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Raumfahrt - NASA DART spacecraft Asteroiden Mission -Update 6

29.09.2022

DART IMPACT FROM THE GROUND

dart-kb-1

Professionals and amateurs alike were wowed by the dramatic effects of the tiny spacecraft’s crash into the asteroid moon. Not only did the pointlike light from the Didymos system brighten; as astronomers watched, the system shed a crescent-shaped plume of dust, brilliantly illuminated by sunlight. The visible plume didn’t last long, spreading out into invisibility, but the stunning view was captured from numerous locations.

ESA’s Le Makes Observatory in Le Reunion obtained one view of the expanding crescent, but the best images so far came from the Hawai`i-based ATLAS (the Asteroid Terrestrial-impact Last Alert System). Designed to be an early-warning system for near-Earth asteroids approaching Earth, ATLAS scans the entire sky several times a night. Its view of the impact shows the effects in breathtaking detail. At least two separate plumes are visible: one, crescent-shaped, spreads out in the direction opposite to the impact, while another, fainter one jets at an angle behind Didymos’ apparent motion across the sky.

a small white dot moves across a black background
ATLAS Project, University of Hawai`i/NASA
collection of still images showing a small white dot moving across a black background and dissolving into a plume of white dust
The ATLAS project captured stills of the DART mission's impact on Dimorphos. (Scroll down for the animated version.)
Images: ATLAS Project (University of Hawai`i / NASA); Image processing: Emily Lakdawalla.

Although not as finely detailed, a similar view from the South African Astronomical Observatory’s Lesedi telescope provides long parallax and thus an opportunity for astronomers to study the evolution of the plume in stereo.

a white dot moves closer and gets bigger until dissolving into grey dust
Nicolas Erasmus (SAAO) and Amanda Sickafoose (PSI)
collection of thumbnails of a white dot moves closer and gets bigger until dissolving into grey dust
Nicolas Erasmus (SAAO) and Amanda Sickafoose (PSI).

Other ground-based telescopes that captured the impact and shared preliminary versions of their images via Twitter include:

In addition, many telescopes were performing spectral observations in order to study the composition of the plume. Those results must await calibration, but it looks like the Infrared Telescope Facility in Hawai`i obtained good data!

DART IMPACT FROM SPACE

In space, both the Hubble and James Webb Space Telescopes were observing, as was the Lucy mission, and preliminary versions of the Webb Near-infrared Camera (NIRCAM) images are already out:

The black dot at center results from the saturation of NIRCAM’s sensitive detector, and the six arms of a symmetrical star around Dimorphos are diffraction spikes in the instrument optics. But the cloud of dust and streaky plumes are debris from the impact, promising great science to come.

And then there are the DART and LICIAcube images: DART revealed Didymos to be smooth in some places, gullied in others. The smoothly bulging equator is reminiscent of Bennu, the asteroid visited by NASA’s OSIRIS-Rex mission, while the gullies look like those on Saturn’s moon Helene. Dimorphos is extremely blocky, like all near-Earth asteroids seen in such detail: Bennu, Itokawa, and Ryugu.

two large grey rocks pictured next to each other with small yellow circles above each
This reprocessing of DART images allows you to see Didymos in 3D. To see the 3D effect, you'll need to look view the image with your eyes crossed so that the two yellow dots overlap.
NASA / JHUAPL / Alain Mir

And these are the views the Italian Space Agency released from LICIAcube this morning, taken before the spacecraft’s close (55-kilometer) flyby of Didymos. The photos show a streaky plume expanding in all directions from the CubeSat’s point of view:

a white dot floating on a black background in front of a smaller white dot emananting light
ASI / NASA
a close up of a white dot floating on a black background in front of a smaller white dot emananting light
ASI / NASA

Hundreds more images await download from LICIAcube, and we have yet to see photos from Hubble and Lucy. Professional study of these many images will enable astronomers to generate 4D models of the plume evolving over time and space. A special session at December’s American Geophysical Union meeting will feature the early results from this research, so stay tuned for science!

Quelle: Sky&Telescope

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Update: 30.09.2022

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NASA-MISSION DART

Die ersten Fotos vom Einschlag auf dem Asteroiden

 

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