2023-10-18 20:57:00
Located 1,300 light-years from Earth, the exoplanet WASP-17 b orbits a host star and is classified as a “hot Jupiter.” This gas giant is the center of investigations of the Deep Recognition of Exoplanet Atmospheres using Multi-Instrument Spectroscopy —DREAMS— project and has already provided scientists with some surprising discoveries.
Contrary to what was expected, WASP-17 b’s atmosphere is tough and composed of tiny silicon dioxide particles, also known as silicate. Silicate is a mineral rich in silicon and oxygen, and is often found on our planet and in other rocky objects in the form of quartz.
Until now, silicate grains identified in the atmospheres of exoplanets and brown dwarf stars have been predominantly rich in magnesium, not quartz. In this scenario, WASP-17 b is an interesting exception.
The team of scientists, with researchers from NASA and the University of Bristol, used the Mid-Infrared Instrument (MIRI) on the James Webb telescope to analyze this gigantic star. Initially, they expected to find magnesium silicates suspended in the planet’s dense atmosphere, but they were surprised by the discovery of pure quartz particles (SiO2). WASP-17 b is colossal, with seven times the volume of Jupiter and half its mass, making it one of the largest exoplanets ever recorded.
Over the course of nearly 10 hours of painstaking observations, the team collected more than 1,275 “brightness measurements” in the infrared range of the electromagnetic spectrum, specifically between five and 12 microns. Employing the technique of “transmission spectroscopy”, they assessed the impact of the planet’s atmosphere as it transited in front of its host star.
Tech
12 Jul
Tech
03 Jul
During this period, James Webb’s instruments made a remarkable detection at 8.6 microns, which scientists say provides clear evidence of the presence of quartz in the clouds surrounding WASP-17 b. Additionally, using visible light and near-infrared observations collected with the renowned Hubble Space Telescope, the team was able to determine the size of the aerosol crystals, revealing that they are approximately 10 nanometers in diameter.
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