Volume 480, Number 1, March II 2008
|Page(s)||133 - 148|
|Section||Interstellar and circumstellar matter|
|Published online||02 January 2008|
A search for diffuse bands in the circumstellar envelopes of post-AGB stars
Laboratorio de Astrofísica Experimental, Escuela Politécnica Superior de Alcoy, Universidad Politécnica de Valencia, Plaza de Ferrándiz y Carbonell, 03801 Alcoy, Alicante, Spain e-mail: email@example.com
2 Herschel Science Centre, Research and Scientific Support Department of ESA, European Space Astronomy Centre, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
3 W. J. McDonald Observatory. The University of Texas at Austin. 1 University Station, C1400. Austin, TX 78712-0259, USA
4 LUAN, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 2, France
Accepted: 6 November 2007
In this work we present the results of a systematic search for diffuse bands (DBs, hereafter) in the circumstellar envelopes of a carefully selected sample of post-AGB stars. We concentrated on analyzing 9 of the DBs most commonly found in the interstellar medium. The strength of these features is determined using high-resolution optical spectroscopy, and the results obtained are compared with literature data on field stars affected only by interstellar reddening. Based on the weak features observed in the subsample of post-AGB stars dominated by circumstellar reddening, we conclude that the carrier(s) of these DBs must not be present in the circumstellar environment of these sources, or at least not under the excitation conditions in which DBs are formed. This conclusion is applicable to all the post-AGB stars studied, irrespective of the dominant chemistry or the spectral type of the star considered. A detailed radial velocity analysis of the features observed in individual sources confirms this result, as the Doppler shifts measured are found to be consistent with an interstellar origin.
Key words: stars: AGB and post-AGB / ISM: dust, extinction
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.