Key points are not available for this paper at this time.
We report on the first detection of maser emission in the J = 11-10, J = 14-13, and J = 15-14 transitions of the v = 0 vibrational state of SiS toward the carbon-rich star IRC +10216. These masers seem to be produced in the very inhomogeneous region between the star and the inner dust formation zone, located at ≃(5-7) R * , with expansion velocities below 10 km s -1 . We interpret the pumping mechanism as being due to overlaps between v = 1-0 rovibrational lines of SiS and mid-IR lines of C 2 H 2 , HCN, and their 13 C isotopologues. The large number of overlaps found suggest the existence of strong masers for high- J v = 0 and v = 1 SiS transitions, located in the submillimeter range. In addition, it could be possible to find several rotational lines of the SiS isotopologues displaying maser emission.
Agúndez et al. (2006) studied this question.