’Sunscreen’ layer detected on distant planet

On a blazing-hot exoplanet known as WASP-33b, a team of astronomers including researchers from the University of Cambridge has detected a stratosphere, one of the primary layers of Earth's atmosphere. Understanding the links between stratospheres and chemical compositions is critical to studying atmospheric processes in exoplanets - Nikku Madhusudhan The presence of a stratosphere can provide clues about the composition of a planet and how it formed. This atmospheric layer includes molecules that absorb ultraviolet and visible light, acting as a kind of 'sunscreen' for the planet it surrounds. Until now, scientists were uncertain whether these molecules would be found in the atmospheres of large, extremely hot planets in other star systems. The results are published today (12 June) in The Astrophysical Journal . "Detecting the presence of a stratosphere in an exoplanet and the chemical compound causing it is a major advancement in our ability to study exoplanetary atmospheres," said co-author Dr Nikku Madhusudhan of the Institute of Astronomy at Cambridge. In Earth's atmosphere, the stratosphere sits above the troposphere - the turbulent, active-weather region that reaches from the ground to the altitude where nearly all clouds top out.