Small, Frozen World beyond Pluto Appears to Have Thin Atmosphere

SCI News ^ | May 04, 2026 | Enrico de Lazaro

[Red Badger]

A team of astronomers in Japan has detected a thin atmosphere around (612533) 2002 XV93, a trans-Neptunian object about 500 km in diameter — an object far too small and cold to retain one.

An artist’s conception of the trans-Neptunian object 2002 XV93. Image credit: NAOJ.

“In the cold reaches of the outer Solar System lie thousands of small objects known as trans-Neptunian objects (TNOs) because they lie outside the orbit of Neptune,” said Dr. Ko Arimatsu from Ishigakijima Astronomical Observatory and colleagues.

“A thin atmosphere has been observed around Pluto, the most famous TNO, but studies of other TNOs have yielded negative results.”

“Most TNOs are so cold, and their surface gravity so weak, that they are not expected to retain atmospheres.”

The astronomers observed the trans-Neptunian object 2002 XV93 using a stellar occultation, measuring how it briefly dimmed the light of a background star as it passed in front of it.

“2002 XV93, has a diameter of approximately 500 km. For reference, Pluto’s diameter is 2,377 km,” they explained.

“The orbit of 2002 XV93 is such that, as seen from Earth, it passed directly in front of a star on January 10, 2024.”

“As the star disappears behind 2002 XV93, it might gradually fade, indicating that the light is being attenuated as it passes through a thin atmosphere; or it might suddenly wink out as it slips behind the solid surface of the TNO.”

The researchers found that the observations are best explained by a thin atmosphere surrounding 2002 XV93.

Their calculations indicate that such an atmosphere would dissipate in less than 1,000 years unless it is somehow replenished.

That means it must have formed — or been replenished — relatively recently.

“Observations by the NASA/ESA/CSA James Webb Space Telescope show no signs of frozen gases on the surface of 2002 XV93 that might sublimate to form an atmosphere,” the authors said.

“One possibility is that some event brought frozen or liquid gases from deep inside the TNO to the surface.”

“Another possibility is that a comet crashed into 2002 XV93, releasing gas that formed a temporary atmosphere.”

“Further observations are needed to distinguish between these two scenarios.”

“This discovery shows that even a few-hundred-kilometer TNO can host, at least transiently, an atmosphere, challenging standard volatile-retention scenarios,” they concluded.

“Our findings suggest that a fraction of distant icy minor planets can exhibit atmospheres, potentially sustained by ongoing cryovolcanic activity or produced by a recent impact of a small icy object.”

The team’s paper was published in the journal Nature Astronomy.

_____

K. Arimatsu et al. Detection of an atmosphere on a trans-Neptunian object beyond Pluto. Nat Astron, published online May 4, 2026; doi: 10.1038/s41550-026-02846-1

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TOPICS: Astronomy; History; Science; TV/Movies
KEYWORDS: 2002xv93; astronomy; chadtrujillo; mikebrown; plutino; plutinos; science; tno; xplanets

[SunkenCiv]

Thanks!.

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[Mr. Blond]

First they came for Pluto, and I said nothing. Then they came for Mercury, and I said nothing.

[SunkenCiv]

The rest of the TNO keyword, sorted:

• Astronomers Discover Rare Object in Perfect Sync with Neptune's Orbit [2020 VN40] [07/16/2025]
• Astronomers discover a cosmic 'fossil' at the edge of our solar system. Is this bad news for 'Planet 9'? [07/16/2025]
• Scientists Just Announced a New Solar System Member -- And It's Unlike Anything We've Seen [05/23/2025]
• Asteroid, Comet... or Something Else? Mysterious Activity on "Oddball" Space Object Raises New Questions [01/07/2025]
• Planet Nine: Is the search for this elusive world nearly over? [09/01/2024]
• SOMETHING IS AFFECTING GRAVITY IN OUR SOLAR SYSTEM, AND ASTRONOMERS SAY IT COULD BE AN UNKNOWN PLANET [04/24/2024]
• Surprising Changes in Neptune's Temperatures Detected by Astronomers [02/17/2024]
• Are We about to Discover a New Planet in Our Solar System? [02/12/2024]
• Is Pluto a Planet? [01/03/2024]
• A dwarf planet beyond Neptune has a mysterious ring that astronomers can't explain [02/09/2023]
• Strange Ripples Have Been Detected at The Edge of The Solar System [10/10/2022]
• New Webb Image Captures Clearest View of Neptune's Rings in Decades [09/22/2022]
• Cosmic objects with strange orbits discovered beyond Neptune [09/14/2021]
• What if Planet Nine is a baby black hole? [03/17/2021]
• Is 'Planet Nine' actually a grapefruit-sized black hole? Big new telescope could find out [07/12/2020]
• Over a Hundred New Large Objects Found in the Kuiper Belt [03/13/2020]
• Planet Nine could be a primordial black hole, new research suggests [09/30/2019]
• Proof of 'Planet Nine' May Be Sewn into Medieval Tapestries [02/28/2019]
• 12 years after launch, New Horizons probe zeroes in on mysterious Ultima Thule [12/02/2018]
• Newfound Dwarf Planet 'The Goblin' May Lead to Mysterious Planet Nine [10/02/2018]
• No Need for Planet Nine? Small Objects' Gravity Could Explain Weird Orbits [06/05/2018]
• A star disturbed the comets of the solar system 70,000 years ago [03/20/2018]
• Space Weird Orbits Suggest Solar System May Harbor Another Hidden Planet [06/24/2017]
• New clues in search for Planet Nine [07/05/2016]
• Centaurs Keep Their Rings From Greedy Gas Giants [06/26/2016]
• Astronomy Picture of the Day -- Pluto at Night [06/09/2016]
• Stolen World: 'Planet 9' Likely Came from Another Star [06/02/2016]
• Planet Nine's profile fleshed out [04/09/2016]
• Newly discovered planet could destroy Earth any day now [04/06/2016]
• Mysterious planet wiped out life on Earth once and could do it again THIS MONTH [04/06/2016]
• Researcher links mass extinctions to 'Planet X' [04/02/2016]
• Scientists just found more evidence that Planet Nine exists in our Solar System [03/29/2016]
• Search Narrows For Planet Nine [02/25/2016]
• Don't Blame 'Planet Nine' for Earth's Mass Extinctions [01/26/2016]
• Researchers find evidence of a real ninth planet [01/20/2016]
• There's a ninth planet in our solar system - we just can't see it yet, study says [01/20/2016]
• Ninth Planet May Exist in Solar System Beyond Pluto, New Evidence Suggests [01/20/2016]
• Scientists may have found Planet X, the mysterious presence that has eluded astronomers [12/12/2015]
• The Chilling Regularity of Mass Extinctions [11/03/2015]
• 10 Years of Haumea [09/16/2015]
• Is there a Planet X, a 'massive perturber,' hidden beyond Pluto? [09/05/2015]
• What is the Oort Cloud? [08/10/2015]
• Pluto a Planet Again? It May Happen This Year [06/08/2015]
• New Examination of Trans-Neptunian Objects Suggests Two Planets Lurk in Outer Solar System [01/16/2015]
• Astronomers are Predicting at Least Two More Large Planets in the Solar System [01/15/2015]
• The Dark Energy Survey Begins to Reveal Previously Unknown Trans-Neptunian Objects [01/07/2015]
• Strange Object Boosts Kuiper Belt Mystery [ 2002 UX25 ] [12/25/2013]
• Dwarf planet Eris may reveal quantum gravity [01/25/2013]
• When straying Jupiter went on the pull [02/15/2012]
• Giant planet ejected from the solar system [11/11/2011]
• Three New "Plutos"? Possible Dwarf Planets Found [08/16/2011]
• 'Jupiter swallowed planet 10 times the size of Earth' [08/13/2010]
• Search on for Death Star that throws out deadly comets.. [03/19/2010]
• On the Fringe: Astronomers look to the Kuiper belt for clues to the solar system's history [01/14/2010]
• A ghost of Christmas past [ Kuiper Belt Object 2009 YE7 discovered ] [01/03/2010]
• Asteroid Belt Loaded with Former Comets [07/16/2009]
• The Curious Case of Missing Asteroids [03/03/2009]
• Were Mercury and Mars separated at birth? [01/19/2009]
• Are Jupiters Hard to Come By? [08/12/2008]
• The Chaotic Genesis of Planets [ FREE PREVIEW ] [05/01/2008]
• Jupiter Increases Risk Of Comet Strike On Earth [08/24/2007]
• Gas Giants Jump Into Planet Formation Early [06/27/2007]
• New insights into composition of giant planets [10/18/2006]
• Largest known dwarf planet named after Greek goddess of chaos [HAIL ERIS!] [09/13/2006]
• Planet 10? Tiny 'Plutino' Almost Qualifies [ 2000 EB173 October 2000 ] [08/18/2006]
• Death Spiral: Why Theorists Can't Make Solar Systems [03/29/2006]
• NASA Finds Another Solar System Mystery based on Stardust mission [03/13/2006]
• Stellar encounters as the origin of distant Solar System objects in highly eccentric orbits [12/02/2004]
• If this is not 'Planet X', what is it? (biggest solar system body found in more than 70 years) [10/07/2002]

[SunkenCiv]

I think your vaping hypothesis holds water.

Oh dang, it’s “XGV” in the clip...

My Cousin Vinny - Mr. Wilbur - examination
https://www.youtube.com/watch?v=Ei-EeDQyDS0

[SunkenCiv]

https://www.spacereference.org/asteroid/612533-2002-xv93

https://en.wikipedia.org/wiki/(612533)_2002_XV93

[wally_bert]

Mondas, where the original Cybermen came from?

[left that other site]

Its still a planet to me, and always will be.

Me Too.