Photometric study of polar-ring galaxies. II. IC 1689.

The results are given of detailed surface B,V, and R_c_ photometry of IC 1689- a galaxy with an inner polar ring. It is shown that the central galaxy is a normal S0-type galaxy with a relatively short and warped stellar disk. The inner polar ring (its radius is only about 2kpc) has blue colour (B-V=+0.3, V-R_c_=+0.3) and comparatively high surface brightness (μ_B_=~23.2). Comparison of observed surface brightnesses and colours B-V for all single polar rings studied earlier show that there is a dependence between these characteristics. We interpret this dependence as a consequence of the fact that global bursts of star formation may occur (with a burst strength up to 0.15) in many polar rings in the course of their evolution.