A brown dwarf candidate in the Praesepe Open Cluster
  We present optical and infrared observations of RPr1, a faint (I = 21.01) and very red object (I - K = 4.57) discovered in a deep CCD survey, covering an area of 800 square arcmin of the Praesepe open cluster. A low resolution spectrum shows that RPr1 is a very late object, the latest object in Praesepe for which a spectrum has been taken to date. Our estimates give a mass between 0.063 and 0.084 solar masses, and indicate that RPr1 may turn out to be the first brown dwarf in this cluster. 
A. Magazzu, R. Rebolo, M. R. Zapatero Osorio, E. L. Martin, S. T.   Hodgkin