首页> 外文OA文献 >Gyroscopic pumping of large-scale flows in stellar interiors, and application to Lithium Dip stars
【2h】

Gyroscopic pumping of large-scale flows in stellar interiors, and application to Lithium Dip stars

机译:在恒星内部的陀螺抽水大规模流动,和   适用于锂浸星

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务,本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文,但由于OA文献来源多样且变更频繁,仍可能出现获取不到、文献不完整或与标题不符等情况,如果获取不到我们将提供退款服务。请知悉。

摘要

The maintenance of large-scale differential rotation in stellar convectiveregions by rotationally influenced convective stresses also drives large-scalemeridional flows by angular--momentum conservation. This process is an exampleof ``gyroscopic pumping'', and has recently been studied in detail in the solarcontext. An important question concerns the extent to which thesegyroscopically pumped meridional flows penetrate into nearby stably stratified(radiative) regions, since they could potentially be an important source ofnon-local mixing. Here we present an extensive study of the gyroscopic pumpingmechanism, using a combination of analytical calculations and numericalsimulations both in Cartesian geometry and in spherical geometry. The variousmethods, when compared with one another, provide physical insight into theprocess itself, as well as increasingly sophisticated means of estimating thegyroscopic pumping rate. As an example of application, we investigate theeffects of this large-scale mixing process on the surface abundances of thelight elements Li and Be for stars in the mass range 1.3-1.5 solar masses(so-called ``Li-dip stars''). We find that gyroscopic pumping is a veryefficient mechanism for circulating material between the surface and the deepinterior, so much in fact that it over-estimates Li and Be depletion by ordersof magnitude for stars on the hot side of the dip.However, when the diffusionof chemical species back into the surface convection zone is taken intoaccount, a good fit with observed surface abundances of Li and Be as a functionof stellar mass in the Hyades cluster can be found for reasonable choices ofmodel parameters.
机译:受旋转影响的对流应力维持恒星对流区域的大规模差动旋转,也通过角动量守恒来驱动大子午流。此过程是``陀螺抽水''的一个示例,最近在太阳能环境下进行了详细研究。一个重要的问题涉及这些经陀螺泵浦的子午流渗透到附近的稳定分层(辐射)区域的程度,因为它们可能是非局部混合的重要来源。在这里,我们结合笛卡尔几何和球形几何中的解析计算和数值模拟,对陀螺泵浦机理进行了广泛的研究。相互比较时,各种方法提供了对过程本身的物理洞察力,以及越来越复杂的估算陀螺泵送速度的方法。作为应用示例,我们研究了这种大规模混合过程对质量范围为1.3-1.5太阳质量的恒星(所谓的``浸锂恒星'')中Li和Be的光元素表面丰度的影响。我们发现陀螺仪抽水是使物质在地表和深部内部之间循环的一种非常有效的机制,事实上,它以高的数量级高估了Li和Be的损耗,对于浸入热侧的恒星。考虑到返回到表面对流区的化学物质,可以合理选择模型参数,从而找到与Hyades团簇中恒星质量相关的Li和Be表面丰度的良好拟合。

著录项

  • 作者单位
  • 年度 2010
  • 总页数
  • 原文格式 PDF
  • 正文语种 {"code":"en","name":"English","id":9}
  • 中图分类

相似文献

  • 外文文献
  • 中文文献
  • 专利

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号