The dust in the dust coma of interstellar object 2I/Borisov is large (exceeding ~1 mm radius) and compact, differing from the fluffy aggregates typically found in Solar System comets. This compact dust is presumably a result of impacts in the comet’s home system, and suggests 2I/Borisov formed in a collapsing pebble cloud.
- Bin Yang
- Aigen Li
- Eric Villard