WISE J231921.92+764544.4: a Newly Found L Class Brown Dwarf in Argus

Discovery of an L4β Candidate Member of Argus in the Planetary Mass Regime: WISE J231921.92+764544.4

Authors:

Castro et el

Abstract:

We present the discovery of a young L dwarf, WISE J231921.92+764544.4, identified by comparing the Wide-field Infrared Survey Explorer (WISE) All-Sky Catalog to the Two Micron All Sky Survey (2MASS). A medium-resolution optical spectrum provides a spectral type of L4β, with a photometric distance estimate of 26.1±4.4 pc. The red WISE W1−W2 color provides additional evidence of youth, while the 2MASS J−Ks color does not. WISE J231921.92+764544.4 is a candidate member of the young moving group Argus, with the space motion and position of WISE J231921.92+764544.4 giving a probability of 79% membership in Argus and a probability of 21% as a field object, based on BANYAN II. WISE J231921.92+764544.4 has a mass of 12.1±0.4 MJup based on membership in Argus, within the planetary mass regime.