Mass loss and jet outflow in the Orion Nebula proplyd LV 2

被引:52
作者
Henney, WJ
O'Dell, CR
Meaburn, J
Garrington, ST
Lopez, JA
机构
[1] Univ Nacl Autonoma Mexico, Inst Astron, Morelia 58089, Michoacan, Mexico
[2] Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA
[3] Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England
[4] Univ Nacl Autonoma Mexico, Inst Astron, Ensenada 22800, Baja California, Mexico
关键词
HII regions; ISM : clouds; ISM : individual (Orion nebula); stars : formation;
D O I
10.1086/338055
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We have obtained Hubble Space Telescope (HST) Space Telescope Imaging Spectrometer high-resolution spectra of the Orion proplyd LV 2 in the C III doublet at 1906.68 and 1908.73 Angstrom. New images at the 6 cm wavelength with MERLIN complement earlier HST images at a similar spatial resolution. This object is one of the closest proplyds to theta(1) Ori C, the source of the photoionizing and photoevaporating radiation. Combining the spectra with the HST images and detailed theoretical models has allowed a determination of the mass-loss rate as 8.2 x 10(-7) M. yr(-1) +/- 10%. This rate of mass loss is used to address the conundrum of the continued existence of proplyds. Even though they should be photoevaporated in only about 10(5) yr, there is no evidence for their destruction. It is concluded that the only explanation is that the age of theta(1) Ori C is less than 105 yr. These spectra and previously unpublished ground-based spectra in [O III] also show the presence of a monopolar microjet, redshifted by about 100 km s(-1) with respect to the systemic velocity. This jet is more visible in the 6 cm MERLIN images than in HST images, and this image together with the spectra are used to determine the flow parameters for the jet. Our spectra also include the stand-off shock that lies between LV 2 and theta(1) Ori C. This is the result of the high-velocity wind coming from the hot star theta(1) Ori C with the low-velocity wind coming from the proplyd. As expected, this shock is at rest with respect to the two objects.
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页码:315 / 331
页数:17
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