Astronomers using the James Webb Space Telescope have obtained new data on one of the most extreme known exoplanets — the gas giant HD 80606 b, located 217 light-years from Earth. This planet exhibits truly hellish conditions: during its close approach to its star, its temperature sharply spikes to 600 °C, leading to serious changes in the chemical composition of its atmosphere, according to Space.com.

A "hot Jupiter" with an unusual orbit

HD 80606 b belongs to the class of "hot Jupiters" — gas giants that orbit very close to their stars. However, this planet has a highly elongated (elliptical) orbit. One revolution around the star takes 111 days, and at its closest point (perihelion), it approaches its star at an extremely small distance.

It is precisely at this moment that the temperature on the planet rises sharply. JWST observed HD 80606 b before, during, and after its close approach to the star, which made it possible for the first time to study in detail how conditions in its atmosphere change.

The lead researcher, Tiffany Kataria from NASA's Jet Propulsion Laboratory, noted that hot Jupiters are already considered some of the most extreme exoplanets known, but even among them, HD 80606 b is one of the most extreme.

What the James Webb telescope showed

Using the MIRI (Mid-Infrared Instrument), the telescope was able to analyze the chemical composition of the planet's atmosphere in detail. The observations confirmed that the heating during the close approach to the star was even more intense than previously estimated from Spitzer telescope data.

Kataria added that JWST showed the planet's temperature increase to be even more extreme than they had expected based on Spitzer data.

Significance of the discovery

HD 80606 b has become an ideal object for studying the extreme atmospheres of gas giants. Its highly elongated orbit allows observation of how temperature and atmospheric chemistry change sharply depending on distance from the star. This helps astronomers better understand the processes occurring on such worlds.

The new method of analyzing atmospheric changes depending on orbital position could also be applied to other ultra-hot planets, allowing comparisons of conditions across a larger number of exoplanets.

In brief

The James Webb telescope studied the ultra-hot Jupiter HD 80606 b, whose temperature rises to 600 °C during its close approach to its star. The planet has a highly elongated orbit, leading to sharp changes in its atmosphere. It is one of the most extreme known worlds, serving as a valuable object for studying hot gas giants. The research results were presented at the 248th meeting of the American Astronomical Society.