The SPITZER c2d Survey of Weak-Line T Tauri Stars. I. Initial Results-猫眼课题宝

DOI：

10.1086/504374

发表时间：

2006-07

期刊：

The Astrophysical Journal

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

D. Padgett;L. Cieza;K. Stapelfeldt;N. Evans II;D. Koerner;A. Sargent;M. Fukagawa;E. V. van Dishoeck;J. Augereau;L. Allen;G. Blake;T. Brooke;N. Chapman;P. Harvey;A. Porras;S. Lai;L. Mundy;P. Myers;W. Spiesman;Z. Wahhaj

利用斯皮策太空望远镜，我们在蛇夫座、狼座、变色龙和金牛座的恒星形成区域附近观测到了90颗弱线和经典的金牛座T星，这是斯皮策遗产项目（c2d）的一部分。除了斯皮策的数据外，我们还获得了同期光学光度测定法，以协助构建光谱能量分布。这些天体被特别选择为太阳型年轻恒星，具有低水平的Hα发射，强x射线发射和锂吸收，即弱线金牛座T星，其中大部分在IRAS调查中未被探测到。弱线T型金牛座恒星在确定磁盘演化可能发生的时间尺度方面是潜在的极其重要的对象。我们的目标是确定这些年轻的恒星是没有圆盘的，还是有残留的圆盘，这些圆盘低于以前红外任务的探测阈值。我们发现，只有5/83的弱线金牛座T星在3.6 ~ 70 μm之间有可检测到的过量辐射，这将表明存在从一个天文单位的内部的几十个天文单位到行星形成区域的尘埃。在这些光源中，有两个光源在24 μm处有较小的过盈，与光学薄盘一致；其他的有光学厚的圆盘，已经被以前的红外调查检测到。所有7颗经典的金牛座T星在24 μm和70 μm波段都显示出过量的辐射，尽管它们的特性在较短波长处有所不同。我们的初步结果表明，圆盘在年轻恒星中是罕见的，因为它们的弱Hα辐射被选中。

Using the Spitzer Space Telescope, we have observed 90 weak-line and classical T Tauri stars in the vicinity of the Ophiuchus, Lupus, Chamaeleon, and Taurus star-forming regions as part of the Cores to Disks (c2d) Spitzer Legacy project. In addition to the Spitzer data, we have obtained contemporaneous optical photometry to assist in constructing spectral energy distributions. These objects were specifically chosen as solar-type young stars with low levels of Hα emission, strong X-ray emission, and lithium absorption, i.e., weak-line T Tauri stars, most of which were undetected in the mid- to far-IR by the IRAS survey. Weak-line T Tauri stars are potentially extremely important objects in determining the timescale over which disk evolution may take place. Our objective is to determine whether these young stars are diskless or have remnant disks that are below the detection threshold of previous infrared missions. We find that only 5/83 weak-line T Tauri stars have detectable excess emission between 3.6 and 70 μm, which would indicate the presence of dust from the inner few tenths of an AU out to the planet-forming regions a few tens of AU from the star. Of these sources, two have small excesses at 24 μm consistent with optically thin disks; the others have optically thick disks already detected by previous IR surveys. All of the seven classical T Tauri stars show excess emission at 24 and 70 μm although their properties vary at shorter wavelengths. Our initial results show that disks are rare among young stars selected for their weak Hα emission.

The SPITZER c2d Survey of Weak-Line T Tauri Stars. I. Initial Results

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