New molecules in IRC +10216: confirmation of C5S and tentative identification of MgCCH, NCCP, and SiH3CN

  title={New molecules in IRC +10216: confirmation of C5S and tentative identification of MgCCH, NCCP, and SiH3CN},
  author={Marcelino Ag'undez and Jos{\'e} Cernicharo and Michel Gu'elin},
  journal={Astronomy and Astrophysics},
The carbon-star envelope IRC +10216 harbors a rich variety of molecules, with more than 80 detected to date. During the course of a λ 3m m survey of IRC+10216 carried out with the IRAM 30-m telescope we have detected various weak lines, with antenna temperatures of a few mK, which we assign to rotational transitions of four new molecules. The observation of three lines of C5S confirms a previous tentative identification of this molecule based on a line at 24.0 GHz. We also report the tentative… 

Figures and Tables from this paper

Discovery of methyl silane and confirmation of silyl cyanide in IRC +10216.

The observed profiles and models for the expected emission of methyl silane suggest that the molecule is formed in the inner zones of the circumstellar envelope, 1-40 R*, with an abundance of (0.5-1) × 10-8 relative to H2.

Discovery of Interstellar Isocyanogen (CNCN): Further Evidence that Dicyanopolyynes Are Abundant in Space

It is estimated that NCCN could be fairly abundant, in the range 10-9-10-7 relative to H2, as other abundant nitriles like HCN and HC3N.

Carbon Chemistry in IRC+10216: Infrared Detection of Diacetylene

We present the detection of C4H2 for first time in the envelope of the C-rich AGB star IRC+10216, based on high spectral resolution mid-infrared observations carried out with the Texas

Discovery of two new magnesium-bearing species in IRC+10216: MgC3N and MgC4H.

The synthesis of these magnesium cyanides and acetylides in IRC +10216 can be explained in terms of a two-step process initiated by the radiative association of Mg+ with large cyanopolyynes and polyynes followed by the dissociative recombination of the ionic complexes.

The Abundance of C2H4 in the Circumstellar Envelope of IRC+10216.

High spectral resolution mid-IR observations of ethylene (C2H4) towards the AGB star IRC+10216 were obtained using the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF), and it is found to be rotationally under local thermodynamical equilibrium (LTE) and vibrationally out of LTE.

Probing non polar interstellar molecules through their protonated form: Detection of protonated cyanogen (NCCNH+).

The first solid evidence of the presence of cyanogen in interstellar clouds through the detection of its protonated form toward the cold dark clouds TMC-1 and L483 is presented.

Interstellar nitrile anions: Detection of C3N- and C5N- in TMC-1.

The detection of C5N- in TMC-1 gives strong support for assigning to this anion the lines found in IRC +10216, as it excludes the possibility of a metal-bearing species, or a vibrationally excited state.

TMC-1, the starless core sulfur factory: Discovery of NCS, HCCS, H2CCS, H2CCCS, and C4S and detection of C5S.

The detections of C5S for the first time in a cold cloud through the observation of five lines in the 31-50 GHz range underline the need to improve chemical networks dealing with S-bearing species.

Vibrational satellites of C2S, C3S, and C4S: microwave spectral taxonomy as a stepping stone to the millimeter-wave band.

The present study illustrates the utility of microwave spectral taxonomy as a tool for complex mixture analysis, and as a powerful and convenient 'stepping stone' to higher frequency measurements in the millimeter and submillimeter bands.



Detection of the CCP Radical (X2Πr) in IRC +10216: A New Interstellar Phosphorus-containing Species

The CCP radical (X2Πr) has been detected in the circumstellar gas of IRC +10216, the fifth phosphorus-bearing molecule identified in interstellar space. This identification was made on the basis of

Detection of C3O in IRC +10216: Oxygen-Carbon Chain Chemistry in the Outer Envelope

The oxygen-bearing species C3O has been identified in the circumstellar envelope of the carbon star IRC +10216. The J = 8 → 7, 9 → 8, 10 → 9, 14 → 13, and 15 → 14 transitions were detected at 2 and 3

Tentative detection of phosphine in IRC +10216

Aims. The JK = 10−0_0 rotational transition of phosphine (PH_3) at 267 GHz has been tentatively identified with a TMB ~ 40 mK spectral line observed with the IRAM 30-m telescope in the C-star

More Metal Cyanide Species: Detection of AlNC (X 1 Σ + ) toward IRC +10216

A new metal-containing species, AlNC, has been detected toward the circumstellar envelope of the late-type carbon star IRC +10216, using the IRAM 30 m telescope. The J = 11 → 10, 12 → 11, and 13 → 12


Phosphine (PH3) was tentatively identified a few years ago in the carbon star envelopes IRC +10216 and CRL 2688 from observations of an emission line at 266.9 GHz attributable to the J = 1–0

Detection of a new circumstellar carbon chain molecule, C4Si

A new interstellar carbon chain molecule, C4Si, has been detected in the envelope of the evolved star IRC + 10216. This molecule is the carrier of six unidentified lines which had been detected

A Search for Phosphine in Circumstellar Envelopes: PH3 in IRC +10216 and CRL 2688?

We present the results of a search for the JK = 10→ 00 transition of PH3 (phosphine) at 267 GHz toward several circumstellar envelopes using the Arizona Radio Observatory 10 m Submillimeter Telescope

A λ2 mm molecular line survey of the C-star envelope IRC+10216

The mm-wave spectrum of the C-star envelope IRC+10216 has been continuously surveyed between 129.0 and 172.5 GHz with the IRAM 30-m telescope. 380 lines are detected, of which 317 have been identied.

On the formation of metal cyanides and related compounds in the circumstellar envelope of IRC + 10216

Various pathways to the metal cyanides Na(CN), Mg(CN) and Al(CN) - some of which have been detected in the circumstellar envelope IRC + 10216 - are critically assessed. Calculations of rate

Laboratory Spectroscopy of MgNC: The First Radioastronomical Identification of Mg-bearing Molecule

The linear MgNC radical was detected, for the first time, by laboratory microwave spectroscopy, and six unidentified lines in IRC +10216 reported by Guelin et al. (1986) were assigned to the