We propose to perform PACS range spectroscopy around the 69 micronforsterite dust feature of evolved stars. With the spectral resolutionand sensitivity of PACS weare able to fit the profile of the forsterite feature which is verysensitive to temperature and composition of the grain. Based on a sample, observed in earlier GT programmes, of about 15 evolved stars, including OH/IR stars, post-AGB and PNs, we find that the olivinedust is purely Mg-rich and contains no iron. We find differences betweenthe .outflow. sources and sources which have disks, likely indicating adifferent formation history. The modelling of the mid-infrared bands (observed with SWS) in combination of the 69 micron band of the heavily obscured OH/IR stars allows to study the dust distribution and search for deviations fromspherical symmetry or changes in mass loss history. With the new observations of a new set of 13 stars we want to substantiate ourfindings. The combination of SWS and PACS spectroscopy will provide a legacydataset for future studies of crystalline dust.
Publication
THROES: a caTalogue of HeRschel Observations of Evolved Stars. I. PACS range spectroscopy | Ramos-Medina J. et al. | Astronomy & Astrophysics Volume 611 id.A41 38 pp. | 611 | 10.1051\\/0004-6361\\/201731940 | 2018A&A...611A..41R | http://adsabs.harvard.edu/abs/2018A%26A...611A..41R
PACS and SPIRE range spectroscopy of cool, evolved stars | Nicolaes D. et al. | Astronomy & Astrophysics Volume 618 id.A143 42 pp. | 618 | 10.1051\\/0004-6361\\/201833168 | 2018A&A...618A.143N | http://adsabs.harvard.edu/abs/2018A%26A...618A.143N
Herschel/PACS observations of the 69 mm band of crystalline olivine around evolved stars | Blommaert J. A. D. L. et al. | Astronomy & Astrophysics Volume 565 id.A109 16 pp. | 565 | 10.1051\\/0004-6361\\/201322554 | 2014A&A...565A.109B | http://adsabs.harvard.edu/abs/2014A%26A...565A.109B
The problematically short superwind of OH/IR stars. Probing the outflow with the 69 mm spectral band of forsterite | de Vries B. L. et al. | Astronomy & Astrophysics Volume 561 id.A75 14 pp. | 561 | 10.1051\\/0004-6361\\/201322546 | 2014A&A...561A..75D | http://adsabs.harvard.edu/abs/2014A%26A...561A..75D
Instrument
PACS_PacsRangeSpec_point
Temporal Coverage
2012-03-26T00:24:48Z/2012-10-05T00:29:21Z
Version
SPG v14.2.0
Mission Description
Herschel was launched on 14 May 2009! It is the fourth cornerstone mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
European Space Agency, blommaert et al., 2013, 'Study of the cool forsterite dust around evolved stars', SPG v14.2.0, European Space Agency, https://doi.org/10.5270/esa-ol0w174
