DETECTION OF PHOSPHORUS, SULPHUR, AND ZINC IN THE CARBON-ENHANCED METAL-POOR STAR BD+44 493

摘要

The carbon-enhanced metal-poor star BD+ 44 degrees 493 ([Fe/H] = -3.9) has been proposed as a candidate second-generation star enriched by metals from a single Pop III star. We report the first detections of P and S and the second detection of Zn in any extremely metal-poor carbon-enhanced star, using new spectra of BD+ 44 degrees 493 collected by the Cosmic Origins Spectrograph on the Hubble Space Telescope. We derive [P/Fe] - -0.34 +/- 0.21, [S/Fe] = +0.07 +/- 0.41, and [Zn/Fe] = -0.10 +/- 0.24. We increase by 10-fold the number of Si I lines detected in BD+44 degrees 493, yielding [Si/Fe] = +0.15 +/- 0.22. The [S/Fe] and [Zn/Fe] ratios exclude the hypothesis that the abundance pattern in BD+44 degrees 493 results from depletion of refractory elements onto dust grains. Comparison with zero-metallicity supernova (SN) models suggests that the stellar progenitor that enriched BD+44 degrees 493 was massive and ejected much less than 0.07 M-circle dot of Ni-56, characteristic of a faint SN.