CCD Observations of IRC +10 216

Abstract

High resolution CCD observations of IRC +10 216 obtained at wavelengths from 0.55 microns to 1.0 micron are presented. These images were obtained at CFHT in 0.7 arc-second seeing and display structure on this scale near the center. The very center of this object is elongated N-S with the elongation rotating to a position angle of 30° approximately 2 arc-seconds from the center. There is also evidence of dumpiness in the image within 5 arc-seconds. Scattered light from the extended envelope of this object is detected out to large radii at all wavelengths with emission being seen at a radius of at least 40 arc-seconds in V(0.55 micron). The relative intensity as a function of radius falls much more slowly at the shorter wavelengths implying that the grain material has a much higher albedo at these wavelengths. This is consistent with the grains being composed of graphite or amorphous graphite. Also visible are discreet shells of higher intensity at radii from 15 to 30 arc-seconds. These shells are interpreted as direct evidence for periodic outbursts of higher mass loss rates. Using the expansion velocity of 14 km/s, these outbursts have a duration of 200–400 years.