کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8137934 | 1523551 | 2014 | 35 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Sub-millimeter observation of water vapor at 557Â GHz in Comet C/2002 T7 (LINEAR)
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم فضا و نجوم
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![عکس صفحه اول مقاله: Sub-millimeter observation of water vapor at 557Â GHz in Comet C/2002 T7 (LINEAR) Sub-millimeter observation of water vapor at 557Â GHz in Comet C/2002 T7 (LINEAR)](/preview/png/8137934.png)
چکیده انگلیسی
We present sub-millimeter observations of the ground-state rotational transition (110-101) of water vapor from Comet C/2002 T7 (LINEAR) obtained with the MIRO instrument on the ESA Rosetta spacecraft (s/c) orbiter on April 30, 2004. At the time of the observations, the comet was at a distance of 0.63 AU from the Sun, 0.68 AU from the MIRO telescope, and about 7.5 days after its perihelion. The ground state rotation transition of ortho-water at 556.936 GHz was observed and integrated for â¼8 h using a frequency switched radiometer to provide short and long term stability. The MIRO beam size is 7.5 arcmin in terms of full width half maximum, corresponding to a radius of 1.1 Ã 105 km at the comet location. The observed signal line area of the water line spectrum is 4.3 ± 0.8 K km/s. Using a molecular excitation and radiation transfer model and assuming the spherically symmetric and constant radial expansion of gas in the coma, we estimate that the production rate of water is (1.0 ± 0.2) Ã 1030 molecules/s and the expansion velocity is 1.1 ± 0.2 km/s at the time of the MIRO observation. The present estimation of the water outgassing rate of the comet is in good agreement with other observation-based estimations when the outgassing rates with respect to the time after perihelion are compared. The Doppler-corrected center velocity of the observed line was red-shifted by 0.67 ± 0.13 km/s, of which only 0.18 km/s shift is explained by the model and attributed to a self-absorption effect. The potential sources of the additional red shift are discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Icarus - Volume 239, 1 September 2014, Pages 141-153
Journal: Icarus - Volume 239, 1 September 2014, Pages 141-153
نویسندگان
Seungwon Lee, Mark Hofstadter, Margaret A. Frerking, Samuel Gulkis, Paul von Allmen, Jacques Crovisier, Nicolas Biver, Dominique Bockelée-Morvan, Lucas Kamp, Mathieu Choukroun, Stephen Keihm, Michael Janssen,