%0 Journal Article %T Nombre de classes des tores de multiplication complexe et bornes inferieures pour orbites Galoisiennes de points speciaux %A Emmanuel Ullmo %A Andrei Yafaev %J Mathematics %D 2012 %I arXiv %X We establish a Brauer-Siegel type formula for class numbers of CM tori. We deduce lower bounds for Galois orbits of certain Shimura varieties. %U http://arxiv.org/abs/1209.0942v2