科研之友
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摘要
The NGC1999 reflection nebula features a dark patch with a size of similar to 10 000 AU, which has been interpreted as a small, dense foreground globule and possible site of imminent star formation. We present Herschel PACS far-infrared 70 and 160 mu m maps, which reveal a flux deficit at the location of the globule. We estimate the globule mass needed to produce such an absorption feature to be a few tenths to a few M(circle dot). Inspired by this Herschel observation, we obtained APEX LABOCA and SABOCA submillimeter continuum maps, and Magellan PANIC near-infrared images of the region. We do not detect a submillimer source at the location of the Herschel flux decrement; furthermore our observations place an upper limit on the mass of the globule of similar to 2.4x10(-2) M(circle dot). Indeed, the submillimeter maps appear to show a flux depression as well. Furthermore, the near-infrared images detect faint background stars that are less affected by extinction inside the dark patch than in its surroundings. We suggest that the dark patch is in fact a hole or cavity in the material producing the NGC1999 reflection nebula, excavated by protostellar jets from the V380 Ori multiple system.
- 出版日期2010-8
