The late-type stellar content of NGC 2403

Abstract

The late-type stellar content of three disk fields in NGC 2403 was examined using Cousins RI and VI CCD photometry. The AGB luminosity function has been constructed separately for the inner and outer fields. In both cases, relatively fewer bright AGB stars are seen in the NGC 2403 fields than in the LMC. The shape of the AGB luminosity function for the innermost field is quite different from that of the LMC, and there is an indication that recent star formation may have occurred. Several red and blue supergiants and H II regions are also identified in the field to support this. The luminosity function for the outer NGC 2403 fields appears more similar to that of the LMC, and a difference in the star-formation rate in the two regions of NGC 2403 is suggested. A narrowband photometric technique has been used to identify carbon and M stars in the innermost field. Several late M stars are identified, but the carbon star identifications are, at best, tentative. 38 refs.