New theoretical grounds in Astrochemistry

For the first time, NANOCOSMOS has attempted to reproduce the complex molecular chemistry and stardust formation in circumstellar envelopes (CSEs) of asymptotic giant branch (AGB) stars and interstellar environments under accurate and realistic laboratory conditions. These conditions differ from previous studies and techniques to produce stardust analogs, mostly based on laser ablation and pyrolysis, flames, and other far related conditions from those in the CSEs of AGB stars.

Hence, we have used our innovative setups at CSIC and CNRS, e.g. Stardust, AROMA, PIRENEA 2 and cold plasma reactors, to study the processes that lead to carbon dust formation including polycyclic aromatic hydrocarbons (PAHs) and fullerenes. We have studied the chemistry of atomic silicon and the formation of silicate dust grains. We have also investigated the aromatic content of two different meteorites, Murchison and Almahata Sitta.

In summary, our synergetic results provide significant and surprising breakthroughs in our current understanding of the chemical processes at play in CSEs and meteoritic samples. These new and open theoretical grounds have also important implications in current chemical models. These NANOCOSMOS breakthroughs are the following:

  • Aliphatic nature of carbonaceous cosmic dust analogs. Our realistic laboratory conditions do not lead to the efficient formation of aromatic molecules (PAHs and fullerenes) in the gas phase, contrary to all previous studies (Stardust, AROMA).
  • Efficient mechanism for the formation of silane and disilane in the gas phase from Si, H, and H2 in the innermost regions of the CSEs around AGB stars (Stardust).
  • Further evidence for the role of metal (iron) seeds to increase not only the formation of metal clusters but also catalyzed hydrocarbon growth in the CSEs of AGB stars (Cold plasma reactors, AROMA, PIRENEA 2 and ESPOIRS).

  • First firm detection of fullerenes in meteorites (Almahata Sitta) and co-existence of carbon clusters along with PAHs in this meteorite (AROMA).

    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”.