Basaltic asteroids in the Near-Earth Objects population: a mineralogical analysis

Abstract

Aims. We present reflectance spectra of three V-type Near-Earth Objects obtained at the 3.6 m Telescopio Nazionale Galileo and at the 2.5 m Nordic Optical Telescope covering the near-infrared and visible range, respectively. The range from 0.5 to 2.5 µm, encompassing the 1 and 2 µm pyroxene features, allows a mineralogical characterization of these asteroids. Methods. A preliminary analysis using the classical methods has been applied to establish some constraints on the surface mineralogy of these objects. Then, the Modified Gaussian Method was applied to gain further insight on the possible mineral components present in the surface of the objects. Results. The comparison between these basaltic asteroids in near Earth orbits and the achondrite basaltic meteorites shows a quite clear mineralogical link, corroborating the long-standing hypothesis of the Near-Earth Objects population as the immediate source of these meteorites.

Pyroxene mineralogies of near‐Earth vestoids

“…Our calculated Band I center for (6611) 1993 VW is consistent, within error bars, for the Band I center determined for lower signal-to-noise spectra of 1993 VW by Duffard et al (2006) but our calculated Band II center is at a slightly longer wavelength than the one calculated by Duffard et al (2006).…”

“…Our calculated band centers for the later spectrum of (88188) 2000 XH44 are consistent, within error bars, for band centers determined for the lower signal-to-noise spectra of 2000 XH44 by Duffard et al (2006). Our calculated Band I center for (6611) 1993 VW is consistent, within error bars, for the Band I center determined for lower signal-to-noise spectra of 1993 VW by Duffard et al (2006) but our calculated Band II center is at a slightly longer wavelength than the one calculated by Duffard et al (2006).…”

Mineralogy of V-type asteroids as a constraining tool of their past history

“…Actually, as evidenced by our inferred mineralogies, we have found a considerable content of olivine in almost all of the selected V-type asteroids (see Table 10) and several HED meteorites (see Table 7). Of particular interest is the amount of olivine inferred for (6611) 1993 VW, which is in agreement with the indication pointed out by Duffard et al (2006). Such evidence may favor the magma ocean model of (4) Vesta interior (Righter and Drake, 1997).…”

Mineralogy of Basaltic Material on the Minor Bodies of Our Solar System

“…All the values are shown in Table 1 for all the Eucrite meteorite of the sample. The final values of HCP/(HCP+LCP) and the corresponding melting percentage can be compared with the literature (Sunshine et al 2004, Vernazza et al 2005, Mayne et al 2006, deLeón et al, 2006, Canas et al 2008). Due to the excellent quality and high signal to noise ratio of the spectra, the fitting procedure was straightforward.…”

“…Further collisions ejected fragments into Earth-colliding orbits, becoming the HED meteorites recovered on Earth (Drake 2001). Several observational facts corroborate this scenario: the identification of a Vesta dynamical family (Williams, 1989;Zappalá et al, 1990) called Vestoids, the confirmation that small asteroids in the region near (4) Vesta do have a basaltic surface composition (Binzel and Xu, 1993;Burbine et al, 2001) called V-type asteroids, the identification of a large impact basin on (4) Vesta (Thomas et al, 1997), the discovery of several NEAs with basaltic mineralogical surface composition (McFadden et al, 1985;Cruikshank et al, 1991;Binzel et al, 2004;Duffard et al, 2006) and, last but not least, the identification that most of the HED have similar isotopic composition, indicative of a common origin Mayeda, 1983, 1996;Mittlefehldt et al, 1998). The problem seems to be solved, and all the basaltic material was coming from the surface of Vesta, the only large enough asteroid to be differentiated.…”