The discovery of the “contact binary,” double-lobed, planetesimal Ultima Thule (since renamed as 486958 Arrokoth) “on 26 June 2014 … using the Hubble Space Telescope” prompted mainstream astrophysicists to cite it as evidence for formation via “gravitational accretion.”
It was the object of the New Horizons space probe flyby on January 1, 2019, from which additional data were compiled. [1]