Aperture masking interferometry on the Keck I Telescope: new results from the diffraction limit

A high-resolution aperture-masking interferometry experiment at the Keck-1 telescope has produced images of stellar systems at diffraction-limited angular resolutions in the near-infrared (tens of milliarcsec). Targeting the dusty cocoons of young stellar objects and the circumstellar shrouds surrounding evolved giants and supergiants, these images have revealed a startling range of morphologies. Evolved stars from massive blue Wolf-Rayets to red giants, supergiants and carbon stars have shown dramatic dust plumes, clumps and shells which can dominate the dust halo, showing that mass loss from these objects can sometimes be anything but smooth and isotropic. The photospheres of a handful of red giants were large enough to be resolved with the 10 m baselines available within the Keck pupil. Stellar diameters were found to vary with pulsation phase and with observing wavelength.