We have followed up the three Y0 dwarfs WISEPA J041022.71+150248.5 , WISEPA J173835.53+273258.9 and WISEPC J205628.90+145953.3 using the UKIRT/WFCAM telescope/instruments .
We find parallaxes that are more consistent and accurate than previously published values .
We estimate absolute magnitudes in photometric pass-bands from Y to W 3 and find them to be consistent between the three Y0 dwarfs indicating the inherent cosmic absolute magnitude spread of these objects is small .
We examine the MKO J magnitudes over the four year time line and find small but significant monotonic variations .
Finally we estimate physical parameters from a comparison of spectra and parallax to equilibrium and non-equilibrium models finding values consistent with solar metallicity , an effective temperature of 450-475 K and log g of 4.0-4.5 .