|Far-infrared spectroscopy of fullerene-containing sources: testing the fullerene formation scenario and searching for fullerene-related molecules in evolved stars
|garcia-hernandez, d. a.
|The very recent and unexpected detections of fullerenes (C60 and C70) and graphene (planar C24) in the H-rich circumstellar environments of transition sources evolving from the AGB to the PNe stage indicate that these complex molecules may be not so exotic and can form under conditions which are common to essentially all Solar-like stars at the end of their lives. This result has profound implications on our current understanding of the chemistry of large organic molecules because it demonstrates that formation of large fullerenes does not require a hydrogen-poor environment contrary to many theoretical and experimental expectations. Thus, fullerenes and fullerene-related species (e.g., multishell or endohedral fullerenes) might be ubiquitous in the Universe and continue to be plausible candidates to explain many astrophysical phenomena. The simultaneous presence of fullerenes, graphene, and PAHs in H-rich circumstellar envelopes suggests that these carbon-based molecules may be formed as decomposition products of hydrogenated amorphous carbon grains (HACs). This HACs formation scenario seems to be supported by the strong correlation between the presence of fullerenes and the detection of the unidentified 30um feature, which could also be attributed to HACs. Interestingly, HACs display also a strong and broad feature around 60 um that can be detected by Herschel. We propose Herschel PACS spectroscopic observations of fullerene-containing sources evolving from the AGB to the PNe stage in order to test the HACs formation scenario. The Herschel PACS spectra will be examined for the possible presence of other fullerene-based molecules such as multishell fullerenes and will be compared with laboratory spectra of other fullerene-related molecules. The proposed observations will create a unique Herschel data set of high archival value and will be a step forward on our current understanding of the chemistry of large organic... molecules as well as of the chemical processing of dust grains in space.
|Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
|Publisher And Registrant
|European Space Agency
|European Space Agency, 2012, OT2_dgarciah_1, SPG v14.2.0. https://doi.org/10.5270/esa-cyuex8o