Gaseous planet challenges astronomers' understanding

A planet 10 times larger than Jupiter is surrounded by carbon monoxide, a deadly gas, all year round.

Simulation of exoplanet WASP-18b. Photo: NASA

WASP-18b, a planet 325 light years away from Earth, is 10 times more massive than Jupiter and has an atmosphere filled with carbon monoxide. The planet has no water but has extremely high temperatures, making it a world extremely hostile to life, according to the International Business Times. Researchers have never known of a planet with such a carbon monoxide-filled upper atmosphere.

"The composition of WASP-18b is beyond understanding," said Kyle Sheppard of NASA's Goddard Space Flight Center, lead author of the study published Dec. 1 in the Astrophysical Journal Letters. "We know of no other exoplanet with such a complete dominance of its upper atmosphere by carbon monoxide."

The discovery could change researchers' understanding of how planetary atmospheres form. "The rare combination of elements on WASP-18b opens new doors in our understanding of the physical and chemical processes in exoplanetary atmospheres," said researcher Nikku Madhusudhan of the University of Cambridge.

WASP-18b belongs to a class of planets called "hot Jupiters", gas giants that orbit very close to their host stars and as a result have extremely high temperatures. The planet completes one orbit around its star every 23 hours.

The findings come from a new analysis of observations from the Hubble and Spitzer space telescopes. Researchers also concluded that WASP-18b's atmosphere likely contains 300 times more metals (elements heavier than hydrogen and helium) than any other known "hot Jupiter."

WASP-18b and many other exoplanets will be the focus of further study when the James Webb Space Telescope launches into space in 2019.

According to VNE