Exoplanet WASP-76b May Be More Hellish Than We Thought

In 2016, scientists discovered an exoplanet called WASP-76b. The exoplanet is considered an ultra-hot Jupiter. The planet is so hot that iron is vaporized on the dayside, condenses on the nightside, and falls like rain in the atmosphere. However, new data suggests that WASP-76b may be even hotter than scientists originally believed.

An international team of researchers, including scientists from Cornell, the University of Toronto, and Queens University Belfast, have discovered ionized calcium on the planet. Hints of the ionized calcium were discovered via high-resolution Spectra data obtained using the Gemini North instrument in Hawaii. Researchers discovered rare spectral lines in their observations of the atmosphere of WASP-76b.

First author of the study, Emily Deibert from the University of Toronto, said that there was so much calcium it was a really strong feature of the planet. She believes the spectral signature of ionized calcium indicates that the planet has very strong upper atmospheric winds or the planet's temperature is much higher than scientists thought.

WASP-76b is a tidally locked planet with the same side always facing its star while the other side of the planet is permanently night. Temperatures on the dayside average 4400 degrees Fahrenheit, while on the nightside, temperatures are 2400 degrees Fahrenheit on average. The exoplanet orbits its star, which is hotter than the Sun, very quickly enabling scientists to separate its signal from starlight. They were able to see the calcium imprint moving quickly along with the planet.

WASP-76b is about 640 light-years from Earth. It orbits an F-type star every 1.8 Earth days. Researchers published their findings in the Astrophysical Journal Letters publication on September 28 this year. They presented their findings on October 5 at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society.