Publication Abstracts

Braak et al. 2002

Braak, C.J., J.F. de Haan, J.W. Hovenier, and L.D. Travis, 2002: Galileo photopolarimetry of Jupiter at 678.5 nm. Icarus, 157, 401-418, doi:10.1006/icar.2002.6846.

Brightness and linear polarization measurements at 678.5 nm for four north-south strips of Jupiter are studied. These measurements were obtained in 1997 by the Galileo photopolarimeter/radiometer. The observed brightness exhibits latitudinal variations consistent with the belt/zone structure of Jupiter. The observed degree of linear polarization is small at low latitudes and increases steeply toward higher latitudes. No clear correlations were observed between the degree of linear polarization and the brightness. The observed direction of polarization changes from approximately parallel to the local scattering plane at low latitudes to perpendicular at high latitudes. For our studies, we used atmospheric models that include a haze layer above a cloud layer. Parameterized scattering matrices were employed for the haze and cloud particles. On a pixel-wise basis, the haze optical thickness and the single-scattering albedo of the cloud particles were derived from the observed brightness and degree of linear polarization; results were accepted only if they were compatible with the observed direction of polarization. Using atmospheric parameter values obtained from Pioneer 10 and 11 photopolarimetry for the South Tropical Zone and north component of the South Equatorial Belt, this analysis yielded acceptable results for very few pixels, particularly at small phase angles. However, for almost all pixels, acceptable results were found when the parameterized scattering matrix of the cloud particle was adjusted to produce more negative polarization for single scattering of unpolarized light, especially at large scattering angles, similar to some laboratory measurements of ammonia ice crystals. Using this adjusted model, it was found that the derived latitudinal variation of the single-scattering albedo of the cloud particles is consistent with the belt/zone structure, and that the haze optical thickness steeply increases toward higher latitudes.

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BibTeX Citation

@article{br06000k,
  author={Braak, C. J. and de Haan, J. F. and Hovenier, J. W. and Travis, L. D.},
  title={Galileo photopolarimetry of Jupiter at 678.5 nm},
  year={2002},
  journal={Icarus},
  volume={157},
  pages={401--418},
  doi={10.1006/icar.2002.6846},
}

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RIS Citation

TY  - JOUR
ID  - br06000k
AU  - Braak, C. J.
AU  - de Haan, J. F.
AU  - Hovenier, J. W.
AU  - Travis, L. D.
PY  - 2002
TI  - Galileo photopolarimetry of Jupiter at 678.5 nm
JA  - Icarus
VL  - 157
SP  - 401
EP  - 418
DO  - 10.1006/icar.2002.6846
ER  -

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