Dynamical masses for the triple system HD 28363 in the Hyades cluster

TL;DR

This study determines the dynamical masses of all three stars in the hierarchical triple system HD 28363 in the Hyades cluster by combining spectroscopic, astrometric, and visual data, providing valuable empirical data for stellar evolution models.

Contribution

First dynamical mass measurements of all three stars in the HD 28363 system, integrating multiple observational techniques for a comprehensive analysis.

Findings

Masses of the three stars are precisely measured.

Results support existing stellar evolution models for the Hyades.

The system's properties help refine the empirical mass-luminosity relation.

Abstract

The star HD 28363 in the Hyades cluster has been known for over a century as a visual binary with a period of 40 yr. The secondary is, in turn, a single-lined spectroscopic binary with a 21-day period. Here we report extensive spectroscopic monitoring of this hierarchical triple system that reveals the spectral lines of the third star for the first time. Combined with astrometric information, this makes it possible to determine the dynamical masses of all three stars. Only six other binaries in the Hyades have had their individual component masses determined dynamically. We infer the properties of the system by combining our radial velocity measurements with visual observations, lunar occultation measurements, and with proper motions from the Hipparcos and Gaia missions that provide a constraint on the astrometric acceleration. We derive a mass of 1.341 +/- 0.026/0.024 M(Sun) for the visual primary, and 1.210 +/- 0.021 M(Sun) and 0.781 +/- 0.014 M(Sun) for the other two stars. These measurements along with those for the other six systems establish an empirical mass-luminosity relation in the Hyades that is in broad agreement with current models of stellar evolution for the known age and chemical composition of the cluster.