Scientists Find Atmosphere on 2002 XV93, 5 Times Smaller Than Pluto

6 articles · Updated · BBC Science Focus · May 27

2002 XV93 has been identified as only the second known trans-Neptunian object with an atmosphere, after researchers saw starlight fade and recover gradually during a Jan. 10, 2024 occultation.
Three Japanese observatories captured the event, and the softened light curve indicated gases bending the star’s light rather than the sharp cutoff expected from an airless body.
The atmosphere is estimated to be 5 million to 10 million times thinner than Earth’s and should escape within 100 to 1,000 years, implying it is being replenished.
Researchers say the leading explanations are cryovolcanic outgassing from beneath the icy surface or gas released by a recent impact on the minor planet.
At roughly one-fifth Pluto’s size and orbiting the Sun every 247 years, 2002 XV93 suggests small Kuiper Belt worlds may be more active than previously thought, though only about 10 observatories can currently probe such thin atmospheres.

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