Icarus 165 (2003) 215–218 www.elsevier.com/locate/icarus Note Quantified mineralogical evidence for a common origin of 1929 Kollaa with 4 Vesta and the HED meteorites Michael S. Kelley, a,∗,1 Faith Vilas, a Michael J. Gaffey, b,1 and Paul A. Abell c,1 a NASA Johnson Space Center, Mail Code SR, Houston, TX 77058, USA b Department of Space Studies, University of North Dakota, Grand Forks, ND 58202-9008, USA c Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA Received 16 December 2002; revised 2 May 2003 Abstract In this paper, we present the first correlation of derived mineral abundances of V-class Asteroid 1929 Kollaa, 4 Vesta, and the HED meteorites. We demonstrate that 1929 Kollaa has a basaltic composition consistent with an origin within the crustal layer of 4 Vesta, and show a plausible genetic connection between Kollaa and the cumulate eucrite meteorites. These data support the proposed delivery mechanism of HED meteorites to the Earth from Vesta, and provide the first mineralogical constraint derived from the observation of a small V-class, Vesta family asteroid on the crustal thickness of 4 Vesta.  2003 Elsevier Inc. All rights reserved. Keywords: Asteroids; Vesta; Surfaces, asteroids; Asteroids, composition; Spectroscopy Since 1970, it has been recognized that asteroid 4 Vesta has spectral properties that closely resemble those of the basaltic achondrite (howardite, eucrite and diogenite, or “HED”) meteorites (McCord et al., 1970). This led to the first suggestions that Vesta could be the parent body of this group of achondrites (Consolmagno and Drake, 1977; Feierberg and Drake, 1980; Gaffey, 1983). However, Vesta’s orbit is unfavorably situated to deliver ejecta directly into Earth-crossing orbits (Wasson and Wetherill, 1979; Wether- ill and Chapman, 1988). In 1993, new visible-region spectra of members of the Vesta dynamical family (Zappalà et al., 1990; Williams, 1992) with orbits bridging the gap between Vesta, the 3:1 resonance at 2.5 AU, and the ν 6 resonance, showed that these small asteroids also belonged to the tax- onomic V class (Tholen, 1984; Binzel and Xu, 1993). If these small V-class objects were derived from 4 Vesta, the proximity of some of them to these resonances would allow * Corresponding author. Present address: Department of Geology and Geography, Georgia Southern University, Statesboro, GA 30460-8149, USA. E-mail address: mkelley@gasou.edu (M.S. Kelley). 1 Visiting Astronomer, Infrared Telescope Facility, operated by the Uni- versity of Hawaii under contract for the National Aeronautics and Space Administration. relatively efficient delivery of Vesta fragments from the main asteroid belt to the inner solar system. Hubble Space Telescope images obtained in 1996 re- vealed a giant impact basin 460 km in diameter and 13-km deep in the south polar region of Vesta (Thomas et al., 1997). Approximately 1% of Vesta’s volume was excavated by this event—an amount sufficient to account for many more V-class asteroids than we now know reside between Vesta and the resonances. By the late 1990’s, the existence of a mechanism for ejecting large fragments from Vesta was established and a pathway for getting them to a dynami- cal source region for meteorites had been found (Asphaug, 1997). What was still lacking was solid mineralogical evi- dence connecting any other V-class asteroid to either Vesta or the HED meteorites. This was due to the absence of spec- tra for small V-class asteroids with sufficient, appropriate wavelength coverage to quantify the mineralogy of the py- roxenes identified by the presence of the deep 1- and 2-μm mafic silicate absorption features in the visible/near IR spec- tra. Mainbelt asteroid 1929 Kollaa is ∼ 14 km in diameter and has been listed as a member of the Vesta dynamical asteroid family. We observed Kollaa as part of the Family Asteroid Compositional Evaluation Survey (FACES); a project that seeks to identify genetic asteroid families within the variety 0019-1035/$ – see front matter  2003 Elsevier Inc. All rights reserved. doi:10.1016/S0019-1035(03)00149-0