| Description |
With the discovery of G77-61 (Dahn et al. 1977) at a mere 58 pc and therefore relatively low luminosity, a category of dwarf carbon (dC) stars was finally recognized. This, however, presented a puzzle because a low mass star is incapable of the helium fusion needed to create the carbon seen in its atmosphere. A reolution was proposed and generally accepteda second member of a system could .dump. carbon on it through an AGB stage into a circumstellar disk which would replenish the fully convective atmosphere in a reasonable period. Current understanding of the formation and evolution of dC.s is, however, limited by the small number of objects and observations. We propose observations of each carbon dwarf with Herschel PACS 100/160 um, to to detect the proposed redsidual circumstellar disk. The proposed model for creating carbon dwarfs is based on three objects and the mechanism for dumping material on these low-mass stars and building the debris systems are currently unexplored. Thus the opportunity afforded by thisr program to add observational proof is valuable, especially for the very ill-studied carbon dwarfs. Only Herscehl can provide the spectral range and sensitivity to gain the observations needed in understanding the cold circumstellar disk and dissipation timescales around evolved stars placing carbon in our ISM- a building block of life as we know it. |
