000007666 001__ 7666
000007666 005__ 20251226133336.0
000007666 037__ $$aSCART-2025-0157
000007666 100__ $$aBoyer, M.L.
000007666 245__ $$aDiscovery of SiC and Iron Dust Around AGB Stars in the very Metal-Poor Sextans A Dwarf Galaxy with JWST: Implications for Dust Production at High Redshift 
000007666 260__ $$c2025
000007666 520__ $$aLow-resolution infrared spectroscopy from JWST confirms the presence of SiC and likely metallic iron dust around asymptotic giant branch (AGB) stars in the Sextans A dwarf galaxy, which has a metallicity ∼1%–7% Z⊙. While metal-poor carbon-rich AGB stars are known to produce copious amounts of amorphous carbon dust owing to the dredge up of newly synthesized carbon, this is the first time that Si- and Fe-bearing dust has been detected at this extreme metallicity. Of the six AGB stars observed, one is an intermediate-mass (∼1.2–4 M⊙ ) carbon star showing SiC dust, and another is an oxygen-rich M-type star with mass ∼4–5 M⊙ that is likely undergoing hot bottom burning. The infrared excess of the M-type star is strong, but featureless. We tested multiple dust species, and found that it is best fit with metallic iron dust. Assuming its dust-production rate stays constant over the final 2–3 × E4 yr of its evolution, this star will produce ∼0.9–3.7 times the iron dust mass predicted by models, with the range depending on the adopted stellar mass. The implications for dust production in high-redshift galaxies are potentially significant, especially regarding the assumed dust species used in dust evolution models and the timescale of AGB dust formation. Stars on the upper end of the AGB mass range can begin producing dust as early as 30–50 Myr after they form, and they may therefore rival dust production by supernovae at high redshift.
000007666 594__ $$aNO
000007666 6531_ $$aJames Webb Space Telescope
000007666 6531_ $$aAsymptotic giant branch stars
000007666 6531_ $$aCarbon stars
000007666 6531_ $$aCircumstellar dust
000007666 6531_ $$aDwarf galaxies (416)
000007666 700__ $$aSloan, G.C. 
000007666 700__ $$aNanni, A.
000007666 700__ $$aTarantino, E. 
000007666 700__ $$aMcDonald, I. 
000007666 700__ $$aGoldman, S. 
000007666 700__ $$aBlommaert, J.A.D.L. 
000007666 700__ $$aDell'Agli, F.
000007666 700__ $$aDi Criscienzo, M.
000007666 700__ $$aGarcia-Hernandez, D.A. 
000007666 700__ $$aGehrz, R.D.
000007666 700__ $$aGroenewegen, M.A.T.
000007666 700__ $$aJavadi, A.
000007666 700__ $$aJones, O.C. 
000007666 700__ $$aKemper, F. 
000007666 700__ $$aMarengo, M. 
000007666 700__ $$aMcQuinn, K.B.W.
000007666 700__ $$aOliveira, J.M. 
000007666 700__ $$aPastorelli, G. 
000007666 700__ $$aRoman-Duval, J. 
000007666 700__ $$aSahai, R.  
000007666 700__ $$aSkillman, E.D. 
000007666 700__ $$aSrinivasan, S. 
000007666 700__ $$avan Loon, J.Th. 
000007666 700__ $$aWeisz, D.R. 
000007666 700__ $$aWhitelock, P.A.W.
000007666 773__ $$c24$$pastrophysical journal$$v991$$y2025
000007666 8560_ $$fmartin.groenewegen@ksb-orb.be
000007666 8564_ $$s1232242$$uhttp://publi2-as.oma.be/record/7666/files/BoyerSloanNanni_ea_2025_ApJ991_24_JWST_SextansA_SiC.pdf
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000007666 8564_ $$s9509$$uhttp://publi2-as.oma.be/record/7666/files/BoyerSloanNanni_ea_2025_ApJ991_24_JWST_SextansA_SiC.gif?subformat=icon$$xicon
000007666 905__ $$apublished in
000007666 980__ $$aREFERD