Astronomers image smallest exoplanet yet

With the central star removed, it's possible to directly image the planet.

ESO

We're aware of a huge number of exoplanets now, but we've only seen about a dozen. Most of the rest have been detected through their effects on the light emitted by the stars they orbit. Some of the bodies we've imaged directly may not even be planets; they're so large that they may have briefly undergone fusion, which puts them in the brown dwarf category.

But astronomers have now imaged an object that very clearly falls into the planetary category, as it may be as little as four times the mass of Jupiter (if one could ever use "little" for a planet that size). Like all good scientific findings, it comes with a bit of mystery: we don't think a planet that size can form where this one orbits.

The exoplanet was discovered as part of a survey of young stars that are relatively close to the Sun. "Close to the Sun" simply means that we can obtain more light from them; "young stars" mean that any planets orbiting them will also be young. In the case of gas giants, that means they'll be hot, as they will still be radiating away the heat of their formation. One of the stars the survey imaged was HD 95086, which is about 300 light years from Earth. In addition to being young—previous estimates have placed the star at either 10 or 17 million years old—the star was already known to have a dusty environment, which could indicate a planet-forming disk.