The strange blend of surface chemistry on Nix and Hydra raises big question about the evolution of the Pluto system.

by Kimberly M. S. Cartier

10 December 2024

Pluto's minor moons Nix (left) and Hydra (right) were discovered in 2005 by the Hubble Space Telescope. Credit: (left) NASA/JHU-APL/SwRI/Roman Tkachenko/Wikimedia Commons, Public Domain; (right) Italyoz484/Wikimedia Commons, CC BY-SA 4.0

The solar system past Neptune is filled with an uncounted number of small, unusual worlds, from barely visible specks of ice to sugar-coated snowmen to Pluto and its five known satellites. These trans-Neptunian objects (TNOs) are the icy leftovers of planet formation and provide a glimpse into the early composition and evolution of the solar system.

Recently, astronomers observed the Pluto system with the James Webb Space Telescope (JWST) and discovered that two of Pluto's small moons, Nix and Hydra, have surface compositions unlike any TNO studied thus far.

The moons have abundant water like distant dwarf planet Haumea, ammonia like Pluto, and reddish material like Pluto's major moon, Charon, explained Bryan Holler, a planetary scientist at the Space Telescope Science Institute in Baltimore, Md. This blend of surface chemistry has not been seen anywhere else.

"What is going on here? What is causing these objects to have these surface compositions that are unique in the outer solar system?" he asked. Answering these questions could reveal the mysterious and likely chaotic history of the Pluto system.

More:

https://eos.org/articles/plutos-small-moons-are-unlike-any-other