Astronomers have discovered a rare giant planet outside our solar system that could help scientists better understand how large planets form and evolve.
The newly found world, called NGTS-38 b, is about 8% larger than Jupiter and nearly five times as massive. Because of its huge size, it is known as a “super-Jupiter.”
The discovery was led by scientists from Queen’s University Belfast, working with researchers from several universities around the world.
Their findings have been published in the Monthly Notices of the Royal Astronomical Society.
NGTS-38 b is an exoplanet, which means it is a planet that orbits a star other than our sun. What makes this planet especially interesting is that it takes about 180 days to complete one orbit around its star.
This is one of the longest orbital periods ever found using the transit method, a popular way of discovering exoplanets.
The journey began on Christmas Day in 2020 when NASA’s Transiting Exoplanet Survey Satellite (TESS) detected a single small dip in the brightness of a distant star. This tiny drop in light suggested that a planet had passed in front of the star, briefly blocking some of its light.
However, seeing only one transit was not enough to confirm the planet. The research team then used telescopes from the Next Generation Transit Survey (NGTS) in Chile to watch the same star for more than 200 nights.
After months of careful observation, they finally caught part of a second transit, confirming the planet’s long orbit.
The scientists also studied the star’s light in great detail to measure tiny movements caused by the planet’s gravity. These measurements allowed them to calculate the planet’s size, mass, and orbit.
Finding planets with long orbits is much more difficult than finding planets that circle close to their stars. Short-orbit planets pass in front of their stars more often, giving astronomers many chances to spot them. In contrast, a planet that takes six months to complete one orbit may only pass in front of its star a few times, making it much easier to miss.
NGTS-38 b also follows a slightly oval-shaped orbit instead of a nearly circular one. At its closest point, it is a little farther from its star than Mercury is from the sun. At its farthest point, it is almost as far away as Earth is from the sun.
Even so, the planet is still hotter than Earth because its host star is larger and hotter than our sun.
Researchers believe this giant planet may even be able to hold onto moons or rings because of its strong gravity and its greater distance from its star. Although no exoplanet has yet been confirmed to have moons or rings, NGTS-38 b could become an exciting target for future observations.
Scientists say discoveries like this show how far planet-hunting technology has advanced. By finding more planets with long orbits, researchers hope to improve their chances of eventually discovering worlds that are more like Earth and learning more about how planetary systems develop across our galaxy.
