Bibcode
                                    
                            Montiel, E. J.; Clayton, Geoffrey C.; Sugerman, B. E. K.; Evans, A.; Garcia-Hernández, D. A.; Kameswara Rao, N.; Matsuura, M.; Tisserand, P.
    Bibliographical reference
                                    The Astronomical Journal, Volume 156, Issue 4, article id. 148, 25 pp. (2018).
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                        10
            
                        2018
            
  Citations
                                    15
                            Refereed citations
                                    13
                            Description
                                    The study of extended, cold dust envelopes surrounding R Coronae
Borealis (RCB) stars began with their discovery by the Infrared
Astronomical Satellite. RCB stars are carbon-rich supergiants
characterized by their extreme hydrogen deficiency and their irregular
and spectacular declines in brightness (up to 9 mag). We have analyzed
new and archival Spitzer Space Telescope and Herschel Space Observatory
data of the envelopes of seven RCB stars to examine the morphology and
investigate the origin of these dusty shells. Herschel, in particular,
has revealed the first-ever bow shock associated with an RCB star with
its observations of SU Tauri. These data have allowed the assembly of
the most comprehensive spectral energy distributions (SEDs) of these
stars with multiwavelength data from the ultraviolet to the
submillimeter. Radiative transfer modeling of the SEDs implies that the
RCB stars in this sample are surrounded by an inner warm (up to 1200 K)
and an outer cold (up to 200 K) envelope. The outer shells are suggested
to contain up to 10‑3 M ⊙ of dust and
have existed for up to 105 years depending on the expansion
rate of the dust. This age limit indicates that these structures have
most likely been formed during the RCB phase.
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Nucleosynthesis and molecular processes in the late stages of Stellar Evolution 
            
    Low- to intermediate-mass (M < 8 solar masses, Ms) stars represent the majority of stars in the Cosmos. They finish their lives on the Asymptotic Giant Branch (AGB) - just before they form planetary nebulae (PNe) - where they experience complex nucleosynthetic and molecular processes. AGB stars are important contributors to the enrichment of the
            
            Domingo Aníbal
            
                        García Hernández