The Wide Brown Dwarf Binary Oph 1622–2405 and Discovery of a Wide, Low-Mass Binary in Ophiuchus (Oph 1623–2402): A New Class of Young Evaporating Wide Binaries?

We imaged five objects near the star-forming clouds of Ophiuchus with the Keck Laser Guide Star AO system. We resolved sources 11 (Oph 16222-2405) and 16 (Oph 16233-2402) from Allers and coworkers into binary systems. Source 11 is resolved into a 243 AU binary, the widest known for a very low mass (VLM) binary. The binary nature of source 11 was discovered first by Allers and independently here, during which we obtained the first spatially resolved R similar to 2000 near-infrared (J and K) spectra, mid-IR photometry, and orbital motion estimates. We estimate for 11A and 11B gravities (log g > 3.75), ages (5 plus or minus 2 Myr), luminosities [log(L/L sub( )[unk]) = -2.77 plus or minus 0.10 and -2.96 plus or minus 0.10], and temperatures ( [unk] = 2375 plus or minus 175 K and 2175 plus or minus 175 K). We find self-consistent DUSTY evolutionary model (Chabrier and coworkers) masses of [unk] and [unk] M sub(J), for 11A and 11B, respectively. Our masses are higher than those previously reported (13-15 M sub(J) and 7-8 M sub(J)) by Jayawardhana & Ivanov. Hence, we find that the system is unlikely a "planetary mass binary," as do Luhman and coworkers, but It has the second lowest mass and lowest binding energy of any known binary. Oph 11 and Oph 16 belong to a newly recognized population of wide ( greater than or equal to 100 AU), young (