# Parallaxes and Infrared Photometry of three Y0 dwarfs

## TL;DR

This study provides improved parallax measurements and infrared photometry for three Y0 dwarfs, revealing small magnitude variations and consistent physical parameters with models, enhancing understanding of these ultra-cool objects.

## Contribution

It offers more accurate parallaxes and absolute magnitudes for three Y0 dwarfs, along with spectral analysis to estimate their physical properties, improving prior data accuracy.

## Key findings

- More consistent and accurate parallaxes than previous measurements.
- Small but significant monotonic variations in J-band magnitudes.
- Physical parameters consistent with solar metallicity, T_eff of 450-475 K, and log g of 4.0-4.5.

## 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.