IRAS 03201+5459: a C-rich AGB star with silicate absorption
2000; EDP Sciences; Volume: 362; Issue: 1 Linguagem: Inglês
ISSN
1432-0746
AutoresBW Jiang, R. Szczerba, Shuji Deguchi,
Tópico(s)Astrophysics and Star Formation Studies
ResumoAbstract. IRAS03201+5459isalate–typestarwithacircum-stellarenvelopeaccordingtoitsIRAScolor.Ithasnoidentifica-tion at optical or near–infrared wavelengths. A full ISO–SWSspectrum between 2.3 and 43µm was taken at a resolution ofabout ∼300 to investigate its nature. The spectrum shows the9.7µm feature in absorption, usually seen in O–rich envelopes,and the 3µm feature in absorption which is related to C–richlate–type stars. Furthermore, modeling of the spectral energydistribution indicates the necessity of C–based dust. To under-stand these conflicting spectral features, we have estimated in-terstellar extinction in the direction of IRAS03201+5459 bydifferent methods. In no case can we get a sufficiently large A V to explain the observed strength of the 9.7µm absorption fea-ture as due to interstellar extinction. Therefore, we investigatedthe hypothesis that a central C–rich star is surrounded by aninner C–rich shell and an outer O–rich shell (the object may bein the transition stage of evolution from an O–rich to a C–richstar). However, this require a very short lifetime of the objectas a C–rich star, and then the similarity between IRAS and ISOspectra makes this hypothesis difficult to sustain. AlternativelyO–rich material around the C–star IRAS03201+5459 might beconfined into more stationary disk–like configuration which isseen (almost) edge–on.Key words: stars: AGB and post-AGB – stars: chemicallypeculiar – stars: circumstellar matter – stars: individual:IRAS03201+54591. IntroductionIRAS03201+5459 (hereafter IRAS03201) was first detectedby the IRAS satellite (see The IRAS Point Source Catalogue)(PSC 1988). Fluxes at 12 and 25 microns, F
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