WASP-19b, formally named Banksia, is an exoplanet, notable for possessing one of the shortest orbital periods of any known planetary body: 0.79 days or approximately 18.932 hours.
It has a mass close to that of Jupiter, but by comparison has a much larger radius ; making it nearly the size of a low-mass star. It orbits the star WASP-19 in the Vela constellation. At the time of discovery it was the shortest period hot Jupiter discovered as planets with shorter orbital periods had a rocky, or metallic composition.
Comparison of "hot Jupiter" exoplanets (artist concept). From top left to lower right: WASP-12b, WASP-6b, WASP-31b, WASP-39b, HD 189733b, HAT-P-12b, WASP-17b, WASP-19b, HAT-P-1b and HD 209458b.
Hot Jupiters are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter but that have very short orbital periods. The close proximity to their stars and high surface-atmosphere temperatures resulted in their informal name "hot Jupiters".
An artist's impression of a hot Jupiter orbiting close to its star.
Hot Jupiter with hidden water
Comparison of "hot Jupiter" exoplanets (artist concept). From top left to lower right: WASP-12b, Boinayel, WASP-31b, Bocaprins, HD 189733b, Puli, Ditsö̀, Banksia, HAT-P-1b and HD 209458b.