تقرير
Parameterizing the interstellar dust temperature
| العنوان: | Parameterizing the interstellar dust temperature |
|---|---|
| المؤلفون: | Hocuk, S., Szucs, L., Caselli, P., Cazaux, S., Spaans, M., Esplugues, G. B. |
| المصدر: | A&A 604, A58 (2017) |
| سنة النشر: | 2017 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics |
| الوصف: | The temperature of interstellar dust particles is of great importance to astronomers. It plays a crucial role in the thermodynamics of interstellar clouds, because of the gas-dust collisional coupling. It is also a key parameter in astrochemical studies that governs the rate at which molecules form on dust. In 3D (magneto)hydrodynamic simulations often a simple expression for the dust temperature is adopted, because of computational constraints, while astrochemical modelers tend to keep the dust temperature constant over a large range of parameter space. Our aim is to provide an easy-to-use parametric expression for the dust temperature as a function of visual extinction ($A_{\rm V}$) and to shed light on the critical dependencies of the dust temperature on the grain composition. We obtain an expression for the dust temperature by semi-analytically solving the dust thermal balance for different types of grains and compare to a collection of recent observational measurements. We also explore the effect of ices on the dust temperature. Our results show that a mixed carbonaceous-silicate type dust with a high carbon volume fraction matches the observations best. We find that ice formation allows the dust to be warmer by up to 15% at high optical depths ($A_{\rm V}> 20$ mag) in the interstellar medium. Our parametric expression for the dust temperature is presented as $T_{\rm d} = \left[ 11 + 5.7\times \tanh\bigl( 0.61 - \log_{10}(A_{\rm V})\bigr) \right] \, \chi_{\rm uv}^{1/5.9}$, where $\chi_{\rm uv}$ is in units of the Draine (1978) UV field Comment: 16 pages, 17 figures, 4 tables. Accepted for publication in A&A. Version 2: the omission of factor 0.921 in equation 4 is corrected |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1051/0004-6361/201629944 |
| URL الوصول: | http://arxiv.org/abs/1704.02763 |
| رقم الأكسشن: | edsarx.1704.02763 |
| قاعدة البيانات: | arXiv |
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