Portal de Periódicos da CAPES

Episodes of particle ejection from the surface of the active asteroid (101955) Bennu

2019; American Association for the Advancement of Science; Volume: 366; Issue: 6470 Linguagem: Inglês

10.1126/science.aay3544

1095-9203

D. S. Lauretta, C. W. Hergenrother, Steven R. Chesley, Jason M. Leonard, John Pelgrift, Coralie D. Adam, M. Al Asad, Peter G. Antreasian, Ronald‐Louis Ballouz, K. J. Becker, C. A. Bennett, Brent J. Bos, W. F. Bottke, M. Brozović, H. Campins, H. C. Connolly, M. G. Daly, A. B. Davis, J. de León, D. N. DellaGiustina, C. Drouet d’Aubigny, Jason P. Dworkin, Joshua P. Emery, Davide Farnocchia, D. P. Glavin, D. R. Golish, Christine Hartzell, Robert A. Jacobson, E. R. Jawin, Peter Jenniskens, John Kidd, Erik J. Lessac‐Chenen, Jian‐Yang Li, G. Libourel, J. Licandro, Andrew J. Liounis, C. Maleszewski, C. Manzoni, B. May, Leilah K. McCarthy, Jay W. McMahon, Patrick Michel, J. L. Molaro, Michael C. Moreau, Derek Nelson, W. M. Owen, B. Rizk, H. L. Roper, B. Rozitis, Eric Sahr, Daniel J. Scheeres, J. A. Seabrook, Sanford Selznick, Yu Takahashi, Florian Thuillet, P. Tricarico, David Vokrouhlický, C. W. V. Wolner,

Astrophysics and Star Formation Studies

Active asteroids are those that show evidence of ongoing mass loss. We report repeated instances of particle ejection from the surface of (101955) Bennu, demonstrating that it is an active asteroid. The ejection events were imaged by the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) spacecraft. For the three largest observed events, we estimated the ejected particle velocities and sizes, event times, source regions, and energies. We also determined the trajectories and photometric properties of several gravitationally bound particles that orbited temporarily in the Bennu environment. We consider multiple hypotheses for the mechanisms that lead to particle ejection for the largest events, including rotational disruption, electrostatic lofting, ice sublimation, phyllosilicate dehydration, meteoroid impacts, thermal stress fracturing, and secondary impacts.