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- Super-Earths are intriguing exoplanets. They are larger than Earth but smaller than Neptune. Astronomers say there are many in our galaxy, even though there aren’t any in our own solar system.
- Astronomers have found a new super-Earth far out from its star, similar to Saturn’s orbit around the sun. Until now, we’d only seen these types of planets closer to their stars. The planet was discovered as part of a larger study on exoplanets.
- So super-Earths can exist at various distances from their stars,. This result suggests they are likely even more common in our galaxy than previously thought.
Super-Earth exoplanets are surprisingly common
Super-Earth exoplanets are unlike any planets in our own solar system. They’re larger and more massive than Earth but smaller than Neptune. Those found so far were in orbits close to their stars. But on April 24, 2025, an international team of researchers said super-Earths can exist as far from their stars as the gas giants are from the sun in our solar system. That’s based on a recent discovery of a new super-Earth with an orbit similar to Saturn’s, our sun’s 6th planet. The result means that super-Earths must be more common in our home galaxy, the Milky Way, than scientists had thought.
Why didn’t we know before? It’s easier to detect planets orbiting close to their stars than those that are farther out. This includes super-Earths. So, until now, more close-in super-Earths were found. But many wondered if super-Earths could also reside in larger orbits. We now know the answer is yes. The team of researchers that detected a super-Earth with a Saturn-like orbit dubbed it OGLE-2016-BLG-0007.
Lead author Weicheng Zang at the Center for Astrophysics | Harvard and Smithsonian in Cambridge, Massachusetts, said:
We found a ‘super Earth’ – meaning it’s bigger than our home planet but smaller than Neptune – in a place where only planets thousands or hundreds of times more massive than Earth were found before.
The researchers published their peer-reviewed findings in the journal Science on April 24, 2025.
Center for Astrophysics | Harvard & Smithsonian (CfA): Astronomers Find Far-flung “Super Earths” Are Not Farfetched cfa.harvard.edu/news/astrono…
— AAS Press Office (@press.aas.org) 2025-04-24T23:54:50.490Z
Microlensing reveals new exoplanet
The astronomers found the planet using microlensing data from the Korea Microlensing Telescope Network (KMTNet). Microlensing is when an object, such as a planet or another star, passes in front of a background star. The gravity of the foreground object amplifies the light coming from the star. Astronomers can use that increase in brightness to help find faint planets. Three telescopes – in Chile, South Africa and Australia – were a part of the discovery.
The data provide new clues about how colder planets, those farther from their stars, form. Co-author Shude Mao at Tsinghua University and Westlake University in China said:
The current data provided a hint of how cold planets form. In the next few years, the sample will be a factor of four larger, and thus we can constrain how these planets form and evolve even more stringently with KMTNet data.
It’s an exciting result, especially since microlensing is difficult. Co-author Richard Pogge at Ohio State university said:
Finding a microlensing star event is hard. Finding a microlensing star with a planet is hard-squared. We have to look at hundreds of millions of stars to find even a hundred of these things.
Super-Earth exoplanets are common
The discovery of this new super-Earth is part of a larger study the astronomers conducted. The study compared the masses of many exoplanets with the stars they orbit. The results – including the super-Earth discovery – suggest that super-Earths are common in the outer regions of planetary systems as well as the inner regions. Which means, of course, that they are common overall throughout our galaxy. As co-author Jennifer Yee at the Smithsonian Astrophysical Observatory – which is part of the Center for Astrophysics – said:
This measurement of the planet population from planets somewhat larger than Earth all the way to the size of Jupiter and beyond shows us that planets, and especially super-Earths, in orbits outside the Earth’s orbit are abundant in the galaxy.
Planetary systems unlike our own
And since our solar system doesn’t have any super-Earths, this also means that many planetary systems are distinctly different from our own. Co-author Youn Kil Jung at the Korea Astronomy and Space Science Institute added:
This result suggests that in Jupiter-like orbits, most planetary systems may not mirror our solar system.
Notably, the study also suggests that super-Earths are just as common as Neptune-sized planets. The findings provide new clues about both super-Earths and exoplanet formation in general. As Pogge noted:
We’re like paleontologists reconstructing not only the history of the universe we live in but the processes that govern it. So helping to bring both of those pieces together into one picture has been enormously satisfying.
Enigmatic and weird worlds
Super-Earths are enigmatic worlds. Generally, they are thought to be rocky, like Earth, but larger and more massive. Evidence suggests they tend to have thinner, more Earth-like atmospheres than mini-Neptunes, which have deep hydrogen atmospheres. Some might have global oceans, with no continents. Or oceans hidden beneath crusts of ice, much like Europa or Enceladus. And others might be weirder, so-called “eyeball planets.” LHS 1140 b could be one of these, with a circular ocean surrounded by ice, making it look like a giant eyeball.
Bottom line: The discovery of a super-Earth orbiting farther from its star than Saturn orbits the sun suggests that super-Earth exoplanets are common in our galaxy.
Source: Microlensing events indicate that super-Earth exoplanets are common in Jupiter-like orbits
Via Center for Astrophysics | Harvard & Smithsonian
Via Ohio State University
Read more: Eyeball ocean world? Webb reveals an intriguing super-Earth
Read more: Super-Earths may have long-lasting oceans
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