WHAT IS POWERING THE ORION KLEINMANN-LOW INFRARED NEBULA

被引:112
作者
MENTEN, KM
REID, MJ
机构
[1] Harvard-Smithsonian Ctr. Astrophys., Cambridge, MA 02138
关键词
ISM; INDIVIDUAL; BECKLIN-NEUGEBAUER; ISM INDIVIDUAL; ORION KLEINMANN-LOW; IRC2; MASERS; STARS; FORMATION;
D O I
10.1086/187913
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We used the Very Large Array to observe the Orion BN/KL region simultaneously at frequencies of 8.4 and 43.1 GHz with 0''.25 resolution. At 8.4 GHz we detect a rich cluster of compact radio continuum sources, some of which are coincident with infrared sources while others do not have known infrared counterparts. At 43.1 GHz we observed continuum emission together with the v = 1, J = 1 --> 0 SiO maser line, allowing precise registration of radio continuum relative to SiO emission. We find that the radio continuum emission from one of the radio sources, I, coincides with the centroid of the SiO maser distribution. Our SiO maser maps show intricate velocity structure indicative of ordered motions that must have a rotating and expanding (or contracting) component. Since source I powers an SiO maser, it must have a high luminosity, most likely exceeding 10(4) L.. Precise astrometry shows that it does not coincide with the mid-infrared source IRc2. Given that the radio emission from source I is not affected by dust extinction, it locates the central (proto)star powering the IRc2 complex. This suggests that the location and morphology of the infrared emission from ''IRc2'' is determined by inhomogeneities of the dust envelope surrounding the central star. Furthermore, this brings into question all previous luminosity estimates of IRc2 and opens the possibility that other sources contribute significantly to the energetics of the Orion KL region. In particular, we suggest that another infrared source, n, which is coincident with a peculiar double radio source, may be responsible for at least some of the energetic phenomena observed in the region.
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页码:L157 / L160
页数:4
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