1. Molecules in planetary atmospheres Emmanuel Lellouch Observatoire de Paris

2. Some history… Detection of methane in Titan Kuiper 1944 « The only reason why I happened to observe the planets and the 10 brightest satellites was that they were nicely lined up in a region of the sky where I had run out of programs stars »

3. Vertical profile of methane from Huygens and Cassini VIMS

4. Some history… CO produced on dayside from CO 2 + h  CO Yet, more CO on Venus nightside than on dayside!

5. Why hunt for molecules in planets? 1. Because we like to see new species and because planetary spectra can be beautiful CH3CN in Titan (IRAM 30-m; Marten et al. 2002)

6. Why hunt for molecules in planets? (even in the infrared…) Detection of C6H6 in Saturn (ISO; Bézard et al. 2001)

7. Disk resolved spectroscopy of Io : detection of S 2 in the Pele plume HST/STIS long-slit spectroscopy of Pele plume Spencer et al. 2000 and even in the UV…

8. Why hunt for molecules in planets? 2. Because it gives information on chemical pathways

9. SATURN

10. Detection of hydrogen peroxide (H 2 O 2 ) on Mars 8 µm (IRTF) 362 GHz (JCMT) Encrenaz (THERESE) et al 2005 Production HO 2 + HO 2  H 2 O 2 +O 2 Destruction H 2 O 2 + h v  2 OH Clancy et al. 2004

11. Why hunt for molecules in planets? 3. Because it gives information on dynamics and the couplings with chemistry VENUS CO lines give maps of - CO vertical profile - Thermal profile - Wind velocity

12. Measuring mesospheric winds on Titan ~300 km ~450 km Moreno and Marten 2005

13. Why hunt for molecules in planets? 4. Because it gives information on the interactions between Solar System objects

14. External water in the outer planets ISO ODIN Interplanetary dust Planetary environments Cometary impacts HERSCHEL

15. CO in Neptune’s atmosphere Discovery (JCMT) Marten et al. 1991 IRAM 30-m: 8x 1 GHz A dual source? - internal - comet impact Lellouch et al. 2005

16. Why hunt for molecules in planets? 4bis) Sometimes, it gives us incomprehensible problems!

17. Evolution of the Shoemaker-Levy 9 debris on Jupiter CO, CS, HCN HCN CO 2 Chemical effect? Dynamical effect?

18. Why hunt for molecules in planets? 5. Because it is a way to study exotic atmospheres (and to make good friends…)

19. SO 2, SO, and NaCl in Io’s atmosphere (IRAM 30-m) SO 2 Origin? Volcanism Sublimation equilibrium (not NaCl)

20. Detection of NaCl in Io’s atmosphere

21. Why hunt for molecules in planets? 6. Because it tells us things about origin and evolution of planets (sorry, this time, I will take a break about helium and deuterium)

22. Isotopic ratios in Titan’s atmosphere 12 C/ 13 C = terrestrial 14 N/ 15 N in HCN = 4.5 times less than terrestrial in N 2 (Cassini) = 1.5 times than terrestrial  ESCAPE of Titan atmosphere + FRACTIONATION in HCN SMA Gurwell 2004

23. Why hunt for molecules in planets? 7. Because it is a race and we are ready to make big efforts for it CO on Pluto 4 days of good Weather Int. time 2090 min. Bockelee-Morvan et al. 2001 Stupid galactic contamination

24. Search for new compounds on Venus from limb- spectroscopy during the June 8 transit (T. Fouchet) ON OFF

25. What do you think it happened? 1.The IRAM TAC did not give time 2.The observations had to be stopped quickly because the telescope started to heat dangerously 3.The observations were performed but nothing was detected (even the 50 % deep CO lines) 4.CO(2-1) only was detected 5.The observations led to the first detection of SO2 in Venus’ upper atmosphere

26. What it happened 1.The IRAM TAC did not give time 2.The observations had to be stopped quickly because the telescope started to heat dangerously 3.The observations were performed but nothing was detected (even the 50 % deep CO lines) – 200 K ripples!! 4.CO(2-1) only was detected 5.The observations led to the first detection of SO2 in Venus’ upper atmosphere

27. Detection of J 2 O on Earth (Cambridge 2005 DPS meeting) J 2 O abundance: 2 bpp * * bottles per person

29. Why hunt for molecules in planets? 5. … or good enemies…