Astrometry and Photometry for $\approx$1000 L, T, and Y Dwarfs from the UKIRT Hemisphere Survey

Adam C. Schneider; Jeffrey A. Munn; Frederick J. Vrba; Justice Bruursema; Scott E. Dahm; Stephen J. Williams; Michael C. Liu; Bryan N. Dorland

arXiv · 2307.11882

Astrometry and Photometry for $\approx$1000 L, T, and Y Dwarfs from the UKIRT Hemisphere Survey

Adam C. Schneider·Jeffrey A. Munn·Frederick J. Vrba·Justice Bruursema·Scott E. Dahm·Stephen J. Williams·Michael C. Liu·Bryan N. Dorland

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Abstract

We present positions, proper motions, and near-infrared photometry for 966 known objects with spectral types later than M observed as part of the the UKIRT Hemisphere Survey (UHS). We augment the photometry and astrometry from UHS with information from Gaia DR3, Pan-STARRS DR2, and CatWISE 2020 to produce a database of homogeneous photometry and astrometry for this sample. The multi-epoch survey strategy of UHS allows us to determine proper motions for most sources, with a median proper motion uncertainty of $\sim$3.6 mas yr$^{-1}$. Our UHS proper motion measurements are generally in good agreement with those from Gaia DR3, Pan-STARRS, and CatWISE 2020, with UHS proper motions typically more precise than those from CatWISE 2020 and Pan-STARRS but not Gaia DR3. We critically analyze publicly available spectra for 406 members of this sample and provide updated near-infrared spectral types for $\sim$100 objects. We determine typical colors as a function of spectral type and provide absolute magnitude vs. spectral type relations for UHS $J$- and $K$-band photometry. Using newly determined proper motions, we highlight several objects of interest, such as objects with large tangential velocities, widely separated co-moving companions, and potential members of young nearby associations.

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Adam C. Schneider, Jeffrey A. Munn, Frederick J. Vrba, Justice Bruursema, Scott E. Dahm, Stephen J. Williams, Michael C. Liu, Bryan N. Dorland. 2023-07-21. Astrometry and Photometry for $\approx$1000 L, T, and Y Dwarfs from the UKIRT Hemisphere Survey. https://arxiv.org/abs/2307.11882

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