Gas Giant Planet HD 209458b (IMAGE) NASA/Goddard Space Flight Center Caption This is an artistic illustration of the gas giant planet HD 209458b in the constellation Pegasus. To the surprise of astronomers, they have found much less water vapor in the hot world's atmosphere than standard planet-formation models predict. Credit NASA, ESA, G. Bacon (STScI) and N. Madhusudhan (UC) 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.