Trumpler's Radial Velocities of Stars in Galactic Star Clusters

TL;DR

This paper evaluates the accuracy of Trumpler's historical radial velocity measurements of stars in Galactic clusters, confirming their reliability and providing extensive data for long-term astrophysical studies.

Contribution

It validates the zero-point and scale of Trumpler's velocities against modern standards and offers a comprehensive dataset for future dynamical research.

Findings

Trumpler's velocities have a 2-7 km/s accuracy.

They share the same zero-point and scale as modern standards.

A dataset of 3,782 velocities is provided online.

Abstract

We assess the accuracy of radial velocities of 671 stars located near Galactic clusters, measured by Robert Trumpler between 1924 and 1947 using the Lick Observatory 36 inch refractor equipped with prism spectrometers. We find that Trumpler's velocities share the same zero-point and scale as modern IAU radial velocity standards. Their accuracy ranges from 2 to 7 km/s. We also provide star identifications, B-band photometry, and notes for many stars. We provide a link to an online PDF that contains all 3,782 of Trumpler's individual stellar radial velocities and associated Julian dates. Trumpler's velocities provide a century-long baseline for detecting long-period stellar companions, gravitational perturbations from passing massive objects, and accelerations due to cluster and Galactic dynamics.