Parallaxes and Infrared Photometry of three Y0 dwarfs
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Author
Smart, R. L.
Apai, Dániel
Kirkpatrick, J. Davy
Leggett, S.K.
Marocco, F.
Morrison, Jane E.
Jones, H. R. A.
Pinfield, D.
Tremblin, P.
Amundsen, D. S.
Attention
2299/20379
Abstract
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 $W3$ 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.