Evidence for the exposure of water ice on Titan's surface

Science

Volumn 300, Issue 5619, 2003, Pages 628-630

  Griffith, Caitlin A ^a   Owen, Tobias ^b   Geballe, Thomas R ^c   Rayner, John ^b   Rannou, Pascal ^d  

^a UNIVERSITY OF ARIZONA   (United States)

^b UNIVERSITY OF HAWAII   (United States)

^c GEMINI OBSERVATORY   (United States)

^d SORBONNE UNIVERSITÉ   (France)

Author keywords

[No Author keywords available]

Indexed keywords

ICE; ORGANIC COMPOUNDS; SPACE RESEARCH; UPPER ATMOSPHERE;

ORGANIC LIQUIDS;

PLANETARY SURFACE ANALYSIS;

ICE; ORGANIC COMPOUND; WATER;

ICE; PLANETARY ATMOSPHERE; PLANETARY SATELLITE; SATURN; TITAN;

ARTICLE; ASTRONOMY; COSMOS; GEOLOGY; LABORATORY; LIQUID; MOON; PRIORITY JOURNAL; ROCK; SEDIMENT; SOLID; STRATOSPHERE; VIBRATION;

ATMOSPHERE; CARBON MONOXIDE; EXTRATERRESTRIAL ENVIRONMENT; ICE; METHANE; ORGANIC CHEMICALS; SATURN; WATER;

EID: 0037466566     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.1081897     Document Type: Article

References (51)

1. Y. L. Yung, M. Atten, J. P. Pinto, Astrophys. J. Suppl. 55, 465 (1984).
2. F. M. Flasar, Science 221, 55 (1983).
3. J. I. Lunine, D. J. Stevenson, Y. L. Yung, Science 222, 1229 (1983).
4. C. A. Griffith, T. Owen, R. Wagener, Icarus 93, 362 (1991).
5. 4 absorption in the 1 to 2 μm windows (least well constrained) is estimated to be 8 to 18 times greater than our values. Their absolute albedos are ∼25 to 50% higher than ours.
6. Haze optical constants come from Khare et al. (39).
7. Spectra of decade-old tholins (40) differ, at 1.2 to 1.4 μm, from spectra of young tholins (41). It is not clear whether the tholin chemistry proceeded in isolation or through contamination.
8. Noll et al. (42) do not consider scattering and emission, causing slightly different results from ours at 5 μm.
9. C. A. Griffith, T. Owen, G. A Miller, T. R. Geballe, Nature 395, 575 (1998). Note that their 1.3 μm surface albedo is incorrect because of faulty normalization of previous observations.
10. J. T. Rayner et al., Publ. Astron. Soc. Pac. 115, 362 (2003).
11. C. A. Griffith, J. L. Hall, T. R. Geballe, Science 290, 509 (2000).
12. O. B. Toon, C. P. McKay, C. A. Griffith, R. P. Turco, Icarus 95, 24 (1992).
13. C. P. McKay, J. B. Pollack, R. Courtin, Icarus 80, 23 (1989).
14. E. Karkoschka, Icarus 133, 134 (1998).
15. E. Karkoschka, Icarus 111, 174 (1994).
16. We adopted a discrete ordinates calculation having eight streams, as described by Stamnes et al. (43). 17. Titan's thermal profile derives from Lellouch et al. (44) and Yelle et al. (45).
17. 4 and CO derive from the line parameters of Husson et al. (46).
18. We varied the vertical optical depth at two altitude regions (40 to 100 km and 100 to 160 km) to derive the range of haze optical depths that fit Titan's spectrum. Haze below ∼40 km is limited by the visibility of Titan's surface at 0.63 μm.
19. Our surface albedos are thus unaffected by variations in the 0.01 shape parameter (or width) of our lognormal particle distribution, the tholin optical constants (6), and details of the haze models.
20. K. Rages, J. B. Pollack, P. H. Smith, J. Geophys. Res. 88, 8721 (1983).
21. P. H. Smith et al., Icarus 119, 336 (1996).
22. J. Richardson, R. D. Lorenz, A. McEwen, in preparation.
23. M. G. Tomasko, P. H. Smith, Icarus 51, 65 (1982).
24. R. A. West et al., J. Geophys. Res. 88, 8699 (1983).
25. R. A. West, P. H. Smith, Icarus 90, 330 (1991).
26. P. Rannou, M. Cabane, R. Botet, E. Chassefière, J. Geophys. Res. 102, 10997 (1997).
27. P. Rannou et al., Icarus 118, 355 (1997).
28. C. P. McKay et al., Planet. Space Sci. 49, 79 (2001).
29. M. G. Tomasko et al., in Huygens: Science Payload and Mission, Vol. ESA-SP 1177, A. Wilson, Ed. (European Space Agency Publications Division, Noordwijk, Netherlands, 1997), pp. 109-138.
30. 2.
31. B. Lutz, C. de Bergh, T. Owen, Nature 220. 1374 (1983).
32. T. Hidayat et al., Icarus 133, 109 (1998).
33. -3.
34. M. Combes et al., Icarus 129, 482 (1997).
35. R. Meier, B. A. Smith, T. C. Owen, R. J. Terrile, Icarus 145, 462 (2000).
36. S. G. Gibbard et al., Icarus 139, 189 (1991).
37. Note that 5-m-deep pools of methane absorb 95% of 1.1- to 5-μm sunlight (47).
38. B. N. Khare, C. Sagan, E. T. Arakawa, F. Suits, T. A. Callcott, M. W. Williams Icarus 60, 127 (1984).
39. T. L. Roush, J. B. Dalton, Conf. 33, abstract 1532, Lunar Planetary Inst., Houston, TX (2002).
40. D. Cruikshank et al., Icarus 94, 345 (1991).
41. K. S. Noll, T. R. Geballe, R. F. Knacke, Y. J. Pendleton, Icarus 124, 625 (1996).
42. K. Stamnes, S. Tsay, W. Wiscombe, K. Jayweera, Appl. Opt. 27, 2502 (1988).
43. E. Lellouch et al., Icarus 79, 328 (1989).
44. R. V. Yelle, D. F. Strobell, E. Lellouch, D. Gautier, in Huygens: Science Payload and Mission, Vol. ESA-SP 1177, A. Wilson, Ed. (European Space Agency Publications Division, Noordwijk, Netherlands, 1997), pp. 243-256.
45. N. Husson, B. Bonnet, N. A. Scott, A. Chédin, The "GEISA" data bank 1991 version (Internal note L.M.D. 163, Laboratoire de Météorologie Dynamique, Palaiseau, France, 1991).
46. W. M. Grundy, B. Schmitt, E. Quirico, Icarus 155, 486 (2002).
47. M. T. Lemmon, E. Karkoschka, M. Tomasko, Icarus 103, 329 (1993).
48. C. A. Griffith, Nature 364, 511 (1993).
49. T. B. McCord et al., J. Geophys. Res. 103, 8603 (1998).
50. T. B. McCord, personal communication.
51. We thank D. Cruikshank for helpful discussions regarding the spectroscopic characteristics of complex organic molecules. This research is supported by the NASA Planetary Astronomy Program.