55 Pegasi b is classified as a gas giant and is roughly 0.84 times the mass of Jupiter, with a radius estimated to be about 1.2 times that of Jupiter. 

55 Pegasi b is located approximately 50 light-years away from Earth in the constellation Pegasus. 

55 Pegasi b does not have a solid surface like terrestrial planets; instead, it has an atmosphere rich in gases. The atmospheric conditions are not well-documented, but it may feature cloud formations, storms, and other meteorological phenomena common in gas giants. 

As a gas giant, 55 Pegasi b is primarily composed of hydrogen and helium. While it likely has a core, the exact internal structure is not well understood. It is assumed to have a composition similar to that of Jupiter, with possible heavier elements in its core. 

As of now, there is no confirmed evidence of moons orbiting 55 Pegasi b. The detection of exomoons is challenging, and while it's possible that moons could exist, none have been observed. 

55 Pegasi b is a "hot Jupiter," the first exoplanet discovered around a sun-like star. Its close orbit results in high temperatures and an eccentric path that affects its atmospheric conditions. 

Discovery Method: Radial Velocity

Year Discovered: 1995

Details: 55 Pegasi b was the first exoplanet discovered orbiting a sun-like star. The detection was made using the radial velocity method, which measures the star's wobble caused by the gravitational pull of the planet. This discovery marked a significant milestone in the search for exoplanets.