http://arxiv.org/abs/1911.12228
The first interstellar object ‘Oumuamua is discovered in 2017. When it travels in interstellar space, it keeps colliding with interstellar medium (ISM). Given a sufficiently long interaction time, its rotation state may change significantly because of the angular momentum transfer with interstellar medium. This research first obtains the torque curve and rotation evolution of the asteroid that collides with interstellar medium by numerical simulation. Several kinds of shapes are generated by method of Gaussian random sphere: spheroidal, oblate, prolate shapes. A pseudo ‘Oumuamua is generated with the dimension ratio 7:1 :1. The results show that asteroids will incline ultimately to a stable orientation such that its axis of maximum moment of inertia is perpendicular to its velocity vector. Oblate shapes are easier to incline than spheroidal and prolate shapes. Pseudo ‘Oumuamua is tested under different initial conditions. When rubble piles rotate so fast that disruption is found to be about 5.05 Gyrs and major axis is in alignment to around 93.5 degree from its velocity vector at disruption. Considering the significant effect of interstellar medium, the excitedly tumbling motion of ‘Oumuamua may result from its collision with interstellar medium. Rotation of asteroids in Oort Cloud may be dominated by ISM collision effect since YORP effect is quite weak at distance of 50000AU from the Sun.
W. Zhou
Thu, 28 Nov 19
60/70
Comments: 7 pages, 9 figures
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