A Candidate Wide Brown Dwarf Binary in the Argus Association: 2MASS J14504216-7841413 and 2MASS J14504113-7841383

Abstract

[not part of Research Note] We report the discovery of a widely-separated low-mass binary as a candidate member of the $\sim$40 Myr Argus Association. Resolved imaging and astrometry with 2MASS and LDSS-3 reveal a common proper motion pair of red sources separated by 4.23''$\pm$0.11'', with the secondary roughly one magnitude fainter at $i$, $z$ and $J$. Resolved spectroscopy indicates component types of M8pec and M9pec, the peculiarities arising from weak Na I and strong VO absorption characteristic of low gravity sources. With its small proper motion and estimated 75$\pm$25 pc distance, the BANYAN II tool indicates a membership probability of 93% in Argus, which would be consistent with a pair of brown dwarfs of mass $\sim$0.04 M$_{\odot}$ separated by $\sim$300 AU.