The influence of Galactic aberration on precession parameters determined from VLBI observations

TL;DR

Galactic aberration significantly affects precession and nutation parameters derived from VLBI data, necessitating correction for accurate modern astrometric models.

Contribution

This paper quantifies the impact of Galactic aberration on precession and nutation parameters from VLBI observations, highlighting its importance for precise astrometric modeling.

Findings

Galactic aberration can cause up to 20 μas per century shifts in celestial pole coordinates.

Correcting for Galactic aberration alters derived low-frequency nutation parameters.

Accounting for Galactic aberration is essential for modern precession models.

Abstract

The influence of proper motions of sources due to Galactic aberration on precession models based on VLBI data is determined. Comparisons of the linear trends in the coordinates of the celestial pole obtained with and without taking into account Galactic aberration indicate that this effect can reach 20 $\mu$as per century, which is important for modern precession models. It is also shown that correcting for Galactic aberration influences the derived parameters of low-frequency nutation terms. It is therefore necessary to correct for Galactic aberration in the reduction of modern astrometric observations.