From: Aki Roberge [view email] Date (v1): Wed, 19 Apr 2006 19:58:12 GMT (458kb) Date (revised v2): Thu, 20 Apr 2006 03:48:51 GMT (451kb)The Carbon-Rich Gas in the Beta Pictoris Circumstellar Disk
The edge-on disk surrounding the nearby young star Beta Pictoris is the archetype of the "debris disks", which are composed of dust and gas produced by collisions and evaporation of planetesimals, analogues of Solar System comets and asteroids. These disks provide a window on the formation and early evolution of terrestrial planets. Previous observations of Beta Pic concluded that the disk gas has roughly solar abundances of elements , but this poses a problem because such gas should be rapidly blown away from the star, contrary to observations of a stable gas disk in Keplerian rotation [1, 2]. Here we report the detection of singly and doubly ionized carbon (CII, CIII) and neutral atomic oxygen (OI) gas in the Beta Pic disk; measurement of these abundant volatile species permits a much more complete gas inventory. Carbon is extremely overabundant relative to every other measured element. This appears to solve the problem of the stable gas disk, since the carbon overabundance should keep the gas disk in Keplerian rotation . New questions arise, however, since the overabundance may indicate the gas is produced from material more carbon-rich than the expected Solar System analogues.Full-text: PDF only
"NASA will host a media teleconference at 1 p.m. EDT Wednesday, June 7, about the discovery of carbon-rich gas around a young star that may be forming terrestrial planets. The discovery was made with NASA's Far Ultraviolet Spectroscopic Explorer spacecraft and will be featured in the June 8 issue of Nature."