This is an artist's rendering of KELT-11b, a 'styrofoam'-density exoplanet orbiting a bright star in the southern hemisphere. Credit: Walter Robinson/ Lehigh University

An unusual planet, discovered 320 light years from Earth, might help astronomers find habitable planets elsewhere in space.

The planet—KELT-11b—orbits around an extremely bright host star, which allows researchers to take precise measurements of its atmospheric properties. The planet is a gas planet, similar to Jupiter or Saturn, but is orbiting very close to its host star in an orbit that lasts less than five days.

Studying this type of planet could help astronomers discover the techniques needed to identify chemicals in planets’ atmospheres and assess habitability or products of life in the atmospheres of other planets.

 “We don't know of any real Earthlike planets or stars for which we can measure their atmospheres, though we expect to discover more in future years,” Joshua Pepper, astronomer and assistant professor of physics at Lehigh University, who led the study in collaboration with researchers from Vanderbilt University and Ohio State University, said in a statement. “These (giant gas) planets are the gold standards or testbeds for learning how to measure the atmospheres of planets.”

KELT-11b has an amazingly low density and is extremely big for its mass. It is a fifth of the mass of Jupiter but is, ‘puffed up,” said Pepper.

 “It is highly inflated, so that while it's only a fifth as massive as Jupiter, it is nearly 40 percent larger, making it about as dense as Styrofoam, with an extraordinarily large atmosphere,” said Pepper in a statement.

KELT-11—the host star which is the brightest host star of a transitioning planet in the southern hemisphere—has begun using up its nuclear fuel and is evolving into a red giant, which will engulf the planet in the next hundred million years.

The researchers used a pair of small robotic telescopes in Arizona and south Africa to scan the sky and measure the brightness of about five million stars.

If a star dims slightly at regular intervals it indicates that there is a planet orbiting the star. Researchers then measure the slight tug the planet exerts on the star as it orbits to verify that the dimming is due to a planet.

“The KELT (Kilodegree Extremely Little Telescope) project is specifically designed to discover a few scientifically valuable planets orbiting very bright stars and KELT-11b is a prime example of that," Pepper said.

The study was published in The Astronomical Journal.