ESTIMATION OF THE LUNAR PHYSICAL LIBRATIONS

Authors
NEWHALL XX WILLIAMS JG
Citation
Xx. Newhall et Jg. Williams, ESTIMATION OF THE LUNAR PHYSICAL LIBRATIONS, Celestial mechanics & dynamical astronomy, 66(1), 1997, pp. 21-30
Citations number
8
Categorie Soggetti
Astronomy & Astrophysics
Journal title
Celestial mechanics & dynamical astronomy → ACNP
ISSN journal
09232958
Volume
66
Issue
1
Year of publication
1997
Pages
21 - 30
Database
ISI
SICI code
0923-2958(1997)66:1<21:EOTLPL>2.0.ZU;2-B
Abstract
The recent long-term integration of JPL ephemeris DE403/LE403 yielded lunar physical librations covering 6000 years. A Fourier analysis of a 718-year subset of this span produced estimates of the component freq uencies of the forced and free librations. A subsequent iterative leas t-squares estimation procedure provided precise values for phases and for time-varying amplitudes and frequencies. Two free libration modes were found; presence of a third is possible but close to the noise.