A new prospect to analyse the spectral properties of v-type asteroids

• Published in: Icarus (New York, N.Y. 1962) N.Y. 1962), 2023-01, Vol.390, p.115320, Article 115320
• Main Authors: Angrisani, M., Palomba, E., Longobardo, A., Raponi, A., Dirri, F., Gisellu, C.
• Format: Article
• Language: English
• Subjects: Asteroids; Asteroids, surfaces; Composition; Regoliths; Spectroscopy
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2022.115320

Among main belt asteroids, some have a spectrum similar to Vesta so they are taxonomically classified as V-type asteroids. Probably they were removed from Vesta and migrated to their current positions via some still unknown dynamical mechanisms. Several issues on the relationship between V-type asteroids, Howardite-Eucrite-Diogenite (HED) meteorites and Vesta are still unresolved. Although some of them can be directly linked to (4) Vesta, forming its dynamical family, others do not appear to have a clear dynamical link, thus suggesting the existence of other basaltic parent bodies. In this work we present a new approach of analysis to investigate 76 VNIR V-type asteroids spectra downloaded from PDS. The composition of the regolith and particle size of V-type asteroid have been investigated with a combination of spectroscopic analysis and Hapke radiative transfer model. Retrieved particle sizes are very small, with a mean value of 20 μm. Therefore, we look for statistically significant differences among the modal mineralogy of V-type asteroids belonging to different dynamical subclasses. It seems there is a possible chronologic link between impact events on Vesta and the V-type families. The most ancient V-type family, e.g. Low-I asteroids, seems to have a eucritic composition compatible with an ejection of the outermost layer of Vesta. The Fugitive V-type were probably ejected in an older cratering event that produced the Veneneia basin while the Vestoids family, whose dynamical parameters are still more similar to Vesta and which seems to be the youngest family among them, could be associated to Rheasilvia basin. The last two families seem to have a diogenitic composition compatible with that of the south of Vesta, where the two huge craters are located. Spartacus asteroid is also analysed and it was found to have a modal mineralogy consistent with the presence of olivine as noted before (Moskovitz et al.,2010; Burbine et al., 2001). •The composition of the regolith particle size of groundbased 76 VIS-NIR normalized spectra of V-type asteroids, has been investigated and a new approach of analysis, i.e., a combination of spectroscopic analysis and Hapke radiative transfer model has been proposed•The obtained information from the scatterplot analysis is used as constrain in the Hapke's bidirectional reflectance model to retrieve modal composition and particle size for each V-type asteroid.•We have look for significant mineralogy differences among the V-type