[X] My Assistant

[Guest_Richard Trigaux_*]

Hello all


This spectrum,, obtained by Cassini's ion and neutral mass spectrometer, shows a lithium ray (ordinate= 7)

and also this figure, a mass spectrogram from the same instrument, also show lithium (abscissa=7)

First of all, I wonder if these rays are real, or if they are intrument defects or artifacts. Otherwise only lithium could have a mass of 7 daltons.

The presence of lithium is not really astonishing by itself (there was sodium in Io's atmosphere) but it implies that Titan's atmosphere would be much more reducing than with hydrogen alone. Also there are no traces of oxygen or water in these spectrograms (oxygen and water are linked through oxydation and photo-dissociation)

In a medium where there is an excess of hydrogen, all the available oxygen is reduced, so that this medium becomes reducing. But lithium is much more reducing than hydrogen, so it would take the oxygen in priority. So the presence of lithium implies that there is a source of lithium in excess over Titan's atmospheric oxygen, and that Titan's atmosphere is much more reducing than with only the presence of hydrogen and hydrocarbons...

Where could this lithium come from? It looks as if Titan's hydrogen would be formed directly from an interstellar cloud, and thus would contain some lithium. But if so, it would also contain helium... which is nearby absent! Right on the countrary the mainstream hypothesis is that this hydrogen comes from the photo-dissociation of methane. Maybe there would be some volcanism, releasing together methane and lithium. But this is incompatible with the presence of an ice surface or underground ocean, as lithium and water react violently.

So, if these rays are not instrument artifacts, they are a complete mystery. As far as I know, there was no comment on this.

Anybody have some idea?

Richard