UBVRI photometry. II - The Cousins VRI system, its temperature and absolute flux calibration, and relevance for two-dimensional photometry

Abstract

The Cousins VRI system is proposed as an ideal system to adopt as the standard system for both Northern and Southern Hemisphere near-IR observations. Comparisons are made between (b-y), (G-R)6, (V-I)jJ, and (V-I)C color indices measured for a large sample of equatorial HR stars which illustrate the precision of the system and the excellent temperature sensitivity of the (V- I)C index. Transformations between the different systems including the Eggen-Kron system are derived, a temperature calibration of (b-y), (R-I)C, and (V-I)C is provided based on empirical temperature determinations, and an absolute flux calibration for UBVRI is derived.Photometry using photographic plates, electronic area detectors, and digital spectra is also discussed, and details given of specific photometric detector systems.