What is an exoplanet? Exoplanets are planets that reside just outside the solar system and orbit a star that is not the Sun.
Recently, astronomers have discovered a new exoplanet, named Planet GJ 367b. This exoplanet is smaller than the Earth, very dense (denser than iron), and hot enough to melt! This is unique because this means the exoplanet could have a molten surface, which is unheard of in space till this day. The combination of size and density of Planet GJ 367b makes it one of the lightest exoplanets (of over 5000 discovered). Although this exoplanet was first spotted in data from NASA’s TESS telescope in 2019, scientists are just beginning to learn about its one-of-a-kind features. Some scientists presume that since Planet GJ 367b is somewhat similar to Mercury, it might have been formed similarly, as a result of a giant impact with another planet that stripped away most of its outer layers. Other scientists argue that the exoplanet could have once been a gaseous planet, and had its atmosphere blasted off due to radiation from its host star. Planet GJ 367b is so close to its host star, in fact, that by now, the exoplanet is most likely covered in melted metallic lava. This proximity to its host star makes Planet GJ 367b 1400 degrees Celsius!!

As time goes on, scientists and astronomers are continuously attempting to find out more and more about this unique planet with a variety of tools and instruments, such as the HARPS instrument and NASA’s Transiting Exoplanet Survey Satellite (TESS). In the near future, it is predicted that we will discover the truth about the surface of Planet GJ 367b and why it is one of the few exoplanets that are not gaseous, but rather rocky and dense, like the Earth.
Sources: https://www.sciencenews.org/article/tiny-exoplanet-made-molten-iron-star, https://phys.org/news/2021-12-exoplanet-gj-367b-iron-planet.html, http://spaceref.com/extrasolar-planets/discovery-of-sub-earth-planet-gj-367b.html