A 3D view of the Hyades stellar and sub-stellar population

TL;DR

This paper creates the first 3D map of the Hyades cluster, combining Gaia data with ground-based parallaxes to identify members across stellar and sub-stellar masses, revealing mass segregation and cluster properties.

Contribution

It integrates Gaia and ground-based data to produce a comprehensive 3D map of the Hyades, including stellar and sub-stellar members, and analyzes its mass function and age.

Findings

Identified 710 candidate members within 30 pc of the Hyades center.

Confirmed brown dwarf membership through proper motions and parallaxes.

Detected mass segregation and a dearth of brown dwarfs in the core.

Abstract

Our scientific goal is to provide a 3D map of the nearest open cluster to the Sun, the Hyades, combining the recent release of Gaia astrometric data, ground-based parallaxes of sub-stellar member candidates and photometric data from surveys which cover large areas of the cluster. We combined the second Gaia release with ground-based H-band parallaxes obtained with the infrared camera on the 2-m robotic Liverpool telescope to astrometrically identify stellar and sub-stellar members of the Hyades, the nearest open cluster to the Sun. We find 1764 objects within 70 degree radius from the cluster center from the Gaia second data release, whose kinematic properties are consistent with the Hyades. We limit our study to 30 pc from the cluster center (47.03+/-0.20 pc) where we identify 710 candidate members, including 85 and 385 in the core and tidal radius, respectively. We determine proper motions and parallaxes of eight candidate brown dwarf members and confirm their membership. Using the 3D positions and a model-based mass-luminosity relation we derive a luminosity and mass function in the 0.04 to 2.5 Msun range. We confirm evidence for mass segregation in the Hyades and find a dearth of brown dwarfs in the core of the cluster. From the white dwarf members we estimate an age of 640$^{+67}_{-49}$ Myr. We identify a list of members in the Hyades cluster from the most massive stars down to the brown dwarfs. We produce for the first time a 3D map of the Hyades cluster in the stellar and sub-stellar regimes and make available the list of candidate members.