THE ASTRONOMICAL JOURNAL    VOLUME 112, NUMBER 6, PAGE 2559       DECEMBER 1996

                    SUPERGIANT STARS IN THE DISK OF NGC 672

                                YOUNG-JONG SOHN

   Yonsei University Observatory, 134 Sinchon-Dong, Seoul 120-749, Korea and
      Dominion Astrophysical Observatory, HIA, NRC, 5071 W. Saanich Road,
                         Victoria, BC, V8X 4M6, Canada
                       Electronic mail: sohn@dao.nrc.ca

                                 T. J. DAVIDGE

  Gemini Canada Project Office, Dominion Astrophysical Observatory, HIA, NRC,
  5071 W. Saanich Road, Victoria, BC, Canada and Department of Geophysics and
        Astronomy, University of British Columbia, 129-2219 Main Hall,
                             Vancouver, BC, Canada
                      Electronic mail: davidge@dao.nrc.ca


                                   ABSTRACT

    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
    15 Msun and 25 Msun, 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.