EPSC Abstracts
Vol. 18, EPSC-DPS2025-665, 2025, updated on 08 Sep 2025
https://doi.org/10.5194/epsc-dps2025-665
EPSC-DPS Joint Meeting 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Pit Chains on Asteroid (52246) Donaldjohanson
Fiona Nichols-Fleming1, Jennifer Scully2, Emily Costello3, Audrey Martin4, Edward Bierhaus5, Olivier Barnouin6, Neil Dello Russo6, Hal Weaver6, Simone Marchi7, Keith Noll8, John Spencer7, Hal Levison7, and the Lucy Team*
Fiona Nichols-Fleming et al.
  • 1Center for Earth and Planetary Studies, Smithsonian National Air and Space Museum, Washington, DC, USA (nichols-flemingf@si.edu)
  • 2Jet Propulsion Lab, California Institute of Technology, Pasadena, CA, USA
  • 3Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, Honolulu, HI, USA
  • 4University of Central Florida, Orlando, FL, USA
  • 5Lockheed Martin, Littleton, CO, USA
  • 6Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
  • 7Southwest Research Institute, Boulder, CO, USA
  • 8NASA Goddard Spaceflight Center, Greenbelt, MD, USA
  • *A full list of authors appears at the end of the abstract

On April 20, 2025, NASA’s Lucy spacecraft [1] completed its closest approach with main-belt asteroid (52246) Donaldjohanson [2]. Donaldjohanson appears to be a contact binary and is about 8 km long with a greater than 2 to 1 axis ratio [3]. High resolution images from L’LORRI (Lucy Long Range Reconnaissance Imager) [4] throughout the flyby show linear clusters of depressions, or pit chains, on Donaldjohanson’s large lobe.

The term “pit chain” is not diagnostic of formation mechanism, and these features can form from a range of processes including primary or secondary impacts, venting, or dilational faulting [e.g., 5–7]. We will discuss the most likely formation mechanism(s) for the pit chains on Donaldjohanson and compare the morphology of these features with that of pit chains observed on other small bodies such as (433) Eros, Phobos, (243) Ida, and (951) Gaspra [8–13].

Under the assumption that Donaldjohanson’s pit chains form due to the drainage of unconsolidated material into subsurface structures, we will use the depths of these pits to calculate a minimum thickness for a layer of unconsolidated regolith-like material on the surface of Donaldjohanson. We will compare this estimate with regolith thickness estimates from the study of impact craters on Donaldjohanson as well as estimates from prior studies of pit chains on Eros, Phobos, Ida, and Gaspra.

 

Acknowledgements: The Lucy mission is funded through the NASA Discovery program on contract No. NNM16AA08C. F. Nichols-Fleming is supported by the Lucy L4 PSP award #80NSSC25K7723.

References: [1] Levison, H. F. et al. (2021) Planet. Sci. J., 2, 171. [2] Levison, H. et al. (2025) EPSC-DPS2025. [3] Mottola, S. et al. (2025) EPSC-DPS2025. [4] Weaver, H. A. et al. (2023) Space Sci Rev, 219, 82. [5] Wyrick, D. et al. (2004) Journal of Geophysical Research: Planets, 109. [6] Wyrick, D. Y. et al. (2010) 41st LPSC, Abstract No. 1413. [7] Wyrick, D. Y. and Buczkowski, D. L. (2022) Journal of Geophysical Research: Planets, 127, e2022JE007281. [8] Thomas, P. et al. (1979) Journal of Geophysical Research: Solid Earth, 84, 8457–8477. [9] Prockter, L. et al. (2002) Icarus, 155, 75–93. [10] Hurford, T. A. et al. (2016) Journal of Geophysical Research: Planets, 121, 1054–1065. [11] Sullivan, R. et al. (1996) Icarus, 120, 119–139. [12] Veverka, J. et al. (1994) Icarus, 107, 72–83. [13] Buczkowski, D. L. et al. (2008) Icarus, 193, 39–52.

Lucy Team:

the Lucy Team

How to cite: Nichols-Fleming, F., Scully, J., Costello, E., Martin, A., Bierhaus, E., Barnouin, O., Dello Russo, N., Weaver, H., Marchi, S., Noll, K., Spencer, J., and Levison, H. and the Lucy Team: Pit Chains on Asteroid (52246) Donaldjohanson, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–12 Sep 2025, EPSC-DPS2025-665, https://doi.org/10.5194/epsc-dps2025-665, 2025.