J. Borissova et al., The red stellar contents of three selected fields of the local group dwarfirregular galaxy IC 1613, REV MEX AST, 36(2), 2000, pp. 151-160
We present a moderately-deep JK photometry for three selected areas of the
dwarf irregular galaxy IC 1613. The color-magnitude diagrams contain a mixt
ure of red supergiants, asymptotic giant branch stars and the brightest red
giant stars. The red supergiants are massive (20-25 M.) and young-with age
s between 8 and 25 Myr. The most important result is the evidence of the de
creasing density of the intermediate age AGB population in the vicinity of
the HII regions in the galaxy. We also find age differences between AGB sta
rs in the main body of the galaxy and those near the HII regions in the Nor
th-East. The former span a range in ages between 1 and 10 Gyr, while the la
tter are younger than 1 Gyr. Using the period-luminosity relation derived b
y Madore & Freedman (1991) and JK magnitudes of the Cepheid variable V20, w
e calculated (m - M)(K) = 24.37 +/- 0.2. The recently discovered Nova (King
, Modjaz, & Li 1999) was identified in Field III. Its presence in our image
s and its brightness questioned its classification as a nova.