Presentation #511.02 in the session Things that Figuratively “Go Bump in the Kuiper Belt, Chapter Two”.
The detached transneptunian objects (TNOs) are those with semimajor axes beyond the 2:1 resonance with Neptune, which are neither resonant nor scattering. Using the detached sample from the OSSOS telescopic survey, we produce the first studies of their orbital distribution based on matching the orbits and numbers of the known TNOs after accounting for survey biases. We show that the detached TNO perihelion (q) distribution cannot be uniform, but is instead better matched by two uniform components with a break near q ≈ 40 au. We produce parameterized two-component models that are not rejectable by the OSSOS data set, and estimate that there are 36000+12000-9000 detached TNOs with absolute magnitudes Hr < 8.66 (D > 100 km) and semimajor axes 48 < a < 250 au (95% confidence limits). Although we believe these heuristic two-parameter models yield a correct population estimate, we then use the same methods to show that the perihelion distribution of a detached disk created by a simulated rogue planet matches the q distribution even better, suggesting that the temporary presence of other planets in the early Solar System is a promising model to create today’s large semimajor axis TNO population. This numerical model results in a detached TNO population estimate of 48000+15000-12000. Given these estimates, we conclude that there are (5 ± 2) × 104 dynamically detached TNOs, which are thus roughly twice as numerous as the entire hot main belt.