The First Photograph of a Planet Orbiting a Brown Dwarf (1995)
This 1995 photograph captures the first ever image of a planet orbiting a brown dwarf, a type of star that is smaller and cooler than a regular star. This image was taken by the Hubble Space Telescope and shows the planet, called Gliese 229b, orbiting the brown dwarf Gliese
Sedna is a dwarf planet in the outermost reaches of the Solar System, orbiting the Sun far beyond the orbit of Neptune. It was discovered in 2003, and is roughly 1,000 km in diameter. Spectroscopic analysis has revealed its surface to be a mixture of the solid ices of water, carbon dioxide, and ethane, along with sedimentary deposits of methane-derived, reddish-colored tholins, a chemical makeup similar to the surfaces of other trans-Neptunian objects. Sedna is not expected to have a substantial atmosphere. Within the range of uncertainty, it is tied with Ceres in the asteroid belt as the largest dwarf planet not known to have a moon. Owing to its lack of known moons, Sedna's mass and density remain unknown.