Carbon-enhanced metal-poor (CEMP) stars are old, low-mass and low-metallicity halo stars that exhibit abundances of carbon relative to iron more than ten times higher than in the Sun, [C/Fe]>1. To understand the origin of CEMP stars it is necessary to investigate stellar evolution and AGB nucleosynthesis, mass transfer in binary systems, and the properties of the metal-poor stellar population in the Milky Way, for example the ages of the observed stars, the initial chemical composition with which they were born, the initial mass function, the fraction of binary stars and the distributions of separations at which binary stars were formed.
In my talk I will show some examples of what can be learned from the study of CEMP stars.