Astronomy and Astrophysics – Astrophysics
Scientific paper
2002-03-21
Astronomy and Astrophysics
Astrophysics
Accepted for publication in A&A
Scientific paper
10.1051/0004-6361:20020411
We present near-IR spectroscopy of a sample of 30 IRAS sources recently identified as late AGB stars, post-AGB stars or early PNe. The spectra obtained are centered at various wavelengths covering the molecular hydrogen v=1-0 S(1) and v=2-1 S(1) emission lines, the recombination lines of hydrogen Br-gamma, Pf-gamma and Br-alpha, and the CO[v=2-0] first overtone bandhead at 2.294 microns. As a result of these observations we have increased from 4 to 13 the total number of proto-PNe detected in molecular hydrogen. When the molecular hydrogen is fluorescence-excited the detection rate is found to be directly correlated with the evolutionary stage of the central star, rather than with the nebular morphology. In contrast, shocked-excited molecular hydrogen is detected only in strongly bipolar proto-PNe, sometimes even at an early stage in the post-AGB phase. The strong correlation of shocked-excited molecular hydrogen emission with bipolarity found confirms the result previously reported by Kastner et al. (1996) in evolved PNe. However, our results show that this correlation does not exist in the case of fluorescence-excited molecular hydrogen.
Conway Gail
Dominguez-Tagle Carlos
Garcia-Hernandez Domingo Anibal
Garcia-Lario Pedro
Manchado Arturo
No associations
LandOfFree
Near-IR spectroscopy of planetary nebulae precursors does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Near-IR spectroscopy of planetary nebulae precursors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Near-IR spectroscopy of planetary nebulae precursors will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-665504