he high-velocity CH stars appear to be deficient in metals but rich in carbon and heavy elements. a comparative curve-of-growth analysis using the G8 III star e Virginis as a standard, we have found t the CH stars, HD 26 and HD 201626, are metal-poor by factors of 5 and 30, respectively. Both stars w a carbon-to-iron ratio 5 times higher than e Vir. There is no evidence for the presence of C'3. In ition, both show an excess of Ba, La, Ce, and Nd with respect to Fe, by factors of about 20. Eu is anced by only a factor of 5 in HD 26, and by less than 2 in HD 201626. Except for their general metal ciency these stars have relative abundances of C : Fe : Ba very similar to the population I Ba ii star, 46407. The abundance anomalies are interpreted as having been produced by helium burning and neutron ition to the iron-peak elements. Two possible models are proposed in which C02 is first produced and a partially processed to C23 by protons that are mixed in. The C'3 is then the source of the neutrons ugh C'3(a, n)O16. The N'4 is destroyed by N'4(a, F'8( + )O18. These events need occur in only 1-3 cent of the mass of stellar material, which is sufficient when mixed with the outer envelope of the star roduce the observed abundance anomalies. The high space velocities and galactic distribution as well as the low metal content indicate that the stars belong to the halo population. The absolute magnitudes of these stars are found to be about .5 and -0.4 for HD 26 and HD 201626, respectively. Combined with their intrinsic colors, B - V = 5, this places them to the right of the nearly vertical part of the giant branch of the color-magnitude ram of globular clusters.
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Wallerstein et al. (1964) studied this question.