Jupiter's hydrocarbons observed with ISO-SWS: vertical profiles of C_2H_6 and C_2H_2, detection of CH_3C_2H
Abstract
We have analysed the ISO-SWS spectrum of Jupiter in the 12-16 mum 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 q=(8.9+1.1-0.6)*E-7 at 0.3 mbar and q=(1.1+0.2-0.1)*E-7 at 4 mbar, giving a slope -dln q / dln P=0.8+/-0.1, while for ethane q=(1.0+/-0.2)*E -5 at 1 mbar and q=(2.6+0.5-0.6)*E-6 at 10 mbar, giving -dln q / dln P=0.6+/-0.2. The ethane slope is consistent with the predictions of Gladstone et al. (\cite{Gladstone96}), 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. (\cite{Gladstone96}) model. At 15.8 mum , methylacetylene is detected for the first time at low jovian latitudes, and a stratospheric column density of (1.5+/-0.4)*E15 molecule cm-2 is inferred. We also derive an upper limit for the diacetylene column density of 7*E13 molecule cm-2.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 2000
- DOI:
- 10.48550/arXiv.astro-ph/0002273
- arXiv:
- arXiv:astro-ph/0002273
- Bibcode:
- 2000A&A...355L..13F
- Keywords:
-
- PLANETS AND SATELLITES: INDIVIDUAL:;
- INFRARED: SOLAR SYSTEM;
- Astrophysics
- E-Print:
- Letter accepted for publication in Astronomy and Astrophysics