V, R, and I CCD images are used to investigate the photometric properties and spatial distribution of supergiants in the nearby interacting galaxy NGC 672. Not counting stars imbedded in H II regions, our sample consists of 237 objects. The (V - R, V - I) two-color diagram indicates that the majority of these stars have spectral types between A - K. Statistical tests show that the outer region of NGC 672 contains a redder population of supergiants than the inner region. Comparisons with theoretical evolutionary tracks indicate that the majority of the supergiants in NGC 672 have progenitor masses between 15M⊙ and 25M⊙, and that the inner regions contain stars that are more massive than in the outer disk, indicating that an age gradient is present. The luminosity functions in all three bandpasses follow power laws, and the exponent in V=0.79±0.06, in good agreement with other galaxies. The brightest RSGs occur at V∼22.0, from which we derive a distance modulus of 29.5, corresponding to 7.9+1.0-0.9 Mpc.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science