Letter to the Editor
Jupiter's hydrocarbons observed with ISO-SWS: vertical profiles of and , detection of
T. Fouchet 1,
E. Lellouch 1,
B. Bézard 1,
H. Feuchtgruber 2,
P. Drossart 1 and
T. Encrenaz 1
Received 3 January 2000 / Accepted 9 February 2000
We have analysed the ISO-SWS spectrum of Jupiter in the 12-16 range, where several hydrocarbons exhibit rovibrational bands. Using temperature information from the methane and hydrogen emissions, we derive the mixing ratios (q) of acetylene and ethane at two independent pressure levels. For acetylene, we find at 0.3 mbar and at 4 mbar, giving a slope , while for ethane at 1 mbar and at 10 mbar, giving . The ethane slope is consistent with the predictions of Gladstone et al. (1996), but that predicted for acetylene is larger than we observe. This disagreement is best explained by an overestimation of the acetylene production rate compared to that of ethane in the Gladstone et al. (1996) model.
At 15.8 , methylacetylene is detected for the first time at low jovian latitudes, and a stratospheric column density of molecule cm-2 is inferred. We also derive an upper limit for the diacetylene column density of molecule cm-2.
Key words: planets and satellites: individual: infrared: solar system
Send offprint requests to: T. Fouchet
This article contains no SIMBAD objects.
© European Southern Observatory (ESO) 2000
Online publication: March 17, 2000