修正了几个博克球的距离
Revised distances to several Bok globules
摘要：
由于各种原因，到博克球状体和小暗星云的距离很重要。我们提供了新的距离估计几个小的云，其中一些已知的港口YSO和分子外流，因此特别感兴趣。我们使用的程序的基础上确定的（H-K）与（J-H）图的折射率，和恒星距离的基础上的依巴谷校准的主序星轨迹：$M_J[(J-K)_0]$。天空中的云局限是由网格中形成的平均（H-K）颜色的轮廓确定的。在视线方向上，由氢原子数密度$n_H\sim A_{V,\star}/D_\star$的变化可以提取出受云消光影响的恒星，从而提供云的距离及其不确定度。根据我们的估计，三个球状体CB 24，CB 25和CB 26位于407+/-27 pc，比以前的估计更远。CB 245和CB 246位于272+/-20 pc，这表明目前到这些云的距离被低估了。对于CB 244，我们在149+/-16 pc处检测到一层，在352+/-18处检测到云，与以前的研究结果一致。CB 52和CB 54虽然在1500 pc，但分别在421+/-28 pc和略高于1000 pc。目前已知的最远的博克球状体CB 3似乎位于1400 pc左右，也比目前公认的要近得多。
英文摘要：
Distances to Bok globules and small dark nebulae are important for a variety of reasons. We provide new distance estimates to several small clouds, some of them known to harbor YSO and molecular outflows, and thus being of particular interest. We use a procedure based on extinctions determined from the (H-K) vs. (J-H) diagram, and stellar distances based on a Hipparcos calibration of the main sequence locus: $M_J[(J-K)_0]$. The cloud confinement on the sky is determined from contours of the average (H-K) color formed in reseaus. Along the sight line stars affected by the clouds extinction may be extracted from the variation of the number density of atomic hydrogen $n_H\sim A_{V,\star}/D_\star$ to provide the cloud distance and its uncertainty. According to our estimates, the group of three globules CB24, CB25 and CB26 is located at 407+/-27 pc, farther than the previous estimates. CB245 and CB246 are found at 272+/-20 pc, suggesting that the current distance to these clouds is underestimated. Toward CB244 we detect a layer at 149+/-16 pc and the cloud at 352+/-18, in good agreement with previous studies. CB52 and CB54, though to be at 1500 pc, are found at 421+/-28 pc and slightly beyond 1000 pc, respectively. It seems that the most distant Bok globule known, CB3, is located at about 1400 pc, also significantly closer than currently accepted.
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