The edge-on disk surrounding the nearby young star βPictoris is the archetype of `debris disks', which are composed of dust and gas produced by collisions between-and evaporation of-planetesimals, analogues of Solar System comets and asteroids. These disks may provide insight into the formation and early evolution of terrestrial planets. Previous work on βPic concluded that the disk gas has roughly solar abundances of elements, but this poses a problem because such gas should rapidly be blown away from the star, contrary to observations showing a stable gas disk in keplerian rotation. Here we report the detection of singly and doubly ionized carbon (CII, CIII) and neutral atomic oxygen (OI) gas in the βPic disk. Carbon is extremely overabundant relative to every other measured element. This appears to solve the problem of the stable gas disk, because the carbon overabundance should keep the gas disk in keplerian rotation. The overabundance may indicate that the gas is produced from material more carbon-rich than expected of Solar System analogues.
- Pub Date:
- June 2006
- Accepted for publication in Nature. PDF document, 12 pages. Supplementary information may be found at http://www.dtm.ciw.edu/akir/Documents/roberge_supp.pdf *** Version 2 : Removed extraneous publication information, per instructions from the Nature editor. No other changes made