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CEMP Starts in Dwarf Galaxies

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CEMP Starts in Dwarf Galaxies CEMP Stars in Dwarf Galaxies - Carina Terese T. Hansen The Observatories of the Carnegie Institution of Science A Celebration of CEMP and Gala of GALAH Melbourne 2017 Terese T. Hansen 1/12 Carbon in the Milky Way Halo 5.0 Milky Way 1394 -0.275 4.0 3.0 2.0 [C/Fe] 1.0 0.0 -1.0 -2.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 1.0 [Fe/H] SAGA database C measurements of Milky Way stars Terese T. Hansen 2/12 Carbon in Dwarf Galaxies 2.5 Bootes I 617 Bootes II Com Ber -0.434 Draco 2.0 Fornax Hercules Reticulum II Sagittarius 1.5 Sculptor Segue 1 Sextans Triangulum II Tucana II 1.0 Ursa Major II Ursa Minor 0.5 [C/Fe] 0.0 -0.5 -1.0 -1.5 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 [Fe/H] SAGA database C measurements of dwarf galaxy stars Terese T. Hansen 3/12 Stars with Carbon Measurements in Carina 10 Carbon enhanced stars - Azzopardi et al. 1986 2 also show s-process enhancement - Abia et al. 2008 Susmitha et al. 2017 2.5 2.0 1.5 [C/Fe] 1.0 0.5 0.0 -3.0 -2.5 -2.0 -1.5 -1.0 [Fe/H] Terese T. Hansen 4/12 Looking for CEMP Stars in Carina Low resolution spectra around Ca H+K of large sample ![Fe=H] Medium resolution to look for C features 12 11 10 9 8 7 6 Flux 5 4 3 2 1 0 4200 4300 4400 Wavelength Terese T. Hansen 5/12 Looking for CEMP stars in Carina Magellan telescopes, Las Campanas Observatory Terese T. Hansen 6/12 Looking for CEMP stars in Carina High resolution spectra to do full abundance analysis 12 12 11 11 10 10 9 9 8 8 7 7 6 6 Flux 5 Flux 5 4 4 3 3 2 2 1 1 0 0 Ba 4250 4260 4270 4280 4290 4300 4310 4320 4330 4340 4350 5852 5854 5856 Wavelength Wavelength Terese T. Hansen 7/12 Six CEMP stars in Carina 19861 [Fe=H] = −2:8, [C=Fe] = 1:6, [Ba=Fe] = −1:0 43615 [Fe=H] = −2:5, [C=Fe] = 1:9, [Ba=Fe] = 2:4 37303 [Fe=H] = −2:4, [C=Fe] = 1:3, [Ba=Fe] = 2:6 74198 [Fe=H] = −2:4, [C=Fe] = 1:0, [Ba=Fe] = 0:9 51686 [Fe=H] = −2:3, [C=Fe] = 1:1, [Ba=Fe] = 1:3 71017 [Fe=H] = −1:5, [C=Fe] = 1:1, [Ba=Fe] = 1:6 Terese T. Hansen 8/12 Comparison to halo CEMP stars - absolute C abundance Susmitha et al. 2017, Yoon et al. 2016, Hansen+ in prep Terese T. Hansen 9/12 Comparison to halo CEMP-s stars SAGA database, Hansen+ in prep Terese T. Hansen 10/12 Special abundance features for CEMP-no stars Halo CEMP-no stars with high Na, Mg, Al, Si and/or Sr abundances CEMP-no stars analysed in Carina and Sculptor show enhancement in light neutron-capture elements (Skuladottir 2015, Susmitha 2017) 19861 - show high Mg abundance, but no enhancement in Sr Terese T. Hansen 11/12 More to come Seven CEMP stars in Carina 2.5 2.0 1.5 [C/Fe] 1.0 0.5 0.0 -3.0 -2.5 -2.0 -1.5 -1.0 [Fe/H] Susmitha et al. 2017, Hansen+ in prep Ongoing work on to find more CEMP star in Carina, Fornax, Sextans, Sculptor Terese T. Hansen 12/12.
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