Swift heavy ion irradiation of interstellar dust analogues
Small carbonaceous species released by cosmic rays
1 Institut d’Astrophysique Spatiale (IAS), CNRS, Univ. Paris Sud, Université Paris-Saclay, 91405 Orsay, France
2 Institut de Physique Nucléaire d’Orsay (IPNO), IN2P3-CNRS, Univ. Paris Sud, Université Paris-Saclay, 91405 Orsay, France
3 Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris Sud, Université Paris-Saclay, 91405 Orsay, France
4 Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS/IN2P3, Univ. Paris Sud, Université Paris-Saclay, 91405 Orsay, France
5 GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
6 Technische Universität Darmstadt, 64287 Darmstadt, Germany
Received: 3 September 2016
Accepted: 21 December 2016
Context. Interstellar dust grain particles are immersed in vacuum ultraviolet (VUV) and cosmic ray radiation environments influencing their physicochemical composition. Owing to the energetic ionizing interactions, carbonaceous dust particles release fragments that have direct impact on the gas phase chemistry.
Aims. The exposure of carbonaceous dust analogues to cosmic rays is simulated in the laboratory by irradiating films of hydrogenated amorphous carbon interstellar analogues with energetic ions. New species formed and released into the gas phase are explored.
Methods. Thin carbonaceous interstellar dust analogues were irradiated with gold (950 MeV), xenon (630 MeV), and carbon (43 MeV) ions at the GSI UNILAC accelerator. The evolution of the dust analogues is monitored in situ as a function of fluence at 40, 100, and 300 K. Effects on the solid phase are studied by means of infrared spectroscopy complemented by simultaneously recording mass spectrometry of species released into the gas phase.
Results. Specific species produced and released under the ion beam are analyzed. Cross sections derived from ion-solid interaction processes are implemented in an astrophysical context.
Key words: astrochemistry / cosmic rays / dust, extinction / evolution / solid state: refractory / methods: laboratory: solid state
© ESO, 2017