XMM-Newton image of Castor & YY Gem

Text & image credit: ROSAT/MPE

With ground-based optical follow-up observations of unidentified ROSAT All-Sky Survey sources, several hundred new T Tauri stars have been identified based on Halpha emission and Lithium absorption. Surprisingly, new T Tauri stars have been found even outside clouds, i.e. outside regions of on-going star formation. Such off-cloud T Tauri stars either have been ejected from their birth places in the clouds or they formed in small cloudlets which have dispersed since then.

IMAGES | By Mission | Stars | Cataclysmic Variables | X-ray Binaries | Pulsars | Supernova Remnants & Planetary Nebulae | Galaxies | Active Galactic Nuclei | Clusters and Groups of Galaxies | X-ray/gamma-ray Background & Deep Fields | Solar System Objects | Gamma Ray Bursts