SOAR Telescope Catches Dimorphos’s Expanding Comet-like Tail After DART Impact
NOIRLab-operated SOAR telescope reveals immense trail of debris from collision with asteroid Dimorphos
3 October 2022
The SOAR Telescope in Chile, operated by NSF’s NOIRLab, imaged the more than 10,000 kilometers long trail of debris blasted from the surface of Dimorphos two days after the asteroid was impacted by NASA’s DART spacecraft.
NASA’s Double Asteroid Redirection Test (DART) spacecraft intentionally crashed into Dimorphos, the asteroid moonlet in the double-asteroid system of Didymos, on Monday 26 September 2022. This was the first planetary defense test in which an impact of a spacecraft attempted to modify the orbit of an asteroid.
Two days after DART’s impact, astronomers Teddy Kareta (Lowell Observatory) and Matthew Knight (US Naval Academy) used the 4.1-meter Southern Astrophysical Research (SOAR) Telescope , at NSF’s NOIRLab's Cerro Tololo Inter-American Observatory in Chile, to capture the vast plume of dust and debris blasted from the asteroid’s surface. In this new image, the dust trail — the ejecta that has been pushed away by the Sun’s radiation pressure, not unlike the tail of a comet — can be seen stretching from the center to the right-hand edge of the field of view, which at SOAR is about 3.1 arcminutes using the Goodman High Throughput Spectrograph. At Didymos's distance from Earth at the time of the observation, that would equate to at least 10,000 kilometers (6000 miles) from the point of impact.
“It is amazing how clearly we were able to capture the structure and extent of the aftermath in the days following the impact,” said Kareta.
“Now begins the next phase of work for the DART team as they analyze their data and observations by our team and other observers around the world who shared in studying this exciting event,” said Knight. We plan to use SOAR to monitor the ejecta in the coming weeks and months. The combination of SOAR and AEON  is just what we need for efficient follow-up of evolving events like this one.”
These observations will allow scientists to gain knowledge about the nature of the surface of Dimorphos, how much material was ejected by the collision, how fast it was ejected, and the distribution of particle sizes in the expanding dust cloud — for example, whether the impact caused the moonlet to throw off big chunks of material or mostly fine dust. Analyzing this information will help scientists protect Earth and its inhabitants by better understanding the amount and nature of the ejecta resulting from an impact, and how that might modify an asteroid’s orbit.
SOAR’s observations demonstrate the capabilities of NSF-funded AURA facilities in planetary-defense planning and initiatives. In the future, Vera C. Rubin Observatory, funded by NSF and the US Department of Energy and currently under construction in Chile, will conduct a census of the Solar System to search for potentially hazardous objects.
 SOAR is designed to produce the best quality images of any observatory in its class. Located on Cerro Pachón, SOAR is a joint project of the Ministério da Ciência, Tecnologia e Inovações do Brasil (MCTI/LNA), NSF’s NOIRLab, the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).
 The Astronomical Event Observatory Network (AEON) is a facility ecosystem for accessible and efficient follow up of astronomical transients and Time Domain science. At the heart of the network, NOIRLab, with its SOAR 4.1-meter and Gemini 8-meter telescopes (and soon the Víctor M. Blanco 4-meter Telescope at CTIO), has joined forces with Las Cumbres Observatory to build such a network for the era of Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST). SOAR is the pathfinder facility for incorporating the 4-meter-class and 8-meter-class telescopes into AEON.
NSF’s NOIRLab, the US center for ground-based optical-infrared astronomy, operates the international Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the Department of Energy’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on Iolkam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O'odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.
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