LOW-RESOLUTION SPECTROPHOTOMETRIC STUDIES OF WATER-VAPOR IN CIRCUMSTELLAR ENVELOPES

For the stars R Lyr, T Cep, R Hya, and o Cet, excess absorption in the 0.93 mum water-vapor band was determined relative to other stars of the same spectral types using low-resolution spectrophotometric data. This excess absorption is thought to be due to the presence of water vapor in circumstellar envelopes. The water column densities for the stars R Lyr, T Cep, R Hya, and o Cet were estimated to be 2 x 10(21), 3 x 10(21), 1.1 x 10(22), and 1.2 x 10(22) cm(-2), respectively.