کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8135813 1523525 2016 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
A radiative transfer model to treat infrared molecular excitation in cometary atmospheres
ترجمه فارسی عنوان
یک مدل انتقال شعاعی برای درمان تحریک مولکولی مادون قرمز در اتمسفر کمیته
کلمات کلیدی
دنباله دار کمیته ها، کما، انتقال شعاعی،
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم فضا و نجوم
چکیده انگلیسی
The exospheres of small Solar System bodies are now observed with high spatial resolution from space missions. Interpreting infrared spectra of cometary gases obtained with the VIRTIS experiment onboard the Rosetta cometary mission requires detailed modeling of infrared fluorescence emission in optically thick conditions. Efficient computing methods are required since numerous ro-vibrational lines excited by the Sun need to be considered. We propose a new model working in a 3-D environment to compute numerically the local incoming radiation. It uses a new algorithm using pre-defined directions of ray propagation and ray grids to reduce the CPU cost in time with respect to Monte Carlo methods and to treat correctly the sunlight direction. The model is applied to the ν3 bands of CO2 and H2O at 4.3 μm and 2.7 μm respectively, and to the CO ∨(1→0) band at 4.7 μm. The results are compared to the ones obtained by a 1-D algorithm which uses the Escape Probability (EP) method, and by a 3-D “Coupled Escape Probability” (CEP) model, for different levels of optical thickness. Our results suggest that the total band flux may vary strongly with azimuth for optically thick cases whereas the azimuth average total band flux computed is close to the one obtained with EP. Our model globally predicts less intensity reduction from opacity than the CEP model of Gersch and A'Hearn (Gersch, A.M., A'Hearn, M.F. [2014]. Astrophys. J. 787, 36-56). An application of the model to the observation of CO2, CO and H2O bands in 67/P atmosphere with VIRTIS is presented to predict the evolution of band optical thickness along the mission.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Icarus - Volume 265, February 2016, Pages 110-124
نویسندگان
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