Efficient Searches for Galactic Stream Interstellar Asteroids (original) (raw)

The volume rate σ v ∞ sampled by surveys as a function of the velocity at infinity, v ∞ , after accounting for gravitational focusing (which changes the cross section, σ). This function provides a proxy for the relative interstellar asteroid detection probability as a function of v ∞. The detection probability for the Pleiades stream is poor compared to slower moving ISOs; the detection of 1I suggests an enhanced ISO density in that stream. Note that present surveys have a streak limit (an upper limit on the angular motions of detectable objects); shown here is the PanSTARRS streak limit of 10• day −1 (which applied at the time of the discovery of 1I). ISOs from the fast moving Hercules stream will be hard to detect without software improvements, such as synthetic tracking.