  Carbonaceous chondrite meteorites are so far the only available samples
representing carbon-rich asteroids and in order to allow future comparison with
samples returned by missions such as Hayabusa 2 and OSIRIS-Rex, is important to
understand their physical properties. Future characterization of asteroid
primitive classes, some of them targeted by sample-return missions, requires a
better understanding of their mineralogy, the consequences of the exposure to
space weathering, and how both affect the reflectance behavior of these
objects. In this paper, the reflectance spectra of two chemically-related
carbonaceous chondrites groups, precisely the Vigrano (CVs) and Karoonda (CKs),
are measured and compared. The available sample suite includes polished
sections exhibiting different petrologic types: from 3 (very low degree of
thermal metamorphism) to 5 (high degree of thermal metamorphism). We found that
the reflective properties and the comparison with the Cg asteroid reflectance
class point toward a common chondritic reservoir from which the CV-CK asteroids
collisionally evolved. In that scenario the CV and CK chondrites could be
originated from 221 Eos asteroid family, but because of its collisional
disruption, both chondrite groups evolved separately, experiencing different
stages of thermal metamorphism, annealing and space weathering.
