Webb, Hubble telescopes capture images of DART asteroid crash. Take a look

The space telescopes observed the impact across an array of wavelengths, revealing the distribution of particle sizes in the expanding dust cloud.
Deena Theresa

NASA released spectacular images of the asteroid-smashing Double Asteroid Redirection Test (DART) probe into the space rock Dimorphos on Monday, captured by two of the space agency's Great Observatories, the James Webb Space Telescope and its older counterpart Hubble Space Telescope.

The observations were the first job the two space telescopes performed in tandem. Their collaboration will reveal new information about the asteroid collision.

While Webb observes the universe in the infrared, the Hubble Space Telescope detects optical light, the one visible to the human eye. Observing the impact across an array of wavelengths will reveal the distribution of particle sizes in the expanding dust cloud, helping to determine whether it threw off lots of big chunks or mostly fine dust, according to a press release. Combining the information with ground-based telescope observations will help astronomers understand the effectiveness of a kinetic impact in modifying an asteroid's orbit.

"Webb and Hubble show what we’ve always known to be true at NASA: We learn more when we work together," NASA Administrator Bill Nelson said in a statement. "For the first time, Webb and Hubble have simultaneously captured imagery from the same target in the cosmos: an asteroid impacted by a spacecraft after a seven-million-mile journey. All of humanity eagerly awaits the discoveries to come from Webb, Hubble, and our ground-based telescopes – about the DART mission and beyond."

Webb observed the impact over five hours

The space telescope took one observation of the impact location before the collision took place, and a couple more observations over the next few hours, with its Near-Infrared Camera (NIRCam). The 10 images captured reveal a tight, compact core, with "plumes of material appearing as wisps streaming away from the center of where the impact took place".

Webb flight operators and science teams were presented with unique challenges as DART approached its target because of the asteroid's speed of travel across the sky. The teams worked round the clock in the weeks leading up to the impact to enable and test a method of tracking asteroids moving over three times faster than the original speed limit set for Webb.

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Webb, Hubble telescopes capture images of DART asteroid crash. Take a look
This image from NASA’s JWST's Near-Infrared Camera instrument shows Dimorphos, the asteroid moonlet in the double-asteroid system of Didymos, about 4 hours after NASA’s DART made impact.

"I have nothing but tremendous admiration for the Webb Mission Operations folks that made this a reality," said principal investigator Cristina Thomas of Northern Arizona University in Flagstaff, Arizona. "We have been planning these observations for years, then in detail for weeks, and I’m tremendously happy this has come to fruition."

The data was collected as part of Webb’s Cycle 1 Guaranteed Time Observation Program 1245 led by Heidi Hammel of the Association of Universities for Research in Astronomy.

Hubble images reveal ejecta from the impact

Hubble also captured observations of the Didymos-Dimorphos system ahead of the impact, then again 15 minutes after DART hit the surface of Dimorphos - resulting in a total of 45 images.

Images from Hubble's Wide Field Camera 3 reveal the impact in visible light; ejecta from the impact resemble rays stretching out from the body of the asteroid. Some of the rays appear slightly curved, but astronomers have yet to determine what this could mean.

Webb, Hubble telescopes capture images of DART asteroid crash. Take a look
These images from NASA’s Hubble Space Telescope, taken 22 minutes, 5 hours, and 8.2 hours after NASA’s DART intentionally impacted Dimorphos, show expanding plumes of ejecta from the asteroid’s body.

According to the Hubble images, the system's brightness increased three-fold after impact. Astronomers saw that brightness hold steady, even eight hours after impact.

"When I saw the data, I was literally speechless, stunned by the amazing detail of the ejecta that Hubble captured," said Jian-Yang Li of the Planetary Science Institute in Tucson, Arizona, who led the Hubble observations. "I feel lucky to witness this moment and be part of the team that made this happen."

The Hubble data was collected as part of Cycle 29 General Observers Program 16674.

More observations ahead

Scientists also plan to observe the asteroid system in the coming months using Webb's Mid-Infrared Instrument (MIRI) and Near-Infrared Spectrograph (NIRSpec). Spectroscopic data will provide researchers with insight into the asteroid’s chemical composition.

Meanwhile, Hubble plans to monitor the Didymos-Dimorphos system 10 more times over the next three weeks. As per the release, "these regular, relatively long-term observations as the ejecta cloud expands and fades over time will paint a more complete picture of the cloud’s expansion from the ejection to its disappearance".

Andy Rivkin, DART investigation team lead of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, summarized the event perfectly: "This is an unprecedented view of an unprecedented event."

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