Lynds 1622 : a nearby star forming cloud projected on Orion B ?

We present results of optical spectroscopic and photometric observation of the premain sequence stars associated with the cometary shaped dark cloud Lynds 1622, and CO and CO observations of the cloud. We determined the effective temperatures and luminosities of 14 pre-main sequence stars associated with the cloud from their positions in the Hertzsprung–Russell diagram, as well as constructed their spectral energy distributions using optical, 2MASS and Spitzer IRAC and MIPS data. We derived physical parameters of L 1622 from the molecular observations. Our results are not compatible with the assumption that L 1622 lies on the near side of the Orion– Eridanus loop, but suggest that L 1622 is as distant as Orion B. At a distance of 400 pc the mass of the cloud, derived from our CO data, is 1100M⊙, its star formation efficiency is ∼ 1.8%, and the average age of its low-mass pre-main sequence star population is about 1 million years.