Webb and Hubble also observed the DART impact on an asteroid

Sep. 29 () –

Two of the great space observatories, the NASA/ESA Webb and Hubble telescopes, have captured views of the impact of the DART spacecraft against a small asteroid 11 million km.

Observations of the impact of DART (Double Asteroid Redirection Test) of NASA mark the the first time Webb and Hubble have been used to simultaneously observe the same celestial target.

DART intentionally crashed on September 26 into Dimorphos, the asteroid’s small moon in the Didymos double-asteroid system. It was the world’s first test of the kinetic impact technique using a spacecraft to deflect an asteroid by changing the object’s orbit. DART is a test to defend the Earth against possible dangers from asteroids or comets.

The Webb and Hubble observations together will allow scientists to gain insight into the nature of Dimorphos’s surface, how much material was ejected by the collision, and how quickly it was ejected. Additionally, observing the impact over a wide range of wavelengths between Webb and Hubble will reveal the distribution of particle sizes in the expanding dust cloud, helping to determine whether it ejected many large chunks or mostly fine dust. Combining this information will help scientists understand how effectively a kinetic impact can change an asteroid’s orbit, informs the ESA, one of the operators of both telescopes.

Webb took one observation of the impact location before the collision occurred, then several observations over the next several hours. Images from Webb’s Near Infrared Camera (NIRCam) show a tight, compact core, with plumes of material that appear as wisps moving away from the center where the impact took place.

Observing the impact with Webb presented the flight operations, planning and science teams with unique challenges. Due to the asteroid’s speed of travel across the sky, teams worked in the weeks leading up to impact to enable and test an asteroid tracking method. that move three times faster than the original speed limit set for Webb.

Scientists also plan to observe the asteroid in the coming months using the Webb Near-Infrared Spectrograph (NIRSpec), developed under ESA leadership, and the Mid-Infrared Instrument (MIRI), which was a joint creation of ESA and The NASA. Spectroscopic data from these innovative instruments They will provide researchers with information about the chemical composition of the asteroid.

Webb observed the impact for a total of five hours and captured 10 images. The data was collected as part of the Webb 1245 Cycle 1 Guaranteed Time Observing Program led by Heidi Hammel of the Association of Universities for Research in Astronomy (AURA).

Hubble also managed to capture observations of the small moon before impact, then again 15 minutes after DART encountered Dimorphos’s surface. Images from Hubble’s Wide Field Camera 3 show the impact in visible light. The ejecta from the impact appear as rays extending from the body of the asteroid. The bolder and more widespread ejection peak to the left of the asteroid is where DART impacted.

Some of the rays appear to be slightly bent, but astronomers need to take a closer look to determine what this might mean. In the Hubble images, astronomers estimate that Didymos’ brightness increased threefold after the impact, and they are also particularly intrigued by how that brightness remained stable. even eight hours after impact.

Hubble will monitor Dimorphos ten more times over the next three weeks. These periodic, 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 ejection to disappearance.

Hubble captured 45 images in the time immediately before and after the DART impact with Dimorphos.