Artist’s conception of this research showing an imagined time sequence as a star passes behind a TNO with an atmosphere. (Credit: NAOJ)
A tiny world that orbits way beyond Neptune surprised astronomers with a thin atmosphere that they did not expect to find. Now, scientists are trying to determine how it formed.
What we know:
The trans-Neptunian object (TNO), dubbed (612533) 2002 XV93, is approximately 310 miles (500 km) in diameter, less than a quarter of the diameter of Pluto, the National Astronomical Observatory of Japan (NAOJ) explained in a statement. At more than 3.4 billion miles (5.5 billion km) away, it takes twice as long to complete one orbit as it does for Neptune to make three.
Most TNOs are too small and too cold to have an atmosphere. Pluto is the only other TNO to have an atmosphere.
What we don't know:
Astronomers say the world is too small to have a sustainable atmosphere, and they are trying to figure out how long it has been there and how it formed, the NAOJ statement continued. They expect the atmosphere to last another 1,000 years, unless something replenishes it. That indicates to them that the atmosphere either formed or was replenished recently.
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What they're saying:
"It changes our view of small worlds in the solar system, not only beyond Neptune," NAOJ lead researcher Ko Arimatsu wrote in an email to the Associated Press.
Dig deeper:
Scientists pointed the James Webb Space Telescope at the planet and did not find any frozen gases on the object’s surface that could replenish the atmosphere. In the statement, they suggested that an unknown event may have released frozen or liquid gases from within it. Another possibility, they said, is that a comet crashed into the object and released the gas.
Arimatsu said future observations could indicate which option is more likely. He posited that if the atmosphere dissipates soon, that would suggest an impact; however, if it goes up and down seasonally, that would hint at an internal gas supply.
The Source: Information for this article was taken from National Astronomical Observatory of Japan and The Associated Press. This story was reported from Orlando.