Lucy's Main Belt Target Has Its Features Named

When considering the unnamed major features of all the moons, asteroids, and comets in our solar system there are still a lot of places out there that need proper names. That means the International Astronomical Union (IAU), the non-governmental body responsible for naming astronomical objects, has its work cut out for them. Recently they tackled a relatively easy challenge by approving a series of names on the asteroid Donaldjohnson, the first and only target of NASA’s Lucy mission in the main asteroid belt. With those names come a whole new way to talk about one of the asteroids that humanity has studied most closely thus far.

Lucy the mission was named after Lucy the fossil, one of the most important paleoanthropological finds in history. Dated to 3.2 million years ago, the Lucy skeleton is part of a species we now call Australopithecus afarensis, one of the forebearers of modern day Homo sapiens. With this discovery in the Afar region of Ethiopia in 1974, American paleoanthropologist Donald Johanson cemented his legacy in the annals of scientific history.

The IAU also allowed him to be etched into the history books of astronomy as well, when it agreed to name the asteroid in the main belt that the Lucy mission would pass on its way to its main mission in the Trojan asteroid belt after him. Asteroid Donaldjohanson measures about 8 km long by 3.5 km wide, and weighs about 8x1013 kg. Its shape provides some very unique places to name, and Lucy’s team tried to take full advantage of that in the names they submitted to the IAU.

All of the names deal somehow with paleoarchaeological history, though only some are directed related to Donald Johanson himself. The two main “lobes” of the asteroid are named Afar, after the region in Ethiopia where the Lucy fossil was discovered, and Olduvai, a river gorge in Tanzania where there were plenty of other discoveries of early humans.

Joining the two lobes is Windover Collum, named after an archeological site near Cape Canaveral Florida, where Lucy was launched, and which provide insight into the lives of humans living there over 7,000 years ago. Two flat surfaces on the collum, which can be thought of as the asteroid’s “neck”, are called Hadar, after the specific site Lucy was found in, and Minatogawa, the site of the oldest hominid remains found in Japan. While JAXA, Japan’s space agency, didn’t help with this mission in particular, they’ve been a major collaborator of NASA for decades.

Major boulders and craters received names as well. Mungo, named after the Lake Mungo archaeological site in New South Wales Australia, is a crater near the end of the Olduvai lobe. Boxgrove is a boulder nearby named after an almost 500,000 fossil from England. Narmada is another crater named after archaic remains from India, and it is near boulders named Cashel, after a 4,000 year old discovery in Ireland, and Kennewick, an 8,500 year old skeleton from Washington state near the Columbia River in the US. ALl of those are also on the Olduvai lobe, which is the larger of the two.

Another feature on the Windover section is another ridge named after Luzia, a 11,500 year old skeleton from Brazil. There are undoubtedly features on the other side of the asteroid, but unfortunately Lucy only performed a brief flyby and couldn’t capture it in its entirety.

However, that was because it's on its way to its main mission, which is to visit eight Trojan asteroids. That will give the mission team plenty more naming opportunities. We’ll see what they come up with - and what the IAU will approve - beginning in 2027 when its mission truly starts.