Publication Abstracts

Rathbun et al. 2004

Rathbun, J.A., J.R. Spencer, L.K. Tamppari, T.Z. Martin, L. Barnard, and L.D. Travis, 2004: Mapping of Io's thermal radiation by the Galileo photopolarimeter-radiometer (PPR) instrument. Icarus, 169, 127-139, doi:10.1016/j.icarus.2003.12.021.

Between 1999 and 2002, the Galileo spacecraft made 6, close flybys of to during which many observations of Io's thermal radiation were made with the photopolarimeter-radiometer (PPR). While the NIMS instrument could measure thermal emission from hot spots with T > 200 K, PPR was the only Galileo instrument capable of mapping the lower temperatures of older, cooling lava flows, and the passive background. We tabulate all data taken by PPR of Io during these flybys and describe some scientific highlights revealed by the data. The data include almost complete coverage of Io at better than 250 km resolution, with extensive regional coverage at higher resolutions. We found a modest poleward drop in nighttime background temperatures and evidence of thermal inertia variations across the surface. Comparison of high spatial resolution temperature measurements with observed daytime SO2 gas pressures on Io provides evidence for local cold trapping of SO2 frost on scales smaller than the 60 km resolution of the PPR data. We also calculated the power output from several hot spots and estimated total global heat flow to be about 2.0-2.6 W m-2. The low-latitude diurnal temperature variations for the regions between obvious hot spots are well matched by a laterally-inhomogeneous thermal model with less than 1 W m-2 endogenic heat flow.

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BibTeX Citation

  author={Rathbun, J. A. and Spencer, J. R. and Tamppari, L. K. and Martin, T. Z. and Barnard, L. and Travis, L. D.},
  title={Mapping of Io's thermal radiation by the Galileo photopolarimeter-radiometer (PPR) instrument},

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RIS Citation

ID  - ra08300g
AU  - Rathbun, J. A.
AU  - Spencer, J. R.
AU  - Tamppari, L. K.
AU  - Martin, T. Z.
AU  - Barnard, L.
AU  - Travis, L. D.
PY  - 2004
TI  - Mapping of Io's thermal radiation by the Galileo photopolarimeter-radiometer (PPR) instrument
JA  - Icarus
VL  - 169
SP  - 127
EP  - 139
DO  - 10.1016/j.icarus.2003.12.021
ER  -

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