|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'504'928
Articles rated: 2609
25 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Time-dependent models of dense PDRs with complex molecules | | O. Morata
; E. Herbst
; | | Date: |
22 Sep 2008 | | Abstract: | We present a study of the chemistry of a dense photon-dominated region (PDR)
using a time-dependent chemical model. Our major interest is to study the
spatial distribution of complex molecules such as hydrocarbons and
cyanopolyynes in the cool dense material bordering regions where star formation
has taken place. Our standard model uses a homogeneous cloud of density 2x10e4
cm-3 and temperature T=40 K, which is irradiated by a far-ultraviolet radiation
field of intermediate intensity, given by X=100. We find that over a range of
times unsaturated hydrocarbons (e.g., C2H, C4H, C3H2) have relatively high
fractional abundances in the more external layers of the PDR, whereas their
abundances in the innermost layers are several orders of magnitudes lower. On
the other hand, molecules that are typical of late-time chemistry are usually
more abundant in the inner parts of the PDR. We also present results for models
with different density, temperature, intensity of the radiation field and
initial fractional abundances. Our results are compared with both high- and
moderate-angular resolution observations of the Horsehead nebula. Our standard
model is partially successful in reproducing the observations. Additional
models run with different physical parameters are able to reproduce the
abundance of many of the observed molecules, but we do not find a single model
that fits all the observations at the same time. We discuss the suitability of
a time-dependent model of a dense PDR such as ours as an estimator of the age
of a PDR, provided that enough observational data exist. | | Source: | arXiv, 0809.3668 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER