Measurements of Mercury librations from image and altimeter data

Abstract

The libration of Mercury provides through its dependence on the inertial axes a possibility to get a better understanding of the internal structure of the planet. We present a new method which allows the determination of the libration by a combination of two complementary data sets. The laser altimetry data provide a high height resolution and by several Obrservation also a temporal distribution. However, the stereo models derived from image data have a better lateral resolution and are fixed in time. Based on the latest observations from the MESSENGER spacecraft we present the first results of our measurements.