Discovery of an L dwarf co-moving BD+60 1417

For the primary we obtained new optical spectroscopy and analyzed all available literature information for youth indicators. We conclude that the LiI abundance, its loci on color-magnitude and color-color diagrams, and the rotation rate revealed in multiple TESS sectors are all consistent with an age of 50-150Myr. Using our re-evaluated age of the primary and the Gaia parallax, along with the photometry and spectrum for W1243, we find Teff=1303+/-31K, log g=4.3+/-0.17cm/s^2^, and a mass of 15+/-5MJup.

We find a physical separation of ~1662au and a mass ratio of ~0.01 for this system. Placing it in the context of the diverse collection of binary stars, brown dwarfs, and planetary companions, the BD+60 1417 system falls in a sparsely sampled area where the formation pathway is difficult to assess.