  In this paper, we characterize the morphology of the disk-integrated phase
functions of satellites and rings around the giant planets of our Solar System.
We find that the shape of the phase function is accurately represented by a
logarithmic model (Bobrov, 1970, in Surfaces and Interiors of Planets and
Satellites, Academic, edited by A. Dollfus). For practical purposes, we also
parametrize the phase curves by a linear-exponential model (Kaasalainen et al.,
2001, Journal of Quantitative Spectroscopy and Radiative Transfer, 70, 529-543)
and a simple linear-by-parts model (Lumme and Irvine, 1976, Astronomical
Journal, 81, 865-893), which provides three morphological parameters : the
amplitude A and the Half-Width at Half-Maximum (HWHM) of the opposition surge,
and the slope S of the linear part of the phase function at larger phase
angles. Our analysis demonstrates that all of these morphological parameters
are correlated with the single scattering albedos of the surfaces. By taking
more accurately into consideration the finite angular size of the Sun, we find
that the Galilean, Saturnian, Uranian and Neptunian satellites have similar
HWHMs (0.5 degrees), whereas they have a wide range of amplitudes A. The Moon
has the largest HWHM (2 degrees). We interpret that as a consequence of the
solar size bias, via the finite size of the Sun which varies dramatically from
the Earth to Neptune. By applying a new method that attempts to morphologically
deconvolve the phase function to the solar angular size, we find that icy and
young surfaces, with active resurfacing, have the smallest values of A and
HWHM, whereas dark objects (and perhaps older surfaces) such as the Moon,
Nereid and Saturn C ring have the largest A and HWHM.
