Scientists from Queen’s University Belfast have led an international team in the discovery of a rare new planet, which is larger than Jupiter and orbits a distant star every 180 days. Named NGTS-38 b, it is an exoplanet—a planet that orbits a star beyond our solar system. It is about 8% larger than Jupiter and almost five times more massive. Planets of this size and mass are often referred to as “super-Jupiters.”
The experts first spotted the planet when analyzing data from NASA’s Transiting Exoplanet Survey Satellite (TESS), which searches for tiny dips in a star’s brightness. These dips happen when a planet passes in front of the star—an event known as a transit.
The scientists say that the 180-day orbit is one of the longest periods ever discovered using this method.
Incredible discovery
Toby Rodel, a Ph.D. student in the School of Mathematics and Physics at Queen’s, led the discovery under the supervision of Professor Christopher Watson. Rodel states, “This has been an incredible discovery. We’re very good at finding planets on very short orbits, close to their stars. So, finding one much farther out at 180 days is a big deal!
“The journey began when the planet was first detected by TESS from just a single transit on Christmas Day 2020. Our team then pointed telescopes from the Next Generation Transit Survey (NGTS) in Chile at the star for more than 200 nights before we caught the final moments of a second transit.
“We were able to measure tiny changes in the star’s movements by splitting up the light from the star. This allowed us to detect the tiny gravitational pull of the planet on its star. Analyzing all this data together, we were able to reveal that the planet completes one orbit—which marks the length of its year—every 180 days.”
The scientists say this is significant because planets on long and wide orbits are much harder to pinpoint because they’re less likely to pass in front of their stars and do so infrequently.
Unique path
Rodel adds, “This planet has a much cooler temperature than most of the other planets we can study in detail so it’s a great opportunity to study what happens to planets at these cooler temperatures.
“Most planets in our solar system have almost circular orbits, but this new planet follows a slightly more unusual and oval-shaped path. At its closest approach, it lies only slightly farther from its star than Mercury is from the sun. At its most distant, it is almost as far away as the Earth is from the sun. However, because its host star is larger and hotter than our sun, the planet is hotter than Earth.
“Because the planet is so massive, it also has a really strong gravitational pull and is far enough away from its star that it might be able to hold on to moons or rings, which is really exciting as we’ve never found moons or rings around any planet outside our solar system.”
Years of detective work
The research has been published in the Monthly Notices of the Royal Astronomical Society. The Queen’s experts led an international team, including scientists from the universities of Leiden, Geneva, Warwick, Birmingham and New Mexico, among others.
Professor Christopher Watson says, “This discovery was the culmination of years of detective work. Because the planet takes around six months to complete each orbit, we only had a small number of opportunities to observe another transit.”
He adds, “Pushing the capability of detecting planets at longer orbital periods is essential if we wish to find another planet like the Earth. This planet is nothing like the Earth, of course, but demonstrates how the game has moved on remarkably over the last two decades.”
Another team, led by Felipe Rojas and Dr. Rafael Brahm from Universidad Adolfo Ibáñez in Santiago, Chile, also independently discovered the system and released their own paper on the arXiv preprint server.
Felipe comments, “This planet stands out among the transiting exoplanets known to date, with a mass of 4.5 Jupiters, a half-year orbit and a mild eccentricity. Worlds like this have barely been explored, and their properties preserve the fingerprints of their formation, making this system a great case for studying the origin of giant planets.”
Publication details
Toby Rodel et al, TIC-65910228 b / NGTS-38 b, a 180 d transiting warm super-Jupiter, Monthly Notices of the Royal Astronomical Society (2026). DOI: 10.1093/mnras/stag1061
Felipe I. Rojas et al, TIC65910228b: A single-transit discovery of a massive long-period warm Jupiter with TESS, arXiv (2026). DOI: 10.48550/arxiv.2602.13125
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Scientists discover rare ‘super-Jupiter’ planet with 180-day long orbit (2026, July 8)
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