Radius and limb topography of Mercury obtained from images acquired during the MESSENGER flybys

Analysis of images obtained by the MESSENGER spacecraft during its three flybys of Mercury yields a new estimate for the planet's mean radius of 2439.25±0.69 km, in agreement with results from Mariner 10 and Earth-based observations, as well as with MESSENGER altimeter and occultation data. The...

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Bibliographic Details
Published in:Planetary and space science 2011-12, Vol.59 (15), p.1918-1924
Main Authors: Oberst, Jürgen, Elgner, Stephan, Turner, F. Scott, Perry, Mark E., Gaskell, Robert W., Zuber, Maria T., Robinson, Mark S., Solomon, Sean C.
Format: Article
Language:English
Subjects:
Imaging
Mercury
MESSENGER
Radius
Topography
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Summary:Analysis of images obtained by the MESSENGER spacecraft during its three flybys of Mercury yields a new estimate for the planet's mean radius of 2439.25±0.69 km, in agreement with results from Mariner 10 and Earth-based observations, as well as with MESSENGER altimeter and occultation data. The mean equatorial radius and polar radius are identical to within error, suggesting that rotational oblateness is negligible when compared with other sources of topography. This result is consistent with the small gravitational oblateness of the planet. Minor differences in radius obtained at different locations reflect regional variations in topography. Residual topography along three limb profiles has a dynamic range of 7.4 km and a root-mean-square roughness of 0.8 km over hemispherical scales. Following MESSENGER's entry into orbit about Mercury in March 2011, we expect considerable additional improvements to our knowledge of Mercury's size and shape. ► We analyze images obtained by the MESSENGER spacecraft during three flybys of Mercury. ► We obtain a new estimate for Mercury's mean radius of 2439.25±0.69 km. ► The mean equatorial radius and polar radius of Mercury are identical to within error. ► The residual topography along the Mercury limb has a dynamic range of 7.4 km and a root-mean-square roughness of 0.8 km.
ISSN:0032-0633
1873-5088
DOI:10.1016/j.pss.2011.07.003