Crater population on asteroid (101955) Bennu indicates impact armouring and a young surface

被引：28

作者：

Bierhaus, E. B. ^{[1
]}

Trang, D. ^{[2
]}

Daly, R. T. ^{[3
]}

Bennett, C. A. ^{[4
]}

Barnouin, O. S. ^{[3
]}

Walsh, K. J. ^{[5
]}

Ballouz, R. -l. ^{[4
]}

Bottke, W. F. ^{[5
]}

Burke, K. N. ^{[4
]}

Perry, M. E. ^{[3
]}

Jawin, E. R. ^{[6
,7
]}

McCoy, T. J. ^{[6
]}

Connolly, H. C., Jr. ^{[4
,8
]}

Daly, M. G. ^{[9
]}

Dworkin, J. P. ^{[10
]}

DellaGiustina, D. N. ^{[4
]}

Gay, P. L. ^{[11
]}

Brodbeck, J. I. ^{[4
]}

Nolau, J. ^{[12
]}

Padilla, J. ^{[4
]}

Stewart, S. ^{[4
]}

Schwartz, S. ^{[4
,11
]}

Michel, P. ^{[13
]}

Pajola, M. ^{[14
]}

Lauretta, D. S. ^{[4
]}

机构：

[1] Lockheed Martin Space, Littleton, CO 80120 USA

[2] Univ Hawaii Manoa, Hawaii Inst Geophys & Planetol, Honolulu, HI USA

[3] Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA

[4] Univ Arizona, Lunar & Planetary Lab, Tucson, AZ USA

[5] Southwest Res Inst, Boulder, CO USA

[6] Natl Museum Nat Hist, Smithsonian Inst, Washington, DC USA

[7] Smithsonian Inst Natl Air & Space Museum, Washington, DC USA

[8] Rowan Univ, Dept Geol, Glassboro, NJ USA

[9] York Univ, Ctr Res Earth & Space Sci, Toronto, ON, Canada

[10] NASA Goddard Spaceflight Ctr, Solar Syst Explorat Div, Greenbelt, MD USA

[11] Planetary Sci Inst, Tucson, AZ USA

[12] Univ Cent Florida, Dept Phys, Orlando, FL USA

[13] Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Nice, France

[14] INAF, Astron Observ Padova, Padua, Italy

来源：

NATURE GEOSCIENCE | 2022年 / 15卷 / 06期

关键词：

DISTRIBUTIONS; EVOLUTION; EJECTA;

D O I：

10.1038/s41561-022-00914-5

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

The impactor-to-crater size scaling relationships that enable estimates of planetary surface ages rely on an accurate formulation of impactor-target physics. An armouring regime, specific to rubble-pile surfaces, has been proposed to occur when an impactor is comparable in diameter to a target surface particle (for example, a boulder). Armouring is proposed to reduce crater diameter, or prevent crater formation in the asteroid surface, at small crater diameters. Here, using measurements of 1,560 craters on the rubble-pile asteroid (101955) Bennu, we show that the boulder population controls a transition from crater formation to armouring at crater diameters -2-3 m, below which crater formation in the bulk surface is increasingly rare. By combining estimates of impactor flux with the armouring scaling relationship, we find that Bennu's crater retention age (surface age derived from crater abundance) spans from 1.6-2.2 Myr for craters less than a few meters to -10-65 Myr for craters >100 m in diameter, reducing the maximum surface age by a factor of >15 relative to previous estimates. The range of crater retention ages, together with latitudinal variations in large-crater spatial density, indicate that ongoing resurfacing processes render the surface many times younger than the bulk asteroid.

引用

页码：440 / +

页数：20