Carbon stars spectra and photometry values

The spectra extend from 0.3um to 2.4um with a resolving power above ~8000. The sample contains stars with a broad range of (J-K) color and pulsation properties located in the Milky Way and the Magellanic Clouds.

We show that the distribution of spectral properties of carbon stars at a given (J-K) color becomes bimodal (in our sample) when (J-K) is larger than about 1.5. We describe the two families of spectra that emerge, characterized by the presence or absence of the absorption feature at 1.53um, generally associated with HCN and C_2_H_2_. This feature appears essentially only in large-amplitude variables, though not in all observations.