A team of scientists led by NASA determined that WASP-18b, a "hot Jupiter" located 325 light years from Earth, has a suffocating stratosphere that is laden with carbon monoxide or CO, but has no signs of Water .
"The composition of WASP-18b defies all expectations," said Kyle Sheppard of NASA's Goddard Space Flight Center in Greenbelt, Maryland.
"We do not know of any other extrasolar planet where carbon monoxide completely dominates the upper atmosphere," Sheppard said.
The findings, published in the
Astrophysical Journal Letters
, come from a new badysis of observations made by the Hubble and Spitzer space telescopes.
The formation of a stratospheric layer in the atmosphere of a planet is attributed to "solar protective" molecules, which absorb ultraviolet (UV) and visible radiation coming from the star and then releasing that energy as heat.
The new study suggests that the "hot Jupiter" WASP-18b, a mbadive planet orbiting very close to its host star, has an unusual composition, and the formation of this world could have been quite different from that of Jupiter and the gaseous giants in other planetary systems.
On Earth, ozone absorbs UV rays in the stratosphere, protecting our world from much of the sun's harmful radiation.
the handful of exoplanets with stratospheres, the absorber is thought to be a molecule like titanium oxide, a close relative of titanium dioxide, which is used on Earth as a paint pigment and sunscreen ingredient.
Researchers observe ed in the data collected for WASP-18b as part of a survey to find exoplanets with stratospheres.
The heavyweight planet, which has the mbad of 10 Jupiter, has been observed repeatedly, allowing astronomers to accumulate a large number of data.
The badysis revealed the unique fingerprint of WASP-18b, which does not resemble any exoplanet examined so far. To determine which molecules were most likely to match, the team conducted extensive computer modeling.
"The only consistent explanation for the data is an overabundance of carbon monoxide and very little water vapor in the atmosphere of WASP-18b, in addition to the presence of a stratosphere," said Nikku Madhusudhan, co-author of the study. the University of Cambridge.
"This rare combination of factors opens a new window for our understanding of physicochemical processes in exoplanetary atmospheres." Madhusudhan said. ISANS