کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1773065 | 1523550 | 2014 | 22 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Thermal measurements of dark and bright surface features on Vesta as derived from Dawn/VIR
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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: Thermal measurements of dark and bright surface features on Vesta as derived from Dawn/VIR Thermal measurements of dark and bright surface features on Vesta as derived from Dawn/VIR](/preview/png/1773065.png)
چکیده انگلیسی
Remote sensing data acquired during Dawn's orbital mission at Vesta showed several local concentrations of high-albedo (bright) and low-albedo (dark) material units, in addition to spectrally distinct meteorite impact ejecta. The thermal behavior of such areas seen at local scale (1-10Â km) is related to physical properties that can provide information about the origin of those materials. We use Dawn's Visible and InfraRed (VIR) mapping spectrometer hyperspectral data to retrieve surface temperatures and emissivities, with high accuracy as long as temperatures are greater than 220Â K. Some of the dark and bright features were observed multiple times by VIR in the various mission phases at variable spatial resolution, illumination and observation angles, local solar time, and heliocentric distance. This work presents the first temperature maps and spectral emissivities of several kilometer-scale dark and bright material units on Vesta. Results retrieved from the infrared data acquired by VIR show that bright regions generally correspond to regions with lower temperature, while dark regions correspond to areas with higher temperature. During maximum daily insolation and in the range of heliocentric distances explored by Dawn, i.e. 2.23-2.54Â AU, the warmest dark unit found on Vesta rises to a temperature of 273Â K, while bright units observed under comparable conditions do not exceed 266Â K. Similarly, dark units appear to have higher emissivity on average compared to bright units. Dark-material units show a weak anticorrelation between temperature and albedo, whereas the relation is stronger for bright material units observed under the same conditions. Individual features may show either evanescent or distinct margins in the thermal images, as a consequence of the cohesion of the surface material. Finally, for the two categories of dark and bright materials, we were able to highlight the influence of heliocentric distance on surface temperatures, and estimate an average temperature rate change of 1% following a variation of 0.04Â AU in the solar distance.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Icarus - Volume 240, 15 September 2014, Pages 36-57
Journal: Icarus - Volume 240, 15 September 2014, Pages 36-57
نویسندگان
F. Tosi, M.T. Capria, M.C. De Sanctis, J.-Ph. Combe, F. Zambon, A. Nathues, S.E. Schröder, J.-Y. Li, E. Palomba, A. Longobardo, D.T. Blewett, B.W. Denevi, E. Palmer, F. Capaccioni, E. Ammannito, T.M. Titus, D.W. Mittlefehldt, J.M. Sunshine,