“Mini Neptune” outside the solar system may soon give signs of life | outer planets

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After rethinking what types of planets might be habitable, experts said, signs of life outside our solar system may be detectable within two to three years.

Researchers have mostly searched for planets of the same size, mass, temperature, and composition of Earth’s atmosphere. But astronomers at the University of Cambridge believe there may be more promising possibilities after recent work suggested that ‘Little Neptune’ more than twice the radius of Earth and more than eight times the radius may be habitable.

They have now identified a new class of habitable exoplanets, called bright planets — hot, covered in oceans and hydrogen-rich atmospheres — that are more numerous and observable than Earth-like planets. Miniature Neptune, known as K2-18b, is one and there could be many more in existence.

“The migrants are basically watery worlds with hydrogen-rich atmospheres,” said Dr Niko Madhusudan, lead author of the research from the University of Cambridge. He said the focus on haiken could speed up efforts to find extraterrestrial life.

“We’re saying that in two to three years we might see the first biological discovery if these planets are hosts,” he said, adding that the James Webb Space Telescope – due to launch in November – could help with the research.

Madhusudan said the small size of Earth-like planets relative to Sun-like stars has resulted in weak atmospheric signals, making it difficult to detect signs of life.

However, the radius of Heiken can be more than twice the Earth’s radius of about 10 times the mass, and considerably hotter, with average atmospheric temperatures of about 200 degrees Celsius.

Madhusudan said that larger planets are not only more common than Earth-sized planets but are easier to find, and their atmospheres can be more easily detected.

Furthermore, the formation of the asteroid planets means that it is possible to search for a larger range of molecules that might indicate the presence of life.

Writing in The Astrophysical Journal, the team wrote that bright planets are defined as having a hydrogen-rich atmosphere, a rocky core that accounts for at least 10% of the planet’s mass, and a layer of water that accounts for up to 90% of the planet. planet mass.

Life may be possible even on the shadowy side of the planets, which the team dubbed “dark heydays.” These sit close to their star and are gradually turned off, which means that the same side of the planet is always in the light – potentially too hot to live on.

The team said that any life on Haykens would necessarily be aquatic because the planets, by definition, would be covered in a watery layer. But what form this life might take is an open question, according to Madhusudan.

“At a minimum, microbial life should be possible,” he said, adding that this is how life on Earth began.

Professor Beth Beller, who studies exoplanets at the University of Edinburgh’s Institute of Astronomy and was not involved in the research, welcomed the work. “There is such diversity among the exoplanets discovered so far and it really makes sense to study non-Earth-like planets that would most likely host life,” she said.

But Beller added that searching for biometric fingerprints on massive planets has so far been difficult. “Searching for biosignatures of Earth twins is already very difficult – most of them rely on proving that the atmosphere is not in equilibrium by discovering a set of different biosignature gases that should not exist together in equilibrium. This is possible in principle for raging planets Also, but obviously without Earth as an example, it is difficult in any given case to rule out false positives.”

For both types of planets, Beller said, data from a large number of bodies would be needed to understand which might be habitable.

“[The James Webb space telescope] It will already provide some interesting spectra of massive planets in the next few years, but it’s hard to say yet whether these spectra will be conclusive.

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