First Observational Evidence for Condensation of Io's SO2 Atmosphere on the Nightside
The volcanically active Jovian satellite Io has a tenuous SO2 atmosphere. The color of SO2 is.
IO Atmosphere↗
Engineering topics
Buratti, B.
Publications and source records attributed to Buratti, B..
The Dark Side of Iapetus: Additional Evidence for an Exogenous Origin
The Saturnian satellite Iapetus presents one of the most unusual appearances of any object in the.
Iapetus Exogenous Origin↗
The Clementine Mission to Geographos, A Near-Earth Asteroid
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Clementine Geographos Asteroid Naval Research Labo↗
Outer Planet Icy Satellites
An outer planet icy satellite is any one of the celestial bodies in orbit around Jupiter, Saturn, Uranus, Neptune, or Pluto. They range from large, planet-like geologically active worlds with significant atmospheres to tiny irregular objects tens of kilometers in diameter. These bodies are all believed to have some type of frozen volatile, existing alone or in combination with other volatiles.
outer planets↗
Ultraviolet Spectra and Geometric Albedos of 45 Asteroids
Spectral reflectances and geometric albedos between 2300 and 3250 Angstroms are determined for 45 asteroids from data acquired by the International Ultraviolet Explorer satellite. The geometric albedos are consistently low, ranging from ~0.02 for C-type asteroids to ~0.08 for M-type asteroids. An exception is the single E-type asteriod (44 Nysa) with a geometric albedo of 0.3 at 2950 Angstroms. We find that the three major asteroid taxonomic classes persist into the UV. The taxonomic classes are distinguished primarily by their albedos, but S-types are generally redder than C- or M-types. The first ultraviolet phase curves of asteroids are presented.
International↗
Hands-On Activities: Let's Get Real
This paper describes ways to make to hands-on activities more closely aligned with the science education guidelines of the National Science Standards and the California Science Framework.
N/A↗
Ultraviolet Spectra of Asteroids: Comparison with Visual Classification
This paper describes how previously published spectra were revised using improved solar spectra and additional observations.
N/A↗
Bidirectional reflectance properties of planetary surface materials
Laboratory measurements using a spectrogoniometer to separate the effects of surficial texture and albedo in the characterization of planetary surface materials are discussed. An investigation of the surface of Io is discussed. A number of technical improvements to the goniometer are summarized.
Buratti, B.↗
Voyager photometry of Iapetus
Voyager images of Saturn's satellite Iapetus ranging in phase angle from 8 to 90 deg have been used to define the satellite's photometric properties and construct an albedo map of its surface. Iapetus shows variations in reflectance across its surface of a factor of 10 to 20, the greatest albedo range known for a solar system object. It is darkest at the apex of orbital motion, becomes brighter away from the apex, and is brightest near the poles. The 'boundary' between light and dark material is gradual rather than sharp. The photometric properties of the surface are adequately described by a lunarlike photometric function, but the surface phase function varies with albedo. The dark material on Iapetus is reddish, the bright material somewhat less so.
Squyres, S. W.↗
Voyager photometry of Rhea, Dione, Tethys, Enceladus and Mimas
Voyager imaging observations provide new photometric data on Saturn's satellites at large phase angles (up to 133 deg in the case of Mimas) not observable from earth. Significant new results include the determination of phase integrals ranging from 0.7 in the case of Rhea to 0.9 for Enceladus. For Enceladus an average geometric albedo 1.04 and a Bond albedo of 0.9 are found. The data indicate an orbital lightcurve with an amplitude of 0.2 mag, the trailing side being the brighter. For Mimas, the lightcurve amplitude is probably less than 0.1 mag. The value of the geometric albedo of Mimas reported here, is definitely higher than the currently accepted value of about 0.5. For Dione, the Voyager data show a well-defined orbital lightcurve of amplitude about 0.6 mag, with the leading hemisphere brighter than the trailing one.
Buratti, B.↗
Photometry of icy satellites: How important is multiple scattering in diluting shadows?
Voyager observations have shown that the photometric properties of icy satellites are influenced significantly by large-scale roughness elements on the surfaces. While recent progress was made in treating the photometric effects of macroscopic roughness, it is still the case that even the most complete models do not account for the effects of multiple scattering fully. Multiple scattering dilutes shadows caused by large-scale features, yet for any specific model it is difficult to calculate the amount of dilution as a function of albedo. Accordingly, laboratory measurements were undertaken using the Cornell Goniometer to evaluate the magnitude of the effect.
Buratti, B.↗
Comparison of Hapke's photometric theory with Voyager observations of Europa, Enceladus, Rhea and Mimas
Voyager imaging observations of the satellites of Jupiter and Saturn provide an excellent test for various photometric theories that were proposed to describe the scattering properties of planetary and satellite surfaces. Not only does the Voyager data set include observations of surfaces ranging widely in albedo, but it provides measurements (in both disc-integrated and disc-resolved forms) over a wide range of phase angles. A detailed comparison of the above models with Voyager data for Europa, Enceladus, Rhea, and Mimas was described. These satellites were selected because they cover a range of reflectances from 0.65 to 1.0 and because for them the Voyager photometric data sets are most complete.
Buratti, B.↗
Voyager photometry of Europa
The photometric properties of Europa are derived through an analysis of 90 Voyager images with 3-143 deg phase angles in the spectral range from 0.34 to 0.58 microns. It is noted that, at small phase angles, the disk-integrated phase curve shows almost no evidence of an opposition effect. The scattering properties of Europa in general, and of the bright plain and dark mottled terrain types, cannot be represented by a lunar-like photometric law, although an equation which is a linear superposition of a lunar-like scattering law and a Lambert component provides an adequate and simple representation of scattering properties. The plains are photometrically more homogeneous than the mottled terrain, and these two terrain types exhibit an average normal reflectance of 0.71 on both leading and trailing hemispheres and of 0.60 on leading and 0.48 on trailing hemispheres, respectively.
Buratti, B.↗
The effects of scattering geometry on the spectrophotometric properties of powdered material
The characteristics of reflectance spectra are being used as a basis in investigations to infer the composition of planetary surfaces. However, the reflectance spectra of powdered materials depend not only on the composition of these materials, but also on other variables. A description is presented of the results of an exploratory series of measurements designed to investigate the importance of scattering geometry as a variable in determining the shapes of spectral reflectance curves, taking into account half a dozen materials of planetary interest. It is noted that the considered results are consistent with those reported by Adams and Felice (1967), especially the results on the variation with phase angle of the Red/Blue color ratio for various silicate materials. The measurements demonstrate in detail that scattering geometry does affect the shapes of spectral reflectance curve. In some cases this effect is quite significant.
Gradie, J.↗