An investigation of stellar motions: VIII. Secular parallaxes, luminosity distribution, and distances for stars of ninth to eleventh magnitudes

The secular parallaxes from McCormick proper motion material have been carefully investigated for systematic errors and considerable confidence in the material has been gained. The parallaxes derived from the motions in right ascension are in fair agreement with those derived from the motins in declination. The combined values agree well with those derived from peculiar motions in the Selected Areas. The parallaxes derived from the motions of the First McCormick Catalogue, however, show a certain amount of systematic difference in high latitudes from those derived from the motions of the Second Catalogue. An increasing number of dwarfs among the later spectral types is clearly evident with increasing magnitude. Estimates are given as to the relative numbers of giants and dwarfs in the various spectral groups. Remarkedly good agreement is found with the luminosity distribution among the stars of various spectral types in Stenquist's spectrophotometric study of the Cambridge proper motion stars. Mean distances have been derived for the stars in those spectral groups where the dispersion in absolute magnitudes in not too great.