1 research outputs found
PACS and SPIRE range spectroscopy of cool, evolved stars
Context: At the end of their lives AGB stars are prolific producers of dust
and gas. The details of this mass-loss process are still not understood very
well. Herschel PACS and SPIRE spectra offer a unique way of investigating
properties of AGB stars in general and the mass-loss process in particular.
Methods: The HIPE software with the latest calibration is used to process the
available PACS and SPIRE spectra of 40 evolved stars. The spectra are convolved
with the response curves of the PACS and SPIRE bolometers and compared to the
fluxes measured in imaging data of these sources. Custom software is used to
identify lines in the spectra, and to determine the central wavelengths and
line intensities. Standard molecular line databases are used to associate the
observed lines. Because of the limited spectral resolution of the spectrometers
several known lines are typically potential counterparts to any observed line.
To help identifications the relative contributions in line intensity of the
potential counterpart lines are listed for three characteristic temperatures
based on LTE calculations and assuming optically thin emission. Result: The
following data products are released: the reduced spectra, the lines that are
measured in the spectra with wavelength, intensity, potential identifications,
and the continuum spectra, i.e. the full spectra with all identified lines
removed. As simple examples of how this data can be used in future studies we
have fitted the continuum spectra with three power laws and find that the few
OH/IR stars seem to have significantly steeper slopes than the other oxygen-
and carbon-rich objects in the sample. As another example we constructed
rotational diagrams for CO and fitted a two-component model to derive
rotational temperatures.Comment: A&A accepte