Spectroscopy of Hyades L dwarf candidates

TL;DR

This study confirms several L dwarf candidates as Hyades cluster members using spectroscopy and astrometry, providing valuable data on their properties and updating the cluster's mass function near the hydrogen-burning limit.

Contribution

It presents spectroscopic and astrometric confirmation of L dwarf members in the Hyades, bridging the gap between M and T dwarfs and refining the cluster's mass function.

Findings

Confirmed several L dwarf candidates as Hyades members.

Provided spectral templates at 625 Myr age and super solar metallicity.

Updated the Hyades mass function across the hydrogen-burning limit.

Abstract

We present the results of photometric, astrometric, and spectroscopic follow-up of L dwarf candidates identified in the Hyades cluster by Hogan et al. (2008). We obtained low-resolution optical spectroscopy with the OSIRIS spectrograph on the Gran Telescopio de Canarias for all 12 L dwarf candidates as well as new J-band imaging for a subsample of eight to confirm their proper motion. We also present mid-infrared photometry from the Wise Field Infrared Survey Explorer (WISE) for the Hyades L and T dwarf candidates and estimate their spectroscopic distances, effective temperatures, and masses. We confirm the cool nature of several L dwarf candidates and confirm astrometrically their membership, bridging the gap between the coolest M dwarfs and the two T dwarfs previously reported in the Hyades cluster. These members represent valuable spectral templates at an age of 625 Myr and slightly super solar metallicity (Fe/H=+0.13). We update the Hyades mass function across the hydrogen-burning limit and in the substellar regime. We confirm a small number numbers of very-low-mass members below ~0.1 Msun belonging to the Hyades cluster.