Analysis of the carbon star G77-61

The carbon star G77-61 was investigated using model calculations. Observational data on G77-61 is presented. The computer program for the construction of model atmospheres is described. The mass estimation of carbon stars is discussed. It is shown that an observed spectrum allows ambiguity concerning the stellar parameter. The parameters of G77-61 were determined using observation data. The error bars of the resulting data are discussed, especially the deviations between spectroscopic and other data. The consequences of the obtained parameters, and especially the very low abundance of metals, for the development of G77-61, are discussed.