On the Correlation between Co Absorption and Far-ultraviolet Non-linear Extinction toward Galactic Ob Stars
نویسندگان
چکیده
A sample of 59 sight lines to reddened Galactic OB stars was examined for correlations of the strength of the CO Fourth Positive (AΠ − XΣ) absorption band system with the ultraviolet interstellar extinction curve parameters. We used archival high-dispersion NEWSIPS IUE spectra to measure the CO absorption for comparison to parametric fits of the extinction curves from the literature. A strong correlation with the non-linear far-UV curvature term was found with greater absorption, normalized to E(B − V ), being associated with more curvature. A weaker trend with the linear extinction term was also found. Mechanisms for enhancing CO in dust environments exhibiting high non-linear curvature are discussed. Subject headings: Dust, extinction — ISM: abundances — ISM: molecules — ultraviolet: ISM
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