Infrared Spectroscopic Study on Swift-Ion Irradiation of Solid N 2 O–H 2 O Samples: Synthesis of N–O Bearing Species in Astrophysical Ices
Résumé
As of early 2022, only six species bearing an N−O
bond have been detected toward cold molecular clouds and regions
of star formation. It is not clear yet if the small number of N−O
bond species found in the interstellar medium so far stems from
physical and technological limitations of astronomical detection
techniques, or whether in fact molecules that bear an N−O bond
are for some reason rare in these objects of the interstellar medium.
Astronomical N−O bearing molecules are important because they
are part of astrochemical models which propose that they are
precursors of hydroxylamine (NH2OH), a species linked to the
formation of prebiotic amino acids in space. The aim of this study
is the better understanding of the open question of the interstellar
synthesis of N−O bearing species. We have analyzed by infrared
spectroscopy an astrophysically relevant polar ice mixture of N2O:H2O processed by 90 MeV 136Xe23+ ions, which can mimic the
physicochemical processes triggered by cosmic rays in water-covered interstellar ice grains. The results show the formation of N2O3
and of H2O2, but no HN−O species of any kind were detected. Such findings are discussed in light of recent studies from our group
and from the literature.