Home Science Space Exoplanet With 18-Hour Orbit Around Its Sun on Edge of Destruction

Exoplanet With 18-Hour Orbit Around Its Sun on Edge of Destruction

Astronomers have observed an exoplanet orbiting a star in just over 18 hours, the shortest orbital period ever observed for a planet of its type. It means that a single year for this hot Jupiter — a gas giant similar in size and composition to Jupiter in our own solar system — passes in less than a day of Earth time.

The discovery is detailed in a new paper published for the Monthly Notices of the Royal Astronomical Society and the scientists believe that it may help to solve a mystery of whether or not such planets are in the process of spiraling toward their suns to their destruction.

The planet NGTS-10b was discovered around 1000 light-years away from Earth as part of the Next-Generation Transit Survey (NGTS), an exoplanet survey based in Chile that aims to discover planets down to the size of Neptune using the transit method. This involves observing stars for a telltale dip in brightness that indicates that a planet has passed in front of it. At any one time, the survey observes 100 square degrees of the sky, which includes around 100,000 stars.

Out of those 100,000 stars, this one caught the astronomers’ eye due to the very frequent dips in the star’s light caused by the planet’s rapid orbit. Lead author Dr. James McCormac, from the University of Warwick Department of Physics, said:

NGTS-10b orbits so rapidly because it is very close to its sun — only twice the diameter of the star which, in the context of our solar system, would locate it 27 times closer than Mercury is to our own Sun. The scientists have noted that it is perilously close to the point that tidal forces from the star would eventually tear the planet apart.

The planet NGTS-10b was discovered around 1000 light-years away from Earth as part of the Next-Generation Transit Survey (NGTS), an exoplanet survey based in Chile that aims to discover planets down to the size of Neptune using the transit method. This involves observing stars for a telltale dip in brightness that indicates that a planet has passed in front of it. (Image: University of Warwick)

The planet is likely tidally locked so one side of the planet is constantly facing the star and constantly hot — the astronomers estimate the average temperature to be more than 1000°C. The star itself is around 70 percent the radius of the Sun and 1000 degrees cooler than the Sun, about 4000 degrees. NGTS-10b is also an excellent candidate for atmospheric characterisation with the upcoming James Webb Space Telescope.

Using transit photometry, the scientists know that the planet is 20 percent bigger than our Jupiter and just over twice the mass according to radial velocity measurements, caught at a convenient point in its lifecycle to help answer questions about the evolution of such planets.

Massive planets typically form far away from the star and then migrate either through interactions with the disc while the planet is still forming, or from interactions with additional planets much further out later in their life. The astronomers plan to apply for time to get high-precision measurements of NGTS-10b, and to continue observing it over the next decade to determine whether this planet will remain in this orbit for some time to come — or will spiral into the star to its death. Co-author Dr. David Brown adds:

Co-author Dr. Daniel Bayliss said:

Provided by: University of Warwick [Note: Materials may be edited for content and length.]

Like this article? Subscribe to our weekly email for more!     



  • Troy was born and raised in Australia and has always wanted to know why and how things work, which led him to his love for science. He is a professional photographer and enjoys taking pictures of Australia's beautiful landscapes. He is also a professional storm chaser where he currently lives in Hervey Bay, Australia.

Most Popular