Previous abstract Next abstract
The study of NGC 2023 by Depoy, Lada, Gatley and Probst, (Ap.J. 356, L55, 1990), which extended previous data to K = 15, showed a truncation of the luminosity function for stars fainter the K = 12. This was unexpected, since the Salpeter IMF predicts that approximately 50 more stars brighter than K = 15 should be present. They concluded that the low luminosity stars are either enshrouded by dust or that no low mass star formation occured. If the stars are enshrouded by dust, they should be detectable at longer infrared wavelengths. To search for these infrared sources, which mark the presence of low mass stars, we used the UCSD 10 micron imaging array (16x64 pixels, 1 pixel = 0.83") to obtain a mosaic image of the cluster. We also obtained a mosaic image of NGC 2024, which agrees with the Salpeter IMF, as a comparison with NGC 2023. Integration times were 12.5 minutes for NGC 2023 and 2.5 minutes for NGC 2024. This leads to a 5-sigma detection limit of 5 magnitudes and 4 magnitudes respectively. No new sources were discovered in either cluster; so we conclude that NGC 2023 has not formed any significant number of low mass stars.
Wednesday program listing