An enormous and scorching hot exoplanet has an atmosphere made of titanium, making its discovery a rare find for scientists.

The atmospheric ingredient is titanium oxide, to be specific, and it tells scientists a lot about what conditions must be like on that exoplanet, dubbed WASP-19b.

To determine its composition, the team analyzed the exoplanet’s atmosphere using data from when it passed in front of its host star. WASP-19b is so close to the star that this happens every 19 hours. At that point in each orbit, the starlight passing through the exoplanet’s atmosphere on its way to Earth’s telescopes interacts with the atoms and molecules up there. Scientists can study that interaction to figure out what’s inside.

The scientists reported their observations of the exoplanet in the journal Nature, saying that in addition to titanium oxide, a combination of titanium and oxygen that is rarely found on Earth, they detected sodium and water.

This is the first time titanium oxide has been discovered in an exoplanet’s atmosphere, although it has previously been seen in the atmospheres of some stars, particularly lower-temperature ones.

According to the study, scientists usually find lighter elements like hydrogen, oxygen, carbon, sodium and potassium when observing the atmospheres of large, hot exoplanets like this one, which are known as hot Jupiters because their masses are comparable to that of Jupiter in our own solar system but they have much higher temperatures because of their proximity to their stars.

eso1729a An artist’s impression depicts exoplanet WASP-19b, a “hot Jupiter” planet whose atmosphere contains the heat-absorbing titanium oxide. Photo: ESO/M. Kornmesser

WASP-19b is located in the constellation Vela, known for its resemblance to the sails of a ship. When it was first described several years ago, scientists estimated it to be about 600 million years old and just slightly larger and more massive than Jupiter.

Titanium oxide helps the scientists understand WASP-19b because of what they know about how the compound absorbs heat. The European Southern Observatory explained that when it is concentrated enough, it acts as a barrier that stops heat from entering or exiting, which would make the upper atmosphere of this exoplanet hotter than the lower atmosphere — a reversal of normal conditions. Ozone does something similar in Earth’s stratosphere.

“The presence of titanium oxide in the atmosphere of WASP-19b can have substantial effects on the atmospheric temperature structure and circulation,” astronomer Ryan MacDonald said in the ESO statement.

The scientists made their observations of WASP-19b, which is estimated to have temperatures around 3,100 degrees Fahrenheit, with the ESO’s Very Large Telescope.

“Detecting such molecules is, however, no simple feat,” astronomer Elyar Sedaghati said in the statement. “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.”

According to the observatory, the findings add to information about this category of exoplanet that will help scientists create models of them in the future.

“To be able to examine exoplanets at this level of detail is promising and very exciting,” researcher Nikku Madhusudhan said in the statement.