Discovery of a ~250 K Brown Dwarf at 2 pc from the Sun

TL;DR

This paper reports the discovery and characterization of a nearby, extremely cold brown dwarf at about 2 parsecs from the Sun, using multi-epoch infrared astrometry from WISE and Spitzer.

Contribution

It presents the identification and detailed astrometric analysis of a new nearby brown dwarf, including its temperature, mass, and motion, expanding our understanding of the solar neighborhood.

Findings

Closest known brown dwarf at 2.2 pc

Coldest brown dwarf with temperature 225-260 K

High proper motion of 8.1 arcsec/year

Abstract

Through a previous analysis of multi-epoch astrometry from the Wide-field Infrared Survey Explorer (WISE), I identified WISE J085510.83-071442.5 as a new high proper motion object. By combining astrometry from WISE and the Spitzer Space Telescope, I have measured a proper motion of 8.1+/-0.1"/yr and a parallax of 0.454+/-0.045" (2.20+0.24/-0.20 pc) for WISE J085510.83-071442.5, giving it the third highest proper motion and the fourth largest parallax of any known star or brown dwarf. It is also the coldest known brown dwarf based on its absolute magnitude at 4.5um and its color in [3.6]-[4.5]. By comparing M4.5 with the values predicted by theoretical evolutionary models, I estimate an effective temperature of 225-260 K and a mass of 3-10 Mjup for the age range of 1-10 Gyr that encompasses most nearby stars.