Left: raw yield as a function of BDT selections and extracted contributions from prompt and non-prompt \Dstar mesons with $3\pt5 \GeVc$. Right: the spin density matrix element (\rzzo) with respect to the helicity axis as a function of $f_{\rm non\text{-}prompt}$ in $3\pt5 \GeV/c$ for charm- and beauty-enhanced samples. Only statistical uncertainties are shown. The red line represents the linear fit to the data with the blue band indicating its $1\sigma$ confidence interval.