A VLBI Resolution of the Pleiades Distance Controversy

Abstract

Because of its proximity and its youth, the Pleiades open cluster of stars has been extensively studied and serves as a cornerstone for our understanding of the physical properties of young stars. This role is called into question by the "Pleiades distance controversy" wherein the cluster distance of 120.2+/-1.5 pc as measured by the optical space astrometry mission Hipparcos is significantly different from the distance of 133.5+/-1.2 pc derived with other techniques. We present an absolute trigonometric parallax distance measurement to the Pleiades cluster that uses very long baseline radio interferometry. This distance of 136.2+/-1.2 pc is the most accurate and precise yet presented for the cluster and is incompatible with the Hipparcos distance determination. Our results cement existing astrophysical models for Pleiades-age stars.