  We report the first VLBI map of the v=0 J=1-0 maser line of 29SiO in the
long-period variable star IRC+10011. We have found that this maser emission is
composed of multiple spots distributed in an incomplete ring, suggesting that
this maser is also amplified tangentially, as already proposed in other SiO
circumstellar masers. We present also VLBI maps for the 7 mm 28SiO v=1 and 2
J=1-0 and the 3 mm v=1 J=2-1 lines. The 29SiO masing region appears to be
located in a layer in between the 28SiO v=1 J=1-0 and 28SiO v=1 J=2-1 lines. In
addition, we confirm that the 86 GHz maser v=1 J=2-1 forms in an outer region
of the circumstellar envelope compared to the other 28SiO masers studied.
Finally, we discuss the possible implications of the observational results on
the SiO maser pumping theory.
