On the night of September 26-27, 2022, shortly after midnight, NASA’s Dart probe is due to collide with an asteroid to test a planetary defense technique for the first time. The event will be scrutinized by a battery of powerful telescopes. But according to recent calculations, it could also be observed by amateur astronomers and more modest instruments.
Released in November 2021 from the Vandenberg military base in California, the US probe (Double asteroid redirection test, which also means “dart” in English) is now very close to its target: the asteroid Dimorphos, which measures 160 meters in diameter and orbits about 11 million kilometers from our planet. Mission Objective: Hit this asteroid head-on to test our ability to deflect a threatening celestial object. A first in the history of mankind.
A nanosatellite closer to impact
If all goes according to plan, the collision should occur on the night of September 26-27, at 00:14, very precisely, Paris time. It will be observed from space by the nanosatellite Lycia Cube (Light Italian CubeSat for imaging asteroids) embarked by the Dart probe and released shortly before the accident. And from Earth, through a battery of powerful international telescopes such as the Lowell Discovery in the United States, the Las Campanas observatory in Chile, or the Gran Telescopio de Canarias in Spain.
But the impact could also be visible by small instruments, a team of astronomers. Starting from well-defined parameters, such as the mass (570 kg) or the speed of the probe (24 km/h), and other more uncertain ones such as the density of the asteroid (2200 kg/m3), calculated that the projections of material from the impact could reach a maximum of 5,710 m3. However, if 5% of these ejecta are fine dust, then the apparent magnitude will reach 6.5 (with an uncertainty of 1.5). “Which would make observations of the Dart impact on Dimorphos possible with small ground-based telescopes.”, conclude the researchers.
“If the ejecta cloud is as bright as this paper predicts, it will be almost visible to the unaided eye from a dark site, and thus visible with telescopes of any size.Y[…]