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On its first asteroid flyby on Nov. 1,NASA ’s Lucy mission discovered that themain belt asteroid Dinkinesh has a small moon orbiting it . Now , additional images have disclose another surprise : Dinkinesh ’s moon is not one , but two modest satellites . The matching moons initially appeared as one because they are so close together , they extend to as they orb .
Dinkinesh — dear screw as " Dinky " — is about 2,500 feet ( 790 meters ) in diam , making it the smallest main belt asteroid ever explored by a space vehicle . Astronomers have been observing Dinkinesh since 1999 , and they hump that the asteroid was somewhat strange by the way its brightness fluctuated . But they did not auspicate that the diminutive asteroid was harboring a moonlight — allow alone two . found on Lucy ’s images , its moons come along to be a combined 720 feet ( 220 m ) around .
Dinky asteroid’s hidden ‘moon’ is actually two moons in disguise.
When a pair of celestial object orb this closemouthed together , scientists call it a " contact binary . " These binaries conjointly take on a Arachis hypogaea or pear shape , and they may not be rare in thesolar organization . For example , the New Horizons spacecraftconfirmed that Arrokoth , an arctic object in the Kuiper Belt beyond the celestial orbit of Neptune , was a striking binary in 2019 . A fistful of other asteroid and comets seem to be contact binaries as well .
What make Dinkinesh ’s lunation strange is that both lobes are some the same sizing ; The vast majority of inter-group communication binaries are cockeyed . It ’s a turn of a mystery as to how two equally - sized body would stick together gravitationally , according to NASA research worker . “It is vex , to say the least,“Hal Levison , an stargazer at the Southwest Research Institute and one of Lucy ’s chief investigators , said in astatement . " This is die to be fun for the scientific biotic community to figure out . "
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A diagram showing the trajectory of the NASA Lucy spacecraft (red) during its flyby of the asteroid Dinkinesh and its satellite (gray). “A” marks the location of the spacecraft at 12:55 p.m. EDT (1655 UTC) Nov. 1, 2023, and an inset shows the L’LORRI image captured at that time. “B” marks the spacecraft’s position a few minutes later at 1 p.m. EDT (1700 UTC), and the inset shows the corresponding L’LORRI view at that time.
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Dinkinesh is n’t even Lucy ’s primary finish — the asteroid flyby was tot to the investigation ’s agenda as a warm - up for its main commission , survey Jupiter ’s Trojan asteroids for the first time . If all goes well , Lucy will reach these upstage space stone in 2027 . But this initial trial betoken that Lucy ’s equipment is working even better than uranologist require . The research team now be after to have Lucy snap images of another main belt asteroid , Donaldjohanson , as it zoom by in 2025 .
