It is often referred to as ‘hot Jupiter’ due to its hellishly hot temperatures of 2,000°C, and similar mass to the largest planet in our solar system.
But until now, very little has been known about the atmosphere of Wasp-19b, which is 800 light years from Earth.
In a new study, astronomers have analysed the exoplanet’s atmosphere for the first time, and detected small amounts of titanium oxide, water and sodium.
The researchers hope the findings will allow much better modelling of exoplanet atmospheres in the future.
In a new study, astronomers have analysed Wasp-19b for the first time, and detected small amounts of titanium oxide, water and sodium in its atmosphere (artist’s impression pictured)
Wasp-19b has about the same mass as Jupiter, but is so close to its parent star that it completes an orbit in just 19 hours.
As it passes in front of its parent star, some of the starlight passes through the planet’s atmosphere, leaving subtle fingerprints in the light that eventually reaches Earth.
Researchers from the European Space Agency (Eso) have now used the Very Large Telescope to carefully analyse this light over a year.
By measuring the variations in the planet’s radius at different wavelengths of light that passed through the exoplanet’s atmosphere, they could extrapolate different properties, such as the chemical content.
Their findings revealed that Wasp-19b’s atmosphere contains small amounts of titanium oxide, water and traces of sodium, alongside a strongly scattering global haze.
Elyar Sedaghati, who worked on the project, said: ‘Detecting such molecules is, however, no simple feat.
‘Not only do we need data of exceptional quality, but we also need to perform a sophisticated analysis.
‘We used an algorithm that explores many millions of spectra spanning a wide range of chemical compositions, temperatures, and cloud or haze properties in order to draw our conclusions.’
By measuring the variations in the planet’s radius at different wavelengths of light that passed through the exoplanet’s atmosphere, they could extrapolate different properties, such as the chemical content (artist’s impression pictured)
Wasp-19b has about the same mass as Jupiter, but is so close to its parent star that it completes an orbit in just 19 hours. This chart shows the location of the star WASP-19 in the constellation of Vela
While titanium oxide is known to exist in the atmosphere of cool stars, it is rarely seen on Earth.
But in the atmospheres of hot planets like Wasp-19b, it acts as a heat absorber.
If present in large enough quantities, these molecules prevent heat from entering or escaping through the atmosphere, leading to a thermal inversion.
This means that the temperature is higher in the upper atmosphere and lower further down – the opposite of the normal situation.
Ozone plays a similar role in Earth’s atmosphere, where it causes inversion in the stratosphere.
Ryan MacDonald, who also worked on the study, said: ‘The presence of titanium oxide in the atmosphere of WASP-19b can have substantial effects on the atmospheric temperature structure and circulation.
‘To be able to examine exoplanets at this level of detail is promising and very exciting.’
The researchers hope their findings will allow for much better modelling of exoplanet atmospheres in the future – including those that may possibly be habitable.