There is evidence for clouds and haze in the atmosphere surrounding a hot, puffy gas giant planet that is outside the solar system.
The most detailed of its kind to date, the observation, which reveals the presence of specific gas molecules based on tiny decreases in the brightness of precise colors of light, is the most advanced of its kind to date.
While the Hubble Space Telescope has analyzed numerous exoplanet atmospheres over the past two decades, capturing the first clear detection of water in 2013).
WASP-96 b is one of thousands of planets in the universe. It is a type of gas giant that has no analogue in our solar system. WASP-96 b is 1.2 times larger than the Sun and has a mass less than half that of Jupiter. It is much hotter when it is over 1000F. One circuit every 312 Earth-days is how close WASP-96 b is to the Sun.
WASP-96 b is an ideal target for atmospheric observations due to the combination of large size, short orbital period, and puffy atmosphere.
Light from the WASP-96 system was measured for 6.4 hours by the Near-Infrared Imager and Slitless Spectrograph. There is a light curve showing the dimming of starlight during the transit and a transmission spectrum showing the brightness change of individual wavelength of light.
The transmission spectrum reveals previously hidden details of the atmosphere, including the signature of water, indications of haze, and evidence of clouds that were thought not to exist.
A transmission spectrum is made by comparing the starlight from a planet to the starlight from another planet, when the planet is next to the star. The locations and heights of peaks on the graph allow researchers to detect and measure the abundances of key gases in the atmosphere. In the same way that people have unique fingerprints, atoms and Molecules have different patterns of wavelength that they absorb.
The spectrum of WASP-96 b captured by NIRISS is not only the most detailed near-infrared transmission spectrum of an atmosphere captured to date, but it also covers a wide range of wavelengths, including visible red light. This part of the spectrum is sensitive to water as well as other key molecule like oxygen, methane, and carbon dioxide, which are not immediately obvious in the WASP-96 b spectrum.
They can use this information to figure out how the planet came to be. The blue line on the graph is a best-fit model that takes into account the data, the known properties of WASP-96 b and its star.
The design of the measurement is state-of-the-art. The mirror has a gold coating and is 270 square feet in size. Light is spread out into a rainbow of colors. There are subtle differences in brightness. The difference between green and yellow is about 50 microns and the difference between the colors of a few hundred parts per million.
A million miles away from Earth's atmosphere, and with its extreme stability, it is possible to see and analyze clean data in a relatively short time.
The spectrum made by analyzing the entire spectrum at the same time gives a hint of what's to come. Several dozen exoplanets, from small rocky planets to gas- and ice-rich giants, will be analyzed by researchers over the next year. A quarter of the observation time is used to study exoplanets and the materials that make them.
The NIRISS observation shows that it is possible to see the atmospheres of exoplanets.
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