2002/03/14 by M. Matsuura, I. Yamamura, A. A. Zijlstra +1 · 2 citations
Chemistry · Physics and Astronomy · #Astrophysics and Star Formation Studies #Spectroscopy and Laser Applications #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1051/0004-6361:20020391
10 pages, 7 figures, accepted by A&A
arxiv created 2002/03/14 · openalex publication_date 2002/05/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We analyze ISO/SWS spectra of the RV Tau star R Scuti. The infrared spectra are dominated by H2O emission bands. The near- and mid-infrared excess is attributed to H2O; the dust contribution is less important. We also identify CO, SiO and CO2 bands. The various molecular emission bands originate from an extended atmosphere, an atmosphere above the photosphere. The extended atmosphere of R Sct is formed from matter which gradually have lifted up from the photosphere through the pulsations of the star. In contrast to the abundant molecules around the star, the silicate dust feature is weak and the dust mass-loss rate is only yr-1. This implies that there might be a process to inhibit dust formation from molecules. RV Tau stars are commonly considered as post-AGB stars. While a detached dust envelope around R Sct is consistent with such an interpretation, we show that its period evolution is slower than expected. We argue that R Sct may be a thermal-pulsing AGB star, observed in a helium-burning phase.