An Empirical Explanation of the Anomalous Increases in the Astronomical Unit and the Lunar Eccentricity

TL;DR

This paper proposes that small additional radial accelerations proportional to orbital velocity can explain observed anomalies in the astronomical unit and lunar eccentricity, aligning with the Hubble constant.

Contribution

It introduces a phenomenological model with a radial acceleration term proportional to orbital velocity to explain orbital anomalies.

Findings

The model accounts for the anomalous increase in the astronomical unit.

The model explains the lunar eccentricity anomaly.

Numerical agreement with observed anomalies using the Hubble parameter.

Abstract

Both the recently reported anomalous secular increase of the astronomical unit, of the order of a few cm yr^-1, and of the eccentricity of the lunar orbit e_ = (9+/-3) 10^-12 yr^-1 can be phenomenologically explained by postulating that the acceleration of a test particle orbiting a central body, in addition to usual Newtonian component, contains a small additional radial term proportional to the radial projection vr of the velocity of the particle's orbital motion. Indeed, it induces secular variations of both the semi-major axis a and the eccentricity e of the test particle's orbit. In the case of the Earth and the Moon, they numerically agree rather well with the measured anomalies if one takes the numerical value of the coefficient of proportionality of the extra-acceleration approximately equal to that of the Hubble parameter H0 = 7.3 10^-11 yr^-1.