Interstellar extinction in the direction of the open cluster IC 348 and the Per OB2 association

The relationship between interstellar extinction and distance in the direction of dark clouds in the areas around the open cluster IC 348 and the association Per 0B2 is determined using the results of photoelectric photometry of 189 stars in the Vilnius photometric system. Two absorbing layers are found. The nearest layer, covering the whole area around IC 348, shows the mean extinction Ay of ~0.7 mag. It begins at the distance of 160 pc and probably is an extension of the Taurus dark clouds to the north-west. The second absorbing layer has the form of a chain of dark condensations, named L1468, L1470 and L1471 and is at 260 pc distance. This layer has a higher density, its mean extinction being ~2.0 mag. The cluster IC 348 is at about the same distance and is physically related with the dark cloud L1470. Distance of the Per OB2 association is found to be 340 pc, the mean extinction of its members is 0.95 mag. A model of spatial distribution of the Perseus and Taurus dark clouds based on photometric distance determinations in this and previous papers is proposed. Six stars in the IC 348 area are suspected to have an emission in the Ha line.