High angular resolution observations of late-type stars

This paper presents speckle observations of Mira (o Cet) and late-type stars with the PISCO speckle camera of Pic du Midi during the period 1995-1998. A survey for binarity among a sample of late-type stars was performed, which led to 7 positive detections out of 36 objects. Photometric and color variations of the companion of Mira were searched for, but no significant brightness variations could be found over a time scale of ∼5–10 minutes. The position and photometry measurements, the restored images with high angular resolution of the binary system Mira A-B (ADS 1778) are in full agreement with HST data obtained atthe same epoch. A new orbit has been derived for Mira A-B.