Global photometric properties of Asteroid (4) Vesta observed with Dawn Framing Camera

•Global averaged 554nm geometric albedo 0.38±0.04, bolometric Bond albedo 0.18±0.01.•Single-peaked albedo distribution despite large variations, different from the Moon.•Photometric properties similar to S-type asteroids, but with twice high albedo.•Recommend Hapke model and Akimov model for Vesta d...

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Veröffentlicht in:Icarus (New York, N.Y. 1962) N.Y. 1962), 2013-11, Vol.226 (2), p.1252-1274
Hauptverfasser: Li, Jian-Yang, Le Corre, Lucille, Schröder, Stefan E., Reddy, Vishnu, Denevi, Brett W., Buratti, Bonnie J., Mottola, Stefano, Hoffmann, Martin, Gutierrez-Marques, Pablo, Nathues, Andreas, Russell, Christopher T., Raymond, Carol A.
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Sprache:eng
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Zusammenfassung:•Global averaged 554nm geometric albedo 0.38±0.04, bolometric Bond albedo 0.18±0.01.•Single-peaked albedo distribution despite large variations, different from the Moon.•Photometric properties similar to S-type asteroids, but with twice high albedo.•Recommend Hapke model and Akimov model for Vesta data photometric correction.•Traditional approach of photometric correction validated for Vesta. Dawn spacecraft orbited Vesta for more than one year and collected a huge volume of multispectral, high-resolution data in the visible wavelengths with the Framing Camera. We present a detailed disk-integrated and disk-resolved photometric analysis using the Framing Camera images with the Minnaert model and the Hapke model, and report our results about the global photometric properties of Vesta. The photometric properties of Vesta show weak or no dependence on wavelengths, except for the albedo. At 554nm, the global average geometric albedo of Vesta is 0.38±0.04, and the Bond albedo range is 0.20±0.02. The bolometric Bond albedo is 0.18±0.01. The phase function of Vesta is similar to those of S-type asteroids. Vesta’s surface shows a single-peaked albedo distribution with a full-width-half-max ∼17% relative to the global average. This width is much smaller than the full range of albedos (from ∼0.55× to >2× global average) in localized bright and dark areas of a few tens of km in sizes, and is probably a consequence of significant regolith mixing on the global scale. Rheasilvia basin is ∼10% brighter than the global average. The phase reddening of Vesta measured from Dawn Framing Camera images is comparable or slightly stronger than that of Eros as measured by the Near Earth Asteroid Rendezvous mission, but weaker than previous measurements based on ground-based observations of Vesta and laboratory measurements of HED meteorites. The photometric behaviors of Vesta are best described by the Hapke model and the Akimov disk-function, when compared with the Minnaert model, Lommel–Seeliger model, and Lommel–Seeliger–Lambertian model. The traditional approach for photometric correction is validated for Vesta for >99% of its surface where reflectance is within ±30% of global average.
ISSN:0019-1035
1090-2643
DOI:10.1016/j.icarus.2013.08.011