Morphology of asteroid (4179) Toutatis as imaged by Chang'E‐2 spacecraft

Zhu, M. H.; Fa, Wenzhe; Ip, W.-H.; Ji, Huang; Liu, Tiantian; Meng, Liang; Yan, Jun; Xu, A.; Tang, Zesheng; Wang, Xiaolei; Dong, Qiao

doi:10.1002/2013gl058914

Cited by 20 publications

(15 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The radar shape models revealed a highly elongated and irregular shape. Several large‐scale fractures were also observed on the surface of Toutatis (Zhu et al, ). Material appears to be segregated along the asteroid's long axis.…”

Section: Datamentioning

confidence: 93%

Power Laws of Topography and Gravity Spectra of the Solar System Bodies

2018

View full text Add to dashboard Cite

When a spacecraft visits a new planetary body, it is useful to know the properties of its shape and gravity field. This knowledge helps predict the magnitude of the perturbations in the motion of the spacecraft due to nonsphericity of a body's gravity field as well as planning for an observational campaign. It has been known for the terrestrial planets that the power spectrum of the gravity field follows a power law, also known as the Kaula rule (Kaula, 1963, https://doi.org/10.1029Rapp, 1989 Rapp, , https://doi.org/10.1111 Rapp, /j.1365 Rapp, -246X.1989. A similar rule was derived for topography (Vening Meinesz, 1951). The goal of this study is to generalize the power law dependence of the gravity and topography spectra for solid surface solar system bodies across a wide range of body sizes. Traditionally, it is assumed that the gravity and topography power spectra of planets scale as g −2 , where g is the surface gravity. This gravity scaling also works for the minor bodies to first order. However, we find that a better fit can be achieved using a more general scaling based on the body's radius and mean density. We outline a procedure on how to use this general scaling for topography to provide an a priori estimate for the gravity power spectrum. We show that for irregularly shaped bodies the gravity power spectrum is no longer a power law even if their topography spectrum is a power law. Such a generalization would be useful for observation planning in the future space missions to the minor bodies for which little is known. Plain Language SummaryWe used the available models of shape and gravity field of the solar system bodies. We study how the amplitude of the mountains and valleys in gravity and topography depends on their size. Mountains on Mars are greater than on the Earth and yet larger on asteroid Vesta compared relative to the body's size. The same is true for gravity: Relative variations in gravity are larger on smaller bodies. We quantify this dependence and develop a method to predict the variations in gravity and topography depending on the body's size and density.

show abstract

Section: Datamentioning

confidence: 93%

Power Laws of Topography and Gravity Spectra of the Solar System Bodies

2018

View full text Add to dashboard Cite

show abstract

“…Benner et al 2006 estimated that ~10% of NEAs > 200m are contact binaries, following a strict definition for contact binary, where two lobes and bi-model mass distribution is required. Note that this definition would exclude objects such as Itokawa and Toutatis that have a shape suggestive of multiple components, but at a higher mass ratio between components (Fujiwara et al 2006, Zhu et al 2014. Using a relaxed definition that allows mass ratios between components as low as 4:1, which includes Itokawa and Toutatis, the fraction of the NEA population grows to ~14% (Taylor et al 2012).…”

Section: Odd Shapes and How To Reshape A Rubble Pilementioning

confidence: 99%

“…[ Figure 10: The asteroid Toutatis is a km-scale NEA that shows a bifurcated shape. It was visited by the Chang'E-2 spacecraft (Zhu et al 2014). ]…”

Section: Odd Shapes and How To Reshape A Rubble Pilementioning

confidence: 99%

Rubble Pile Asteroids

Walsh

2018

Annu. Rev. Astron. Astrophys.

144

View full text Add to dashboard Cite

The moniker "rubble pile" is typically applied to all solar system bodies 200m < Diameter < ~10km -where in this size range there is an abundance of evidence that nearly every object is bound primarily by self-gravity with significant void space or bulk porosity between irregularly shaped constituent particles. The understanding of this population is derived from wide-ranging population studies of derived shape and spin, decades of observational studies in numerous wavelengths, evidence left behind from impacts on planets and moons and the in situ study of a few objects via spacecraft flyby or rendezvous. The internal structure, however, which is responsible for the name "rubble pile", is never directly observed, but belies a violent history. Many or most of the asteroids on near-Earth orbits, and the ones most accessible for rendezvous and in situ study, are likely byproducts of the continued collisional evolution of the Main Asteroid Belt.

show abstract

“…In the past (see, e.g., Barucci et al, 2011), a few missions were dedicated to asteroids as a prime objective, e.g., NEAR-Shoemaker (NASA, 1996) to 433 Eros in 2000, Deep Space 1 (NASA, 1998 to 9969 Braille in 1999 andHayabusa (JAXA, 2003) to 25143 Itokawa in 2005, or as secondary objectives like Galileo (NASA, 1989) to fly-by 951 Gaspra in 1991 and 243 Ida in 1993, NEARShoemaker (NASA, 1996) to (243) Mathilde in 1997, Stardust (NASA, 1999 (Zhu et al, 2014).…”

Section: -Introductionmentioning

confidence: 99%