HD 189733b Exoplanet Animation

ANIMATION Using NASA’s Hubble Telescope, scientists detected a stratosphere on the planet WASP-33b. A stratosphere occurs when molecules in the atmosphere absorb ultraviolet and visible light from the star. This absorption warms the stratosphere and acts as a kind of sunscreen layer for the planet below.Watch this video on YouTube. ILLUSTRATION WASP-33b’s stratosphere was detected by measuring the drop in light as the planet passed behind its star (top). Temperatures in the low stratosphere rise because of molecules absorbing radiation from the star (right). Without a stratosphere, temperatures would cool down at higher altitudes (left). STILL IMAGE Artist concept of the giant planet WASP-33b transiting its sun, the Delta Scuti variable star WASP-33 (HD 15082). Using NASA’s Hubble Space Telescope, scientists have detected a stratosphere, one of the primary layers of Earth’s atmosphere, on a massive and blazing-hot exoplanet known as WASP-33b.The presence of a stratosphere can provide clues about the composition of a planet and how it formed. This atmospheric layer includes molecules that absorb ultraviolet and visible light, acting as a kind of “sunscreen” for the planet it surrounds. Until now, scientists were uncertain whether these molecules would be found in the atmospheres of large, extremely hot planets in other star systems.Learn more on NASA.gov. For More InformationSee [NASA.gov](http://www.nasa.gov/press-release/nasa-s-hubble-telescope-detects-sunscreen-layer-on-distant-planet) Related pages

Alien Atmospheres Although most of the planets outside of our solar system (called "exoplanets") are too distant to be seen, astronomers have developed indirect methods to determine their size, mass, and even their atmospheric makeup - taking us one step closer to finding a world like our own.Watch this video on the NASAexplorer YouTube channelFor complete transcript, click here. Exoplanet Animation - Transit Light CurveWhen a planet crosses directly between us and its star, we see the star dim slightly because the planet is blocking out a portion of the light. We can make a plot called a light curve with the brightness of the star versus time. Using this plot, we can see what percentage of the star's light the planet blocks and how long it takes the planet to cross the disk of the star. Larger planets block out more light. Exoplanet Animation - AbsorptionThe molecules in a planet's atmosphere absorb certain wavelengths of a star's transmitted light. We can see this absorption as the planet transits the star's disk, and we can thus identify the molecules in the planet's atmosphere. This version of the animation includes "absorbed" and "transmitted" labels. Exoplanet Animation - Absorption without labelsThe molecules in a planet's atmosphere absorb certain wavelengths of a star's transmitted light. We can see this absorption as the planet transits the star's disk, and we can thus identify the molecules in the planet's atmosphere. This version of the animation does not include labels. Exoplanet Animation - Transit Depth vs WavelengthAn individiual planetary transit can appear different when observing the star at different wavelengths. That's because a planet's atmosphere blocks out more light at some wavelengths and less light at other wavelengths. Studying these differences in transit depths can reveal information about the composition, size, and density of the transiting planet's atmosphere. Exoplanet Image - Crescent TransitThis planet is about to cross in front of its star. Credit: ESA/Hubble Exoplanet Image - LimbAn exoplanet's atmosphere can filter out certain wavelengths of its star's light. Exoplanet Image - Atmospheric DepthTransit methods can help us determine the depth of an exoplanet's atmosphere as it passes in front of its star. Exoplanet Image - WASP-19b Transit Depth Curve and MolecluesExoplanet WASP-19b is a "hot Jupiter", a gas giant that orbits close to its star. Analyzing its transit across different wavelengths shows varying transit depths. This variation indicates high abundance of hydrocarbons like methane and hydrogen cyanide in the planet's thick atmosphere, and low abundance of water - probably not your next vacation destination! Exoplanet Image - WASP-19b Transit Depth CurveExoplanet WASP-19b is a "hot Jupiter", a gas giant that orbits close to its star. Analyzing its transit across different wavelengths shows varying transit depths. This variation indicates high abundance of hydrocarbons like methane and hydrogen cyanide in the planet's thick atmosphere, and low abundance of water - probably not your next vacation destination! Since the early 1990's, astronomers have known that extrasolar planets, or "exoplanets," orbit stars light-years beyond our own solar system. Although most exoplanets are too distant to be directly imaged, detailed studies have been made of their size, composition, and even atmospheric makeup - but how? By observing periodic variations in the parent star's brightness and color, astronomers can indirectly determine an exoplanet's distance from its star, its size, and its mass. But to truly understand an exoplanet astronomers must study its atmosphere, and they do so by splitting apart the parent star's light during a planetary transit. For More InformationSee [http://www.nasa.gov/content/goddard/hubble-traces-subtle-signals-of-water-on-hazy-worlds/](http://www.nasa.gov/content/goddard/hubble-traces-subtle-signals-of-water-on-hazy-worlds/) Related pages

Short narrated videoFor complete transcript, click here. This artist's rendering illustrates the evaporation of HD 189733b's atmosphere in response to a powerful eruption from its host star. NASA's Hubble Space Telescope detected the escaping gases and NASA's Swift satellite caught the stellar flare. Swift's Ultraviolet/Optical Telescope captured this view of HD 189733b's host star on Sept. 14, 2011. The image is 6 arcminutes across. Credit: NASA/Swift/Stefan Immler Strong X-ray emission makes the host star of HD 189733b stand out in this view from Swift's X-Ray Telescope. The image combines data from Sept. 13 and 14, 2011, and is 6 arcminutes across. Credit: NASA/Swift/Stefan Immler An international team of astronomers using data from NASA's Hubble Space Telescope has detected significant changes in the atmosphere of a planet located beyond our solar system. The scientists conclude the atmospheric variations occurred in response to a powerful eruption on the planet's host star, an event observed by NASA's Swift satellite.The exoplanet is HD 189733b, a gas giant similar to Jupiter, but about 14 percent larger and more massive. The planet circles its star at a distance of only 3 million miles, or about 30 times closer than Earth's distance from the sun, and completes an orbit every 2.2 days. Its star, named HD 189733A, is about 80 percent the size and mass of our sun.Astronomers classify the planet as a "hot Jupiter." Previous Hubble observations show that the planet's deep atmosphere reaches a temperature of about 1,900 degrees Fahrenheit (1,030 C).HD 189733b periodically passes across, or transits, its parent star, and these events give astronomers an opportunity to probe its atmosphere and environment. In a previous study, a group led by Lecavelier des Etangs used Hubble to show that hydrogen gas was escaping from the planet's upper atmosphere. The finding made HD 189733b only the second-known "evaporating" exoplanet at the time.The system is just 63 light-years away, so close that its star can be seen with binoculars near the famous Dumbbell Nebula. This makes HD 189733b an ideal target for studying the processes that drive atmospheric escape.When HD 189733b transits its star, some of the star's light passes through the planet's atmosphere. This interaction imprints information on the composition and motion of the planet's atmosphere into the star's light.In April 2010, the researchers observed a single transit using Hubble's Space Telescope Imaging Spectrograph (STIS), but they detected no trace of the planet's atmosphere. Follow-up STIS observations in September 2011 showed a surprising reversal, with striking evidence that a plume of gas was streaming away from the exoplanet.The researchers determined that at least 1,000 tons of gas was leaving the planet's atmosphere every second. The hydrogen atoms were racing away at speeds greater than 300,000 mph. Because X-rays and extreme ultraviolet starlight heat the planet's atmosphere and likely drive its escape, the team also monitored the star with Swift's X-ray Telescope (XRT). On Sept. 7, 2011, just eight hours before Hubble was scheduled to observe the transit, Swift was monitoring the star when it unleashed a powerful flare. It brightened by 3.6 times in X-rays, a spike occurring atop emission levels that already were greater than the sun's. Astronomers estimate that HD 189733b encountered about 3 million times as many X-rays as Earth receives from a solar flare at the threshold of the X class. For More InformationSee [http://www.nasa.gov/topics/universe/features/exoplanet-atmosphere.html](http://www.nasa.gov/topics/universe/features/exoplanet-atmosphere.html) Related pages