  Flow measurements of multi-strange baryons from Au + Au collisions at RHIC
energies demonstrate that collectivity develops before hadronization, among
partons. To pin down the partonic EOS of matter produced at RHIC, the status of
thermalization in such collisions has to be addressed. We propose to measure
collective flow of heavy-flavor quarks, e.g. charm quarks, as an indicator of
thermalization of light flavors ($u,d,s$). The completion of the time of flight
barrel and the proposed upgrade with a $\mu$Vertex detector for heavy-flavor
identification in STAR are well suited for achieving these goals.
