Exoplanets

Exoplanets

More than 4000 planets have been discovered orbiting other stars. These extrasolar planets, or exoplanets, span a vast range of properties, and most form systems very different than our own, ranging from "hot Jupiters," gas giants that are closer to their stars than Mercury is to our Sun, to tightly-packed systems of multiple "super-earths" orbiting faint red stars. Planets are hundreds of thousands of times to billions of times fainter than stars, making them nearly impossible to detect. The vast majority of these planets have been discovered through indirect techniques—changes in the parent star’s velocity or brightness caused by the presence of a planet. The exoplanet group at Stanford specializes in direct imaging of exoplanets, blocking out the light of the parent star to separate the planetary signal. With current technology such as the Gemini Planet Imager (GPI), this is only practical for massive young planets—the equivalent of our Jupiter, but only tens of millions of years old and shining brightly in infrared with the heat released by their formation. Once these planets are detected, we can use spectroscopy to characterize them and determine their atmospheric compositions and natures. Ultimately, the same technology will be applied to study Earth-like planets, allowing us to probe their atmospheres and hunt for chemical compositions that could indicate life.

Video Gallery

Pictures of Distant Worlds - Discover Our Universe

Direct Imaging of Exoplanets - Bruce Macintosh (SETI Talks)