SIMBAD references

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 - K_s 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% for 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 M_Jup based on membership in Argus, within the planetary mass regime.