The Young Substellar Companion ROXs 12 B: Near-infrared Spectrum, System Architecture, and Spin-Orbit Misalignment

ROXs 12 (2MASS J16262803-2526477) is a young star hosting a directly imaged companion near the deuteriumburning limit. We present a suite of spectroscopic, imaging, and time-series observations to characterize the physical and environmental properties of this system. Moderate-resolution near-infrared spectroscopy of ROXs. 12. B from Gemini-North/NIFS and Keck/OSIRIS reveals signatures of low surface gravity including weak alkali absorption lines and a triangular H-band pseudocontinuum shape. No signs of Pa beta emission are evident. As a population, however, we find that about half (46%. +/- 14%) of young (less than or similar to 15 Myr) companions with masses less than or similar to 20 M-Jup possess actively accreting subdisks detected via Pa beta line emission, which represents a lower limit on the prevalence of circumplanetary disks in general, as some are expected to be in a quiescent phase of accretion. The bolometric luminosity of the companion and age of the host star (6(2)(+4) Myr) imply a mass of 17.5 +/- 1.5 M-Jup for ROXs 12 B based on hot-start evolutionary models. We identify a wide (5100 au) tertiary companion to this system, 2MASS J16262774-2527247, that is heavily accreting and exhibits stochastic variability in its K2 light curve. By combining v sin i(*) measurements with rotation periods from K2, we constrain the line-of-sight inclinations of ROXs 12 A and 2MASS J16262774-2527247 and find that they are misaligned by 60(-11)(+7)degrees In addition, the orbital axis of ROXs. 12. B is likely misaligned from the spin axis of its host star, ROXs. 12. A, suggesting that ROXs 12 B formed akin to fragmenting binary stars or in an equatorial disk that was torqued by the wide stellar tertiary.