X-RAY PROPERTIES OF LOW-MASS PRE-MAIN SEQUENCE STARS IN THE ORION TRAPEZIUM CLUSTER
X-RAY PROPERTIES OF LOW-MASS PRE-MAIN SEQUENCE STARS IN THE ORION TRAPEZIUM CLUSTER
复制标题
猎户座梯形星团中低质量前主序星的 X 射线特性
DOI：
10.1088/0004-637x/810/1/55
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
C. Canizares
中科院分区：
文献类型：
--
作者：
N. Schulz;D. Huenemoerder;M. Guenther;P. Testa;C. Canizares
钱德拉HETG猎户座遗留项目(HOLP)是对非常年轻的大质量星团的第一套全面的观测，它提供了非常年轻恒星在大质量范围(0.7-2.3M⊙？>；)的高分辨率X射线光谱。在这篇文章中，我们集中在六个最亮的X射线源与TTauri恒星对应的，它们在光学和红外波长上都得到了很好的表征。所有恒星的柱状密度都比光学消光时预期的要小得多，这表明相对于观测者来说，源位于星团的近侧，这些恒星嵌入了更多尘埃的环境中。恒星的X射线光度远高于1031erg S−1，在某些情况下在相当长一段时间内超过1032erg S−1。在这些观测过程中，恒星没有显示出耀斑，但持续明亮。用10mK和40mK两个温度等离子体组分可以很好地拟合光谱，后者平均以6：1的比例控制通量。总排放量范围为3-8×10~(54)cm−~3，与活动冕源相当。对Ne_x-He类K壳线的拟合表明，禁止与低密度极限相一致的组合间线比。观测到的丰度与这些来源的日冕性质背后的活动冕源相比较好。这个0.6-2.3M⊙？>；经典T金牛座恒星的表面通量表明，在0.1岁到10Myr岁之间，日冕活动显著增加。这些结果证明了X射线线诊断在研究年轻星团中T-Tauri星的日冕特性方面的能力。
The Chandra HETG Orion Legacy Project (HOLP) is the first comprehensive set of observations of a very young massive stellar cluster that provides high-resolution X-ray spectra of very young stars over a wide mass range (0.7–2.3 M ⊙ ?> ). In this paper, we focus on the six brightest X-ray sources with T Tauri stellar counterparts that are well-characterized at optical and infrared wavelengths. All stars show column densities which are substantially smaller than expected from optical extinction, indicating that the sources are located on the near side of the cluster with respect to the observer as well as that these stars are embedded in more dusty environments. Stellar X-ray luminosities are well above 1031 erg s−1, in some cases exceeding 1032 erg s−1 for a substantial amount of time. The stars during these observations show no flares but are persistently bright. The spectra can be well fit with two temperature plasma components of 10 MK and 40 MK, of which the latter dominates the flux by a ratio 6:1 on average. The total emission measures range between 3–8 × 1054 cm−3 and are comparable to active coronal sources. The fits to the Ne ix He-Like K-shell lines indicate forbidden to inter-combination line ratios consistent with the low-density limit. Observed abundances compare well with active coronal sources underlying the coronal nature of these sources. The surface flux in this sample of 0.6–2.3 M ⊙ ?> classical T Tauri stars shows that coronal activity increases significantly between ages 0.1 and 10 Myr. The results demonstrate the power of X-ray line diagnostics to study coronal properties of T Tauri stars in young stellar clusters.
DOI：
10.1088/0004-637x/693/1/397
发表时间：
2008-11
期刊：
The Astrophysical Journal
影响因子：
--
作者：
M. Reid;K. Menten;A. Brunthaler;X. Zheng;L. Moscadelli;Ye Xu;Ye Xu
通讯作者：
M. Reid;K. Menten;A. Brunthaler;X. Zheng;L. Moscadelli;Ye Xu;Ye Xu
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell