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Name themes for Pluto system features approved by IAU

Features on Pluto and Charon in false color

This composite of enhanced-color images of Pluto (lower right) and Charon (upper left) was taken by NASA’s New Horizons spacecraft as it passed through the Pluto system on July 14, 2015. This image highlights the striking differences between Pluto and Charon. The color and brightness of both Pluto and Charon have been processed identically to allow direct comparison of their surface properties and to highlight the similarity between Charon’s polar red terrain and Pluto’s equatorial red terrain. Pluto and Charon are shown with approximately correct relative sizes, but their true separation is not to scale. The image combines blue, red, and infrared images taken by the spacecraft’s Ralph / Multispectral Visual Imaging Camera (MVIC). Image & Caption Credit: NASA / JHU-APL / SwRI

A set of naming themes for features on Pluto and its five moons, informally used by the New Horizons mission, has been approved by the International Astronomical Union (IAU), which has overseen the naming of celestial objects and their surface features since 1919.

The themes chosen for each object in the Pluto system emerged from the mission’s “Our Pluto” campaign, organized in conjunction with NASA and the SETI Institute in Mountain View, California, in early 2015.

“Our Pluto”, which sought public suggestions for names of features the spacecraft was expected to reveal in its July 2015 flyby of the system, received IAU endorsement ahead of the flyby.

Hubble Space Telescope image of five moons orbiting the dwarf planet Pluto.

This image, taken by NASA’s Hubble Space Telescope, shows five moons orbiting the distant, icy dwarf planet Pluto. Styx (initially designated P5) is the innermost of the moons found by Hubble over a period of seven years up to Styx’s discovery in 2012. This image was taken with Hubble’s Wide Field Camera 3 on July 7, 2012. Image Credit: NASA / ESA / L. Frattare (STScI)

Specific themes selected during the “Our Pluto” project were assigned to Pluto, Charon, Nix, Hydra, Styx, and Kerberos. Several continue the focus on mythologies of the underworld, ruled by the Roman god Pluto, while others commemorate both historic and fictional exploration.

Themes for features on Pluto:

  • Gods, goddesses, and other beings associated with the underworld in folklore, mythology, and literature.
  • Names for underworld locations from various cultures around the world.
  • Mythical heroes and explorers of the underworld.
  • Scientists and engineers involved in the study of Pluto and the Kuiper Belt.
  • Pioneering space missions and spacecraft.
  • Historic pioneers in the exploration of the Earth, ocean, and sky.

Themes for features focusing on Charon:

  • Fictional narratives and include destinations of fictional space missions and exploration projects.
  • Fictional and mythological ships and spacecraft.
  • Fictional and mythological voyagers, travelers, and explorers.
  • Artists and authors of works about space exploration, with a specific focus on the Kuiper Belt and Pluto.

Themes for features on the smaller moons:

  • River gods for Styx.
  • Deities of the night for Nix.
  • Dogs from mythology, history, and literature for Kerberos.
  • Legendary dragons and serpents for Hydra.

New Horizons revealed Pluto to be an unusually active geological world with flowing glaciers, cryovolcanoes, ice mountains, canyons, cliffs, and a large nitrogen glacier. Charon is no longer geologically active, but many diverse features were found on its surface as well as on the surfaces of the smaller moons.

“Imagine the thrill of seeing your name on a future map of Pluto and its moons. Months after the Pluto flyby, the New Horizons mission continues to engage and inspire,” said Jim Green, director of NASA’s Planetary Science Division.

Noteworthy names informally assigned to features on the system’s worlds, such as Sputnik Planitia and Cthulhu Regio on Pluto have excited imaginations worldwide.

Mission principal investigator Alan Stern of the Southwest Research Institute applauded the successful partnership and process between New Horizons scientists and the IAU that resulted in approval of “wonderful, inspiring, and engaging naming themes” for features on Pluto and its moons and said mission scientists look forward to submitting specific names for individual features on each world.



Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.

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