Before revision:  Motivated by recent "tail-wing" refinements of this moment formula, we first derive a novel tail expansion for the Heston density, sharpening previous work of Dr \u{a} gulescu and Yakovenko [Quant.
After revision:  Motivated by recent "tail-wing" refinements of this moment formula, we first derive a novel tail expansion for the Heston density, sharpening previous work of \u{a} gulescu and Yakovenko [Quant.