The perihelion precession of Saturn, planet X/Nemesis and MOND

TL;DR

This paper proposes that Saturn's observed perihelion precession can be explained by a distant, unseen body X, with its properties and location estimated, and discusses implications for MOND and the hypothetical Nemesis object.

Contribution

It introduces a model linking Saturn's perihelion precession to a localized distant body X, estimating its possible properties and location, and explores implications for MOND and Nemesis.

Findings

Distant body X can explain Saturn's perihelion precession.

Estimated distances for X vary from 80 au to 10 kau depending on its mass.

X's position could mimic effects predicted by MOND's External Field Effect.

Abstract

We show that the retrograde perihelion precession of Saturn \Delta\dot\varpi, recently estimated by different teams of astronomers by processing ranging data from the Cassini spacecraft and amounting to some milliarcseconds per century, can be explained in terms of a localized, distant body X, not yet directly discovered. From the determination of its tidal parameter K = GM_X/r_X^3 as a function of its ecliptic longitude \lambda_X and latitude \beta_X, we calculate the distance at which X may exist for different values of its mass, ranging from the size of Mars to that of the Sun. The minimum distance would occur for X located perpendicularly to the ecliptic, while the maximum distance is for X lying in the ecliptic. We find for rock-ice planets of the size of Mars and the Earth that they would be at about 80-150 au, respectively, while a Jupiter-sized gaseous giant would be at approximately 1 kau. A typical brown dwarf would be located at about 4 kau, while an object with the mass of the Sun would be at approximately 10 kau, so that it could not be Nemesis for which a solar mass and a heliocentric distance of about 88 kau are predicted. If X was directed towards a specific direction, i.e. that of the Galactic Center, it would mimick the action of a recently proposed form of the External Field Effect (EFE) in the framework of the MOdified Newtonian Dynamics (MOND).