EXTRASOLAR PLANETS

In the 1980's, astronomers using IRAS data discovered about two dozen stars which had infrared-emitting dust surrounding them, extending hundreds of astronomical units from the stars. This discovery inspired astronomers to make more detailed observations of these stars. What they found around these stars were flat, disk-shaped, areas of dust in which planets have formed or could be forming. These findings have led the way to one of the most exciting new areas of research in astronomy - the search for planets around other stars. Among the stars studied were Beta Pictoris, HL Tauri, Vega, Epsilon Eridani and Alpha Piscis Austrinus. The discovery of these disks provided the first significant evidence that other solar systems might exist.

Credit Left Image: J.-L. Beuzit et al. (Grenoble Obs.), ESO
Credit Right Image: G. Schneider (Steward Observatory, U. Arizona), B.Smith (U. Hawaii), NIC MOS/IDT

The above left image is an infrared image of Beta Pictoris taken at the European Southern Observatory The presence of a warp in this disk indicates the existence of a Jupiter-sized planet around this star. There is also evidence for the existence of comets around Beta Pictoris. With the exception of Beta Pictoris, these disks of material are not seen by visible light telescopes. The visible light from a planet or disk of material is hidden by the brightness of the star that it orbits. In the infrared, where planets have their peak brightness, the brightness of the star is reduced, making it possible to detect a planet in the infrared. To aid in the detection of planets, infrared astronomers use occulting disks to mask out the light from a star allowing for a better view of possible planets. The above right image is an infrared view of a disk around the star HR 4796A taken with the Hubble's NICMOS camera. In this image you can clearly see where the light from the star (which is about 1000 times brighter than the disk) is blocked so we can better see the ring of material around the star.

Exciting new infrared space missions such as the Spitzer Space Telescope and the future TPF (The Terrestrial Planet Finder) as well as ground-based missions such as the Keck Interferometer will concentrate their efforts on the discovery and study of extrasolar planets.

Infrared Universe Index | Star Formation | Stars | Extrasolar Planets | Our Galaxy | Other Galaxies | Between the Stars | Missing Mass - Brown Dwarfs? | The Early Universe