The Stellar Content of the Polar Rings in the Galaxies NGC 2685 and NGC 4650A

Abstract

We present the results of stellar photometry of polar ring galaxies NGC 2685 and NGC 4650A, using the archival data obtained with the Hubble Space Telescope's Wide Field Planetary Camera 2. Polar rings of these galaxies were resolved into ~800 and ~430 stellar objects in the B, V, and IC bands, a considerable part of which are blue supergiants located in the young stellar complexes. The stellar features in the CM diagrams are best represented by isochrones with metallicity Z=0.008. The process of star formation in the polar rings of both galaxies was continuous, and the age of the youngest detected stars is about 9 Myr for NGC 2685 and 6.5 Myr for NGC 4650A. Based on observations made with the NASA/ESO Hubble Space Telescope, obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.