Astronomers May Have Detected an Atmosphere Around a Tiny, Icy World Past Pluto

"The Associated Press is reporting on a new study in Nature Astronomy suggesting that a tiny, icy world beyond Pluto harbors a thin, delicate atmosphere that may have been created by volcanic eruptions or a comet strike," writes longtime Slashdot reader fahrbot-bot. From the report: Just 300 miles (500 kilometers) or so across, this mini Pluto is thought to be the solar system's smallest object yet with a clearly detected global atmosphere bound by gravity, said lead researcher Ko Arimatsu of the National Astronomical Observatory of Japan. This so-called minor planet -- formally known as (612533) 2002 XV93 -- is considered a plutino, circling the sun twice in the time it takes Neptune to complete three solar orbits. At the time of the study, it was more than 3.4 billion miles (5.5 billion kilometers) away, farther than even Pluto, the only other object in the Kuiper Belt with an observed atmosphere. This cosmic iceball's atmosphere is believed to be 5 million to 10 million times thinner than Earth's protective atmosphere, according to the the study [...].

It's 50 to 100 times thinner than even Pluto's tenuous atmosphere. The likeliest atmospheric chemicals are methane, nitrogen or carbon monoxide, any of which could reproduce the observed dimming as the object passed before the star, according to Arimatsu. Further observations, especially by NASA's Webb Space Telescope, could verify the makeup of the atmosphere, according to Arimatsu.

Meanwhile...

[Randseed]

Meanwhile, back in a secret bunker, hidden beneath a nondescript concrete building:

General: Mr. President, it appears that we have located... Planet X!

Georgio: I'm not saying it's aliens... but it's aliens.

Sitchin: It's Nibiru! The Anunnaki are returning!

Non-paywalled source

[Tx]

A preprint of the article is available on the arXiv (https://arxiv.org/pdf/2605.02243 [arxiv.org], for those that don't have access behind Nature's paywall.

Re:

[Tx]

*paper

Math conversion

[null etc.]

circling the sun twice in the time it takes Neptune to complete three solar orbits

Even more impressive, it circles the sun four times in the time it takes Neptune to complete six solar orbits!

Similar to that of Pluto, but let's sensationalize

[Fly Swatter]

Or very roughly 250 "Earth years." In fact it's almost exactly the same as Pluto at 248 years. Why all the fractional crap - it's nearly the same as Pluto*.

* Formerly known as a Planet.

Re:Similar to that of Pluto, but let's sensational

[Anonymous Coward]

It's interesting to people who understand orbital dynamics

The 2:3 orbital resonance is the primary reason that Pluto and other plutinos (like 2002 XV93) can exist in stable orbits despite crossing Neptune's path.This specific ratio provides several critical evolutionary and mechanical benefits:

1. Collision Avoidance ("Phase Protection")Even though many plutinos have highly elliptical orbits that technically cross inside Neptune’s orbit, they never actually collide or even come close to the planet. The 2:3 resonance ensures that whenever a plutino reaches its perihelion (the point closest to the Sun where it crosses Neptune's path), Neptune is consistently a quarter of an orbit away. This "phase protection" keeps them at a safe minimum distance of billions of kilometres at all times.

Re: Similar to that of Pluto, but let's sensationa

[ThurstonMoore]

Then maybe they should have put that info in the article for those interested in reading Nature for their orbital dynamics fix.

Re:

[sabbede]

Your math is off. So was mine the first time. For every 2 Neptune orbits, this sucker orbits 3 times. That means it must be orbiting faster than Neptune (164.8 years), not slower. That 2:3 ratio means it takes 2/3rds the time to orbit that Neptune does, so its period is more like 109 years. Put another way, it's 50% faster than Neptune, with 1.5 orbits for each of Neptune's. Which is shockingly fast and violates the otherwise consistent relationship between the radius and period of planetary orbits.

Re:

[Fly Swatter]

circling the sun twice in the time it takes Neptune to complete three solar orbits

thats 2x for 2002 XV93 versus 3x for Neptune. that is slower than Neptune.

direct form the summary. check your dyslexia, it's something I am always aware I have and double check.

Re:

[sabbede]

Aw, hell, you're right. That's what I get for trying to do math while still half-asleep.

Still faster than Pluto despite being further out, right?

Re:

[angel'o'sphere]

Did you notice that the new discovered 'non planet' is called a 'Plutoist'?

H2S content

[ahoffer0]

Reminds me of that time I detected an atmosphere around Uranus. It was primarily N2 and CH4, but had a surprisingly high H2S content. It lingered, then dissipated.

Great marketing for Aphelion!

[David E. Smith]

I'm impressed with Dontnod's marketing - actually putting a planet on the far edge of the solar system, to promote their new game "Aphelion" which is set on a previously-undiscovered planet on the far edge of the solar system. That's commitment.

Nah, it's a simulation

[RogueWarrior65]

It's just people playing ArcticFox on an Amiga 1000.