2003ApJ...588.1064W

The size and variability of the continuum photosphere of ο Ceti have been measured with 11 µm heterodyne interferometry to an accuracy of about 1%. Narrow bandwidths (∼0.17 cm^–1) were used to avoid spectral lines and measure continuum only. The resulting 11 µm diameter of ο Cet is larger than the previously measured visible and near-infrared sizes. In addition, variations in the diameter with phase and a possible elongation have been observed. Visibilities were also measured at wavelengths known to contain strong H₂O spectral contamination, giving larger apparent stellar sizes and information on the distribution of hot H₂O gas.