• 金额: $ 0.89万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-03-15 至 1990-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8714186&HistoricalAwards=false
• 关键词: U.S.; Netherlands; Cooperative; Research; Hydrodynamic

This award will enable Professor Bruce Balick of the University of Washington to collaborate with Professor Vincent Icke of the University of Leiden, The Netherlands, in a study of planetary nebulae, which are hot, ionized clouds of gas associated with the final stages of stellar life. Their collaboration will involve obtaining improved observational descriptions of planetary nebulae and developing improved models to explain the causes of the intricate and symmetrical shapes of the nebulae. Professor Balick has an extensive observational data base on planetary nebulae and he has experience in testing model predictions by detailed observations. Professor Icke is an expert in theoretical nebular hydrodynamics, and has developed a very sophisticated computer simulation program that has been successfully adapted for modelling other stellar objects such as supernovae remnants. Collaboration with Dr. Balick will facilitate access to a U.S. supercomputer to run the complex programs needed to model nebular dynamics. Planetary nebulae are gaseous shells ejected by aging stars. The ejection is thought to occur in two stages, first as a rather slow "wind" containing the outer layers of the star (over a period of thousands of years), then a much faster expulsion of deeper layers in only a few centuries. Theoretical models and recent observations suggest that the nebulae acquire their shapes as this fast wind overtakes and interacts with the outer layers ejected earlier. A recent survey of 50 planetary nebulae shows that the concept of wind shaping is generally valid, but that the models developed to explain the phenomenon are much too simplistic. The goal of this project is to develop and test more complex models to explain the shapes and evolutions of planetary nebulae. Three-dimensional hydrodynamic models require years to develop and can only reasonably be tested with the aid of a supercomputer. Development of the enhanced models needed to explain nebular shapes will be greatly facilitated by the combination of Dr. Balick's observational data and model testing skills with Dr. Icke's theoretical insights and ability to modify the computer code he has already developed. Ultimately, their collaboration should contribute to resolving some longstanding questions about the shapes and evolution of planetary nebulae.

该奖项将使伦敦大学的布鲁斯巴利克教授 华盛顿与文森特·艾克教授合作， 荷兰莱顿大学，研究行星 星云，这是热的，电离的气体云与 恒星生命的最后阶段 他们的合作将涉及 改进行星状星云的观测描述 并开发改进的模型来解释复杂的 星云的对称形状。 Balick教授有一个 广泛的观测数据基础上行星状星云，他有 通过详细的观察来检验模型预测的经验。 Icke教授是理论星云流体动力学方面的专家， 开发了一个非常复杂的计算机模拟程序， 已经成功地用于模拟其他恒星物体 比如超新星遗迹 与Balick博士的合作将 方便访问美国超级计算机来运行复杂的程序 来模拟星云动力学 行星状星云是由年老的恒星喷出的气体外壳。 的 喷射被认为分两个阶段发生，首先是相当缓慢的喷射， 包含星星外层的“风”（在一段时间内 数千年），然后更快地驱逐更深的层， 只有几个世纪。 理论模型和最近的观测 表明星云的形状是由这股高速风形成的 超越并与较早喷出的外层相互作用。 一 最近对50个行星状星云的调查表明，风的概念 塑造通常是有效的，但模型开发来解释 这种现象过于简单化了。 这个项目的目标是 开发和测试更复杂的模型来解释形状， 行星状星云的演化 三维水动力 模型需要数年的时间来开发，并且只能进行合理的测试 借助超级计算机。 增强模型的开发 解释星云形状所需要的， Balick博士的观察数据和模型测试的结合 技能与博士艾克的理论见解和能力，以修改 他已经开发的计算机代码。 最终提高他们的 合作应该有助于解决一些长期存在的问题。 关于行星状星云的形状和演化的问题。