Improvement of the IAU 2006 precession model with an updated Earth's J2 long-term variation

• Autores: Liu, J.- C.
• Año de publicación: 2025
• Idioma: inglés
• Tipo de recurso: documento de conferencia
• Materia: Ciencias Astronómicas; IAU 2006 precession; Earth dynamical flattening (J2); Satellite Laser Ranging (SLR)
• Institución: Universidad Nacional de La Plata

At its 2006 General Assembly, IAU has adopted a standard precession theory, called the "IAU 2006 precession”. The linear variation of the Earth’s dynamical flattening J2 was considered for the precession rate in longitude. However, the uncertainty in the J2 model is one of the greatest sources of uncertainty in this precession theory. In this report, we use the latest observational data from the satellite laser ranging (SLR) to investigate the effect of J2 long-time variations in solving the precession of the equator. The polynomial expressions for precession quantities are developed with a method similar to the IAU 2006 approach and are checked using the latest VLBI observations. The newly developed precession solution is clearly more consistent with VLBI observations and can reduce most of the curvature signals in the CPO series. Since the improvement relative to the IAU 2006 precession model is quite significant, we propose that a serious study for updating the IAU precession be carried out by relevant IAU Working Groups.
Facultad de Ciencias Astronómicas y Geofísicas