- Scientists found a thin atmosphere on Trans Neptunian Object 2002 XV93 beyond Neptune
- The atmosphere is 5 to 10 million times thinner than Earth's and barely perceptible
- 2002 XV93's weak gravity may lose its atmosphere within 100 to 1,000 years without replenishment
Scientists have discovered that a tiny frozen world located far beyond Neptune has an atmosphere, making it only the second known object in that distant region of the Solar System, after Pluto, to have one. The discovery was published in the journal Nature Astronomy, reported BBC.
The object, known as 2002 XV93, is a minor planet and a Trans Neptunian Object (TNO). It orbits the Sun beyond Neptune in an area called the Kuiper Belt.
Extremely Thin Atmosphere Detected
Researchers found that the atmosphere around 2002 XV93 is extremely thin, around 5 to 10 million times thinner than Earth's atmosphere. Scientists said the atmosphere is so thin that a person standing on the surface would not even feel a breeze.
Until now, Pluto was the only TNO known to have signs of an atmosphere. However, Pluto is more than five times larger than 2002 XV93.
Because of its small size, 2002 XV93 has very weak gravity, which means any atmosphere around it can easily escape into space. Researchers predict that the atmosphere could disappear completely within 100 to 1,000 years.
Researchers believe something must be continuously replenishing the atmosphere, and they have proposed two possible explanations.
The first theory involves cryovolcanism, a process that happens in extremely cold conditions where substances such as water, methane and ammonia behave like rock or magma.
Study lead Ko Arimatsu from the National Observatory of Japan explained that volatile material may escape from beneath the icy surface through cryovolcanic-like activity, and these gases could form the atmosphere.
However, scientists noted that cryovolcanic activity has previously only been observed on much larger worlds.
The second theory suggests that a small icy object may have recently collided with 2002 XV93. According to Arimatsu, such an impact could have released gases or exposed material rich in volatile substances.
He added that while these impacts are believed to be rare, the possibility cannot be ruled out.
Scientists detected the atmosphere while observing an occultation event, which occurs when an object passes in front of a star.
Arimatsu explained that if an object has no atmosphere, the star's light disappears and reappears sharply. However, if an atmosphere is present, gases around the object slightly bend the starlight, causing a gradual change.
On January 10, 2024, three observatories in Japan observed an occultation caused by 2002 XV93. During the observation, researchers noticed that the starlight faded and returned gradually near the edge of the shadow.
According to the team, this effect was best explained by the presence of a very thin atmosphere around the object.
The research team has requested observation time using the James Webb Space Telescope to study the composition of the atmosphere.
Scientists said more occultation observations would help determine whether the atmosphere is fading, remaining stable or changing over time. According to Arimatsu, a steadily fading atmosphere would support the impact theory, while a stable or changing atmosphere could indicate gases are continuing to emerge from inside the object.
