[Previous] | [Session 17] | [Next]
B. Schmidt (Lunar and Planetary Laboratory), B. J. Buratti (Jet Propulsion Laboratory), B. D. Herbert (Cornell), J. M. Bauer, M. D. Hicks (Jet Propulsion Laboratory)
Since the 1989 Voyager flyby recorded plumes on Neptune's satellite Triton, its surface has been under scrutiny. Our recent measurements of Triton's light curve show a dramatic increase in amplitude versus Voyager era observations. Models of a steady-state surface suggest that a light curve amplitude of 0.045-0.021 magnitudes for the 400-900 nm range should be currently expected (Hillier et al., 1991). Monitoring of Triton's color (Hicks et al., 2003) shows progressive changes based on sub-observer longitude, as well as episodic reddening. Photometric observations in the BVRI and 890 nm filters taken in 2000, 2003 and 2004, show filter-dependent light curve amplitudes nearing 0.20 +/- 0.05 magnitudes. Observations cover the full rotational period. The non-sinusoidal shape of the light curve is suggestive of regional variation. Such marked changes to Triton's surface albedo are indicative of the sublimation and movement of surface volatiles. Thus, changes in the light curve suggest the presence of seasonal variations and the possibility of Triton's trace-volatile atmosphere changing through sublimation and freezing. Additionally a possible opposition surge was recorded at phases ~0.08 and lower, with a maximum shift of 0.4 +/-0.05 magnitudes (see Herbert et al., 2004), which may have important implications on ice grain size and reflectivity on Triton.
The author(s) of this abstract have provided an email address for comments about the abstract: britneys@email.arizona.edu
[Previous] | [Session 17] | [Next]
Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.