Puff N Stuff Planet...

An artist’s rendering of KELT-11b, a “Styrofoam-density” planet recently discovered by Lehigh astronomers that orbits a bright star in the Southern Hemisphere. (Image by Walter Robinson/Lehigh University)

Topics: Astronomy, Astrophysics, Exoplanets, Space Exploration

Fifth-graders making Styrofoam models of the solar system may have the right idea. Lehigh researchers have discovered a new planet orbiting a star 320 light years from Earth that has the density of Styrofoam. This “puffy planet” outside our solar system may help solve the long-standing mystery of the existence of a population of highly inflated giant planets.

“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 thick atmosphere,” said Joshua Pepper, astronomer and assistant professor of physics at Lehigh, who led the study with researchers from Vanderbilt University and Ohio State University, along with researchers at universities and observatories and amateur astronomers around the world.

The research, “KELT-11b: A Highly Inflated Sub-Saturn Exoplanet Transiting the V+8 Subgiant HD 93396,” is published in The Astronomical Journal.

The planet, called KELT-11b, is an extreme version of a gas planet, like Jupiter or Saturn, but is orbiting very close to its host star in an orbit that lasts less than five days. The star, KELT-11, has started using up its nuclear fuel and is evolving into a red giant, so the planet will be engulfed by its star and will not survive the next hundred million years.

Lehigh University: ‘Styrofoam’ Planet May Help Solve Mystery of Giant Planets
Amy White, Kurt Pfitzer