Mini-Neptunes with an elliptical orbits (IMAGE) National Institutes of Natural Sciences Caption Diagram of discovered exoplanet orbits. The orbits of exoplanets close to their parent stars tend to become circular over time, but three of the newly discovered exoplanets, except the bottom left, have maintained elliptical orbits despite being over a billion years old. Credit Astrobiology Center Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.