  In a paper from 2016 D. R. Yafaev considers Hankel operators associated with
Hamburger moment sequences q_n and claims that the corresponding Hankel form is
closable if and only if the moment sequence tends to 0. The claim is not
correct, since we prove closability for any indeterminate moment sequence but
also for certain determinate moment sequences corresponding to measures with
finite index of determinacy. It is also established that Yafaev's result holds
if the moments satisfy \root{2n}\of{q_{2n}}=o(n).
