Abstract
In view of the many interesting aspects attached to the study of stars of spectral type G, a preliminary investigation is made of the suitability of the uvby photometric system for such stars. At least for stars on the main sequence and the giant branch, the gravity and temperature resolution from uvby photometry is thought to be better than that obtained from the high-quality MK classification. It is noted that for the same stars, the resolving power of the uvby system with respect to metallicity is very good. A comparison is made with model-based color-color relations in the uvby system. Even though the basic properties of these relations are confirmed, certain corrections are thought necessary, concerning both the gravity and the metallicity model-based parameters. A considerable number of G-type stars of intermediate population II are found which belong to the main sequence as well as to the giant branch. At the same time, red horizontal-branch stars are seen as extremely rare in the solar neighborhood, if they are present at all.
