1. W.-H. Ip Zhongyi Lin, Ian Lai, Vickie Lee. Yuan Li NCU/MUST
Rosetta/OSIRIS
W.-H. Ip
Zhongyi Lin, Ian Lai, Vickie Lee. Yuan Li
NCU/MUST

2. Outline
4. Pits

3. W2 D=3.3x4.0x3.5 km
T1 D=7.6x4.9 km2
T1 D=7.6x4.9 km2
T1 D=7.6x4.9 km2
T1 D=7.6x4.9 km
H2 D= km

4. 81P Wild 2
Depressions with quasi-circular p;anforms at size up to 2 km across/depth ~ 140 m.
Nearly vertical wall/rubbles found at base.
Size frequency distribution lies well above equilibrium cratering on Phobos and Deimos.
Vapor flow driven-erosion and collapse and subsidence.

5. Cumulative Size Frequency Distribution/Wild 2

6. Comparison with Impact Craters

7. Sublimation-driven erosion?
Impact crater ?
Steep-walled flat-floored circular depression

8. 8P Tempel 1 Layering/repeated fluidization flow episodes
because of release of supervolatile (CO/CO2) vapor trapped in amorphorous water ice
~ 100 m deep (Belton and Melosh 2009)?

9. 103P Hartley 2 No Wild 2 crater-like depressions/no Tempel 1 layering.
High outgassing activity.
Water vapor emerging mostly from the waist region and CO2 from the small end.

10. Surface evolutionary track
Belton (2010, 2012)
Wild 2 (new) -> Tempel 1 -> Hartley 2 (old)
Cheng, Lisse and A’Hearn (2013)
Hartley 2 (new) -> Wild 2 -> Tempel 1 (old)
67P has characteristics of all three types.

11. Hatmehit and other landforms

12. 67P circular depressions
NAC_ T Z_ID30_ _F22
NAC_ T Z_ID30_ _F22
WAC_ T Z_ID30_ _F18_2

13. NAC_ T Z_ID30_ _F22
NAC_ T Z_ID30_ _F15
WAC_ T Z_ID30_ _F18
WAC_ T Z_ID30_ _F18
WAC_ T Z_ID30_ _F18
WAC_ T Z_ID30_ _F18

14. Wild2 circle depression
n2075we02r
n2069we02r

15. Size-frequency distribution

16. Size-frequency distribution

17. Possible Erosion Effect
Cheng, Lisse and A’Hearn (2013)

18. The q – variation of 67P (100 clones)

19. The q – variation of 81P Wild 2 (100 clones)

20. The q – variation of 9P Tempel 1 (100 clones)

21. Orbital History
81P Wild 2
103P Hartley 2
67P and 103P Hartley 2

22. Orbital statistics Comet Wild 2 youngest
To be followed by comet Hartley 2
Comet Tempel 1 and comet 67P oldest

23. Pits & Jetlets
Vincent et al. (2015)
Vincent et al. (2015)

24. Lunar pits

25. Evolution of a cometary pit
Lunar pits
Lunar pits
Lunar pits
Evolution of a cometary pit
Vincent et al. (2015) (2013)

26. Active pits
Vincent et al. (2015)

34. Sublimation-driven erosion?
Impact crater ?
Steep-walled flat-floored circular depression