Invariant-mass distributions $\Delta M$ of \Dstar candidates with $4 < p_{\rm T} < 6$ GeV/$c$ and $0.0 < |\cos \theta^{*}|< 0.2$ (left panel), and with $15 < p_{\rm T} < 30$ GeV/$c$ and $0.8 < |\cos \theta^{*}|< 1.0$ (right panel) in the rapidity interval $0.3< |y| < 0.8$ for the 30$-$50% centrality class.