High-resolution spectroscopy of R CrB - pulsations, shells and mass loss

Abstract

High spectral resolution observations obtained in 1994 and spanning three pulsation cycles of R CrB are discussed along with available UBV photometric observations for the same epochs. Model atmosphere based analyses of the spectra at pulsation light maximum and minimum show the atmosphere to be cooler by 500 K at minimum. Radial velocities of high- and low-excitation lines at maximum light show, on one occasion, a marked velocity difference. Weak blueshifted Hα emission is seen in spectra at the phase of minimum light. In addition to a photospheric component, the Na i D lines show absorption components from circumstellar gas. One strong component not seen in 1990 or early 1993 may be a result of gas ejected during the late-1933 deep decline.