Ejecta from the DART-produced active asteroid Dimorphos

• Main Authors: Li, Jian-Yang, Hirabayashi, Masatoshi, Farnham, Tony L, Sunshine, Jessica M, Knight, Matthew M, Tancredi, Gonzalo, Moreno, Fernando, Murphy, Brian, Opitom, Cyrielle, Chesley, Steve, Scheeres, Daniel J, Thomas, Cristina A, Fahnestock, Eugene G, Cheng, Andrew F, Dressel, Linda, Ernst, Carolyn M, Ferrari, Fabio, Fitzsimmons, Alan, Ieva, Simone, Ivanovski, Stavro L, Kareta, Teddy, Kolokolova, Ludmilla, Lister, Tim, Raducan, Sabina D, Rivkin, Andrew S, Rossi, Alessandro, Soldini, Stefania, Stickle, Angela M, Vick, Alison, Vincent, Jean-Baptiste, Weaver, Harold A, Bagnulo, Stefano, Bannister, Michele T, Cambioni, Saverio, Bagatin, Adriano Campo, Chabot, Nancy L, Cremonese, Gabriele, Daly, R. Terik, Dotto, Elisabetta, Glenar, David A, Granvik, Mikael, Hasselmann, Pedro H, Herreros, Isabel, Jacobson, Seth, Jutzi, Martin, Kohout, Tomas, La Forgia, Fiorangela, Lazzarin, Monica, Lin, Zhong-Yi, Lolachi, Ramin, Lucchetti, Alice, Makadia, Rahil, Epifani, Elena Mazzotta, Michel, Patrick, Migliorini, Alessandra, Moskovitz, Nicholas A, Orm, Jens, Pajola, Maurizio, nchez, Paul S, Schwartz, Stephen R, Snodgrass, Colin, Steckloff, Jordan, Stubbs, Timothy J, Trigo-Rodriguez, Josep M
• Format: Journal Article
• Language: English
• Published: 03-03-2023
• Subjects: Physics - Earth and Planetary Astrophysics
• DOI: 10.48550/arxiv.2303.01700

Some active asteroids have been proposed to be the result of impact events.
Because active asteroids are generally discovered serendipitously only after
their tail formation, the process of the impact ejecta evolving into a tail has
never been directly observed. NASA's Double Asteroid Redirection Test (DART)
mission, apart from having successfully changed the orbital period of
Dimorphos, demonstrated the activation process of an asteroid from an impact
under precisely known impact conditions. Here we report the observations of the
DART impact ejecta with the Hubble Space Telescope (HST) from impact time T+15
minutes to T+18.5 days at spatial resolutions of ~2.1 km per pixel. Our
observations reveal a complex evolution of ejecta, which is first dominated by
the gravitational interaction between the Didymos binary system and the ejected
dust and later by solar radiation pressure. The lowest-speed ejecta dispersed
via a sustained tail that displayed a consistent morphology with previously
observed asteroid tails thought to be produced by impact. The ejecta evolution
following DART's controlled impact experiment thus provides a framework for
understanding the fundamental mechanisms acting on asteroids disrupted by
natural impact.