Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate

Details Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate

2003-02-06

arxiv.org/abs/astro-ph/0302106v1

Astronomy and Astrophysics

Astrophysics

6 pages, Nature, in press

Scientific paper

10.1038/nature01498

The H3+ molecular ion plays a fundamental role in interstellar chemistry, as it initiates a network of chemical reactions that produce many interstellar molecules. In dense clouds, the H3+ abundance is understood using a simple chemical model, from which observations of H3+ yield valuable estimates of cloud path length, density, and temperature. On the other hand, observations of diffuse clouds have suggested that H3+ is considerably more abundant than expected from the chemical models. However, diffuse cloud models have been hampered by the uncertain values of three key parameters: the rate of H3+ destruction by electrons, the electron fraction, and the cosmic-ray ionisation rate. Here we report a direct experimental measurement of the H3+ destruction rate under nearly interstellar conditions. We also report the observation of H3+ in a diffuse cloud (towards zeta Persei) where the electron fraction is already known. Taken together, these results allow us to derive the value of the third uncertain model parameter: we find that the cosmic-ray ionisation rate in this sightline is forty times faster than previously assumed. If such a high cosmic-ray flux is indeed ubiquitous in diffuse clouds, the discrepancy between chemical models and the previous observations of H3+ can be resolved.

Affiliated with

Also associated with

No associations

Rating

Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate 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 Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-99156