A deep large‐area search for very low‐mass members of the Hyades open cluster

ABSTRA C T We present the results of a comprehensive I- and Z-band photometric survey of 10.5 deg 2 of the Hyades to search for low-mass stellar and substellar members. The survey, which is * 95 per cent photometrically complete to IC < 20:3, has unearthed a total of 20 candidates, 14 of which are previously uncatalogued. Despite follow-up observations indicating that nine display spectral energy distributions consistent with cluster membership, a detailed astrometric study of all 20 reveals that only one, the previously known stellar member RHy297, displays a proper motion typical of a Hyad. We discuss our failure to detect further low-mass members in terms of the shape of the present-day mass function of the Hyades and find that dynamical evolution has probably led to their preferential evaporation from the cluster.

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