’Oumuamua as a Cometary Fractal Aggregate: The “Dust Bunny” Model

Jane X. Luu (1, 2) , Eirik G. Flekkøy (3) , Renaud Toussaint (4, 3)

1 CEED - Centre for Earth Evolution and Dynamics [Oslo]
2 Institute of Theoretical Astrophysics [Oslo]
3 PoreLab [Oslo]
4 IPGS - Institut de physique du globe de Strasbourg

The first known interstellar object, 1I/2017 U1 ’Oumuamua, displayed such unusual properties that its origin remains a subject of much debate. We propose that ’Oumuamua’s properties could be explained as those of a fractal dust aggregate (a "dust bunny") formed in the inner coma of a fragmenting exo-Oort cloud comet. Such fragments could serve as accretion sites by accumulating dust particles, resulting in the formation of a fractal aggregate. The fractal aggregate eventually breaks off from the fragment due to hydrodynamic stress. With their low density and tenuously bound orbits, most of these cometary fractal aggregates are then ejected into interstellar space by radiation pressure.

Mots clés: asteroid; interstellar; 'oumuamua

Domaines: Astrophysique [astro-ph]

Jane X. Luu, Eirik G. Flekkøy, Renaud Toussaint. ’Oumuamua as a Cometary Fractal Aggregate: The “Dust Bunny” Model. The Astrophysical journal letters, 2020, 900 (2), pp.L22. ⟨10.3847/2041-8213/abafa7⟩. ⟨hal-03011068⟩