Very hot planet discovered orbiting an even larger, hotter star

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Move over Jupiter, because there is a new gas giant in town, with astronomers having found a gas planet that is hotter than most stars. Scientists are confident that KELT-9b is the hottest gas planet they have ever found. Whilst the planet itself emanates a large amount of heat, its’ star, a blue A-Type star named KELT-9, is even hotter; so hot in fact that it is consuming 9b through evaporation.

The giant planet is 2.8 times larger than Jupiter but only half as dense due to its’ atmosphere being puffed up by its’ proximity to its’ star. A year on 9b is the equivalent of two Earth days, and the properties exhibited on the planet suggest little to no life could survive on the planet. Following the trend, KELT-9 is also quite large, with the star more than twice the size of our sun, and also relatively young, with astronomers placing its’ age at roughly 300 million years old.

KELT-9b orbiting host star, hottest exoplanet found — Illustration of KELT-9b orbiting host start. Courtesy NASA/JPL-Caltech

The star’s immense power and closeness to the gas planet are directly to blame for its’ hot temperatures and size, which scientists believe will eventually be the downfall of the planet. Paper co-author and Vanderbilt University’ Keivan Stassun, explains more:

“KELT-9 radiates so much ultraviolet radiation that it may completely evaporate the planet. KELT-9 will swell to become a red giant star in a few hundred million years. The long-term prospects for life, or real estate for that matter, on KELT-9b are not looking good.”

KELT-9 and its’ hot gas planet were initially discovered by one of the two Kilodegree Extremely Little Telescope (KELT) operating in the United States in 2016. The planet itself was detected after astronomers noticed a slight dimming in the star’s brightness every 1.5 days, the planet’s “yearly” orbit time. Once its’ existence was hypothesized, scientists worked together using KELT technology to prove it. The results and findings of their research published this week in the journal Nature, a feat that KELT technician and astronomer Joshua Pepper says rests on the scientific field’s ability to work together.

“This discovery is a testament to the discovery power of small telescopes, and the ability of citizen scientists to directly contribute to cutting-edge scientific research.”

A rare sight that had yet to be observed by astronomers, the intriguing relationship between both the star and the planet illustrates the depth of knowledge scientists are hoping to fill as they continue to scour the universe for never before seen phenomena.