HAT-P-26b (IMAGE) University of Maryland Caption The atmosphere of the distant 'warm Neptune' HAT-P-26b, illustrated here, is unexpectedly primitive, composed primarily of hydrogen and helium. By combining observations from NASA's Hubble and Spitzer space telescopes, researchers determined that, unlike Neptune and Uranus, the exoplanet has relatively low metallicity -- an indication of the how rich the planet is in all elements heavier than hydrogen and helium. Credit NASA/GSFC Usage Restrictions None License Licensed 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.