An Exoplanet So Hot It Has Clouds Made of Quartz

A recent study published in The Astrophysical Journal Letters utilized data from the James Webb Space Telescope’s Mid-Infrared Instrument (MIRI) to discover tiny quartz crystals high up in the atmosphere of exoplanet WASP-17 b.

This exoplanet is about 1,324 light-years away from Earth and is much bigger than Jupiter, with 0.78 times its mass and 1.87 times its radius.

WASP-17 b is what scientists call a “puffy” hot Jupiter because it is really close to its star and only takes 3.7 days to complete an orbit.

This close proximity means it gets especially hot, and this extreme heat can lead to some unusual chemistry in its atmosphere. Even so, the scientists were surprised by what they found.

“We were thrilled!” exclaimed Dr. David Grant, a researcher from the University of Bristol in the UK and the main author of the study. This research involved more than three dozen other scientists as co-authors.

“We knew from Hubble observations that there must be aerosols—tiny particles making up clouds or haze—in WASP-17 b’s atmosphere, but we didn’t expect them to be made of quartz,” stated Dr. David Grant.

Exoplanet atmosphere has only quartz

What makes this discovery special is that up until now, exoplanets were mostly thought to have magnesium-rich silicates, pyroxene, or olivine.

However, the James Webb Space Telescope’s MIRI found something unexpected. There is only quartz in the atmosphere of an exoplanet. This finding could teach us new things about how exoplanet clouds and their atmospheres come into being and change over time, according to Universe Today.

Webb found the 1st evidence of silicon dioxide (silica/quartz) in an exoplanet atmosphere! Webb data shows quartz nanocrystal clouds on WASP-17 b. pic.twitter.com/YDqj87CMn4

— Yogesh Chandel (@Y0GESHCHANDEL) October 16, 2023

On Earth, quartz crystals are typically a few centimeters big, and the biggest one ever found was a massive 6.1 meters long, 1.5 meters wide, and 1.5 meters high, weighing 39,916 kilograms (88,000 pounds).

However, on WASP-17 b, they are tiny at only about ten nanometers across. This is especially small at about one-millionth of a centimeter.

WASP-17 b is extremely hot—around 1,500 degrees Celsius

WASP-17 b is incredibly hot, with temperatures soaring to about 1,500 degrees Celsius (2,700°F). The pressure in its atmosphere is about one-thousandth of what we experience on Earth’s surface, explained Dr. Grant.

In these extreme conditions, solid crystals can form directly from the gas without first becoming a liquid, he further added.

This planet was discovered back in 2009, and it is quite unique. Specifically, it is known to travel in a “retrograde” orbit. This means it orbits in the opposite direction of its star’s rotation.

In 2013, scientists detected water in its atmosphere, and another study revealed the presence of sodium. Even though WASP-17 b is smaller than Jupiter, it is really puffy, and it takes up more space than seven Jupiters combined.