Interstellar Reddening in the North Galactic Polar Cap I. The Dependence on Distance from the Galactic Plane

Abstract

AbstractInterstellar reddening within the North Galactic Polar Cap (b11 ≥ 60 °) is determined from published UBV photometry of 38 stars with spectral type earlier than A. The detailed discussion of line‐blanketing and effects of surface gravity reveals that the horizontal‐branch stars and the hot subdwarfs among the sample can be treated like ordinary main‐sequence stars of Population I as far as the determination of colour excesses is concerned. No reddening is detected for stars with distances from the galactic plane less than 250 pc. For larger distances the mean colour excess slowly rises and keeps constant at EB—V = 0.033 mag for stars beyond 1000 pc from the sun. The latter objects show a considerable scatter in the individual amounts of reddening.