A revised moving cluster distance to the Pleiades open cluster

TL;DR

This paper presents a revised moving cluster method to estimate the distance to the Pleiades, aligning well with recent Gaia and VLBI measurements, and addressing previous discrepancies with Hipparcos data.

Contribution

It introduces an updated implementation of the convergent point method applied to a large star sample, providing a new, precise distance estimate for the Pleiades cluster.

Findings

Derived a mean parallax of 7.44 mas for Pleiades stars.

Estimated a cluster distance of approximately 134.4 pc.

Results favor recent VLBI and Gaia measurements over Hipparcos.

Abstract

Aims: We provide a new distance estimate for the Pleiades based on the moving cluster method, which will be useful to further discuss the so-called Pleiades distance controversy and compare it with the very precise parallaxes from the Gaia space mission. Methods: We apply a refurbished implementation of the convergent point search method to an updated census of Pleiades stars to calculate the convergent point position of the cluster from stellar proper motions. Then, we derive individual parallaxes for 64 cluster members using radial velocities compiled from the literature, and approximate parallaxes for another 1146 stars based on the spatial velocity of the cluster. This represents the largest sample of Pleiades stars with individual distances to date. Results: The parallaxes derived in this work are in good agreement with previous results obtained in different studies (excluding Hipparcos) for individual stars in the cluster. We report a mean parallax of $7.44\pm 0.08$~mas and distance of $134.4^{+2.9}_{-2.8}$pc that is consistent with the weighted mean of $135.0\pm 0.6$pc obtained from the non-Hipparcos results in the literature. Conclusions: Our result for the distance to the Pleiades open cluster is not consistent with the Hipparcos catalog, but favors the recent and more precise distance determination of $136.2\pm 1.2$pc obtained from Very Long Baseline Interferometry observations. It is also in good agreement with the mean distance of $133\pm 5$pc obtained from the first trigonometric parallaxes delivered by the Gaia satellite for the brightest cluster members in common with our sample.