You are not logged in.
We have four topics that contain the word "Kuiper" but none seemed appropriate for posts about discoveries about Kuiper Belt Objects as they occur. This topic is available for NewMars members who might wish to contribute to a store of knowledge about Kuiper belt objects. We will lead off this series with a report of a thin atmosphere around an object that was thought to be to small to support one.
(th)
Offline
Like button can go here
This post is reserved for an index to posts that may be contributed by NewMars members.
Index:
Post #3 will provide a CNN report on a Japanese discovery of a thin atmosphere around a Kuiper belt object.
Post #4 SpaceNut List of important Kuiper belt objects:
https://newmars.com/forums/viewtopic.ph … 72#p239172
Post #5: Calliban - Wikipedia article on discovery of atmosphere
http://newmars.com/forums/viewtopic.php … 82#p239182
(th)
Offline
Like button can go here
This post is about discovery of a thin atmosphere around a Kuiper belt object thought to be too small to retain one.
https://www.cnn.com/2026/05/04/science/ … atmosphere
Astronomers find atmosphere around a solar system object that shouldn’t have one
ByAshley Strickland
Updated 22 hr ago15
An artist’s impression shows (612533) 2002 XV93 passing in front of a background star. Ko Arimatsu/NAOJAstronomers have detected a thin atmosphere around a tiny celestial body in the outer solar system for the first time — an object previously thought to be too small to support the presence of an atmosphere.
Thousands of frozen, rocky bodies called trans-Neptunian objects, or TNOs, exist in the Kuiper Belt on the edge of our solar system, remnants from its formation 4.5 billion years ago.
The dwarf planet Pluto is the largest of these TNOs, so named because they’re found beyond the orbit of Neptune.
The frigid temperatures and weak surface gravity of the small bodies has long caused astronomers to believe they aren’t capable of retaining atmospheres — with the exception of Pluto, which has a thin one. Atmospheres, especially dense ones, typically form around large planets or moons, including Saturn’s biggest satellite, Titan.
Meanwhile, dwarf planets Eris, Haumea, Makemake and dwarf planet candidate Quaoar, the largest TNOs after Pluto, don’t appear to have atmospheres.
During a rare observation opportunity, astronomers in Japan spotted the thin shell of an atmosphere around a TNO known as (612533) 2002 XV93, according to a study published Monday in the journal Nature Astronomy.
While Pluto has a diameter of 1,477 miles (2,377 kilometers), 2002 XV93 only spans about 311 miles (500 kilometers) across.The unexpected discovery — made by Dr. Ko Arimatsu, associate professor and senior lecturer at the National Astronomical Observatory of Japan, and his colleagues — could offer an unprecedented glimpse into how an atmosphere forms and remains around a small object, and change how astronomers think about objects in the Kuiper Belt.
Seizing the observation opportunity
As January 2024 neared, Arimatsu and his colleagues prepared for the unique chance to observe a TNO as it passed in front of a bright star, as seen from Japan.
2002 XV93 has a standard orbit for a Kuiper Belt object and is smaller than a dwarf planet, so it wasn’t considered to be different from other TNOs.
But such moments when a TNO is illuminated by a star in the cosmic background, called stellar occultations, are rare opportunities to study the size, shape and features of a small, distant object, Arimatsu said. The researchers set up at three different locations across Japan, using observatories in Kyoto and the Nagano Prefecture, as well as a citizen scientist-run telescope in Fukushima.
The star’s light gradually faded as the TNO moved in front of it, suggesting the presence of of an atmosphere. If an object has no atmosphere, a star disappears and reappears much more sharply.
An animation shows how gradually starlight fades when passing behind a celestial body with an atmosphere (top), as opposed to an object without one. NAOJ / Shingo Iwashita
“The observation data showed a smooth change of the star’s brightness near the edge of the shadow, lasting about 1.5 seconds,” Arimatsu wrote in an email. “This kind of smooth brightness change is naturally explained if the starlight was bent by a very thin atmosphere around the object.”
The researchers calculated that 2002 XV93 has an atmosphere about 5 million to 10 million times thinner than Earth’s — and suspect two possibilities as to what created it.
The atmosphere could be the product of cryovolcanoes on the small, icy body, which release internal gas such as methane, nitrogen or carbon monoxide from beneath its surface. Or, another Kuiper Belt object such as a comet might have struck 2002 XV93, also releasing gases from the subsurface.
Arimatsu’s team is continuing the search for atmospheres around other TNOs by relying on stellar occultation observations. Their findings could help determine if 2002 XV93 is a rare exception to the rule, or if other similar small objects also possess atmospheres.
“This was an exciting discovery to read about,” said Dr. Scott S. Sheppard, staff scientist at the Carnegie Institution for Science in Washington, DC. “It was thought that objects like 2002 XV93 would be too small to have an atmosphere, but this result shows that is not true.”
Sheppard did not participate in the research, but he has studied and discovered TNOs.
The finding also highlights the discovery of recent activity on 2002 XV93, Sheppard noted, whether it be the eruption of frozen gases or the aftermath of material slowly falling back onto the object’s surface.
“This shows the Kuiper Belt is not a cold dead place,” Sheppard wrote in an email, “but is teeming with activity and has many of the building blocks for life.”
Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
(th)
Offline
Like button can go here
Here is the list of the Key Known Planetoids & Dwarf Planets, to which we are still looking for the gravitational calculation suggests there is a real large planet x (9) that is believed to orbit beyond to ort cloud.
Pluto: The largest and best-known Kuiper Belt Object (KBO), it is a complex icy dwarf planet with multiple moons.
Haumea: An elongated dwarf planet known for its rapid rotation and ring system.
Makemake: A large, reddish dwarf planet and one of the brightest objects in the belt.
Orcus: A large KBO that, like Pluto, is in a 2:3 resonance with Neptune.
Quaoar: A dwarf planet candidate that may possess a mountain taller than Olympus Mons.
Eris: While often categorized as a Scattered Disc Object rather than specifically in the main Kuiper Belt, it is a massive, icy dwarf planet, slightly more massive than Pluto.
Arrokoth: A remarkably pristine, two-lobed object (contact binary) visited by the New Horizons spacecraft in 2019
Offline
Like button can go here
Interesting discovery of atmosphere on 2002_XV93.
https://en.wikipedia.org/wiki/(612533)_2002_XV93
This little world is just 470km in diameter and surface gravity is ~1% Earth normal. So even a thin atmosphere should dissipate quickly. The authors suggest complete escape in 100 - 1000 years, depending upon composition. The source of the atmosphere is most likely an impact exposing buried volatiles, which subsequently sublimate.
By my estimation, the escape velocity of this body is less than 200m/s. Even at the low temperatures present in the Kuiper Belt, I am surprised that an atmosphere could survive as long as 100 - 1000 years. The gases most likely to be present, N2, CO, CH4, also have relatively low molecular mass. If we take nitrogen as an example gas and assume an atmospheric temperature of 50K, the median gas molecule velocity is 177m/s.
https://cfm-calculator.com/calculator.p … ulator.php
That means that around half of the molecules in the atmosphere will be moving at velocity that exceeds escape velocity. How is it that these gases are not lost on a timeframe measured in hours or days rather than years? How could any atmosphere survive for centuries?
******
Additional: I think the reason that the atmosphere can hang around for so long is due to inertial confinement. The particles that escape first are at the top of the atmosphere, where the mean free path starts to exceed the scale height. The particles beneath are confined by collision with particles above them. This deflects them downward, confining them. Even so, it isn't clear to me why the lower layers wouldn't just expand, pushing the upper atmosphere into space. How escape can happen so gradually is not something that I can explain.
Last edited by Calliban (Yesterday 09:27:07)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
Offline
Like button can go here