Astronomers Discover Alien World Hotter Than Most Stars (vanderbilt.edu)

Science_afficionado writes: An international team of astronomers has discovered a planet like Jupiter zipping around its host star every day and a half, boiling at temperatures hotter than most stars and sporting a giant, glowing gas tail like a comet. From a report via Vanderbilt University: "With a day-side temperature peaking at 4,600 Kelvin (more than 7,800 degrees Fahrenheit), the newly discovered exoplanet, designated KELT-9b, is hotter than most stars and only 1,200 Kelvin (about 2,000 degrees Fahrenheit) cooler than our own sun. In fact, the ultraviolet radiation from the star it orbits is so brutal that the planet may be literally evaporating away under the intense glare, producing a glowing gas tail. The super-heated planet has other unusual features as well. For instance, it's a gas giant 2.8 times more massive than Jupiter but only half as dense, because the extreme radiation from its host star has caused its atmosphere to puff up like a balloon. Because it is tidally locked to its star -- as the moon is to Earth -- the day side of the planet is perpetually bombarded by stellar radiation and, as a result, it is so hot that molecules such as water, carbon dioxide and methane can't form there." The findings have been published in the journal Nature.

Comments

So, the largest planet ever discovered?

[Anonymous Coward]

If those numbers are correct and "density" refers to the mean density over the entire planet, then that would make this the largest planet ever discovered at 7.6 times the radius of Jupiter. As far as I can tell the record was HD 100546 b at 6.9 times the size of Jupiter. Odd that the neither the article nor the summary mentions breaking that record. In light of that, I have a suspicion that someone reported the numbers incorrectly and that it's only 1.8 times the mass of Jupiter. Maybe I missed it but I can't spot the actual mass or size in the article anywhere.