The neutral disk of MWC349

We wish to study the circumstellar disk of the bright radiostar MWC349with the aim to infer the evolutionary state of this prominent butenigmatic massive stellar object. We propose to make a full wavelengthrange scan with PACS and with the SPIRE spectrometer in order todetermine the continuum spectrum of the disk, especially in the ill determined orunexplored wavelength region centered on 200300 microns where theemission from the ionized wind and the warm circumstellar dust arecomparably strong.These spectral scans are at least 10x more sensitive than our ISOdata, and permit a deep search for molecules like water and CO.The presence of water which is being found by Herschel in a range ofaccretion disks young stellar objects would be strong evidence forthe nature of the MWC349 disk as due to accretion, whereas the absenceof water is most easily explained if the disk results from mass loss in a strong stellar wind or ejection event. Our proposed investigationhas thus the potential to resolve the halfcentury old question aboutthe evolutionary state of MWC349. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]