Free Astronomy Magazine November-December 2017

by ESO 52 NOVEMBER-DECEMBER 2017 SPACE CHRONICLES This remarkable planet has about the same mass as Jupiter, but is so close to its parent star that it completes an orbit in just 19 hours and its at- mosphere is esti- mated to have a temperature of about 2000 de- grees Celsius. As WASP-19b passes in front of its par- ent star, some of the starlight passes through the planet’s atmo- sphere and leaves subtle finger- prints in the light that eventually reaches Earth. By using the FORS2 instrument on the Very Large Telescope the team was able to carefully analyse this light and deduce that the atmo- sphere contained small amounts of titanium oxide, water and traces of sodium, alongside a strongly scat- tering global haze. “Detecting such molecules is, however, no simple feat,” explains Elyar Sedaghati, who spent 2 years as ESO student to work on this project. “Not only do we need data of exceptional quality, but we also need to per- form a sophisticated analysis. We used an algorithm that explores many millions of spectra spanning a wide range of chemical composi- tions, temperatures, and cloud or haze properties in order to draw our conclusions.” Titanium oxide is rarely seen on Earth. It is known to exist in the at- mospheres of cool stars. In the at- mospheres of hot planets like WASP-19b, it acts as a heat ab- sorber. If present in large enough quantities, these molecules prevent Inferno world with titanium skies A team of astronomers led by Elyar Sedaghati, an ESO fel- low and recent graduate of TU Berlin, has examined the atmo- sphere of the exoplanet WASP-19b in greater detail than ever before.