Preliminary Evidence That Protoplanetary Disks Eject More Mass Than They Retain

Abstract

If interstellar objects originate in protoplanetary disks, they can be used to calibrate the fraction of mass that such disks eject. The discoveries of interstellar objects 1I/`Oumuamua and 2I/Borisov, taken together with rogue planets statistics, allow for the calibration of mass locked in interstellar objects in size range $\sim 10^{4} - 10^{9} \; \mathrm{cm}$. Here, we show that at least $\sim 10\%$ of stellar mass is required to produce the observed population of interstellar objects, with a 95\% confidence interval spanning $\sim 2\% - 50\%$. We call this quantity the Minimum Ejection Fraction (MEF), representing a new constraint on planetary system formation that necessitates an order of magnitude more mass to be processed per star than in the Minimum Mass Solar Nebula (MMSN) model. Future discoveries of interstellar objects with LSST on the Vera C. Rubin Observatory will provide a test of our predictions and improve the statistics.