Potassium in the Atmosphere of a Hot Jupiter

Observations have shown that there is a lot of diversity in the atmospheres of hot Jupiters. Some hot Jupiters have atmospheres that are obscured by high altitude hazes, while others have relatively clear skies. When a transiting hot Jupiter passes in front of its host star, the amount of starlight it obscures depends on the composition of its atmosphere. This is because the presence of atmospheric species such as sodium and potassium let less light through at certain wavelengths. Since the inferred size of a hot Jupiter is based on the amount of starlight it obscures, the planet’s size can appear slightly larger at wavelengths where the planet’s atmosphere is more opaque. Figure 1: Artist’s impression of a planet transiting a star. Image credit: ESA/ATG medialab.HAT-P-1b is a hot Jupiter in a close-in 4.47 day orbit around a Sun-like star. Being so close to its host star, its dayside is heated to temperatures well over 1,000 °C. HAT-P-1b has 1.319 times the radius and 0.525 times the mass of Jupiter, giving it an average density of only 0.345 g/cm³. A study by Wilson et al. (2015) reports the detection of potassium in the atmosphere of HAT-P-1b. Four transits of HAT-P-1b were ...