Primordial obliquities of brown dwarfs and super-Jupiters from fragmenting gravito-turbulent discs

Super-Jupiters, brown dwarfs, and stars can form from the collapse of self-gravitating discs. Such discs are turbulent, with flocculent spiral arms accelerating gas to transonic speeds horizontally and vertically. Objects that fragment from gravito-turbulent discs should spin with a wide range of directions, reflecting the random orientations of their parent eddies. We show by direct numerical simulation that obliquities of newly collapsed fragments can range up to 45(circle). Subsequent collisions between fragments can further alter the obliquity distribution, up to 90(circle) or down to near-zero. The large obliquities of newly discovered super-Jupiters on wide orbits around young stars may be gravito-turbulent in origin. Obliquely spinning fragments are born on orbits that may be inclined relative to their parent discs by up to 20(circle), and gravitationally stir leftover material to many times the pre-fragmentation disc thickness.