Scientists announce the discovery of a planet twice the size of Earth with a thick atmosphere

An artist’s concept shows the exoplanet 55 Cancri e, also called Janssen, a so-called super-Earth, a rocky planet significantly larger than Earth but smaller than Neptune, along with the star it orbits in this undated illustration released by NASA. NASA, ESA, CSA, Ralf Crawford (STScI)/Handout via REUTERS. THIS IMAGE IS PROVIDED BY A THIRD PARTY. MANDATORY CREDIT

DALLAS (AP) — A thick atmosphere has been detected around a planet twice the size of Earth in a nearby solar system, researchers reported Wednesday.

The so-called super-Earth – known as 55 Cancri e – is one of the few rocky planets outside our solar system with a significant atmosphere, shrouded in a blanket of carbon dioxide and carbon monoxide. The exact amounts are unclear. Earth’s atmosphere is a mixture of nitrogen, oxygen, argon and other gases.

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“It’s probably the strongest evidence yet that this planet has an atmosphere,” said Ian Crossfield, an astronomer at the University of Kansas who studies exoplanets and was not involved in the study.

The research was published in the journal Nature.

Super-Earth refers to the size of a planet: larger than Earth but smaller than Neptune. The boiling temperatures on this planet – which can reach 2,300 degrees Celsius – mean that life is unlikely to occur.

Instead, scientists say the discovery is a promising sign that other similar rocky planets with thick atmospheres could exist that might be more hospitable.

The exoplanet, 41 light-years away, is eight times heavier than Earth and orbits so close to its star Copernicus that it has permanent day and night sides. A light year is almost 6 trillion miles (9.7 trillion kilometers). The surface is covered with magma oceans.

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To identify the composition of the atmosphere, researchers studied Webb Space Telescope observations before and after the planet passed behind its star.

They separated the light emitted by the planet from its star and used the data to calculate the planet’s temperature. There is evidence that the planet’s heat was distributed more evenly across its surface – a party trick that atmospheres are known for.

Gases from the magma oceans can play a key role in keeping the atmosphere stable. Exploring this super-Earth could also provide clues about how Earth and Mars may have first evolved with magma oceans that have since cooled, scientists say.

“It’s a rare window,” said Renyu Hu, a planetary scientist at NASA’s Jet Propulsion Laboratory who was part of the study. “We can investigate this early phase of planetary evolution.”

Left:
An artist’s concept shows the exoplanet 55 Cancri e, also called Janssen, a so-called super-Earth, a rocky planet significantly larger than Earth but smaller than Neptune, along with the star it orbits in this undated illustration released by NASA. NASA, ESA, CSA, Ralf Crawford (STScI)/Handout via REUTERS. THIS IMAGE IS PROVIDED BY A THIRD PARTY. MANDATORY CREDIT