| 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 accepted
a 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. |
