Observation of Warm Gas in Transitional Disks around Herbig Ae/Be Stars: Interpreting their SEDs

了解行星的形成仍然是天文学最有价值的挑战之一，代表了寻找我们自己的宇宙起源的重要组成部分，并关系到其他世界上生命的可能性。虽然人们一致认为，年轻恒星周围的气体和尘埃的演化与行星的形成有关，但关于这种假设耦合的基本问题仍然没有答案。在这里，在他以前的工作的基础上，Brittain博士将使用高分辨率近红外光谱来解决这些问题，以窥视一类被称为Herbig Ae/Be恒星的年轻恒星周围的内盘。 追踪星周盘演化的一个重要工具是测量年轻恒星的光谱能量分布。光谱能量分布的差异导致了这样的建议，即它们反映了从光学厚盘到过渡盘（即具有光学厚外盘和光学薄内盘的盘）再到光学薄盘的演化序列，其时间尺度与行星形成相当。对这种独特的过渡盘形态的规范解释是，它反映了嵌入行星的动力学雕刻。然而，还有其他物理效应-即晶粒生长和光蒸发-可以产生具有不可区分的光谱能量分布的过渡盘。 在这个项目中，将观察赫比格Ae/Be恒星盘中温暖气体的分布，并通过其独特的签名来区分这些效应。这种对过渡盘形态的真正起源的理解对于理解气体的形成具有根本意义。巨型系外行星和未来试图探测它们的直接成像活动。参与该项目的本科生和研究生将有机会通过利用国家光学天文台和克莱姆森，提供了前所未有的访问所需的观测设施-一个有利于启动许多年轻科学家的职业生涯的情况。本科生将通过克莱姆森大学的创新探究倡议参与这个项目。该计划将学生团队与教师导师进行多年项目（通常为五个学期），并提供适度的资金来支持他们的工作。这项工作也将包括一个克莱姆森研究生的博士学位的重要组成部分。论文这项研究的结果将通过同行评审的出版物、座谈会和会议上的谈话向科学界介绍，并向公众传播。这将通过继续向当地社区进行受欢迎的介绍来实现。

Understanding the formation of planets remains one of astronomy''s most rewarding challenges, representing a significant component of the search for our own cosmic origins, and bearing on the possibility of life on other worlds. Although there is consensus that the evolution of gas and dust in disks around young stars is tied to planet formation, fundamental questions about this assumed coupling remain unanswered. Here, building on his previous work, Dr. Brittain will address these questions using high-resolution near-infrared spectroscopy to peer into the inner disks surrounding a class of young stars referred to as Herbig Ae/Be stars. An important tool for tracing the evolution of circumstellar disks is the measurement of the spectral energy distribution of young stars. The differences in the spectral energy distributions have led to the proposal that they reflect an evolutionary sequence from optically thick disks to transitional disks (i.e. disks with optically thick outer disks and optically thin inner disks) to optically thin disks on a timescale commensurate with planet formation. The canonical interpretation of the distinctive transitional disk morphology is that it reflects dynamical sculpting by an embedded planet. However, there are other physical effects - namely grain growth and photo-evaporation - that can give rise to transitional disks with indistinguishable spectral energy distributions. In this project the distribution of warm gas in the disks of Herbig Ae/Be stars will be observed and used to differentiate these effects via their unique signatures. Such an understanding the true origin of transitional disk morphology has fundamental implications for understanding the formation of gas-giant exoplanets and future direct imaging campaigns attempting to detect them.The undergraduate and graduate students involved with this project will have the opportunity to carry out research at one of the frontiers of modern observational astrophysics by exploiting the new partnership between the National Optical Astronomy Observatory and Clemson that provides unprecedented access to the required observing facilities - a situation conducive to launching the careers of many young scientists. Undergraduate students will be involved in this project through Clemson University''s novel Creative Inquiry initiative. This program matches teams of students with a faculty mentor for a multiyear project (typically five semesters) and provides modest funding to support their work. This work will also comprise a significant portion of a Clemson graduate student''s Ph.D. dissertation. The results of this research will be presented to the scientific community through peer-reviewed publications, colloquia, and talks at meetings as well as disseminated to the general public. This will be accomplished through continued popular presentations to the local community.