Stellar content of nearby galaxies. I - BVRI CCD photometry for IC 1613
1988; Institute of Physics; Volume: 96; Linguagem: Inglês
10.1086/114878
ISSN1538-3881
Autores Tópico(s)Stellar, planetary, and galactic studies
ResumoBVRI photometry of over 2000 stars in two fields in IC 1613 has been obtained from CCD frames taken at the prime focus of the Canada-France-Hawaii telescope. The disk of IC 1613 is seen to contain stars with a range of ages: (1) young stars indicated by a distinctive plume of luminous blue stars, yellow super- giants, Cepheids, and a smaller number of red supergiant candidates at comparable luminosities, (2) intermediate-age stars, typified by very red extended asymptotic-giant-branch stars and carbon stars, and, finally (3) a population consistent with that of an old, red giant population, the bright tip of which is found to resolve at V~21.8 mag. The I photometry of resolved stars defining the tip of this red giant branch yields a distance-modulus estimate for IC 1613 of 24.2 +/- 0.2 mag, in good agreement with previous estimates of this modulus. The metallicity of the giant-branch stars is obtained from its (V-I) color, and this population component is found to be metal poor with [Fe/H] ~ -1.3 dex and a dispersion of about +/- 0.8 dex. A visual inspection of good-seeing CCD frames and plates indicates that the number of clusters in IC 1613 is very low, confirming Baade's original suggestion. Finally, color-magnitude diagrams of ten of the Hodge associations in the two CCD fields are presented.
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