Exoplanets: Super-Earths apparently much more common than assumed
Super-Earths are exoplanets that are much larger than our home, but smaller than Neptune and Uranus. They are likely much more common than assumed so far.
Artistic representation of a super earth
(Image: NASA)
There should be at least one super-Earth around every third star, orbiting as far away as Jupiter orbits our sun. This has been determined by an international research team based on a possible discovery of an exoplanet and a larger sample. This means that these exoplanets, which are more massive than the Earth and lighter than ice giants such as Neptune and Uranus, would be much more widespread than previously assumed. The finding therefore also suggests that super-Earths and gas giants are formed by different formation processes, but more research is needed to provide conclusive answers.
Insights into the formation of planets
For the work now presented, the research team led by Andrew Gould from Ohio State University used the microlensing method to search for exoplanets. This utilizes the so-called microlensing effect, which ensures that a massive object directly in front of a star minimally deflects its light and thus appears to brighten it. If they are correctly aligned, exoplanets can be found that are too far away from their star to be detected using other methods. Gould's team used this method to find the exoplanet OGLE-2016-BLG-0007, a super-Earth that is further away from its star than Saturn is from the Sun.
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Together with the evaluation of a larger survey of microlensing measurements, the discovery of the exoplanet therefore suggests that such celestial bodies must be much more common than previous analyses have suggested. At the same time, it is now easier to distinguish between these super-Earths and the much larger gas giants. This should now also help with further research into the formation of the two types of planets, as two competing theories could still apply. “We are like paleontologists who are not only researching the history of the universe, but also the processes that control it,” explains Richard Pogge, another co-author. The work was published in the scientific journal Science.
(mho)
