| 1. |
- Coustenis, A., et al.
(författare)
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TandEM : Titan and Enceladus mission
- 2009
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Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:3, s. 893-946
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Tidskriftsartikel (refereegranskat)abstract
- TandEM was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini-Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (MontgolfiSre) and possibly several landing probes to be delivered through the atmosphere.
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| 2. |
- Richardson, V., et al.
(författare)
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The reactivity of methanimine radical cation (H2CNH.+) and its isomer aminomethylene (HCNH2.+) with methane
- 2021
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 775
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Tidskriftsartikel (refereegranskat)abstract
- Experimental and theoretical studies are presented on the reactions of the isomeric radical cations H2CNH+ and HCNH2+ with CH4. Ionic isomers were generated selectively by VUV dissociative photoionization of azetidine and cyclopropylamine precursors respectively. Both exclusively give H2CNH2+ plus CH3 as products, but differences are observed related to a competition between stripping and complex-mediated H-transfer. Astrochemical implications for Titan’s atmosphere are briefly discussed, where the presence of methanimine (H2CNH), a key prebiotic molecule and a potential precursor for tholins, is proposed on the basis of atmospheric models and the observation of CH2NH2+ ions in Cassini mass spectrometric data.
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| 3. |
- Sundelin, David, et al.
(författare)
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The reactivity of methanimine radical cation (H2CNH•+) and its isomer aminomethylene (HCNH2•+) with C2H4
- 2021
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 777
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Tidskriftsartikel (refereegranskat)abstract
- Experimental and theoretical studies are presented on the reactivity of H2CNH'+ (methanimine) and HCNH2'+ (aminomethylene) with ethene (C2H4). Selective isomer generation is performed via dissociative photoionization of suitable neutral precursors and reactive cross sections and branching ratios are measured as a function of photon and collision energies. Differences between isomers' reactivity are discussed in light of ab-initio calculations on reaction mechanisms. The main products, for both isomers, are H-elimination, most likely occurring from covalently bound adducts (giving c-CH2CH2CHNH+/CH2NHCHCH2+) and H' atom transfer to yield H2CNH2+. The astrochemical implications of the results are briefly addressed.
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