Earth-like planet orbiting most common star type may be uninhabitable: Study

A new study has revealed that an Earth-like planet orbiting an M dwarf, the most common type of star in the universe, may have no atmosphere at all and therefore unlikely to harbor living things. This discovery could dramatically narrow the search for extraterrestrial life.

The no-atmosphere planet, named GJ 1252b, orbits its star twice during the course of a single day on Earth. The planet is slightly larger than Earth, and is much closer to its star than Earth is to the sun, making it intensely hot and inhospitable.

For this discovery, astronomers, led by Ian Crossfield at the University of Kansas, measured infrared radiation from the planet as its light was obscured during a secondary eclipse, which occurs when a planet passes behind a star and the planet's light, as well as light reflected from its star, is blocked.

The radiation revealed GJ 1252b's scorching daytime temperatures, estimated to reach 2,242 degrees Fahrenheit - that's hot enough to melt gold, silver, and copper on the planet. The heat, coupled with assumed low surface pressure, led the team to believe that the planet lacks an atmosphere. Even with a tremendous amount of carbon dioxide, which traps heat, the researchers concluded GJ 1252b would still not be able to hold on to an atmosphere.

"The planet could have 700 times more carbon than Earth has, and it still wouldn't have an atmosphere. It would build up initially, but then taper off and erode away," Stephen Kane, UC Riverside (UCR) astrophysicist and study co-author, said in a statement.

Michelle Hill, UC Riverside astrophysicist and study co-author, said, "It's possible this planet’s condition could be a bad sign for planets even further away from this type of star. This is something we'll learn from the James Webb Space Telescope, which will be looking at planets like these."

The study, published in The Astrophysical Journal Letters, also included scientists from UC Riverside as well as NASA's Jet Propulsion Laboratory, Caltech, University of Maryland, Carnegie Institution for Science, Max Planck Institute for Astronomy, McGill University, University of New Mexico, and the University of Montreal.