Researchers using NASA’s James Webb Space Telescope have detected evidence for quartz nanocrystals in the high-altitude clouds of WASP-17 b, a hot Jupiter exoplanet 1,300 light-years from Earth.
The detection, which was uniquely possible with MIRI (Webb’s Mid-Infrared Instrument), marks the first time that silica (SiO2) particles have been spotted in an exoplanet atmosphere.
The quartz crystals are only about 10 nanometers across, so small that 10,000 could fit side-by-side across a human hair. Their size and composition of pure silica were reported in “JWST-TST DREAMS: Quartz Clouds in the Atmosphere of WASP-17b,” published in Astrophysical Journal Letters.
“Hubble data actually played a key role in constraining the size of these particles. We know there is silica from Webb’s MIRI data alone, but we needed the visible and near-infrared observations from Hubble for context, to figure out how large the crystals are,” said co-author Nikole Lewis, associate professor of astronomy in the College of Arts and Sciences, member of the Carl Sagan Institute and leader of the Webb Guaranteed Time Observation (GTO) program designed to help build a three-dimensional view of a hot Jupiter atmosphere.
Webb observed the WASP-17 system for nearly 10 hours, collecting more than 1,275 brightness measurements of 5- to 12-micron mid-infrared light as the planet crossed its star. By subtracting the brightness of individual wavelengths of light that reached the telescope when the planet was in front of the star from those of the star on its own, the research team was able to calculate the amount of each wavelength blocked by the planet’s atmosphere.
2023-10-16 20:00:05
Article from phys.org rnrn