Herschel-SPIRE FTS Spectroscopy of Evolved Stars

摘要

We present far-infrared and submillimetre spectra of evolved objects observed with the SPIRE Fourier-transform spectrometer on board the Herschel Space Observatory. The observations cover wavelengths 195-670 μm, a region of the electromagnetic spectrum hitherto difficult to study. The far-infrared spectra of these objects are rich and complex. We determine physical conditions from observations of the rotational lines of several molecules, and present initial large velocity gradient models for AFGL 618. We detect water in AFGL 2688 for the first time, and confirm its presence in AFGL 618 in both ortho and para forms. In addition, we detect of the J = 1-0 line of CH+ in NGC 7027. Finally, we present new Herschel-SPIRE spectroscopic observations of both O-rich and C-rich evolved sources, and discuss preliminary investigations into their physical conditions.