Searching for habitable planets in the Goldilocks Zone of K stars

habitable planets k stars 742541main kepler 62morningstar 1 full
An artist’s concept of a planet orbiting in the habitable zone of a K star. NASA Ames/JPL-Caltech/Tim Pyle

Not too hot, not too cold — this one’s just right. To identify potentially habitable worlds, astronomers search in the “Goldilocks Zone” around stars to find planets where liquid water can exist on the surface. Now a new study has identified types of star called K stars which make especially promising targets to host habitable planets.

K stars are less bright than our Sun, but brighter than the dimmest stars — called M stars or red dwarfs. This means K stars shine for a much greater length of time than our Sun, lasting between 17 billion and 70 billion years as compared to our Sun’s 10 billion years. The K stars are also more stable, experiencing less extreme activity when they are young than M stars which go through dramatic phases of stellar flares, and give off so much energy that they could boil oceans on nearby planets. All together, these factors mean that K stars have long periods when they are stable, giving plenty of time for potential life to evolve.

“I like to think that K stars are in a ‘sweet spot’ between Sun-analog stars and M stars,” Giada Arney of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a statement.

Traditionally, the search for habitable planets has focused primarily on M stars because they are so prevalent, making up about three quarters of all the stars in the universe. But K stars may make better targets for the search, not only because they are long-lived and stable, but also because it is easier to spot potential signs of life near them.

One way to see potential sites of life is to look for a planet with both oxygen and methane in its atmosphere. These two gases usually react and destroy each other, so if you see both present at the same time it suggests that something must be producing them both — and that something could be life. But in order to detect oxygen and methane in a planet’s atmosphere from a long way off, they both must be present in large quantities.

Arney used computer modelling to see how different types of planetary atmosphere would respond to different star hosts. She found that the biosignature of oxygen and methane would be strongest when the planet in question orbited around a K star.

“When you put the planet around a K star, the oxygen does not destroy the methane as rapidly, so more of it can build up in the atmosphere,” Arney said in the same statement. “This is because the K star’s ultraviolet light does not generate highly reactive oxygen gases that destroy methane as readily as a Sun-like star.”

Arney also indicated particular K stars which would be prime targets for investigation, including 61 Cyg A/B, Epsilon Indi, Groombridge 1618, and HD 156026.

Emerging Tech

Take a dip in the Lagoon Nebula in first image from SPECULOOS instrument

The European Southern Observatory has released the first image collected by their new SPECULOOS instrument, and it's a stunning portrait of the Lagoon Nebula, a swirling cloud of dust and gas where new stars are born.
Computing

Delete tracking cookies from your system by following these quick steps

Cookies are useful when it comes to saving your login credentials and other data, but they can also be used by advertisers to track your browsing habits across multiple sites. Here's how to clear cookies in the major browsers.
Emerging Tech

Cosmic dust bunnies: Scientists find unexpected ring around Mercury

A pair of scientists searching for a dust-free region near the Sun have made an unexpected discovery: a vast cosmic dust ring millions of miles wide around the tiny planet Mercury.
Emerging Tech

New Hubble image displays dazzling Messier 28 globular cluster

Messier 28 is a group of stars in the constellation of Sagittarius, located 18,000 light-years from our planet. Thousands of stars are packed tightly together in this sparkling image.
Emerging Tech

Researchers gave alligators headphones and ketamine, and all for a good cause

Researchers in Germany and the United States recently gave ketamine and earphones to alligators to monitor how they process sounds. Here's what it reveals about alligator evolution.
Emerging Tech

Cheese tastes different when it listens to Led Zeppelin, Swiss study finds

A funky new study says that exposing cheese to music changes its aroma and flavor. What’s more, the genre of music matters. Researchers from the Bern University of Arts played music to nine, 22-pound wheels of Emmental cheese.
Emerging Tech

Twitter is officially a teenager now. Are we raising a monster?

On March 21, 2006, Jack Dorsey sent the first ever tweet. Thirteen years later, Twitter has fundamentally changed the way we communicate. Here are some of the myriad ways it's done that.
Emerging Tech

Astronomers plan to beam Earth’s greatest hits into deep space, and you can help

A new project from the SETI Institute (search for extraterrestrial intelligence) will give the public the chance to submit compositions to be beamed into space, with the aim of connecting people around the world through music.
Emerging Tech

Scientists have a way to turn off alcoholism: Blasting the brain with lasers

Researchers from Scripps Research have demonstrated that it is possible to reverse the desire to drink in alcohol-dependent rats by targeting a part of the brain using lasers. Here's how.
Emerging Tech

China has cloned its best police dog. Now it wants to mass-produce more

Scientists in China have cloned the Sherlock Holmes of police sniffer dogs, with possible plans to mass produce it in the future. Here's why its creators think that's a great idea.
Emerging Tech

Scientists use drone to map Icelandic cave in preparation for Mars exploration

Researchers from the SETI Institute and Astrobotic Technology have demonstrated a way that astronauts may be able to map Martian caves using a Lidar-equipped drone that can travel autonomously without GPS.
Emerging Tech

A 3D printer the size of a small barn will produce entire homes in Saudi Arabia

If you’re looking for a 3D printer that can comfortably fit on the side of your desk… well, Danish company Cobod International’s enormous new 3D house printer probably isn’t for you.
Deals

Need a ride? Amazon is slashing prices on popular electric scooters

If you’re not much of a cyclist or if you’re looking for a lazier way to zip about town, an electric scooter should be right up your alley. Two of our favorites, the foldable Glion Dolly and the eco-friendly Razor scooter, are on sale…
Emerging Tech

Unexpected particle plumes discovered jetting out of asteroid Bennu

The OSIRIS-REx craft traveled to asteroid Bennu last year and won't return until 2023. But the mission is already throwing up unexpected findings, like plumes of particles which are being ejected from the surface of the asteroid.