  We calculate the masses of the resonances D_{s0}^*(2317) and D_{s1}(2460) as
well as their bottom partners as bound states of a kaon and a D^*- and
B^*-meson, respectively, in unitarized chiral perturbation theory at
next-to-leading order. After fixing the parameters in the D_{s0}^*(2317)
channel, the calculated mass for the D_{s1}(2460) is found in excellent
agreement with experiment. The masses for the analogous states with a bottom
quark are predicted to be M_{B^*_{s0}}=(5696\pm 40) MeV and M_{B_{s1}}=(5742\pm
40) MeV in reasonable agreement with previous analyses. In particular, we
predict M_{B_{s1}}-M_{B_{s0}^*}=46\pm 1 MeV. We also explore the dependence of
the states on the pion and kaon masses. We argue that the kaon mass dependence
of a kaonic bound state should be almost linear with slope about unity. Such a
dependence is specific to the assumed molecular nature of the states. We
suggest to extract the kaon mass dependence of these states from lattice QCD
calculations.
