Open charm hadron production via hadronic decays at STAR

In this article, we report on the STAR results of open charm hadron production at mid-rapidity in $p+p$ and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and $p+p$ collisions at $\sqrt{s}$ = 500 GeV. The measurements cover transverse momentum range from 0.6 to 6 GeV/c for $p+p$ 200 GeV collisions, from 1 to 6 GeV/c for $p+p$ 500 GeV collisions and from 0 to 6 GeV/c for Au+Au 200 GeV collisions. $D^0$ nuclear modification factor and elliptic flow in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV are presented.