ALMA/IRAM observations

HighlightsFeaturesDescription
Discovery of molecular species in IRC+10216Methyl silane (CH3SiH3) and silyl cyanide (SiH3CN, first time in Space)We propose a formation mechanism through catalytic reactions on the surface of dust grains by hydrogenation of silicon-carbon species in the inner dust formation zone
Formation of SiC dust in C-rich AGBsSiC2, CS, SiO and SiS gas-phase precursors of dustDecline in the abundances of these molecular species with increasing density in the envelopes of C-rich AGB stars. Important constraints for Stardust experiments on SiC dust formation.
Formation of dust in O-rich AGBsSiO and SO gas-phase precursors of dustDecline in the abundances of these molecular species with increasing density in the envelopes of O-rich AGB stars
Discovery of molecular species in the Interstellar Medium7 molecules, including one protonated form and isotopologs (2 of them, first time in Space)See dedicated descriptions below (under construction)
Major NANOCOSMOS highlights in “ALMA/IRAM observations” (see dedicated descriptions below)

NANOCOSMOS has performed several key observations of the circumnuclear envelopes -CSEs- of AGB stars with the IRAM 30m radio telescope and the ALMA interferometer. These observations are mandatory to foster the study of the gas-phase precursors of dust in these envelopes. We have made fruitful efforts in the study of the Si-C chemistry in these objects.

NANOCOSMOS has discovered methyl silane, CH3SiH3 and silyl cyanide (SiH3CN) in the envelope of the C-rich AGB star IRC +10216. We suggest that both are formed in the inner zones of the circumstellar envelope through catalytic reactions on the surface of dust grains by hydrogenation of silicon-carbon species.

We have also performed two molecular surveys with the IRAM facility, one to study the envelopes of 25 C-rich AGB stars to search for emission lines of SiC2, SiC, Si2C, CS, SiO and SiS and another one with a sample of 30 O-rich AGB stars to investigate the potential role of SiO, CS, SiS, SO, and SO2 in the formation of dust in these environments.

Our results show strong evidences that the observed decline in the molecular abundances of these species with increasing density in the envelopes are due to their incorporation to the solid phase. Furthermore, we establish that SiC2, CS, SiO and SiS (tentatively) are very likely gas-precursors of SiC dust in C-rich envelopes of AGB stars and SiO and SO (tentatively) in O-rich AGB stars.

Finally, the team has detected 7 molecules in the Interstellar Medium, some of them of key importance to constrain chemical models. These are the c-C3D isotopologs, the metastable and polar isomer isocyanogen (CNCN), the isocyanate radical NCO, the thioformyl radical (HCS) and its metastable isomer HSC, all of them in the dark cold cloud core L483, which contains a low-mass protostar. We have also detected ethyl formate (CH3CH2OCOH) and NS+ in the young protostellar system Barnard 1b with ALMA and IRAM respectively.

NANOCOSMOS at the Guillermo Haro School on Molecular Astrophysics (Puebla, Mexico)

Prof. José Cernicharo has been awarded with the Guillermo Haro Visiting Professorship 2016 at the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE, posterGH16Puebla, Mexico). Following this award, INAOE has organized the Guillermo Haro School on Molecular Astrophysics (October 11 – 21, 2016). Several NANOCOSMOS scientists (Asunción Fuente from CNIG-IGN, Nuria Marcelino, José Pablo Fonfría and Luis Velilla from ICMM-CSIC) will give lectures on the following topics:

  • Molecular Astrophysics, Spectroscopy, Chemistry in the ISM (José Cernicharo)
  • Physical and chemical processes in the ISM, Protoplanetary disks (Asunción Fuente)
  • Observational methods and interpretation (Nuria Marcelino)
  • Molecular excitation and radiative transfer, Circumstellar medium (José Pablo Fonfría)
  • Chemistry in the circumstellar medium, atmospheric  effects and calibration (Luis Velilla)

José Cernicharo will give a public talk in Puebla downtown on Thursday 13: “Moléculas en el espacio: Astroquímica”.

Javier R. Goicoechea awarded for a study of the interstellar clouds

Composite image obtained from the emission of 12CO (blue), 13CO (green), and C18O (red) of the Orion B molecular cloud (IRAM 30m telescope). Credit: J. Pety.

Javier R. Goicoechea, astronomer at the ICMM-CSIC

 
 

The Société Française d’Astronomie et d’Astrophysique (SF2A) and the Sociedad Española de Astronomía (SEA) have awarded Javier R. Goicoechea (ICMM-CSIC) and Jérôme Pety (IRAM, France) with the SEA-SF2A 2015 prize for their outstanding achievements in the study of interstellar clouds illuminated by ultraviolet radiation from nearby massive stars, in a French-Spanish scientific research cooperation.

Congrats to both¡¡¡

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