کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5487239 | 1523492 | 2018 | 62 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The Ceres gravity field, spin pole, rotation period and orbit from the Dawn radiometric tracking and optical data
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم فضا و نجوم
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Ceres' gravity field and rotational parameters have been precisely measured using 1.5 years of radiometric Doppler and range data and optical landmark tracking from the Dawn spacecraft in orbit about the dwarf planet. As was the case with Dawn at Vesta, the gravity field, orientation parameters, landmark locations, and Ceres' orbit are jointly estimated in a global solution. Even though Dawn's radio science investigation at Ceres was complicated by additional thrusting for attitude control, the resulting spherical harmonic gravity field has a half-wavelength resolution of up to 82â¯km (degree 18) near the equator, which is similar harmonic resolution to that of Vesta. The gravity field is consistent with Airy isostatic compensation, and this model assumption limits Ceres' crustal density to be between 1200 and 1600â¯kg/m3 for two-layer and three-layer models with mean crustal thickness between 27 and 43â¯km. The compensation depth is determined using admittance between gravity and gravity from topography and is superior to admittance between gravity and topography. The gravitational mass of Ceres is determined to better than 0.002% (GMCeresâ=â62.62736â±â0.00040âkm3/s2), the spin pole location is improved by 10à over previous results with right ascension (αâ=â291.427°) and declination (δâ=â66.760°) uncertainty less than 0.001°, and the rotation rate is improved by â¼100à over previous determinations from Hubble Space Telescope (HST) images. Ceres' heliocentric orbit has also been improved, with about 17 months of precision range measurements reducing ephemeris uncertainties to about 10â¯m during the Dawn timeframe.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Icarus - Volume 299, 1 January 2018, Pages 411-429
Journal: Icarus - Volume 299, 1 January 2018, Pages 411-429
نویسندگان
A.S. Konopliv, R.S. Park, A.T. Vaughan, B.G. Bills, S.W. Asmar, A.I. Ermakov, N. Rambaux, C.A. Raymond, J.C. Castillo-Rogez, C.T. Russell, D.E. Smith, M.T. Zuber,