Puffy helium planets could explain exoplanet size mystery

First image of an exoplanet — courtesy of the Very Large Telescope, European Southern Observatory, in 2004 — shows an exoplanet orbiting brown dwarf 2M1207

‘This really is a planet, the first planet that has ever been imaged outside of our solar system.’ — Faint light observed in April 2004, first imaged in June 2004, turns out to be discovery of an exoplanet approximately five times the mass of Jupiter

Astronomers find a potentially habitable exoplanet right in Earth's galactic backyard