This Planet’s Atmosphere Is Melting – Meet KELT-9b, a Hot Jupiter Exoplanet That ‘Rips Apart’ Own Molecules
According to a report from CNN, new data from the soon-to-be-decommissioned NASA Spitzer Space Telescope has revealed that the exoplanet KELT-9b is hotter than most stars – and the molecules in its atmosphere are constantly being shredded under the intense heat.
Exoplanet KELT-9b belongs to a strange class of exoplanet called "hot Jupiters." Hot Jupiters are gas giants that orbit extremely close to their host star, which superheats the planets' gases. KELT-9b is so hot that its atmosphere includes "vaporized iron and titanium." It completes one orbit of star KELT-9 every 1.5 Earth days and is tidally locked, meaning that it only ever shows one side of itself to the host star (like our moon). During daylight, the hydrogen gas molecules in its atmosphere are torn apart under the intense heat, and can't reconstruct themselves until they reach the nighttime side of the planet – which is only slightly extreme in temperature.
"As the planet gets closer to the star, it feels a burst of starlight, or radiation. The atmosphere becomes a cauldron of chemical reactions, and the winds ramp up far beyond hurricane force," said Greg Laughlin, the co-author on a separate NASA Spitzer study of hot Jupiters.
"This kind of planet is so extreme in temperature, it is a bit separate from a lot of other exoplanets," explained Megan Mansfield, a graduate student at the University of Chicago who is the lead author of this most recent study and paper which has been published in The Astrophysical Journal Letters.
The KELT-9 star system is located near the brightest star in the Cygnus constellation: Deneb, which is about 1,500 light-years away from Earth. The star itself, KELT-9, is a little over 600 light-years away (which gives you some idea of what counts as "close" in space) and is an A-type star. A-type stars are the third-hottest type of main-sequence star; they burn bright blue and consume mostly hydrogen. The star Sirius is one famous example of an A-type star.
The NASA Spitzer Space Telescope was used because it "sees" infrared radiation, which emits heat. It was able to detect the temperature fluctuations on KELT-9b, revealing that the planet even has a "hot spot" on one side.
Learn more about some of the most extreme planets ever discovered – from the real-life version of Hoth to a world with "burning ice" – in the video below.
Cover Image Credits – Composite: NASA/JPL-Caltech and NASA, ESA, and J. Olmsted (STScI) – CC BY 4.0