 |
| Titel |
Exploring external time-dependent sources of H2O into Titan's atmosphere |
| VerfasserIn |
Luisa-Maria Lara, Emmanuel Lellouch, Marta Gonzalez, Raphaël Moreno, Miriam Rengel |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087555
|
| Publikation (Nr.) |
 EGU/EGU2014-1610.pdf |
|
|
|
|
|
| Zusammenfassung |
| Recent observations (Cottini et al., 2012, and Moreno et al., 2012) and steady-state
photochemical modelling (Moreno et al., 2012; Dobrijevic et al., 2014) indicate that the
amounts of CO2 and H2O in Titan’s stratosphere imply relatively inconsistent values of the
OH/H2O input flux. Moreno et al. (2012) proposed that the oxygen source is time-variable,
whereas Dobrijevic et al. (2014) arrived to the same conclusion of Moreno et al. (2012) that
the HSO (Herschel Space Observatory) measured H2O profile is“inconsistent" with the CO2
abundance. Furthermore, Dobrijevic et al. (2014) also found that reconciliation was
possible if abundances reported by Cottini et al. (2012) are correct instead, though
in this situation and for an Enceladus source, their model tended to overpredict
the thermospheric abundance of H2O , compared to the upper limit by Cui et al.
(2009).
We attempt to reconcile the H2O and CO2 observed profiles in Titan’s atmosphere by
considering several time-dependent scenarios for the infux/evolution of oxygen species. To
explore this, we use a time-dependent photochemical model of Titan’s atmosphere to
calculate effective lifetimes and the response of Titan’s oxygen compounds to changes in the
oxygen input flux. We consider a time-variable Enceladus source, as well as the evolution of
material delivered by a cometary impact.
We will show results on effective H2O and CO2 effective lifetimes, on the feasibility of
time-variable Enceladus source, and on an additional H2O loss-to-the-haze. Regarding CO2,
we will analyse its production following a cometary impact.
A summary on viable scenarios to explain the H2O / CO2 puzzle will be given.
References
Moreno, R., Lellouch, E., Lara, L. M., et al. 2012, Icarus, 221, 753.
Cottini, V., Nixon, C. A., Jennings, D. E., et al. 2012, Icarus, 220, 855.
Cui, J., Yelle, R. V., Vuitton, V., et al. 2009, Icarus, 200, 581.
Dobrijevic, M., Hébrard, E., Loison, J., and Hickson, K. 2014, Icarus, 228, 324. |
|
|
|
|
|
|