THE SPECTROSCOPIC ORBIT OF THE EVOLVED BINARY HD-197770

We have used spectra taken between 1992 and 1997 to derive the spectro scopic orbit of the eclipsing double-lined spectroscopic binary HD 197 770. This binary has a period of 99.69 +/- 0.02 days and K amplitudes of 31.2 +/- 0.8 and 47.1 +/- 0.4 km s(-1) for components A and B, resp ectively. The m sin(3) i values for A and B are 2.9 and 1.9, respectiv ely, and are close to the actual masses because of the eclipsing natur e of this binary. Both components of HD 197770 have spectral types nea r B2 III. This means that both components are undermassive by about a factor of 5 and, thus, are evolved stars. Additional evidence of the e volved nature of HD 197770 is found in 25, 60, and 100 mu m IRAS image s of HD 197770. These images show two apparent shells centered on HD 1 97770, a bright 60 mu m shell with a 28' diameter and a larger (0 degr ees.8 diameter) bubble-like feature. At least one of the components of HD 197770 is likely to be a post-asymptotic giant branch star.