Bilgesu Erdem
Recent findings showcase a rare atmospheric component in the universe, quartz crystals, in the atmosphere of WASP-17 b, a hot Jupiter exoplanet situated 1,300 light-years away. This discovery comes from data obtained by NASA’s James Webb Space Telescope, marking the first-ever identification of silica (SiO2) particles in an exoplanet atmosphere.
Surprising Atmospheric Composition
Unlike the common magnesium-rich silicates such as olivine and pyroxene typically found in the cosmos, the clouds of WASP-17 b exhibit pure quartz. Silicates, essential components of Earth, the Moon, and many other rocky objects, dominate our understanding of mineral composition in our galaxy. Hence, discovering the presence of quartz alone has shifted scientific perceptions regarding the formulation and transformation of exoplanetary clouds.
Characteristics of WASP-17 b
WASP-17 b stands out not just for its unique atmosphere but also for its impressive dimensions. Boasting a volume surpassing that of Jupiter by over seven times, yet having a mass under half of Jupiter’s, this hot Jupiter is among the universe’s most voluminous exoplanets. Moreover, its brief orbital period of 3.7 Earth days makes it an excellent subject for transmission spectroscopy, which delves into how a planet’s atmosphere affects starlight.
The Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope detected an unanticipated feature at 8.6 microns during its observations. This anomaly couldn’t be associated with the likes of magnesium silicates or aluminum oxide, aligning instead with the spectral signature of quartz.
Origin of the Quartz Crystals
The formation of these quartz crystals, a mere 10 nanometers in diameter, occurs directly in WASP-17 b’s atmosphere. On this exoplanet, the ambient temperature soars to approximately 1,500 degrees Celsius, and the atmospheric pressure is a tiny fraction of what we encounter on Earth. Under these extreme conditions, crystals materialize straight from gas, bypassing the liquid phase.
While these exoplanetary conditions seem alien to us, understanding the composition of such clouds is pivotal for gaining insights into the planet’s holistic environment. Despite hot Jupiters like WASP-17 b primarily comprising hydrogen and helium, these quartz crystals reveal essential details about the different materials present and their collective influence on the planet’s ambiance.
Dynamics of the Clouds
Given the tidally locked nature of WASP-17 b, with a perpetually blazing day side and a cooler night side, it’s likely that the clouds circulate throughout the planet. Dr. David Grant, from the University of Bristol, suggests that these clouds mainly appear along the day/night boundary, a zone extensively probed by the observations.
The presence of quartz in WASP-17 b’s atmosphere provides an enriching insight into the potential materials that shape the exoplanets. It also opens up avenues for revisiting previous hypotheses about exoplanetary atmospheres and their development. As the exploration of the universe continues, the mysteries it holds continue to enthral and challenge our understanding of the cosmos.
