KELT-11b is one of the brightest transiting exoplanets in the southern hemisphere. It’s one fifth the size of Jupiter, but is most famous for it’s ‘inflated atmosphere’ that is often described as similar to styrofoam.
It’s entirely possible that KELT-11b (a true gas giant) could float on water.
The planet was discovered during the KELT (Kilodegree Extremely Little Telescope) survey. In order to locate the object, two telescopes (one in South Africa and one in Arizona) work together to find transiting objects. A transit or astronomical transit is the phenomenon of at least one celestial body appearing to move across the face of another celestial body, hiding a small part of it, as seen by an observer at some particular vantage point.
“The KELT project is specifically designed to discover a few scientifically valuable planets orbiting very bright stars, and KELT-11b is a prime example of that. 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.”
KELT’s inflated atmosphere is 1,700 miles or 2,760 kilometers across. It’s 320 light-years from Earth and is so close to it’s parent star that it completes an orbit every 5 days. KELT-11b has the third lowest density of any accurately measured exoplanet.
“We don’t know of any real Earth-like planets or stars for which we can measure their atmospheres, though we expect to discover more in future years. These (giant gas) planets are the gold standards or testbeds for learning how to measure the atmospheres of planets.” adds Joshua Pepper.
Astronomers are trying to figure out the cause for KELT-11b’s inflation and further study is needed to analyze the data. The planet’s large atmosphere can also provide a mechanism for testing hability products in new and uncharted atmospheres.
We’ll need new tools to analyze the atmosphere of planet’s such as KELT; there’s a big hope that the upcoming launch of the James Webb Space Telescope can provide answers to questions like these.