Key points are not available for this paper at this time.
This paper presents the first purely photometric derivation of the stellar main-sequence luminosity function to absolute magnitude MV = + 19, which is comparable to the minimum mass for thermonuclear burning. The observations consist of COSMOS measures of UK Schmidt telescope plates in the V, R and I bands. They provide a complete sample of every star in 18. 24 square degrees towards the South Galactic Pole, brighter than I = 17. 0. Absolute magnitudes and distances are derived by photometric parallax from the |Mₕ/V-I\, and\, Mₕ/I-K| relations, which have been carefully calibrated on our photometric system. For |+\, 9\, \, Mₕ\, \, +19|, the photometrically defined luminosity function is in agreement with that derived from samples of nearby stars, and by proper motion techniques. There is no evidence for any excess of intrinsically faint stars, even though this survey reaches some 5mag deeper into the luminosity function than previous photometric surveys. Re-analysis of subsamples of other photometric studies of the local stellar density removes any evidence for a significant excess of M dwarfs relative to the kinematically derived luminosity function. The missing mass in the solar neighbourhood, if any, does not reside in main-sequence stars brighter than |Mₕ\, \, +\, 17| mag.
Reid et al. (Mon,) studied this question.