Kepler452b is a planet orbiting the star-like star Kepler-453 around 1,400 light-years away from Earth in our constellation Cygnus, in the southern sky. It was discovered by the NASA's Kepler space telescope, and it was announced publicly by NASA on January 24th, 2020. Kepler452b's orbit is not very well known yet, but it has a very tight one that's similar to the orbit of Neptune and so it may not be that close to the star. The planet was discovered using a new technique called spectroscopy, which allows astronomers to determine the presence of gases on a planet by looking at the light they give off as they pass through its atmosphere.
If the planet is like planets in our Solar System, then it would be a rocky planet with hydrogen on the surface and helium in its core, just like our Moon, Mercury, Mars, Jupiter, Saturn, Uranus and Neptune. In other words, it would be quite similar to Uranus, Neptune and Pluto. However, it is much too hot for these planets, so it is very different from any of them. Instead, it is cooler than Mercury, Neptune and Uranus and very hot compared to Mars. Since it is very close to its star, it is very likely that it has an atmosphere, which means that it could have an ocean of water.
As well as being an exoplanet, the planet also passes through another class of planet called a hot Jupiter. Hot Jupiters are very similar to planets orbiting very close to their stars (a distance of less than one solar-system's distance from the star) in that they have very high levels of water in their atmospheres, including methane and oxygen. There are some differences though, as hot Jupiters tend to form from rocky planets that were born close to their star (with a relatively large distance between the planets), and thus it will have had time to develop a thick cloud of atmosphere around it. If it is an ocean planet, then it will have a thicker atmosphere as well. In this case, it will look like a planet similar to Jupiter. We will see if other astronomers use the new method of determining the planet's orbit for more planets in the future.
