BHR 160 is a virtually unstudied cometary globule within the Sco OB4 association in Scorpius at a distance of 1600pc. It is part of a system of cometary clouds which face the luminous O star HD155806. BHR 160 is special because it has an intense bright rim. We attempt to derive physical parameters for BHR 160 and to understand its structure and the origin of its peculiar bright rim. BHR 160 was mapped in the $^{12}$CO, $^{13}$CO and C$^{18}$O (2-1) and (1-0) and CS (3-2) and (2-1) lines. These data, augmented with stellar photometry derived from the ESO VVV survey, were used to derive the mass and distribution of molecular material in BHR 160 and its surroundings. Archival mid-infrared data from the WISE satellite was used to find IR excess stars in the globule and its neighbourhood. An elongated 1' by 0.6' core lies adjacent to the globule bright rim. $^{12}$CO emission covers the whole globule, but the $^{13}$CO, C$^{18}$O and CS emission is more concentrated to the core. The $^{12}$CO line profiles indicate the presence of outflowing material near the core, but the spatial resolution of the mm data is not sufficient for a detailed spatial analysis. The BHR 160 mass estimated from the C$^{18}$O mapping is 100$\pm$50Msun(d/1.6kpc)$^2$ where d is the distance to the globule. Approximately 70 percent of the mass lies in the dense core. The total mass of molecular gas in the direction of BHR 160 is 210$\pm$(d/1.6kpc)$^2$ Msun when estimated from the more extended VVV NIR photometry. We argue that the bright rim of BHR 160 is produced by a close-by early B-type star, HD 319648, that was likely recently born in the globule. This star is likely to have triggered the formation of a source, IRS 1, that is embedded within the core of the globule and detected only in Ks and by WISE and IRAS.
Bok globule CB17: Polarization, extinction and distance
本文介绍了博克球CB 17在光波和亚毫米波段的偏振研究结果。2016年3月9日，在印度奈尼塔尔ARIES的1.04米Sampurnanand望远镜上进行了R波段（$λ$ = 630 nm，$Δλ$ = 120 nm）的光学偏振观测，而亚毫米偏振数据来自SCUPOL数据档案，该档案已被重新分析。Herschel \footnote{Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.} SPIRE 500 $μm$尘埃连续辐射CB 17的轮廓（典型的彗星状球状体）与偏振矢量（光学和亚毫米）一起叠加在CB 17的DSS图像上。球核处的磁场强度估计为$99μ$ G。利用近红外测光技术和\emph{Gaia}数据，发现到CB 17的距离为$253 \pm 43$秒差距。还研究了小球的各种数量之间的相关性。据观察，磁场在云核中所揭示的偏振测量在亚毫米尘埃排放被发现几乎是沿着短轴的球状体，这符合磁调节恒星形成模型。同时还发现了核尺度磁场方向与分子流出方向的错位。
