کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1781600 1022292 2011 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Measurement of the radius of Mercury by radio occultation during the MESSENGER flybys
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فیزیک زمین (ژئو فیزیک)
پیش نمایش صفحه اول مقاله
Measurement of the radius of Mercury by radio occultation during the MESSENGER flybys
چکیده انگلیسی

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft completed three flybys of Mercury in 2008–2009. During the first and third of those flybys, MESSENGER passed behind the planet from the perspective of Earth, occulting the radio-frequency (RF) transmissions. The occultation start and end times, recovered with 0.1 s accuracy or better by fitting edge-diffraction patterns to the RF power history, are used to estimate Mercury's radius at the tangent point of the RF path. To relate the measured radius to the planet shape, we evaluate local topography using images to identify the high-elevation feature that defines the RF path or using altimeter data to quantify surface roughness. Radius measurements are accurate to 150 m, and uncertainty in the average radius of the surrounding terrain, after adjustments are made from the local high at the tangent point of the RF path, is 350 m. The results are consistent with Mercury's equatorial shape as inferred from observations by the Mercury Laser Altimeter and ground-based radar. The three independent estimates of radius from occultation events collectively yield a mean radius for Mercury of 2439.2±0.5 km.


► Radio-frequency occultations are used to estimate Mercury's radius.
► Measurement accuracy is 150 m.
► Radius measurements are adjusted for local topography.
► Results are consistent with those of the Mercury Laser Altimeter.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Planetary and Space Science - Volume 59, Issue 15, December 2011, Pages 1925–1931
نویسندگان
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