DISCOVERY OF SiCSi IN IRC+10216: A MISSING LINK BETWEEN GAS AND DUST CARRIERS OF Si–C BONDS

We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with the IRAM 10 30m radio telescope. Owing to the close coordination between laboratory experiments and astrophysics, 112 lines have now been detected in the carbon-rich star CW Leo. The derived frequencies yield improved rotational and centrifugal distortion constants up to sixt h order. From the line profiles and interferometric maps with the Submillimeter Array 11 , the bulk of the SiCSi emission arises from a region of 6 ′′ in radius. The derived abundance is comparable to that of SiC2. As expected from chemical equilibrium calculations, SiCSi and SiC2 are the