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Author Jenkins, Edward B. ♦ Wallerstein, George
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ABSORPTION ♦ COSMIC GAMMA BURSTS ♦ DUSTS ♦ ELEMENT ABUNDANCE ♦ GAMMA RADIATION ♦ INTERSTELLAR SPACE ♦ MAGELLANIC CLOUDS ♦ MASS ♦ METALLICITY ♦ MILKY WAY ♦ POLYCYCLIC AROMATIC HYDROCARBONS ♦ QUASARS ♦ SPECTRA ♦ STARS ♦ SUBSTRATES ♦ ULTRAVIOLET RADIATION
Abstract We present data on the gas-phase abundances for 9 different elements in the interstellar medium of the Small Magellanic Cloud (SMC), based on the strengths of ultraviolet absorption features over relevant velocities in the spectra of 18 stars within the SMC. From this information and the total abundances defined by the element fractions in young stars in the SMC, we construct a general interpretation on how these elements condense into solid form onto dust grains. As a group, the elements Si, S, Cr, Fe, Ni, and Zn exhibit depletion sequences similar to those in the local part of our Galaxy defined by Jenkins. The elements Mg and Ti deplete less rapidly in the SMC than in the Milky Way, and Mn depletes more rapidly. We speculate that these differences might be explained by the different chemical affinities to different existing grain substrates. For instance, there is evidence that the mass fractions of polycyclic aromatic hydrocarbons in the SMC are significantly lower than those in the Milky Way. We propose that the depletion sequences that we observed for the SMC may provide a better model for interpreting the element abundances in low-metallicity Damped Lyman Alpha (DLA) and sub-DLA absorption systems that are recorded in the spectra of distant quasars and gamma-ray burst afterglows.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-04-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 838
Issue Number 2


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