The New Horizons mission revealed scores of surface features on Pluto in 2015, and now many of those craters, mountains, and other topographic treasures possess official names. This is the first set of Pluto place names officially adopted by the International Astronomical Union (IAU), with more forthcoming. As with most things Pluto, some of the designations, as well the naming process itself, feature Flagstaff ties.
The 14 names honor people and spacecraft that impacted scientists’ study of Pluto and its neighbors, as well as a variety of mythological stories from cultures around the world. Scientists have been informally using many of the names for the past two years, with Tombaugh Regio probably the most well-known. This iconic, heart-shaped region is named after Clyde Tombaugh, who discovered Pluto in 1930 from Lowell Observatory.
A second name with a Flagstaff connection is Elliot Crater, named for Jim Elliot. He was an astronomer at MIT who pioneered the use of stellar occultations — events occurring when a planet, asteroid, or other relatively nearby celestial object passes in front of a more distant star. Using this method, Elliot worked with astronomers at other observatories, including Lowell, to discover the rings of Uranus and detect Pluto’s tenuous atmosphere, among other things. Elliot also established a summer internship program at Lowell in which MIT students traveled to Flagstaff to work with astronomers at Lowell, NAU, the USNO, and USGS.
Another name familiar to many who know the story of Pluto’s discovery is Burney Crater. This celebrates Venetia Burney, who is credited with first suggesting the name Pluto in 1930. At the time, this English girl was 11 years old. Lowell staff liked the name Pluto and submitted it as the planet’s official name.
This process of submitting a name to a governing body for official recognition is still followed today. In the case of the new Pluto names, a group of New Horizons team members assembled a list of candidates, many suggested by the general public. This nomenclature working group consisted of nine people, including Lowell’s Will Grundy and former Lowell researchers Cathy Olkin and Amanda Zangari. They submitted the list to the IAU, which officially approves names of astronomical bodies and their surface features.
A committee of the IAU — the Working Group on Solar System Nomenclature — then evaluated the list. This group of astronomers and space experts includes Flagstaff’s Rose Hayward of the USGS and astronomy historian Bill Sheehan. They debated the merits of the names and submitted their recommendations to the IAU.
Other new names recognizing people include Virgil Fossae (depressions on Pluto’s surface honoring the Roman poet Virgil) and Al-Idrisi Montes (mountains recognizing 12th-century Arab mapmaker and geographer Ash-Sharif al-Idrisi). Then there are Hillary Montes and Tenzing Montes, after Sir Edmund Halley and his Indian/Nepali Sherpa guide who first climbed to the summit of Mt. Everest.
Spacecraft were honored with Sputnik Planitia (a large plain named after the Soviet Union’s Sputnik, the first space satellite), Voyager Terra (a large land mass honoring NASA’s Voyager spacecraft, which carried out the first close-up survey of the giant planets Jupiter, Saturn, Uranus, and Neptune), and Hayabusa Terra, after the Japanese spacecraft that in the early 2000s performed the first asteroid sample return.
From mythology comes Sleipnir Fossa (after the Norse eight-legged horse), Adlivun Cavus (a deep depression named in honor of the Inuit underworld), Tartarus Dorsa (a ridge honoring the deepest pit of the underworld in Greek mythology), and Djanggawul Fossae (after the trio of Australian beings that created the landscape).
This group of 14 is just a start, with more new names coming soon. We'll no longer think of Pluto as that enigmatic dot, but as an intriguing new world with features we can now call by name.