دورية أكاديمية
Dissociative Recombination of Rotationally Cold OH+ and Its Implications for the Cosmic Ray Ionization Rate in Diffuse Clouds
| العنوان: | Dissociative Recombination of Rotationally Cold OH+ and Its Implications for the Cosmic Ray Ionization Rate in Diffuse Clouds |
|---|---|
| المؤلفون: | Ábel Kálosi, Lisa Gamer, Manfred Grieser, Robert von Hahn, Leonard W. Isberner, Julia I. Jäger, Holger Kreckel, David A. Neufeld, Daniel Paul, Daniel W. Savin, Stefan Schippers, Viviane C. Schmidt, Andreas Wolf, Mark G. Wolfire, Oldřich Novotný |
| المصدر: | The Astrophysical Journal Letters, Vol 955, Iss 2, p L26 (2023) |
| بيانات النشر: | IOP Publishing, 2023. |
| سنة النشر: | 2023 |
| المجموعة: | LCC:Astrophysics |
| مصطلحات موضوعية: | Diffuse interstellar clouds, Diffuse molecular clouds, Laboratory astrophysics, Electron recombination reactions, Reaction rates, Astrochemistry, Astrophysics, QB460-466 |
| الوصف: | Observations of OH ^+ are used to infer the interstellar cosmic ray ionization rate in diffuse atomic clouds, thereby constraining the propagation of cosmic rays through and the shielding by interstellar clouds, as well as the low energy cosmic ray spectrum. In regions where the H _2 -to-H number density ratio is low, dissociative recombination (DR) is the dominant destruction process for OH ^+ and the DR rate coefficient is important for predicting the OH ^+ abundance and inferring the cosmic ray ionization rate. We have experimentally studied DR of electronically and vibrationally relaxed OH ^+ in its lowest rotational levels, using an electron–ion merged-beams setup at the Cryogenic Storage Ring. From these measurements, we have derived a kinetic temperature rate coefficient applicable to diffuse cloud chemical models, i.e., for OH ^+ in its electronic, vibrational, and rotational ground level. At typical diffuse cloud temperatures, our kinetic temperature rate coefficient is a factor of ∼5 times larger than the previous experimentally derived value and a factor of ∼33 times larger than the value calculated by theory. Our combined experimental and modeling results point to a significant increase for the cosmic ray ionization rate inferred from observations of OH ^+ and H _2 O ^+ , corresponding to a geometric mean of (6.6 ± 1.0) × 10 ^−16 s ^−1 , which is more than a factor of 2 larger than the previously inferred values of the cosmic ray ionization rate in diffuse atomic clouds. Combined with observations of diffuse and dense molecular clouds, these findings indicate a greater degree of cosmic ray shielding in interstellar clouds than has been previously inferred. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 2041-8213 2041-8205 |
| العلاقة: | https://doaj.org/toc/2041-8205Test |
| DOI: | 10.3847/2041-8213/acf71d |
| الوصول الحر: | https://doaj.org/article/ee44bbeaed5f4d07a0540f0350257bd7Test |
| رقم الانضمام: | edsdoj.44bbeaed5f4d07a0540f0350257bd7 |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 20418213 20418205 |
|---|---|
| DOI: | 10.3847/2041-8213/acf71d |