Production of H$_3^+$ via photodissociation of organic molecules in interstellar clouds

Details Production of H$_3^+$ via photodissociation of organic molecules in interstellar clouds Production of H$_3^+$ via photodissociation of organic molecules in interstellar clouds

2006-12-14

arxiv.org/abs/astro-ph/0612402v1

Mon.Not.Roy.Astron.Soc.375:1488-1494,2007

Astronomy and Astrophysics

Astrophysics

The paper contains 7 pages, 3 figures and 3 tables. Accepted to be published on MNRAS on 2006 December 14. Received 2006 Decem

Scientific paper

10.1111/j.1365-2966.2006.11415.x

We present experimental results obtained from photoionization and photodissociation processes of abundant interstellar CH$_3$-X type organic molecules like methanol (CH$_3$OH), methylamine (CH$_3$NH$_2$) and acetonitrile (CH$_3$CN) as alternative route for the production of H$_3^+$ in interstellar and star forming environments. The measurements were taken at the Brazilian Synchrotron Light Laboratory (LNLS), employing soft X-ray photons with energies between 200 and 310 eV and time of flight mass spectrometry. Mass spectra were obtained using the photoelectron-photoion coincidence techniques. Absolute averaged cross sections for H$_3^+$ production by soft X-rays were determined. We have found that, among the channels leading to molecular dissociation, the H$_3^+$ yield could reach values up to 0.7% for single photoionization process and up to 4% for process involving double photoionization. The H$_3^+$ photoproduction cross section due to the dissociation of the studied organic molecules by photons over the C1s edge (200-310 eV) were about 0.2-1.4 $\times$ 10$^{-18}$ cm$^2$. Adopting the typical X-ray luminosity $L_X \gtrsim 10^{31}$ erg s$^{-1}$ which best fit the observational data for AFGL 2591 (Stauber et al. 2005) we derive an estimative for the H$_3^+$ photoproduction rate due to methyl-compounds dissociation process. The highest value for the H$_3^+$ column density from methanol dissociation by soft X-rays, assuming a steady state scenario, was about $10^{11}$ cm$^2$, which gives the fraction of the photoproduced H$_3^+$ of about 0.05%, as in the case of dense molecular cloud AFGL 2591. Despite the extreme small value, this represent a new and alternative source of H$_3^+$ into dense molecular clouds and it is not been considered as yet in interstellar chemistry models.

Affiliated with

Also associated with

No associations

Rating

Production of H$_3^+$ via photodissociation of organic molecules in interstellar clouds 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 Production of H$_3^+$ via photodissociation of organic molecules in interstellar clouds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Production of H$_3^+$ via photodissociation of organic molecules in interstellar clouds will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-475944