James Webb Space Telescope Feed Post

NASA’s Webb Maps Weather on Planet 280 Light-Years Away (Artist Concept)

Looking for a 5-day forecast? One side of planet WASP-43 b is constantly illuminated by its star, the other in permanent darkness. Webb tells us this gas giant is clear on its dayside and cloudy on its nightside, with equatorial winds of 5,000 miles per hour. WASP-43 b is what is known as a hot Jupiter: smaller than Jupiter, made primarily of hydrogen and helium, and hotter than any of our solar system’s gas giants. This planet orbits its small, cool star closely at 1/25th the distance between Mercury and the Sun, making it tidally locked. Previously, Hubble showed water vapor on the dayside, and along with Spitzer, suggested clouds on the nightside. Webb's precise data demonstrates clear signs of water vapor on both sides of WASP-43 b, and provides new information about temperature, cloud cover, winds, and atmospheric composition. One surprising discovery: Scientists expected to see methane on WASP-43 b’s nightside, yet none could be found. The team believes high wind speeds (of 5,000 miles per hour or more) could be the cause — moving gas around the planet too fast for chemical reactions to produce detectable amounts of methane. Learn more: science.nasa.gov/missions/webb/nasas-webb-maps-weather-on... Artist Concept Credit: NASA, ESA, CSA, Ralf Crawford (STScI) Image Description: Illustration showing a hazy blue planet against the black background of space. The planet is in the left side of the frame. The axis is tilted roughly 20 degrees counter-clockwise from vertical. The eastern side (right half) is lit by a star out of view and the western side (left half) is in shadow. The terminator (the boundary between the day and night sides) is fuzzy. There are white patchy clouds visible on the dayside, near the terminator, along the equator, that appear to be originating from the nightside. Image & Description by NASA