A little more than 2 years after New Horizon’s intrepid flyby of the Pluto system, a committee that speaks for the field of astronomy has approved authoritative names for 14 features that the spacecraft’s images showed on Pluto’s surface.
“The approved designations honor many people and space missions who paved the way for the historic exploration of Pluto and the Kuiper Belt, the farthest worlds ever explored,” said New Horizons’ principal investigator Alan Stern in a statement of support to the International Astronomical Union (IAU) for the new names. The official monikers apply to specific craters, mountains, and plains, including the now renowned heart-shaped region of Pluto that New Horizons discovered in 2015.
In February 2017, the IAU’s Working Group for Planetary System Nomenclature (WGPSN) approved naming themes for features on Pluto and its largest moon, Charon. Later, the committee began soliciting suggestions for names of specific topographies.
On 7 September, the IAU announced the names of the 14 features, which are the first to be officially designated. “These names highlight the importance of pushing to the frontiers of discovery,” WGPSN chair Rita Schulz of the European Space Agency said in the announcement. The IAU stated that it expects to assign names to more features in the coming year.
Discoverers, Explorers, Pioneers, and Underworld Mythos
People who played a part in Pluto’s discovery are commemorated with prominent features on its surface. Tombaugh Regio, Pluto’s famous heart-shaped region, honors Clyde Tombaugh (1906–1997), who discovered the now dwarf planet in 1930. Burney crater recognizes Venetia Burney (1918–2009), who suggested “Pluto” as a name for Tombaugh’s newly discovered planet when she was 11 years old, and Elliott crater acknowledges astronomer James Elliott (1943–2011), who made the first detection of Pluto’s atmosphere.
Mountain ranges received their names from human pioneers. The names of New Zealander Sir Edmund Hillary and Indian/Nepali Sherpa Tenzing Norgay, the first two people to reach the top of Mount Everest and return safely, now adorn Hillary Montes and Tenzing Montes. A third mountain range, Al-Idrisi Montes, is named for noted medieval Arab mapmaker and geographer Ash-Sharīf al-Idrīsī (1100–1165/66).
Even the heart’s curiously smooth left half, known during the 2015 close approach to Pluto as Sputnik Planum, has received a for-the-books name adjustment, to Sputnik Planitia. This new name and those of Hayabusa Terra and Voyager Terra each recognize spacecraft that made significant firsts in our history of solar system exploration. Soviet-launched Sputnik was the first space satellite; NASA’s Voyagers 1 and 2 were the first to visit Jupiter, Saturn, Uranus, Neptune, and the edge of the solar system, and the Japanese spacecraft Hayabusa was the first to return samples from an asteroid.
Returning to a darker naming scheme that was the original source of names for Pluto, Charon, and their smaller moons, Styx, Nix, Kerberos, and Hydra, WGPSN chose names of underworld places and creatures from cultures around the globe for five more of Pluto’s features. Djanggawul Fossae, a series of thin and narrow valleys, invokes three ancestral beings in indigenous Australian mythology who traveled to the island of the dead. Adlivun Cavus, after the Inuit underworld of Adlivun, marks a deep depression near the bottom of Pluto’s heart. Sleipnir Fossa, a valley off the left edge of the heart, recalls the eight-legged horse that the Norse god Odin rode into the underworld. Virgil Fossae, a thin scar to the right of Elliot Crater, honors the Roman poet Virgil, who was also Dante’s fictional guide through hell in the Divine Comedy. Last, Tartarus Dorsa, a ragged terrain next to Tombaugh Reggio, revisits the deepest, darkest pit in the Greek underworld.
What’s in a Name?
Past IAU nomenclature initiatives have included naming minor planets in the outer solar system, a large batch of stars, and famous exoplanets. IAU’s 2015 Name Exo Worlds campaign, which assigned names to 31 exoplanets, received mixed reviews from exoplanet astronomers. These scientists, accustomed to the sometimes clunky designations like 51 Pegasi b and PSR 1257+12 bcd, have balked at using the IAU-approved names.
By contrast, astronomers appear to have embraced this newest IAU naming initiative. Pluto scientists have already written more than a dozen research articles in 2017 with the updated moniker “Sputnik Planitia,” compared to only a single mention of 51 Pegasi b’s new name, “Dimidium,” out of more than 100 related papers since the change in late 2015. It may help that all but two of the newly designated names for Pluto’s features, those of Adlivun Cavus and Tenzing Montes, had already populated the unofficial map of Pluto.
—Kimberly M. S. Cartier (@AstroKimCartier), News Writing and Production Intern