2006A&A...451.1041R

High-angular resolution investigations of carbon stars. Milliarcsecond resolution observations in the near infrared K band by the method of lunar occultations are presented for the carbon stars TU Gem and SS Vir. Although a companion to TU Gem is known from the Tycho catalogue, we were not able to detect it so we place limits on its K-band brightness. For both stars, we determined accurate values of the angular diameters at the phase of the observation, namely 8.37±0.07mas and 4.62±0.15mas for SS Vir and TU Gem. Using distance estimates from the literature, we found that the two stars have radii of about 500R_☉ and 250R_☉, respectively. We also computed their effective temperatures. The result for SS Vir (2445±40K) is in good agreement with estimates, but in the case of TU Gem our value of 3160±110K requires reconsidering currently available models.