Researchers at Leigh University, in collaboration with scientists from Vanderbilt University and Ohio State University, have discovered a distant planet that’s about as dense as Styrofoam.
The planet, described in a paper published in The Astronomical Journal, is considered to be an extreme version of a gas planet. Dubbed as KELT-11b, the new planet orbits very close to its host star and takes less than five Earth days to complete an orbit.
“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 Joshua Pepper, astronomer and assistant professor of physics at Lehigh University, in a press release. “We were very surprised by the amazingly low density of this planet. It’s extremely big for its mass. It’s got a fifth of the mass of Jupiter but is puffed up into this really underdense planet.”
For the study, the researchers used the two small robotic telescope of the KELT (Kilodegree Extremely Little Telescope) survey. These robotic telescopes scan the sky every night, measuring the brightness of about five million stars. As a good indicator of a planet, researchers look for stars that appear to dim temporarily at regular intervals. To verify that the dimming of the star is indeed caused by a planet, the researchers also use other telescopes to measure the gravitational wobble, or the slight tug a planet exerts on the star.
Luckily, KELT-11b orbits the brightest star in the southern hemisphere. The star, KELT-11 is extremely bright and already evolving into a red giant. This means that the KELT-11 has started using up its nuclear fuel and will soon devour the KELT-11b.
The KELT survey was made possible through the contributions of more than 30 institutions, including NASA, Harvard University, Princeton University, University of California-Berkeley and University of Pennsylvania. The project was also joined by some 40 citizen scientists living in 10 countries across four continents.