[PCG26-08] アルマを用いたタイタン大気中アセトニトリルにおける14N/15N同位体比が解き明かす，銀河宇宙線の大気化学過程への影響
キーワード：タイタン、アルマ
By analyzing archival data obtained by the Atacama Large Millimeter/submillimeter Array (ALMA), we have successfully detected rotational transitions of CH3C15N (J = 19--18) at the 338 GHz band in Titan's atmospheric spectra.
Using the radiative transfer analysis, comparing those observations with the simultaneously observed CH3CN (J = 19--18) lines at the 349 GHz band, which probe from 160 to ~400 km altitude, we then derived 14N/15N in CH3CN as 125 (+145/-44). The best-fit value suggests that 14N/15N for CH3CN is higher than values that have been previously observed and theoretically predicted for HCN and HC3N.
This may be explained by the different N2 dissociation sources according to the altitudes, as suggested by a recent photochemical model.
Using the radiative transfer analysis, comparing those observations with the simultaneously observed CH3CN (J = 19--18) lines at the 349 GHz band, which probe from 160 to ~400 km altitude, we then derived 14N/15N in CH3CN as 125 (+145/-44). The best-fit value suggests that 14N/15N for CH3CN is higher than values that have been previously observed and theoretically predicted for HCN and HC3N.
This may be explained by the different N2 dissociation sources according to the altitudes, as suggested by a recent photochemical model.