Recent star formation in the lupus clouds as seen by herschel

Abstract

We present a study of the star formation histories of the Lupus I, III, and IV clouds using the Herschel 70–500μm maps obtained by the Herschel Gould Belt Survey Key-Project. By combining the new Herschel data with the existing Spitzer catalog we obtained an unprecedented census of prestellar sources and young stellar objects in the Lupus clouds, which allowed us to study the overall star formation rate (SFR) and efficiency (SFE). The high SFE of Lupus III and its decreasing SFR suggest that Lupus III is the most evolved cloud, that after having experienced a major star formation event, is now approaching the end of its current star-forming cycle. Lupus I is currently undergoing a large star formation event, apparent by the increasing SFR. Also Lupus IV has an increasing SFR, however, the relative number of prestellar sources is much lower than in Lupus I, suggesting that its star formation has not yet reached its peak.