Astronomy: Evidence of a thin atmosphere around a Pluto relative (Nature Astronomy)
5 May 2026
Observations of a distant object beyond Pluto suggest that it is surrounded by a thin atmosphere, potentially fuelled by ice volcanoes or produced by the impact of a comet-like body, according to research published in Nature Astronomy. This suggests that even relatively small objects at the edge of the Solar System can, at least for a time, have atmospheres.
Planetary bodies that orbit beyond Neptune are called trans Neptunian objects and are leftovers from the formation of the Solar System. Among them, only the dwarf planet Pluto possesses a clearly detected atmosphere.
Ko Arimatsu and colleagues studied an object known as (612533) 2002 XV93 by observing a stellar occultation, in which the object passed in front of a star. The authors observed this event from three different locations in Japan in January 2024, using a mix of professional observatories in Kyoto and the Nagano Prefecture, and a telescope run by a citizen astronomer in Fukushima. In some observations, the light from the star faded gradually over a few seconds as the object passed in front of it, as opposed to dimming more abruptly. This is the expected behaviour for a body that has a thin layer of gas around it, or an atmosphere. The authors calculate that this atmosphere is around 5 to 10 million times thinner than Earth's and suggest that it could be sustained by gas emitted by icy volcanoes, or short lived, generated by materials released after a recent comet-like impact.
The findings challenge previous assumptions that dense atmospheres only form around larger planets. Future observations, especially of more occultations or measurements using space based telescopes, will be needed to see how the atmosphere changes over time and to better understand how it formed.
- Article
- Published: 04 May 2026
Arimatsu, K., Yoshida, F., Hayamizu, T. et al. Detection of an atmosphere on a trans-Neptunian object beyond Pluto. Nat Astron (2026). https://doi.org/10.1038/s41550-026-02846-1
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