Is there enhanced depletion of gas-phase nitrogen in moderately reddened lines of sight?

Adam G. Jensen, Brian L. Rachford, Theodore P. Snow

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

We report on the abundance of interstellar neutral nitrogen (N I) for 30 sight lines, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope (HST). N I column densities are derived by measuring the equivalent widths of several ultraviolet absorption lines and subsequently fitting those to a curve of growth. We find a mean interstellar N/H of 51 ±4 ppm. This is below the mean found by Meyer et al. of 62 -3-4 ppm (adjusted for a difference in f-values). Our mean N/H is similar, however, to the (f-value adjusted) mean of 51 ± 3 ppm found by Knauth et al. for a larger sample of sight lines with larger hydrogen column densities comparable to those in this study. We discuss the question of whether or not nitrogen shows increased gas-phase depletion in lines of sight with column densities log N(Htot) ≥21, as claimed by Knauth et al. The nitrogen abundance in the line of sight toward HD 152236 is particularly interesting. We derive very small N/H and N/O ratios for this line of sight that may support a previous suggestion that members of the Sco OBI association formed from an N-deficient region.

Original languageEnglish (US)
Pages (from-to)955-970
Number of pages16
JournalAstrophysical Journal
Volume654
Issue number2 I
DOIs
Publication statusPublished - Jan 10 2007

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Keywords

  • ISM: abundances
  • Ultraviolet: ISM

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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