On the most reliable value of the Galactic aberration constant

Abstract

Galactic aberration (GA) is a small effect in proper motions of celestial objects with an amplitude of about 5 $\mu$as/yr already noticeable in highly accurate astrometric observations such as VLBI and Gaia. However accurate accounting for this effect faces difficulty caused by the uncertainty in the GA amplitude (GA constant). Its estimates derived from VLBI and Gaia data processing differ significantly, so it would be very desirable to involve another independent method to solve the problem of inconsistency between these two methods. Such a method, that we consider in this paper, is using determination of the Galactic rotation parameters by methods of stellar astronomy. The result obtained in this study showed that the GA constant estimate obtained from stellar astronomy is closer to the estimate obtained from Gaia.