کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5487151 | 1523507 | 2017 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Measuring temperature and ammonia hydrate ice on Charon in 2015 from Keck/OSIRIS spectra
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم فضا و نجوم
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Measuring temperature and ammonia hydrate ice on Charon in 2015 from Keck/OSIRIS spectra Measuring temperature and ammonia hydrate ice on Charon in 2015 from Keck/OSIRIS spectra](/preview/png/5487151.png)
چکیده انگلیسی
In this work we investigated the longitudinal (zonal) variability of H2O and ammonia (NH3) hydrate ices on the surface of Charon through analysis of the 1.65 µm and 2.21 µmabsorption features, respectively. Near-infrared spectra presented here were obtained between 2015-07-14 and 2015-08-30 UT with the OSIRIS integral field spectrograph on Keck I. Spectra centered on six different sub-observer longitudes were obtained through the Hbb (1.473-1.803 µm) and Kbb (1.965-2.381 µm) filters. Gaussian functions were fit to the aforementioned bands to obtain information on band center, band depth, full width at half maximum, and band area. The shift in the band center of the temperature-dependent 1.65 µm feature was used to calculate the H2O ice temperature. The mean temperature of the ice on the observable portion of Charon's surface is 45â±â14 K and we report no statistically significant variations in temperature across the surface. We hypothesize that the crystalline and amorphous phases of water ice reached equilibrium over 3.5 Gyr ago, with thermal recrystallization balancing the effects of irradiation amorphization. We do not believe that cryovolcanism is necessary to explain the presence of crystalline water ice on the surface of Charon. Absorption from ammonia species is detected between 12° and 290°, in agreement with results from New Horizons. Ongoing diffusion of ammonia through the rocky mantle and upper layer of water ice is one possible mechanism for maintaining its presence in Charon's surface ice. Reduced Charon spectra corrected for telluric and solar absorption are available as supplementary online material.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Icarus - Volume 284, 1 March 2017, Pages 394-406
Journal: Icarus - Volume 284, 1 March 2017, Pages 394-406
نویسندگان
B.J. Holler, L.A. Young, M.W. Buie, W.M. Grundy, J.E. Lyke, E.F. Young, H.G. Roe,