Deep into the Hercules constellation, 855 light-years away from Earth, lies a record breaking exoplanet. This newly discovered gas giant was named TOI-2109b, and the thing that makes it so special is the fact it takes just 16 hours to circle its star, making this the shortest known orbit we have ever recorded. In contrast, Earth takes one year to circle around our sun!
Scientists refer to exoplanets such as these as “hot Jupiters”, due to their close range of orbit to their star. Astronomers have named up to 400 hot Jupiters to date, but this out-of-the-ordinary planet has scientists excited. In a statement to MIT, Avi Shporer, a researcher involved in this project said: “Everything was consistent with it being a planet, and we realized we had something very interesting and relatively rare.”
The paper, published in The Astronomical Journal, used data gathered by NASA’s Transiting Exoplanet Survey Satellite, or TESS for short. The machine, which has been orbiting the Earth since April 2018, has so far discovered numerous exoplanets by tracking changes in light patterns of distant stars. Even from this extraordinary distance, scientists can figure out an array of characteristics about TOI-2109b and its star.
The new discovery is located 1.5 million miles away from its star, nearly 100 times closer than we are here on Earth from the Sun. Also, it is the second hottest exoplanet known, with the sun-facing side of the object reaching a scorching 6,000 degrees Fahrenheit! TOI-2109b’s mass is about five times more than Jupiter, and the star it is circling around is around twice the mass of our Sun.
What makes this planet even more intriguing is its accelerating orbit. It seems like the distance between the star and TOI-2109b is getting smaller and smaller, at a rate that has not been recorded before of between 10 and 750 milliseconds per year. Discoveries such as this are important as allow us to gain a further understanding of phenomena such as orbital decay.
“In one or two years, if we are lucky, we may be able to detect how the planet moves closer to its star,” stated Ian Wong, lead author of the paper. “In our lifetime, we will not see the planet fall into its star. But give it another 10 million years, and this planet might not be there.”
Source study: The Astronomical Journal – TOI-2109: An Ultrahot Gas Giant on a 16 hr Orbit