Astronomy and Astrophysics Letters dedicated to ISO

The ISO-SWS Spectrum of NML Cyg

K. Justtanont - T. de Jong - F.P. Helmich - L.B.F.M. Waters - Th. de Graauw - C. Loup - H. Izumiura - I. Yamamura - D.A. Beintema - F. Lahuis - P.R. Roelfsema - E.A. Valentijn


The high resolution spectrum of NML Cyg observed with the ISO-SWS in its slow-speed grating mode (2.4-45 microns) shows a wealth of features never seen before in previous observations. These include ro-vibrational lines of H2O at 2.7 and 6.2 microns,, of OH between 3 and 3.5 microns and a deep absorption band of CO2 at 4.26 microns. We also report on the detection of pure rotational emission lines of H2O between 35 and 45 microns and of the 34.6 micron 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 40 microns which may be related to silicate dust.

stars : AGB and post-AGB - stars : circumstellar matter - stars : individual (NML Cyg) - stars : late-type - infrared : stars

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