On the Earth's tidal perturbations. II. LARES 2 satellite
V. G. Gurzadyan, I. Ciufolini, H. G. Khachatryan, S. Mirzoyan, A. Paolozzi
TL;DR
The paper addresses the need for accurate Earth-tide modeling to extract the frame-dragging signal (Lense–Thirring effect) from laser-ranging satellites, focusing on the LARES 2 mission. It employs Kaula's tidal-potential expansion with spherical harmonics $Y_{lm}$ and frequency-dependent Love numbers $k_{lm}( u)$ to compute 110 significant tidal modes, classified by Doodson numbers, and selects long-period $l=2$ modes with $p=1$, $q=0$, and $m=0,1,2$. The study reports detailed amplitudes $ riangle ilde{ abla}AOmega$ in milliarcseconds and periods (in days) for these modes (Tables 1–3), enabling more precise disentanglement of tidal effects from the frame-dragging signal. By integrating these results with long-baseline laser-ranging data, the work enhances tests of General Relativity and informs geodesy, while contributing to broader constraints on modified gravity theories related to the dark sector and cosmological tensions; the approach hinges on $V_{lm}$, $S_{lmpq}$, and the frequency-dependent $ u$ embedded in $k_{lm}( u)$.
Abstract
Laser-ranging satellites have proved their efficiency in high precision testing of General Relativity and constraining modified gravity theories proposed to explain the dark sector and the cosmological tensions. The LARES 2 satellite launched in 2022, is currently providing improved information regarding the frame-dragging effect predicted by General Relativity, as well as the geodesy, thus essentially complementing the data of already existing laser-ranging satellites. The proper knowledge of the Earth's tidal perturbation modes is essential for accurately extracting the sought frame-dragging signal. We present the results of computation of 110 significant modes in Doodson number classification for the parameters of LARES 2 satellite, continuing our previous study on those obtained for the LARES satellite.