Bibcode
García-Hernández, D. A.; Bunzel, F.; Engels, D.; Perea-Calderón, J. V.; García-Lario, P.
Bibliographical reference
AKARI, a Light to Illuminate the Misty Universe ASP Conference Series, Vol. 418, proceedings of a conference held 16-19 February 2009 at the University of Tokyo, Tokyo, Japan. Edited by Takashi Onaka, Glenn J. White, Takao Nakagawa, and Issei Yamamura. San Francisco: Astronomical Society of the Pacific, 2009, p.435
Advertised on:
12
2009
Citations
3
Refereed citations
3
Description
We present AKARI/IRC and Spitzer/IRS observations of a selected sample
of galactic IRAS sources considered to be heavily obscured AGB /
post-AGB stars based on their characteristic IRAS colours. All of them
are completely invisible in the optical range but extremely bright in
the infrared. Based on AKARI and Spitzer spectroscopy and using DUSTY we
are able to determine the dominant chemistry of their circumstellar
shells as well as the properties of the dust grains contained in these
shells. Most of the sources are found to be C-rich (being the reddest
C-rich stars observed so far). We find only molecular absorptions (and
no PAH features) such as acetylene (C2H2) at 13.7
μm, indicative of an early post-AGB stage. We shortly discuss our
findings in the context of stellar evolution during the hidden
“transition phase” from AGB stars to Planetary Nebulae.