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ESO/L. Calçada.
An artist's illustration of what HR8799e might look like, based on an interpretation of the atmosphere's spectra.

Editor's note: A version of this was previously published on the author's website.

The European Southern Observatory has announced a stunning breakthrough. Its four huge telescopes took spectra of the atmosphere of an exoplanet 129 light-years distant, discovering a violent worldwide storm of blazing-hot carbon monoxide, iron vapor and dust.

Almost seven times as distant as the nearest star to our solar system, the planet is dubbed HR8799e, one of at least four exoplanets orbiting the star HR8799 in the constellation Pegasus. The relatively young star is about 1½ times the mass of our sun, while this exoplanet is characterized as a "hot Jupiter," between 5 and 10 times the size of the actual planet Jupiter, which is by far the largest in the solar system.

"At only 30 million years old, this baby exoplanet is young enough to give scientists a window onto the formation of planets and planetary systems," says an ESO release. "The exoplanet is thoroughly inhospitable — leftover energy from its formation and a powerful greenhouse effect heat HR8799e to a hostile temperature of roughly 1000 °C (1,832° F)."

European Southern Observatory
This photograph shows units of the Very Large Telescope. Drawn onto the photo are tunnels where light from the VLT is shunted to a laboratory in the center, where it is combined by computer, creating the resolution that a telescope up to 328 feet in diameter would have.

The spectra were obtained through optical interferometry, in which light from the planet was gathered by four giant telescopes — each primary mirror measuring nearly 27 feet across — at Cerro Paranal, in northern Chile's Atacama Desert. Tunnels fed the captured light to a laboratory where it was combined by computer. The setup has the resolution of an improbably huge telescope of up to 328 feet in diameter; the four working together are dubbed the Very Large Telescope. The program used a new instrument called GRAVITY in the study.

According to European Southern Observatory officials, the fierce temperature results from energy released by the planet's formation and a "powerful greenhouse effect" resulting from heat trapped in the dusty atmosphere.

The news release added, "This is the first time that optical interferometry has been used to reveal details of an exoplanet, and the new technique furnished an exquisitely detailed spectrum of unprecedented quality — 10 times more detailed than earlier observations. The team's measurements were able to reveal the composition of HR8799e’s atmosphere — which contained some surprises."

One of the biggest surprises was that much more carbon monoxide than methane was present. Team leader Sylvestre Lacour said the best explanation is that vertical winds are preventing carbon monoxide from combining with hydrogen to form methane. Clouds of iron and silicate dust also were detected, according to the observatory. Silica and iron particles rain down from the clouds, Lacour added.

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At an estimated age of only 30 million years, the exoplanet may give scientists insight into the formation of Earth's atmosphere, ESO added.

This writer asked whether the GRAVITY instrument could allow astronomers to glimpse continents on exoplanets. The observatory's Fernando Comerón replied, "The observations produced a spectrum of the whole planet, as current techniques are unable to resolve details in the disk of the planet such as continents. The main result of those observations refers to the details of the composition and circulation of the atmosphere, which can be inferred from the spectrum."