Interstellar extinction in the California Nebula region

Abstract

Vilnius seven-color photometry has been obtained for 238 stars down to ~13 mag in the area of the California Nebula in Perseus. For nearly all of the stars, photometric spectral classes, luminosity classes, absolute magnitudes, interstellar reddenings, extinctions and distances are determined. The versus diagrams give evidence for the presence of one dust layer at ~160 pc distance in the direction of the California Nebula and its nearest surroundings and of two dust layers at distances of 160 pc and 300 pc north-west of the nebula, in the direction of the dark clouds L 1449 and L 1456. The front layer contributes extinction between 0.3 and 1.3 mag, and the second layer gives about 1 mag of additional extinction. It appears likely that the front dust layer is the extension of the Taurus dark clouds. The second dust layer probably belongs to the complex of dark clouds found in other areas of the southern part of Perseus (in the directions of the open cluster IC 348, the reflection nebula NGC 1333, etc.). Both cloud complexes run more or less parallel to the Galactic plane.