The Populations of Carina. II. Chemical Enrichment

摘要: Chemical abundances are presented for 19 elements in a sample of 63 red giants the Carina dwarf spheroidal galaxy (dSph), based on homogeneous 1D/LTE model atmosphere analyses our own observations (32 stars) and data available literature (a further 31 independent stars). The (Fe) metallicity [$\alpha$/Fe] distribution functions have mean values dispersions -1.59 0.33 dex ([Fe/H] range: -2.68 to -0.64), 0.07 0.13 ([$\alpha$/Fe] -0.27 0.25), respectively. We confirm finding Venn et al. (2012) that small percentage (some 10% present investigation) show clear evidence significant enrichment by Type Ia supernovae ejecta. Calcium, with most accurately determined abundance alpha-elements, shows an asymmetric towards smaller [Ca/Fe] at all [Fe/H], significantly over -2.0 < [Fe/H] -1.0, suggestive incomplete mixing ejecta SNe ambient medium each Carina's generations. Approximate color-magnitude-diagram age estimates and, together chemical abundances, compared results previous synthetic CMD analysis, which reported details four well-defined populations. We searched Na-O anti-correlation universally Galaxy's globular clusters, this phenomenon does not exist Carina. also found one 32 stars has extremely enhanced lithium -- A(Li)$_{\text{NLTE}}$ = +3.36, consistent membership ~1% group Li-rich dSph described Kirby