The Population of Interstellar Objects Detectable with the LSST and Accessible for In Situ Rendezvous with Various Mission Designs

The recently discovered population of interstellar objects presents us with the opportunity to characterize material from extrasolar planetary and stellar systems up close. The forthcoming Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will provide an unprecedented increase in sensitivity to these objects compared to the capabilities of currently operational observational facilities. We generate a synthetic population of 'Oumuamua-like objects drawn from their galactic kinematics and identify the distribution of impact parameters, eccentricities, hyperbolic velocities, and sky locations of objects detectable with the LSST, assuming no cometary activity. This population is characterized by a clustering of trajectories in the direction of the solar apex and antiapex, centered at orbital inclinations of similar to 90 degrees. We identify the ecliptic or solar apex as the optimal sky location to search for future interstellar objects as a function of survey limiting magnitude. Moreover, we identify the trajectories of detectable objects that will be reachable for in situ rendezvous with a dedicated mission with the capabilities of the forthcoming Comet Interceptor or proposed Bridge concept. By scaling our fractional population statistics with the inferred spatial number density, we estimate that the LSST will detect of order similar to 15 interstellar objects over the course of its similar to 10 yr observational campaign. Furthermore, we find that there should be similar to 1-3 and similar to 0.0007-0.001 reachable targets for missions with propulsion capabilities comparable to Bridge and Comet Interceptor, respectively. These numbers are lower limits and will be readily updateable when the number density and size-frequency distribution of interstellar objects are better constrained.

Automated summary

The recently discovered population of interstellar objects provides the opportunity to study material from extrasolar planetary and stellar systems. The forthcoming Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will enhance the capabilities to detect these objects compared to current observational facilities. By generating a synthetic population of 'Oumuamua-like objects and analyzing their galactic kinematics, the distribution of detectable objects with the LSST is identified. Additionally, the optimal sky location for future interstellar object searches is determined.