Are 'mega-Earths' real? Stellar activity may explain these oversized rocky worlds

A new study suggests that some of the heaviest rocky planets ever reported may not be as heavy as they look. These so-called 'mega-Earths,' rocky planets weighing more than about 10 Earths, could be an illusion created by activity on their host stars. The paper was posted to the arXiv preprint server on Oct. 8.