A Tale of Two Asteroids

Screenshot of GIF: Shape Model 1999AP10. Credit: Josef Hanuš, Charles University.

Countless asteroids in our solar system, some close, some far — but did you know that some of these space rocks have names? Several years ago, Unistellar held a contest to name an asteroid its citizen astronomers had observed. Now, an asteroid (albeit a different one) finally bears the name the public chose. 

On October 19th, 2020, a near-Earth asteroid named 159402 (1999AP10) was making its close approach to the Earth. This proximity gave professional and citizen astronomers around the world a remarkable opportunity to observe this object. Taking advantage of this chance, astronomers at the SETI Institute enlisted the SETI/Unistellar Network of citizen scientists to gather timely data. Researchers needed such data to reverse engineer the detailed shape of this space rock, allowing them to accurately map this asteroid. 

1999AP10 proved to have the shape of a flattened, lumpy potato while boasting the size of Mount Everest. Although 1999AP10 was the 69th asteroid with a known shape model, this is the first time citizen astronomers made the discovery possible. In celebration of this world first, Unistellar launched a contest where astronomy enthusiasts worldwide could propose and vote on a name for the asteroid. “We worked with the SETI Institute and several astronomy-focused institutions around the world to build and promote a platform so anybody with a bit of creativity and interest in astronomy could submit a name. We received more than 100 different suggestions,” mentioned Dr. Franck Marchis, astronomer and Director of Citizen Science at the SETI Institute, who was a judge on Unistellar’s naming panel. Among the submissions were funny, light-hearted ideas such as “RockyMcRockFace” and “Blind Melon,” but the overwhelming winner was “Ada Carrera,” and quite fittingly so.

Ada Amelia Carrera Rodríguez (1936-2020) was a passionate astronomer and inspiration for women who were as enthusiastic about studying space as she. As a pioneer of spreading astronomical awareness in Mexico, “she was passionate about sharing astronomy with people from all walks of life,” says Lourdes Cahuich, a friend of Carrera’s and amateur astronomer.

To forward her mission of accessible astronomy for everyone, Carrera founded the group Astronomía Educativa (Educational Astronomy) in 1994. This society empowered local amateur astronomers to teach, observe, and conduct outreach within their communities. Alongside her son and fellow observers, she traveled Mexico and South America to visit schools weekly, host numerous star parties, and hunt for celestial events to share with others. Ada Carrera was a powerhouse in the Latin astronomy community, and astronomers have now honored her with a celestial object, ensuring she is remembered.

Ada Amelia Carrera Rodríguez, amateur astronomer and motorcyclist. Source.

Despite her glowing legacy and the petition to have 1999AP10 renamed “159402 AdaCarrera,” this new name unfortunately did not fit the naming standards set by the International Astronomical Union (IAU). According to the IAU, near-Earth asteroids must bear mythological names. As a result, the IAU decided to name a different asteroid after Carrera and her memory.

Nearly five times larger than our near-Earth neighbor 1999AP10 and almost the size of the San Francisco Bay, asteroid 20008 (1991NC3) was officially named after Ada Carrera in 2023. Now known as 20008 Adacarrera, this rocky body does not approach Earth and, therefore, satisfies the IAU’s naming criteria. Instead, 20008 Adacarrera is a “main-belt” asteroid that floats comfortably in the asteroid belt, always staying between the orbits of Mars and Jupiter. Amongst millions of other floating space rocks that call this belt home, 20008 Adacarrera is one of the largest with a diameter greater than 99% of known asteroids. 

One specific space rock may seem small in the context of our Solar System, but amongst their kind, 20008 Adacarrera is monumental — just as Carrera was during her time here. “She was a wonderful person with a wonderful life,” Cahuich fondly recalls, and now her memory will orbit on. This tale may have two asteroids, but one brilliant woman’s legacy is now in the cosmos.