Abstract EANA2024-48

Titan is the most Earth-like body in the Solar System, because it has a moist climate with an active weather cycle, a stable surface liquids, and a thick atmosphere [1] mainly composed of nitrogen and methane, in which they are carried out various physical and chemical processes due to the energy sources that act on it.

The photochemistry in Titan's atmosphere begins with the dissociation and ionization of the main atmospheric components through external energy sources such as Solar UV, Saturn's magnetosphere, solar wind and galactic cosmic rays. The identity and characteristics of this energy sources is important because, among other things, this determines the rate of dissociation of molecular nitrogen and therefore influences the chemistry of the entire atmosphere and the surface of the satellite and its study will help us understand organic chemistry of planetary atmospheres [2,3].

On that basis, in this work we experimentally study the effect of the incidence of cosmic rays on the chemistry of a simulated atmosphere of Titan. To imitate this process, the simulated Titan's atmosphere was subjected to different doses of gamma radiation, which is generated by cobalt (60Co) sources in the Irradiation Unit of the Institute of Nuclear Sciences of the National Autonomous University of Mexico (UNAM).

The simulated atmosphere of Titan (10% methane in nitrogen) is prepared using a gas mixer, subsequently introduced into a Pyrex glass reactor and subjected to the energy source of gamma radiation (to simulate cosmic rays). The compounds generated are separated, identified and quantified using an instrumental technique, comprising a gas chromatograph coupled to a mass spectrometer. Preliminary results show that gamma radiation forms linear and branched saturated hydrocarbons, such as ethane, propane, butane and isobutane; however, the presence of nitriles and aerosols has not been identified.

Finally, with the flow of cosmic rays energy received by Titan's atmosphere determined by theVoyager 1, the formation rate of these four hydrocarbons per year was preliminarily calculated due to the incidence of cosmic rays, obtaining that ethane is the main product and te most abundant, followed by propane, then isobutane and finally butane.

References.

[1] Mitchell, J. L., & Lora, J. M. (2016). The Climate of Titan. Annual Review of Earth and Planetary Sciences, 44(Volume 44, 2016), 353–380. https://doi.org/10.1146/ANNUREV-EARTH-060115-012428/CITE/REFWORKS

[2] Sagan, C., Thompson, W. R., & Khare, B. N. (1992). Titan: a laboratory for prebiological organic chemistry. Accounts of Chemical Research, 25(7), 286–292. https://doi.org/10.1021/AR00019A003

[3] Lavvas, P., Galand, M., Yelle, R. V., Heays, A. N., Lewis, B. R., Lewis, G. R., & Coates, A. J. (2011). Energy deposition and primary chemical products in Titan’s upper atmosphere. Icarus, 213(1), 233-251.