TW Hydrae (IMAGE) National Radio Astronomy Observatory Caption This is an artist's concept of snow line in TW Hydrae showing water covered ice grains in the inner disk (4.5 -- 30 AU, blue) and CO ice covered grains in the outer disk (>30 AU, green). The transition from blue to green marks the CO snow line. Credit Bill Saxton and Alexandra Angelich, NRAO/AUI/NSF 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.