The origin of dwarf carbon stars

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The origin of dwarf carbon stars is a mystery nearly 40 years old. These stars are similar in mass and temperature to the Sun, but are dominated by carbon instead of oxygen. While researchers have hypothesised that such a carbon-rich star can give birth to carbon dominated planetary systems, the working hypothesis is that these stars are the product of binary star evolution. Remarkably, a significant number of dwarf carbon stars appear to belong to the ancient halo population, and thus hold clues to the earliest stages of star formation and Galactic chemical evolution. The observational project will analyse radial velocity and related data to characterise any binary systems for the first time (fraction, periods, mass transfer). Another aspect might be construction of the first spectral sequence of these stars using available data and models. Kinematical information can also be used to establish age and membership in the Galactic halo and disk.