Intermediate-Brightness Spectrophotometric Standards. Standards Near +40° Declination

Abstract

The second stage in our program to compile a list of regional intermediate-brightness spectrophotometric standards has been completed. We have obtained spectral energy distributions for 24 stars with magnitudes near +40° declination. The range λλ3100 7600 Å was studied with a spectral resolution of 50 Å. The relative rms error of our results in the visible is 1 2%, increasing to 3 5% toward the edges of the studied wavelength interval. All the stars are referenced to a single standard, the circumpolar star HD 221525. The energy distributions were used to compute color indices in the UBV, WBVR, and UPXY ZV S systems, as well as in the system of the TYCHO catalog. The computed and observed values for stars in common with the TYCHO catalog are compared.