Atmosphere Found on Outer Solar System Body: Japan Team

Tokyo, May 5 (Jiji Press)--A thin atmosphere has been found to exist on one of thousands of trans-Neptunian objects, or TNOs, small celestial bodies outside Neptune, the outermost planet in the solar system, a research team including the National Astronomical Observatory of Japan said.

It is the first time that an atmosphere has been found on any TNO other than Pluto.

The discovery, which was announced on British journal Nature Astronomy on Monday, was made through coordinated observations by Japanese professional and amateur astronomers using small telescopes, according to the team.

Temperatures in the outer solar system are minus 220 degrees Celsius or lower, and it had been thought that only nitrogen, methane and carbon monoxide can exist in the form of gas, and that there is almost no atmosphere on the surface of TNOs.

While a thin atmosphere has been found only on Pluto, which is about 2,400 kilometers in diameter, it had been believed that smaller TNOs cannot retain atmospheres due to their weak surface gravity.

[Copyright The Jiji Press, Ltd.]