1,2,3,5,6,2,8,10,- 1NASA, GSFC, Greenbelt, MD, USA (keith.s.noll@nasa.gov)
- 2Observatoire de la Côte d’Azur, CNRS, Nice, France
- 3JHU Applied Physics Laboratory, Laurel, MD, USA
- 4Lockheed Martin Space, Littleton, CO, USA
- 5Massachusetts Institute of Technology, Cambridge, MA, USA
- 6Georgia Institute of Technology, Atlanta, GA, USA
- 7Southwest Research Institute, Boulder, CO, USA
- 8Institute of Space Research, DJR, Berlin, Germany
- 9NASA Headquarters, Washington, DC, USA
- 10University of Maryland, College Park, MD, USA
The Lucy spacecraft flew by the Main Belt asteroid (52246) Donaldjohanson, hereafter DJ, on April 20, 2025. Images obtained during the flyby show DJ to be an elongated object, about 8 km long with an axis ratio greater than 2 to 1, consisting of two distinct lobes connected by a narrow neck. A detailed shape model [1] will be required to further quantify this structure.
Similarly shaped small bodies have been directly observed among Near Earth Objects [2-4], the Main Belt [5], comets [6-9] and in the Kuiper Belt [10]. Many more elongated/bilobed objects can be inferred from lightcurve observations [11]. DJ is a potentially valuable addition to understanding these objects because it resides in the Main Belt and is part of a collisional family of known age [12].
We compile estimated lobe dimensions and apparent orientations in a variety of small bodies of similar size to DJ and discuss observable trends. We compare results to expected behavior in collisional systems and accretion models [13-18].
Acknowledgement: The Lucy mission is funded through the NASA Discovery program on contract No. NNM16AA08C
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How to cite: Noll, K., Agrusa, H., Barnouin, O., Bierhaus, E., Binzel, R., Hirabayashi, M., Levison, H., Marchi, S., Marschall, R., Mottola, S., Spencer, J., Statler, T., Sunshine, J., and Lucy Team, T.: (52246) Donaldjohanson and the Architecture of Bilobed Small Bodies, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–12 Sep 2025, EPSC-DPS2025-859, https://doi.org/10.5194/epsc-dps2025-859, 2025.
