The shadow echoes of UW Cen

Geoffrey C. Clayton, Louisiana State University


UW Cen is unique among the cool R Coronae Borealis (RCB) stars in having a visible circumstellar shell. The central star acts like a "lighthouse, " shining through gaps between the near-star dust clouds, and lighting up different portions of the outer nebula. We have obtained HST/ACS images of the UW Cen nebula taken at 5 epochs in 2004. We are using the light echo to calculate an accurate distance to UW Cen and to map out the pattern of dust clouds forming near the star. © 2005 American Institute of Physics.