التفاصيل البيبلوغرافية
| العنوان: |
An enhanced cosmic-ray flux towards ζ Persei inferred from a laboratory study of the H3+–e- recombination rate |
| المؤلفون: |
B. J. McCall, A. J. Huneycutt, R. J. Saykally, T. R. Geballe, N. Djuric, G. H. Dunn, J. Semaniak, O. Novotny, A. Al-Khalili, A. Ehlerding, F. Hellberg, S. Kalhori, A. Neau, R. Thomas, F. |
| المصدر: |
Nature, Nature. 422(6931):500-502 |
| سنة النشر: |
2003 |
| الوصف: |
The H3+ molecular ion plays a fundamental role in interstellar chemistry, as it initiates a network of chemical reactions that produce many molecules1,2. In dense interstellar 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 temperature3,4. But observations of diffuse clouds have suggested that H3+ is considerably more abundant than expected from the chemical models5,6,7. Models of diffuse clouds have, however, been hampered by the uncertain values of three key parameters: the rate of H3+ destruction by electrons (e-), the electron fraction, and the cosmic-ray ionization 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 ζ Persei) where the electron fraction is already known. From these, we find that the cosmic-ray ionization rate along this line of sight is 40 times faster than previously assumed. If such a high cosmic-ray flux is ubiquitous in diffuse clouds, the discrepancy between chemical models and the previous observations5,6,7 of H3+ can be resolved. |
| نوع الوثيقة: |
redif-article |
| اللغة: |
English |
| DOI: |
10.1038/nature01498 |
| الإتاحة: |
https://ideas.repec.org/a/nat/nature/v422y2003i6931d10.1038_nature01498.html |
| رقم الأكسشن: |
edsrep.a.nat.nature.v422y2003i6931d10.1038.nature01498 |
| قاعدة البيانات: |
RePEc |
