Discovery of a Binary Brown Dwarf at 2 Parsecs from the Sun

TL;DR

This paper reports the discovery of a binary brown dwarf system only 2 parsecs from the Sun, identified through multi-epoch astrometry and confirmed via spectroscopy, making it the third closest known system to our star.

Contribution

The study presents the first identification and characterization of a binary brown dwarf system at 2 parsecs, utilizing multi-survey astrometry and spectroscopic analysis.

Findings

Discovered a binary brown dwarf at 2 parsecs from the Sun.

Measured a parallax of 0.496 arcseconds for the system.

Classified the primary as spectral type L8+/-1.

Abstract

I am using multi-epoch astrometry from the Wide-field Infrared Survey Explorer (WISE) to search for new members of the solar neighborhood via their high proper motions. Through this work, I have identified WISE J104915.57-531906.1 as a high proper motion object and have found additional detections in images from the Digitized Sky Survey, the Two Micron All-Sky Survey, and the Deep Near-Infrared Survey of the Southern Sky. I have measured a parallax of 0.496+/-0.037" (2.0+/-0.15 pc) from the astrometry in these surveys, making WISE J104915.57-531906.1 the third closest system to the Sun. During spectroscopic observations with GMOS at Gemini Observatory, an i-band acquisition image resolved it as a 1.5" (3 AU) binary. A spectrum was collected for the primary, which I classify as L8+/-1. The secondary is probably near the L/T transition as well given that it is only modestly fainter than the primary (delta i=0.45 mag).