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