Asymptotic giant branch stars in the Large Magellanic Cloud Results from a deep BV survey and theoretical implications

Late-type stars in part of the Bar West field in the Large Magellanic Cloud, discovered through either grism or near-IR surveys, have been identified with their counterparts in the deep B and V photographic survey published by Hardy et al. in 1984, thus both allowing an assessment of the degree of completeness of carbon star surveys and providing BV photometry for carbon stars as well as non-carbon stars. While existing carbon star surveys appear to be reasonably complete, little can be said about the completeness of surveys of non-carbon AGB stars, as bolometrically bright M type AGB stars are found to overlap normal K giants in the V = (B - V) diagram. Some implications of these findings are then briefly discussed, the question of the paucity in the Magellanic Clouds of bright asymptotic giant branch (AGB) stars is revisited, and the notion is introduced that theoretical calculations may have strongly overestimated the mass limit M(up), below which stars develop an electron degenerate C-O core and experience the thermally pulsing AGB phase, and above which carbon is ignited, and burned in a nondegenerate core. 36 references