1994A&A...285..541Q

The angular diameters of the three carbon stars UU Aur, Y CVn, and TX Psc have been determined with the MkIII Optical Interferometer. Measurements of UU Aur at λλ= 712, 754, and 800nm agree well with each other; the weighted mean for the uniform disk diameter is θ_UD = 11.28 ±0.21mas. For Y CVn, θ_UD = 13.81 ±0.43mas is obtained at 800nm. There are indications of temporal variations of the diameter of TX Psc; values between 9.4 and 11.1mas were measured for this star. Effective temperatures are calculated for these three stars and for six other carbon stars for which diameters measured with the lunar occultation technique have been published. These fundamentally determined effective temperatures correlate well with, but are on average about 100K cooler than, effective temperatures for the same stars obtained with the infrared flux method by Tsuji (1981). Color temperatures determined by Baumert (1972) and by Gow (1977) correlate poorly with effective temperatures.