Ohio Against the Universe

Forget clashes between the Buckeyes and That Team Up North. For space nerds, the real win this weekend was Ohio against the universe.

While the rest of Buckeye Nation was busy crossing out the letter “M,” a planet discovered by a team co-led by Ohio State University astronomers spent last week crushing other planets in an international, intergalactic competition known as the ExoCup. The ExoCup, hosted by a trio of scientists who host a podcast devoted to exoplanets, is a friendly March Madness-style competition that lands the winner the right to claim “best planet outside our solar system.”

“I did not think we were going to make it out of the first round,” said Scott Gaudi, professor of astronomy at The Ohio State University and a leader of the study that identified the planet. “It’s been fun.”

The planet Gaudi and his team discovered is a gas giant nearly twice the size of Jupiter that is almost as hot as our own sun. Planet KELT-9b orbits a star more than 600 light years from Earth in the constellation Cygnus, sometimes also called The Swan, which is visible during summer and fall in the northern sky.

To win the ExoCup finals, KELT-9b had to prevail over four rounds against other planets, including a finals win against PDS 70b, a very young planet that researchers witnessed being “born” earlier this year. Voters cast ballots on Twitter – KELT-9b ended the competition on Friday with 51 percent of the vote.

“May the hottest planet win – and that planet is without a doubt KELT-9b,” Gaudi quipped before the finals.

KELT-9b’s daytime temperature is a balmy 4,600 Kelvin (about 7,800 degrees Fahrenheit) and only 1,700 degrees cooler than our solar system’s sun. It is so hot that astronomers believe there are no solids on KELT-9b – only gases such as hydrogen and helium. In addition to hydrogen and helium, KELT-9b’s atmosphere likely contains gaseous titanium and iron.

“It is literally hotter than most stars,” Gaudi said.

And, because it is latched to its star – a star christened KELT-9, a star twice as large and nearly twice as hot as our own – KELT-9b, with an orbital period of only about 1.5 days, is under constant threat of evaporation.

Gaudi and his co-authors, who include astronomers from Vanderbilt and Lehigh Universities, first reported the new planet in a June 2017 issue of the journal Nature and at a presentation at the American Astronomical Society’s spring meeting.

“It’s a planet by any of the typical definitions based on mass, but its atmosphere is almost certainly unlike any other planet we’ve ever seen just because of the temperature of its day side,” Gaudi said at the time.

As the finals votes came in last week, planet hunters on Twitter debated the merits of each planet, and the telescopes used to find each. KELT-9b was discovered with the equivalent of camera lens; PDS 70b was found through the Gemini telescope in Chile.

In the end, the Buckeye planet was victorious.

"Hats off to a worthy finals adversary: PDS 70b,” Gaudi said. “Thanks to the KELT team and our family of professional and amateur scientists who helped discover KELT-9b. Finally, thanks to everyone out there for voting in the 2018 ExoCup, and reminding us all how exciting exoplanets are!"

This story was updated from a previous version.