Metal-rich T-dwarfs in the Hyades cluster

Jerome Bouvier (1) , Tim Kendall (2) , Gwendolyn Meeus (3)

1 LAOG - Laboratoire d'Astrophysique de Grenoble
2 Centre for Astrophysics Research [Hatfield]
3 AIP - Leibniz-Institut für Astrophysik Potsdam

We present the results of a search for brown dwarfs (BDs) and very low mass (VLM) stars in the 625 Myr-old, metal-rich ([Fe/H]=0.14) Hyades cluster. We performed a deep (I=23, z=22.5) photometric survey over 16 deg$^2$ around the cluster center. We report the discovery of the first 2 BDs in the Hyades cluster, with a spectral type T1 and T2, respectively. Their optical and near-IR photometry, as well as their proper motion, are consistent with them being cluster members. According to models, their mass is about 50 Jupiter masses at an age of 625 Myr. We also report the discovery of 3 new very low mass stellar members and confirm the membership of 15 others.

Mots clés: Stars: low-mass; brown dwarfs; Galaxy: open clusters: Hyades

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Jerome Bouvier, Tim Kendall, Gwendolyn Meeus. Metal-rich T-dwarfs in the Hyades cluster. Cool Stars 15, Jul 2008, United Kingdom. ⟨hal-00330643⟩