Abstract

Within the next few years, several instruments aiming at imaging extrasolar planets will see first light. In parallel, low mass planets are being searched around red dwarfs which oer more favorable conditions, both for radial velocity detection and transit studies, than solar-type stars. We review recent advancements and issues concerning the construction of synthetic spectral libraries for very low mass stars, brown dwarfs and exoplanets. The revised solar oxygen abundances and cloud models allow to reproduce the photometric and spectroscopic properties of this transition to a degree never achieved before, but problems remain in the important M-L transition characteristic of the Te range of characterizable exoplanets.