Spectral Classification of Cold IRAS Stars: Supergiants

We have observed 72 stars with low resolution optical spectra (85 A/mm with 2.3 A/pixel) covering 6000 to 8800 A in an attempt to identify the spectral type and luminosity class of a number of dusty IRAS sources. These stars were chosen from region IIIa of the van der Veen & Habing color-color diagram, where infrared late-type stars are found with generally strong 10μm silicate emission and often OH maser emission. We present here initial classficiation results. These include the probable identification of 19 new M0--4 supergiants and the re-classification of 3 stars formerly categorized as S stars: IRC+70012 (M8 III), NSV12260 (M8 III) and IRC+60374 (M4 I). \begin{tabular}{|l|c|c|c|l|} IRAS name & old type & new type & other name 03572+5509 & M4 & M4 I & AG Cam 05361+4644 & M6 & M3 I & IRC+50149 17360-3140 & M6,K5 & M2 I & IRC-30309 17513-2313 & M5 & M4 I & V774 Sgr 18025-2113 & M2 & M3-4 I & IRC-20427 18135-1740 & M3 & M2 I & IRC-20455 18522+0021 & M5 & M4 I & IRC+00392 18539+0026 & M & M4 I & IRC+00396 19229+1708 & M4e & M3-4 I & 19307+1338 & & M0 I & 19325+2346 & K5,M0 & M2-3 I & 20004+2955 & K8 & K2-4 I & V1027 Cyg 20015+3019 & M4 & M4 I & V719 Cyg 22048+5914 & & M4 I & RAFGL 4286 22480+6002 & & M0 I & IRC+60370 22512+6100 & S & M4 I & IRC+60374 23000+5932 & M3 & M3 I & AS Cep 23252+6010 & & M4 I & 23278+6000 & M4 & M4 I & IRC+60409