THE LUMINOSITY FUNCTION OF M DWARF STARS IN SELECTED AREA 109

This paper presents the photometric luminosity classification of M dwarfs in Kaptyn’ s Selected Area 109 (SA109) as part of an ongoing program at Ball State University to probe low luminosity star contributions to the luminosity function. The reduction of data taken at the Southeastern Association for Research in Astronomy (SARA) telescope is still in the initial phases, but comparisons of this data to previous data from the National Undergraduate Research Observatory (NURO) and the Ball State Observatory (BSO) show that the classification results are consistent. With a limiting magnitude of R=15.25, we have observed nearly half of a square degree in SA109 and have detected approximately 74 percent of the expected M dwarfs, as determined by the luminosity function. The 26 M dwarfs which have been identified using R, I and CaH photometry, are confirmed using 2MASS J, H an K magnitudes. We present the detections of 17±4.1 early type M dwarfs in half of SA109, compared to the expected value of 16±4 for the entire region as determined the accepted luminosity function. Subject headings: stars: luminosity function and mass function