KELT-11b is an exoplanet orbiting around the yellow

subgiant A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution ...

star KELT-11 (HD 93396) about 320 light-years away from

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

. It is an inflated planet, one of the "puffiest planets" (lowest-density) known, as a result of its close orbiting distance with its parent star. It has a radius 1.37 times that of

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

, but only 19% of its mass. It was discovered in 2016. The transmission spectrum study in 2020 have revealed the KELT-11b atmosphere containing sub-solar amount of water vapor, but significant amounts of

hydrogen cyanide Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...

, together with oxides of titanium and aluminum. Also, the nightside flux do indicate a generally cloud-free atmosphere with an effective heat redistribution between dayside and nightside. Later studies have indicated the

spectral features are not well distinguished from spectral lines of

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

and

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

, although

seems to be present in larger amounts, indicating a high carbon/oxygen ratio of the planet.

References

{{2016 in space Exoplanets discovered in 2016 Exoplanets discovered by KELT Sextans