APMPM J0559-2903: The coolest extreme subdwarf known

We present the discovery of the coolest extreme subdwarf known-to date. APM PM J0559-2903 was measured to be esdM7. Unlike for solar metallicity dwarfs , there are no very late type objects known among the extreme subdwarfs. APMPM J0559-2903 was discovered in a new southern high proper motion survey . Follow up spectroscopy at Keck was used to identify the spectral type wit h the help of spectral indices. Using the NextGen grid of model atmospheres by Hauschildt et al. (1999) we measured the effective temperature to be 3100 K and the metallicity to be M /H=-1.5. The theoretical parameters place APMPM J0559-2903 at a distance of 100 pc with a space velocity of 260 km s(-1) relative to the local standar d of rest.