The ISO-SWS spectrum of NML Cyg.
Waters, L. B. F. M.; Beintema, D. A.; Izumiura, H.; de Graauw, T.; Loup, C.; Justtanont, K.; Helmich, F. P.; Roelfsema, P. R.; Yamamura, I.; Lahuis, F.; de Jong, T.; Valentijn, E. A.
Abstract
The high resolution spectrum of NML Cyg observed with the ISO-SWS in its slow-speed grating mode (2.4-45μm) shows a wealth of features never seen before in previous observations. These include ro-vibrational lines of H_2_O at 2.7 and 6.2μm, of OH between 3 and 3.5μm and a deep absorption band of CO_2_ at 4.26μm. We also report on the detection of pure rotational emission lines of H_2_O between 35 and 45μm and of the 34.6μm absorption line of OH which is thought to pump the well known 1612 MHz OH maser line. There are two, as yet, unidentified features at 33 and 40μm which may be related to silicate dust.