caa a22 4500 445862963 CHVBK 20180317145449.0 cr unu---uuuuu 170323e20110101xx s 000 0 eng 10.1007/s10569-010-9314-2 doi (NATIONALLICENCE)springer-10.1007/s10569-010-9314-2 The Moon's physical librations and determination of their free modes [Elektronische Daten] [N. Rambaux, J. Williams] The Lunar Laser Ranging experiment has been active since 1969 when Apollo astronauts placed the first retroreflector on the Moon. The data accuracy of a few centimeters over recent decades, joined to a new numerically integrated ephemeris, DE421, encourages a new analysis of the lunar physical librations of that ephemeris, and especially the detection of three modes of free physical librations (longitude, latitude, and wobble modes). This analysis was performed by iterating a frequency analysis and linear least-squares fit of the wide spectrum of DE421 lunar physical librations. From this analysis we identified and estimated about 130-140 terms in the angular series of latitude librations and polar coordinates, and 89 terms in the longitude angle. In this determination, we found the non-negligible amplitudes of the three modes of free physical libration. The determined amplitudes reach 1.296′′ in longitude (after correction of two close forcing terms), 0.032′′ in latitude and 8.183′′ × 3.306′′ for the wobble, with the respective periods of 1056.13days, 8822.88days (referred to the moving node), and 27257.27days. The presence of such terms despite damping suggests the existence of some source of stimulation acting in geologically recent times. Springer Science+Business Media B.V., 2010 Moon nationallicence Physical librations nationallicence Spin-orbit synchronous resonance nationallicence Rambaux N. Université Pierre et Marie Curie, Paris 6, IMCCE, Observatoire de Paris, CNRS UMR 8028, 77 Avenue Denfert-Rochereau, 75014, Paris, France aut Williams J. Jet Propulsion Laboratory, California Institute of Technology, 91109, Pasadena, CA, USA aut Celestial Mechanics and Dynamical Astronomy Springer Netherlands 109/1(2011-01-01), 85-100 0923-2958 109:1<85 2011 109 10569 https://doi.org/10.1007/s10569-010-9314-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10569-010-9314-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Rambaux N. Université Pierre et Marie Curie, Paris 6, IMCCE, Observatoire de Paris, CNRS UMR 8028, 77 Avenue Denfert-Rochereau, 75014, Paris, France aut NATIONALLICENCE 700 1- Williams J. Jet Propulsion Laboratory, California Institute of Technology, 91109, Pasadena, CA, USA aut NATIONALLICENCE 773 0- Celestial Mechanics and Dynamical Astronomy Springer Netherlands 109/1(2011-01-01), 85-100 0923-2958 109:1<85 2011 109 10569 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer