Collisional elongation: Possible origin of extremely elongated shape of 1I/‘Oumuamua

Sugiura, Keisuke; Kobayashi, Hiroshi; Inutsuka, Shu‐ichiro

doi:10.1016/j.icarus.2019.03.014

Cited by 13 publications

(8 citation statements)

References 52 publications

(65 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, recent research providing explanations for 'Oumuamua's cigar shape (e.g. Katz 2018;Vavilov & Medvedev 2019;Sugiura et al 2019) may need to be revisited. Combining our physical model fitting of 'Oumuamua's light curve with our statistical analysis of the model probability based on the depth of the light curve minima points to a tumbling thin disc experiencing some torque as the most likely model for the asteroid.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Modelling the light curve of ‘Oumuamua: evidence for torque and disc-like shape

Mashchenko

2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present the first attempt to fit the light curve of the interstellar visitor 'Oumuamua using a physical model which includes optional torque. We consider both conventional (Lommel-Seeliger triaxial ellipsoid) and alternative ("black-and-white ball", "solar sail") brightness models. With all the brightness models, some torque is required to explain the timings of the most conspicuous features -deep minima -of the asteroid's light curve. Our best-fitting models are a thin disc (aspect ratio 1:6) and a thin cigar (aspect ratio 1:8) which are very close to being axially symmetric. Both models are tumbling and require some torque which has the same amplitude in relation to 'Oumuamua's linear non-gravitational acceleration as in Solar System comets which dynamics is affected by outgassing. Assuming random orientation of the angular momentum vector, we compute probabilities for our best-fitting models. We show that cigar-shaped models suffer from a fine-tuning problem and have only 16 per cent probability to produce light curve minima as deep as the ones present in 'Oumuamua's light curve. Disc-shaped models, on the other hand, are very likely (at 91 per cent) to produce minima of the required depth. From our analysis, the most likely model for 'Oumuamua is a thin disc (slab) experiencing moderate torque from outgassing.

show abstract

Section: Discussionmentioning

confidence: 99%

“…In particular, recent research providing explanations for 'Oumuamua's cigar shape (e.g. Katz 2018;Vavilov & Medvedev 2019;Sugiura et al 2019) may need to be revisited.…”

Section: Discussionmentioning

confidence: 99%

Modelling the light curve of ‘Oumuamua: evidence for torque and disc-like shape

Mashchenko

2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Shapes of resultant remnants depend on the friction angle, especially for complex shapes (see Sugiura et al 2019). Hence, the fraction of bilobed remnants may be affected by the choice of the friction angle.…”

Section: Resultsmentioning

confidence: 99%

High-resolution simulations of catastrophic disruptions: Resultant shape distributions

Sugiura

Kobayashi

Inutsuka

2020

Planetary and Space Science

Self Cite

View full text Add to dashboard Cite

The members of asteroid families have various shapes. We investigate the origin of their shapes by high-resolution impact simulations for catastrophic disruptions using a Smoothed Particle Hydrodynamics code. Collisional remnants produced through our simulations of the catastrophic disruptions mainly have spherical or bilobed shapes. However, no flat remnants with the ratio of minor to major axis lengths c/a 0.5 are formed. The results of the simulations provide various shapes of asteroids and explain most of the shapes in asteroid families that are supposed to be produced through catastrophic disruptions. However, the present simulations do not explain significantly flat asteroids. We suggest that these flat asteroids may be interlopers or formed through low-velocity collisions between member asteroids.

show abstract

“…Thus, we expect that the SPH method has the advantage of precise control of bulk friction of rubble piles. So far the SPH method has mainly been used to investigate shapes of impact outcomes (e.g., Jutzi & Asphaug 2015;Jutzi & Benz 2017;Leleu et al 2018;Sugiura et al 2018Sugiura et al , 2019Sugiura et al , 2020, and this is the first work applying the SPH method to the rotational deformation of small bodies.…”

Section: Introductionmentioning

confidence: 99%

SPH Simulations for Shape Deformation of Rubble-Pile Asteroids Through Spinup: The Challenge for Making Top-Shaped Asteroids Ryugu and Bennu

Sugiura,

Kobayashi,

Watanabe

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Asteroid 162173 Ryugu and asteroid 101955 Bennu, which were recently visited by spacecraft Hayabusa2 and OSIRIS-REx, respectively, are spinning topshaped rubble piles. Other axisymmetric top-shaped near-Earth asteroids have been observed with ground-based radar, most of which rotate near breakup rotation periods of ∼ 3 hours. This suggests that rotation-induced deformation of asteroids through rotational spinup produces top shapes. Although some previous simulations using the Discrete Element Method showed that spinup of rubble piles may produce oblate top shapes, it is still unclear what kinds of conditions such as friction angles of constituent materials and spinup timescales are required for top-shape formation. Here we show, through Smoothed Particle Hydrodynamics simulations of granular bodies spinning-up at different rates, that the rotation-induced deformation of spherical rubble piles before breakup can be classified into three modes according to the friction angle φ d : quasi-static and internal deformation for φ d ≤ 40 • , dynamical and internal deformation for 50 • ≤ φ d ≤ 60 • , and a set of surface landslides for φ d ≥ 70 • . Note that these apparent large values of friction angle can be acceptable if we consider the effect of cohesion among blocks of a rubble pile under weak gravity. Bodies with φ d ≤ 60 • evolve into oblate spheroids through internal deformation, but never form pronounced equators defining a top shape. In contrast, bodies with φ d ≥ 70 • deform into axisymmetric top shapes through an axisymmetric set of surface landslides if spinup timescales are a few days. In addition, through slow spinups with timescales 1 month, bodies with φ d ≥ 70 • deform into non-axisymmetric shapes via localized sets of landslides. We suggest that rapid spinup mechanisms are preferable for the formation of axisymmetric top shapes.

show abstract

Collisional elongation: Possible origin of extremely elongated shape of 1I/‘Oumuamua

Cited by 13 publications

References 52 publications

Modelling the light curve of ‘Oumuamua: evidence for torque and disc-like shape

Modelling the light curve of ‘Oumuamua: evidence for torque and disc-like shape

High-resolution simulations of catastrophic disruptions: Resultant shape distributions

SPH Simulations for Shape Deformation of Rubble-Pile Asteroids Through Spinup: The Challenge for Making Top-Shaped Asteroids Ryugu and Bennu

Contact Info

Product

Resources

About