JWST Watches HD 80606 bExoplanet Heat Up by 1,100 Degrees in Hours

Some 217 light-years away out there in the galaxy is a weird gas giant called HD 80606 b that spends most of its 111-day-long year in deep freeze but for a brief moment comes closer to its star-like sun. The James Webb Space Telescope took this, and scientists discovered that the temperature of this exoplanet had risen by a whopping 1,100 degrees in just a few hours.

A Furnace Built by Orbital Geometry

HD 80606 b is not your average hot Jupiter. The planet is about four times the mass of Jupiter and is in a highly eccentric 111-day orbit that dips from a chilly distance to just 0.03 astronomical units from its host star at periastron. Tiffany Kataria of NASA's Jet Propulsion Laboratory and her team used Webb's MIRI instrument to observe the planet before, during, and after this closest approach, timing the run to coincide with a secondary eclipse. This feat takes years of careful planning. The team presented these results on June 16 at a meeting of the American Astronomical Society to serve as a reference point for future studies of hot Jupiters.

What the Data Revealed

The spectroscopy from Webb allowed researchers to observe the different wavelengths of the light that was emitted by the star, enabling them to monitor how the temperatures and other characteristics of the planet were changing with time. They managed to observe much higher temperatures (up to 1,100 degrees Fahrenheit or 600 degrees Celsius) than expected: “Even more extreme than we expected, based on Spitzer data,” said Kataria. “Now, we see clear signatures of specific molecules like methane and carbon dioxide,” noted Ryan Challener of Cornell University.