Overview
- The Nature Astronomy paper, published Monday, reports evidence of gas around trans‑Neptunian object (612533) 2002 XV93 based on a multi‑site occultation observed in Japan on January 10, 2024.
- Models fit the data with a surface pressure of about 100 to 200 nanobars, roughly 5 to 10 million times thinner than Earth’s air and about 50 to 100 times thinner than Pluto’s.
- The object is a ~500‑kilometre‑wide plutino in the Kuiper Belt, and the star’s light dimmed smoothly for about 1.5 seconds, a hallmark of starlight bending through a thin atmosphere rather than snapping off against a bare surface.
- Calculations indicate the gas would escape in a few hundred to roughly a thousand years unless it is resupplied, with leading ideas pointing to cryovolcanic outgassing or a recent impact that released volatiles.
- The result relies on a single event, so alternatives like dust or a near‑edge‑on ring remain possible, and teams are planning repeat occultations and James Webb Space Telescope spectroscopy to confirm the gas and identify molecules such as methane, nitrogen or carbon monoxide.