A New Parallax Measurement for the Coldest Known Brown Dwarf

Abstract

WISE J085510.83-071442.5 was recently discovered as the coldest known brown dwarf based on four epochs of images from the Wide-field Infrared Survey Explorer and the Spitzer Space Telescope. We have improved the accuracy of its parallax measurement by obtaining two additional epochs of Spitzer astrometry. We derive a parallactic distance of 2.31+/-0.08 pc, which continues to support its rank as the fourth closest known system to the Sun when compared to WISE J104915.57-531906.1 AB (2.02+/-0.02 pc) and Wolf 359 (2.386+/-0.012 pc). The new constraint on the absolute magnitude at 4.5um indicates an effective temperature of 235-260 K based on four sets of theoretical models. We also show the updated positions of WISE J085510.83-071442.5 in two color-magnitude diagrams. Whereas Faherty and coworkers cited its location in MW2 versus J-W2 as evidence of water clouds, we find that those data can be explained instead by cloudless models that employ non-equilibrium chemistry.

Astrophysical Journal, in press

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Cited by in corpus (9)

• Atmospheric Regimes and Trends on Exoplanets and Brown Dwarfs
• Near-infrared photometry of Y dwarfs: low ammonia abundance and the onset of water clouds
• Self-consistent Models of Y Dwarf Atmospheres with Water Clouds and Disequilibrium Chemistry
• Discovery of a Low-Luminosity, Tight Substellar Binary at the T/Y Transition
• Photometric Monitoring of the Coldest Known Brown Dwarf with the Spitzer Space Telescope
• WISEA J083011.95+283716.0: A Missing Link Planetary-Mass Object
• Physical properties and trigonometric distance of the peculiar dwarf WISE J181005.5$-$101002.3
• Deep $z$-band observations of the coolest Y dwarf
• Discovery of 16 New Members of the Solar Neighborhood using Proper Motions from CatWISE2020