Using some of the world’s most powerful telescopes, the DART investigation team last month completed a six-night observation campaign to confirm earlier calculations of the orbit of Dimorphos—DART’s asteroid target—around its larger parent asteroid, Didymos, confirming where the asteroid is expected to be located at the time of impact. DART, which is the world’s first attempt to change the speed and path of an asteroid’s motion in space, tests a method of asteroid deflection that could prove useful if such a need arises in the future for planetary defense.
In late September to early October, around the time of DART’s impact, Didymos and Dimorphos will make their closest approach to Earth in recent years at approximately 6.7 million miles (10.8 million kilometers) away. Since March 2021 the Didymos system had been out of range of most ground-based telescopes because of its distance from Earth, but early this July the DART Investigation Team employed powerful telescopes in Arizona and Chile — the Lowell Discovery Telescope at Lowell Observatory, the Magellan Telescope at Las Campanas Observatory and the Southern Astrophysical Research (SOAR) Telescope — to observe the asteroid system and look for changes in its brightness. These changes, called “mutual events,” occur when one of the asteroids passes in front of the other because of Dimorphos’ orbit, blocking some of the light they emit.
In October, the team will again use ground-based telescopes around the world to look for mutual events and calculate Dimorphos’ new orbit, expecting that the time it takes the smaller asteroid to orbit Didymos will have shifted by several minutes. These observations will also help constrain theories that scientists around the world have put forward about Dimorphos’ orbit dynamics and the rotation of both asteroids.
For more information about the DART mission.
https://www.nasa.gov/dartmission
https://www.nasa.gov/feature/dart-team-confirms-orbit-of-targeted-asteroid
AR Issue #56
Asteroid Threat Getting Serious New Attention
Early Rays
