Vlt/uves Constraints on the Carbon Isotope Ratio
نویسندگان
چکیده
We analyzed the C i lines associated with the damped Lyα system observed at zabs = 1.15 in the spectrum of HE 0515–4414 to derive the C/C ratio. The spectrum was obtained by means of the UV-Visual Echelle Spectrograph (UVES) at the ESO Very Large Telescope (VLT). The obtained lower limit C/C > 80 (2σ C.L.) shows for the first time that the abundance of C in the extragalactic intervening clouds is very low. This rules out a significant contribution from intermediate-mass stars to the chemical evolution of matter sampled by this line of sight. The estimated low amount of C is in agreement with low abundances of nitrogen observed in damped Lyα systems – the element produced in the same nuclear cycles and from about the same stars as C.
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