K stars more likely to host habitable exoplanets

March 8 (UPI) – Scientists have dubbed K stars "Goldilocks stars". According to a new study, K stars are more likely to host exoplanets than other types of stars.

If life is to be found outside the planet Earth, new research suggests that K stars are the place where astronomers should turn. K stars are orange stars that register a little colder than the sun.

There are billions of stars in the universe. Astronomers looking for signs of extraterrestrial life can barely scratch the surface of the stellar population of the universe. The new research promises to refine the search parameters of astronomers.

As detailed in the Astrophysical Journal Letters, K stars have several advantages. They live a long time, leaving the surrounding planets a lot of time for the development of life. More importantly, K stars have less electromagnetic turbulence.

The larger and more frequent solar flares produced by the M stars can destroy the atmosphere of the inner planets, thus nullifying the chances of development of life.

"I like to think that the K stars are in an ideal situation between the Sun's analogous stars and the M stars," said Giada Arney, planetary scientist at NASA's Goddard Space Flight Center, in a statement. Press.

Scientists have developed models to predict what biosignatures might look like in the atmosphere of an exoplanet orbiting a K – star. Because oxygen and methane get usually destroy, their simultaneous atmospheric presence suggests a type of process – possibly biological – that constantly produces both gases.

Oxygen and methane can be difficult to spot at thousands of light years away, but the models created by Arney and his colleagues have shown that oxygen-methane biosignatures would be more evidence of the "cold". atmosphere of exoplanets in star systems K.

"When you place the planet around a K star, oxygen does not destroy methane as quickly, so a greater amount of it can accumulate in the atmosphere." Atmosphere, "said Arney. "This is because the ultraviolet light of the star K does not generate extremely reactive oxygen gas that destroys methane as easily as a star similar to that of the Sun."

As the K stars are weaker, the exoplanets in orbit should be easier to spot. In their new article detailing the habitability of K star planetary systems, published this week in the journal Astrophysical Journal, the authors identified several nearby K stars to explore in future astronomical surveys.

"I find that some near K stars like 61 Cyg A / B, Epsilon Indi, Groombridge 1618 and HD 156026 could be particularly interesting targets for future biosignature research," Arney said.