Infrared Photometry of Starless Dense Cores
Infrared Photometry of Starless Dense Cores
复制标题
无星致密核心的红外光度测量
DOI：
10.1086/375506
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
P. Myers
中科院分区：
文献类型：
--
作者：
D. Murphy;P. Myers
对八个致密分子核获得了深JHKs测光，并给出了J-H与H-Ks的色-色图。我们的测光，通过35-50等的视觉消光检测到一个1 M的，1 × 106岁的星星的敏感性，显示没有迹象的存在星星/磁盘系统的基础上J-H与H-Ks颜色的检测对象。朝向核心探测到的恒星通常在空间上与核心中心相关，这表明背景起源，尽管我们不能排除在H和Ks单独或Ks单独探测到的一些恒星不是低质量恒星或褐矮星（<0.3 M）的可能性，这些恒星在大量的视觉消光（例如，L183 B为53 mag）。对于探测到的背景恒星，估计了光学折射率的下限，在极端情况下，会遇到高折射率，范围至少为AV = 46，甚至更高。消光数据被用来估计云的质量和密度，这是从分子线研究确定的。云的变化是一致的云密度分布的系统性，和列密度的变化和云的变化被发现是一致的亚毫米波连续研究类似的地区。结果表明，一些核心在子核心尺度（~0.05 pc）上实现了显着的柱密度对比（~30），而没有形成已知的恒星。
Deep JHKs photometry was obtained toward eight dense molecular cores, and J-H versus H-Ks color-color plots are presented. Our photometry, sensitive to the detection of a 1 M☉, 1 × 106 yr old star through ≈35-50 mag of visual extinction, shows no indication of the presence of star/disk systems based on J-H versus H-Ks colors of detected objects. The stars detected toward the cores are generally spatially anticorrelated with core centers, suggesting a background origin, although we cannot preclude the possibility that some stars detected at H and Ks alone or at Ks alone are not low-mass stars or brown dwarfs (<0.3 M☉) behind substantial amounts of visual extinction (e.g., 53 mag for L183B). Lower limits to optical extinctions are estimated for the detected background stars, with high extinctions being encountered, in the extreme case ranging up to at least AV = 46, and probably higher. The extinction data are used to estimate cloud masses and densities that are comparable to those determined from molecular-line studies. Variations in cloud extinctions are consistent with a systematic nature to cloud density distributions, and column density variations and extinctions are found to be consistent with submillimeter-wave continuum studies of similar regions. The results suggest that some cores have achieved significant column density contrasts (~30) on subcore scales (~0.05 pc) without having formed known stars.