Dynamics of stellar atmospheres

恒星的大气层是光产生的外层，因此对星光的分析可以告诉我们这些气体的物理特性。我使用西安大略大学（University of Western Ontario）的高分辨率coude光谱仪来研究来自恒星的光，这些恒星的大气非常动态，这意味着它们被对流搅动，在恒星旋转时在我们眼前旋转，渗透着随时间变化的磁场，显示出被称为黑点的暗冷区域，有巨大的风暴，并向太空中喷射物质。我的研究帮助我们了解恒星是如何“运作”的，这本身就很有趣，但也扩展了我们对地球上类似过程的理解。在宇宙中，最接近恒星动力学的例子是我们的太阳；越来越多的证据表明，太阳活动的变化可能影响地球上的气候。我正在探索温度、对流和磁场的变化，并测量类太阳恒星的自转速率，看看我们的太阳与之相比如何，并通过推断，太阳未来可能会做什么。超巨星参宿四在其大气层中表现出极端的运动。我对这颗恒星的观察揭示了以前看不见的变化，这将是使用强大的计算机建模的挑战。对参宿四大气运动的适当建模将有助于我们了解其他恒星大气中的运动。我们已经知道，这些运动，加上恒星的旋转，产生了磁场，并由此产生了许多动力学行为，包括太阳持续11年的磁周期。从我的光谱学中，我还以目前可用的最高精度确定了恒星的旋转速度。基本的光谱观察和分析是我研究的支柱，它让我们对恒星有了基本的了解。能够以这种有趣的方式为社会做贡献是一种快乐。

The atmosphere of a star is the outer layer from which the light comes, and so analysis of starlight tells us about the physical characteristics of these gases.  I use the high-resolution coude spectrograph at the University of Western Ontario to investigate light from stars where the atmospheres are very dynamic, meaning they are churned by convection, spun before our eyes as the star rotates, permeated with magnetic fields that change with time, show dark-cool regions called spots, have giant storms, and expel mass into space.  My research helps us understand how stars 'work,' which is interesting in its own right, but also expands our understanding of similar processes on earth. In the cosmos, the closest example of stellar dynamics is on our sun; there is increasing evidence that the solar variations may influence climate on earth.  I am exploring variations in temperature, convection, and magnetic fields, and measuring rates of rotation in sun-like stars to see how our sun compares, and by inference, what the sun is likely to do in the future.The supergiant star Betelgeuse shows extreme motions in its atmosphere.  My observations of this star are revealing previously unseen variations that will be a challenge to model using powerful computers.  Proper modeling of the motions in the atmosphere of Betelgeuse will help us understand motions in the atmospheres of other stars.  We already know that these motions, coupled with the rotation of the star, produce magnetic fields and from them stems many of the dynamical behaviors, including magnetic cycles, which on the sun last 11 years.  From my spectroscopy, I also determine rotation rates of stars with the highest precision currently available.Basic spectroscopic observation and analysis, the backbone of my research, gives us a fundamental understanding of stars.  It is a pleasure to be able to contribute to society in this interesting manner.