2013MNRAS.433.3133G

We present the latest and final version of the movie of the SiO masers towards the Mira variable TX Cam. The new version consists of 112 frames (78 successfully reduced epochs) with data covering almost three complete stellar cycles between 1997 May 24 and 2002 January 25, observed with the Very Long Baseline Array. In this paper, we examine the global morphology, kinematics and variability of the masering zone. The morphology of the emission is confined in a structure that usually resembles a ring or an ellipse, with occasional deviations due to localized phenomena. The ring appears to be contracting and expanding, although for the first cycle contraction is not observed. The width and outer boundary of the masering zone follow the stellar pulsation. Our data seem to be consistent with a shock being created once per stellar cycle at maximum that propagates with a velocity of ∼ 7 km s-1. The difference in velocities along different axes strongly suggests that the outflow in TX Cam is bipolar. The contribution of projection is examined and our results are compared with the latest theoretical model.