Discovery of SiCSi in IRC+10216: A missing link between gas and dust carriers of SiC bonds

Abstract

We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with the IRAM 30m radio telescope. Owing to the close coordination between laboratory experiments and astrophysics, 112 lines have now been detected in the carbon-rich star CWLeo. The derived frequencies yield improved rotational and centrifugal distortion constants up to sixth order. From the line profiles and interferometric maps with the Submillimeter Array, the bulk of the SiCSi emis- sion arises from a region of 6 arcseconds in radius. The derived abundance is comparable to that of SiC2. As expected from chemical equilibrium calculations, SiCSi and SiC2 are the most abundant species harboring a SiC bond in the dust formation zone and certainly both play a key role in the formation of SiC dust grains.

To be published in the Astrophysical Journal Letters; Accepted May 6 2015

References in corpus (7)

• Detection of C5N- and vibrationally excited C6H in IRC +10216
• A stubbornly large mass of cold dust in the ejecta of Supernova 1987A
• New molecules in IRC+10216: confirmation of C${}_5$S and tentative identification of MgCCH, NCCP, and SiH${}_3$CN
• Detection of circumstellar CH2CHCN, CH2CN, CH3CCH and H2CS
• Molecular shells in IRC+10216: tracing the mass loss history
• Discovery of Time Variation of the Intensity of Molecular Lines in IRC+10216 in The Submillimeter and Far Infrared Domains
• Si-bearing molecules towards IRC+10216: ALMA unveils the molecular envelope of CWLeo

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• The abundance of C2H4 in the circumstellar envelope of IRC+10216
• Carbon chemistry in IRC+10216: Infrared detection of diacetylene
• A spectral line survey of IRC +10216 between 13.3 and 18.5 GHz
• Silicon and hydrogen chemistry under laboratory conditions mimicking the atmosphere of evolved stars
• Atmospheric molecular blobs shape up circumstellar envelopes of AGB stars
• Impact of metals on (star)dust chemistry: a laboratory astrophysics approach
• The Role of Ultraviolet Photons in Circumstellar Astrochemistry
• A spectral survey of CH3CCH in the Hot Molecular Core G331.512-0.103
• Multi-frequency high spectral resolution observations of HCN toward the circumstellar envelope of Y CVn
• Warm CO in evolved stars from the THROES catalogue. II. Herschel/PACS spectroscopy of C-rich envelopes
• The Significant Role of Hydrogen in the Formation of Silicon Carbide in Evolved Stars