  Neutron skin thickness ($R_{np}$) of the atomic nuclei $^{48}$Ca, $^{132}$Sn
and $^{208}$Pb are considered in the KIDS (Korea:IBS-Daegu-Sungkyunkwan)
density functional formalism. Model parameters most relevant to $R_{np}$ are
constrained from standard nuclear data and neutron star properties determined
from modern observations. Mean values of $R_{np}$ are obtained as 0.161, 0.220
and 0.160 fm for $^{48}$Ca, $^{132}$Sn and $^{208}$Pb, respectively, and the
corresponding standard deviations are 0.011, 0.020 and 0.021 fm. Correlations
between $R_{np}$ of the three nuclei are considered, and we find that
$R_{np}$'s are correlated very strongly. We obtain correlation coefficient
0.978 between $R_{np}$ of $^{48}$Ca and $^{208}$Pb, and 0.996 between $R_{np}$
of $^{132}$Sn and $^{208}$Pb.
