Thousand-mile-per-hour winds are blowing a hail of tiny quartz crystals through the silicate-enhanced, scorching hot atmosphere of a distant gas giant planet called WASP-17b, the James Webb Space Telescope (JWST) has found.
“We knew from Hubble [Space Telescope] observations that there should be aerosols — tiny particles making up clouds or haze — in WASP-17b’s atmosphere, but we didn’t expect them to be product of quartz,” Daniel Grant of the University of Bristol within the UK and leader of a brand new study on the invention, said in a statement.
WASP-17b is an incredible world. Orbiting every 3.7 days at a distance of just 7.8 million kilometers (4.9 million miles) from its star, which sits 1,300 light years away from Earth, WASP-17b is so near its stellar host that its dayside temperature rises to a staggering 1,500 degrees Celsius (roughly 2,700 degrees Fahrenheit). Since the atmosphere is so hot on this exoplanet, the world has actually expanded to about 285,000 kilometers (176,892 miles) across, which is just shy of twice the diameter of Jupiter. And that is despite WASP-17b having only about half of Jupiter’s overall mass. WASP-17b is one among the “puffiest” planets known — and its bloated atmosphere makes it a fantastic goal for the James Webb Space Telescope.
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Grant and fellow astronomers watched WASP-17b transit its star using the JWST’s Mid-Infrared Instrument (MIRI). Because the exoplanet moved in front of its star from the JWST’s viewpoint, MIRI detected starlight that was blocked by the puffy planet itself but partially absorbed by the world’s atmosphere. Such measurements lead to a so-called transmission spectrum, whereby certain wavelengths are blocked out by particular atmospheric molecules.
Like Jupiter, WASP-17b gave the impression to be mostly made out of hydrogen and helium. As well as, MIRI detected carbon dioxide, water vapor and, at a wavelength of 8.6 microns, the absorption signature of pure quartz crystals. Combined with previous observations with the Hubble Space Telescope, these crystals are judged to be shaped like the identical pointy, hexagonal prisms as quartz is on Earth, but only a meager 10 nanometers in size.
Quartz is a type of silicate, that are minerals wealthy in silica and oxygen. Silicates are exceptionally common — all of the rocky bodies within the solar system are made out of them, and silicates have previously been detected within the atmospheres of hot Jupiter exoplanets before. Nonetheless, in those cases they’d been more complex, magnesium-rich crystals of olivine and pyroxene.
“We fully expected to see magnesium silicates,” said Bristol’s Hannah Wakeford. “But what we’re seeing as an alternative are likely the constructing blocks of those, the tiny seed particles must form the larger silicate grains we detect in cooler exoplanets and brown dwarfs.”
WASP-27b can also be tidally locked, meaning it all the time shows the identical face to its star. As winds whip across the planet, carrying along the quartz nanoparticles, they form high-altitude hazes — essentially diffuse clouds of rock crystals — on the day–night termination zone. Those hazes then enterprise into the dayside, and are vaporized in the warmth.
Grant explained how crystals of silicate come to be embedded in a planetary atmosphere in the primary place.
“WASP-17b is amazingly hot … and the pressure where the quartz crystals form high within the atmosphere is just about one-thousandth of what we experience on Earth’s surface,” he said. “In these conditions, solid crystals can form directly from gas, without going through a liquid phase first.”
The findings were published in October in Astrophysical Journal Letters.