2015/08/25 by Adam J. Burgasser, Burgasser, Adam J., Carl Melis +10 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.48550/arxiv.1508.06332
12 pages, 22 figures, accepted for publication to AJ
openalex publication_date 2015/08/25 · arxiv created 2015/08/26 · arxiv updated 2015/08/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report the detection of radio emission and orbital motion from the nearby star-brown dwarf binary WISE J072003.20-084651.2AB. Radio observations across the 4.5-6.5 GHz band with the Very Large Array identify at the position of the system quiescent emission with a flux density of 15±3 μJy, and a highly-polarized radio source that underwent a 2-3 min burst with peak flux density 300±90 μJy. The latter emission is likely a low-level magnetic flare similar to optical flares previously observed for this source. No outbursts were detected in separate narrow-band Hα monitoring observations. We report new high-resolution imaging and spectroscopic observations that confirm the presence of a co-moving T5.5 secondary and provide the first indications of three-dimensional orbital motion. We used these data to revise our estimates for the orbital period (4.1+2.7-1.3 yr) and tightly constrain the orbital inclination to be nearly edge-on (93.6°+1.6°-1.4°), although robust measures of the component and system masses will require further monitoring. The inferred orbital motion does not change the high likelihood that this radio-emitting very low-mass binary made a close pass to the Sun in the past 100 kyr.