On November 1st, 2023, NASA's Lucy mission was scheduled
to flyby and image its first main belt asteroid, Dinkinesh.
However, when the team downloaded
the spacecraft imagery, it made an unexpected discovery.
Asteroid Dinkinesh has a satellite making it a binary asteroid system.
In the first image from the Lucy Long-range Reconnaissance Imager, the team
observed the moon rise of a satellite of its first asteroid Dinkinesh.
This image was taken at 12:55 Eastern, within a minute of closest approach
from a range of approximately 270 miles from the asteroid.
The satellite is visible to the bottom right of the primary asteroid.
Dinkinesh
In the Ethiopian language, Amharic means “you
are marvelous.” And the asteroid truly did live up to its name.
Lucy observations in the weeks leading up to the encounter suggested
that Dinkinesh might hold some surprises.
Sure enough, imagery from the terminal tracking
camera “T2CAM” on the Lucy spacecraft shows Dinkinesh's satellite.
The apparent motion in this sequence of images is due to the motion
of the Lucy spacecraft as it zoomed by at 10,000 miles per hour
as the team downloaded more images that had been taken before
and after closest approach, they were in for another surprise.
That satellite was actually a contact binary.
It was two objects stuck together.
This small satellite has been named Selam.
which means “peace” in Amharic.
The team will continue to study the data from this first encounter as they prepare
for their next rendezvous with the main belt asteroid Donaldjohanson in 2025.