HAL CCSD
The interstellar object 'Oumuamua as a fractal dust aggregate
Flekkøy, Eirik G.
Luu, Jane X.
Toussaint, Renaud
PoreLab [Oslo] ; Department of Physics [Oslo] ; Faculty of Mathematics and Natural Sciences [Oslo] ; University of Oslo (UiO)-University of Oslo (UiO)-Faculty of Mathematics and Natural Sciences [Oslo] ; University of Oslo (UiO)-University of Oslo (UiO)-Norwegian University of Science and Technology [Oslo] (NTNU) ; Norwegian University of Science and Technology (NTNU)-Norwegian University of Science and Technology (NTNU)
Centre for Earth Evolution and Dynamics [Oslo] (CEED) ; Department of Geosciences [Oslo] ; Faculty of Mathematics and Natural Sciences [Oslo] ; University of Oslo (UiO)-University of Oslo (UiO)-Faculty of Mathematics and Natural Sciences [Oslo] ; University of Oslo (UiO)-University of Oslo (UiO)
Institute of Theoretical Astrophysics [Oslo] ; University of Oslo (UiO)
Institut de physique du globe de Strasbourg (IPGS) ; Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Astrophysical Journal Letters, accepted, in press - 8 pages, 3 figures
insu-02348185
https://insu.hal.science/insu-02348185
https://insu.hal.science/insu-02348185
2019
ARXIV: 1910.07135
info:eu-repo/semantics/altIdentifier/arxiv/1910.07135
en
[PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
info:eu-repo/semantics/preprint
Preprints, Working Papers, ...
The first known interstellar object 'Oumuamua exhibited a nongravitational acceleration that appeared inconsistent with cometary outgassing, leaving radiation pressure as the most likely force. Bar the alien lightsail hypothesis, an ultra-low density due to a fractal structure might also explain the acceleration of 'Oumuamua by radiation pressure (Moro-Martin 2019). In this paper we report a decrease in 'Oumuamua's rotation period based on ground-based observations, and show that this spin-down can be explained by the YORP effect if 'Oumuamua is indeed a fractal body with the ultra-low density of $10^{-2}$ kg m$^{-3}$. We also investigate the mechanical consequences of 'Oumuamua as a fractal body subjected to rotational and tidal forces, and show that a fractal structure can survive these mechanical forces.
2019-11-05