NASA’s James Webb Space Telescope has identified water in the atmosphere of a hot, puffy gas giant planet orbiting a Sun-like star over a thousand light-years away, the space agency announced today.
According to NASA, the observation is the most thorough of its kind to date, proving Webb’s unmatched ability to analyse distant atmospheres. WASP-96 b is one of the Milky Way’s more than 5,000 known exoplanets.
It is located approximately 1,150 light-years distant in the southern-sky constellation Phoenix. According to the agency, it represents a form of gas giant with no direct equivalent in our solar system.
WASP-96 b is far chubbier than any planet orbiting our Sun, with a mass less than half that of Jupiter and a diameter 1.2 times larger. It is substantially hotter when the temperature exceeds 538 degrees Celsius.
According to NASA, WASP-96 b orbits its Sun-like star at one-ninth the distance between Mercury and the Sun, completing one cycle every three and a half Earth days.
WASP-96 b is an excellent target for atmospheric investigations due to its massive size, short orbital period, thick atmosphere, and lack of polluting light from surrounding objects in the sky.
While the Hubble Space Telescope has studied numerous exoplanet atmospheres over the last two decades, Webb’s detailed observation represents a significant step forward in characterising potentially habitable planets beyond Earth.
Webb’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) monitored light from the WASP-96 system for 6.4 hours on June 21 as the planet passed across the star.
This produced a light curve depicting the overall lowering of starlight throughout the transit and a transmission spectrum displaying the brightness shift of various wavelengths of infrared radiation ranging from 0.6 to 2.8 microns.
The light curve confirmed properties of the planet that had already been determined from other observations – the planet’s existence, size, and orbit.
The transmission spectrum revealed previously unknown characteristics of the atmosphere, such as the unmistakable signature of water, haze, and evidence of clouds that were once considered not to exist based on earlier observations.
WASP-96 b’s spectrum is not only the most detailed near-infrared transmission spectrum of an exoplanet atmosphere ever captured, but it also covers an impressively broad wavelength range, including visible red light and a portion of the spectrum not previously accessible from other telescopes, according to NASA.
Researchers can utilise the spectrum to estimate the atmosphere’s temperature with depth, measure the amount of water vapour in the atmosphere, constrain the abundance of specific elements such as carbon and oxygen, and measure the amount of water vapour in the atmosphere.
They can then utilise this knowledge to conclude the planet’s overall composition and how, when, and where it originated.
