James Webb finds carbon dioxide on an exoplanet for the first time
The discovery was made during an observation of a gas giant planet orbiting a Sun-like star 700 light years away. The finding suggests that Webb may be able to detect and measure carbon dioxide in the thinner atmospheres of smaller rocky planets too. WASP-39 b is a hot gas giant with a mass roughly one-quarter that of Jupiter (about the same as Saturn) and a diameter 1.3 times greater than Jupiter. Its extreme size is related in part to its high temperature (about 900°C). Unlike the cooler, more compact gas giants in our solar system, WASP-39 b orbits very close to its star – only about one-eighth the distance between the Sun and Mercury – completing one circuit in just over four Earth days. The planet’s discovery, reported in 2011, was made based on ground-based detections of the subtle…