Orgueil is a carbonaceous chondrite meteorite that fell in southwestern France on May 14, 1864 (one of the fragments is shown in the picture to the right). It is one of five known meteorites belonging to the CI chondrite group—a group that is remarkable for having a composition that is essentially identical to that of the Sun.
Orgueil has never melted but has been exposed to modest heating and has been heavily altered by water. When and where this alteration by water occurred (in the interstellar medium? in the solar nebula? on an asteroidal parent body?) is a puzzle.
Comparing Spectra of 2008 EV5 and Orgueil
Based on spectral similarity, it is suggested that the MarcoPolo-R asteroid target 2008 EV5 has a composition similar to Orgueil. In the diagram below, red points indicate Orgueil, while gray and black points indicate 2008 EV5.
Image credit: Reddy, V., Le Corre, L., Hicks, M., Lawrence, K., Buratti, B. J., et al., Composition of near-Earth Asteroid 2008 EV5: Potential target for robotic and human exploration, Icarus, Volume 221, Issue 2, November–December 2012, pp. 678–681, http://dx.doi.org/10.1016/j.icarus.2012.08.035.