
A class of giant exoplanets with very high atmospheric temperatures due to close proximity to their star.Hot Jupiters are a class of exoplanets with masses comparable to Jupiter but orbiting extremely close to their host stars, resulting in atmospheric temperatures of 1,000 K or more. These planets are often tidally locked, meaning one side permanently faces the star, creating extreme temperature contrasts between the day and night sides. Their study provides insights into planetary formation, atmospheric dynamics, and the evolution of planetary systems under intense stellar radiation.
The first hot Jupiter, 51 Pegasi b, was discovered in 1995 by Michel Mayor and Didier Queloz, a finding that earned them the 2019 Nobel Prize in Physics.
The high temperatures cause the planet's atmosphere to expand, and the intense stellar radiation drives strong winds that redistribute heat. Observations of their spectra reveal the presence of molecules like water, carbon monoxide, and even vaporized metals in their atmospheres. Some hot Jupiters show evidence of atmospheric escape, where the heated gas overcomes the planet's gravity and streams away, sometimes forming a comet-like tail.
Hot Jupiters serve as natural laboratories for testing atmospheric models and radiative transfer codes, which are also used in climate science and stellar astrophysics.
Some ultra-hot Jupiters have atmospheres so hot that they contain vaporized iron and silicate clouds that rain molten glass on the night side.




















