Large HI structures linked to southern O-type stars

Abstract

In our search for interstellar bubbles around massive stars we analyze the environs of the O-type stars HD38666, HD124979, HD163758, and HD171589. The location of the stars, far from the galactic plane, favors the formation of large wind bubbles. We investigate the distribution of the neutral and ionized gas based on Hi, CO, and radio continuum data, and that of the interstellar dust based on far infrared IRIS images. Here we report the discovery of neutral gas cavities and slowly expanding shells associated with the four massive stars. IR and optical counterparts were also detected for some of the stars. We discuss the probability that the features have originated by the action of stellar winds on the surrounding gas.