Titan's atmospheric haze: the case for HCN incorporation
Lara, L.-M.; Lellouch, E.; Shematovich, V.
AA( Solar System Division, ESA Space Science Department, ESTEC, P.O. Box 299, 2200 AG Noordwijk, The Netherlands), AB(DESPA, Observatoire de Paris-Meudon, F-92195 Meudon Principal Cedex, France), AC(Institute of Astronomy of the Russian Academy of Sciences, 48 Pjatnitskaja str., 109017 Moscow, Russia)
Astronomy and Astrophysics, v.341, p.312-317 (1999) (A&A Homepage)


It is suggested that the incorporation of HCN in Titan's atmospheric haze may be an important process affecting the HCN profile and the C/N ratio in Titan's haze. By introducing a loss to the haze term for HCN (i.e. a production term of ``poly-HCN") in the photochemical model of Lara et al. (1996), we have improved the model's ability to simultaneously reproduce the observed HCN and C_2 hydrocarbon profiles in Titan's lower stratosphere. The loss rate of HCN by this process may be a few times 10(8) cm(-2) s(-1) . The calculated C/N ratio in the haze, assuming that the haze is primarily produced from C_6H_2, C_8H_2 and ``poly-HCN", is approximately equal to 2, in agreement with the composition of laboratory tholin analogues.