Clouds on Hot Jupiters, illustration. Hot Jupiters are exoplanets that orbit their stars so closely that their temperatures are extremely high, reaching over 2400 degrees Celsius. The daysides of these tidally-locked planets are cloud-free, while the nightsides are heavily clouded. The composition of the clouds depends on the temperature. The temperature range shown here is from 1000 to 2100 Kelvin (K). The seven chemical components of the clouds shown here are (top to bottom): calcium titanate (CaTiO3), aluminium oxide (Al2O3), iron (Fe), magnesium silicate (MgSiO3), chromium (Cr), manganese (II) sulphide (MnS), sodium sulphide (Na2S). This image was published in 2016.