Physics
Scientific paper
Jul 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008hst..prop11737m&link_type=abstract
HST Proposal ID #11737. Cycle 17
Physics
Scientific paper
The degree of elemental abundance homogeneity in the interstellar medium is a function of the enrichment and mixing processes that govern Galactic chemical evolution. Observations of young stars and the interstellar gas within 500 pc of the Sun have revealed a local ISM that is so well-mixed it is having an impact on ideas regarding the formation of extrasolar planets. However, the situation just beyond the local ISM is not so clear. Sensitive UV absorption line measurements have recently revealed a pattern of inhomogeneities in the interstellar O, N, and Kr gas-phase abundances at distances of 500 pc and beyond that appear nucleosynthetic in origin rather than due to dust depletion. In particular, based on a sample of 13 sightlines, Knauth et al. {2006} have found that the nearby stars {d < 500 pc} exhibit a mean interstellar N/O abundance ratio that is significantly higher {0.18 dex} than that toward the more distant stars. Interestingly, all of their sightlines lie in the sky vicinity of the Gould Belt of OB associations, molecular clouds, and diffuse gas encircling the Sun at a distance of 400 pc. Is it possible that mixing processes have not yet smoothed out the recent ISM enrichment by massive stars in the young Belt region? By measuring the interstellar N/O ratios in a strategic new sample of sightlines with STIS, we propose to test the apparent N/O homogeneity inside the Gould Belt and determine if the apparent decline in the N/O ratio with distance is robust and associated with the Belt region.;
No associations
LandOfFree
The Distance Dependence of the Interstellar N/O Abundance Ratio: A Gould Belt Influence? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Distance Dependence of the Interstellar N/O Abundance Ratio: A Gould Belt Influence?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Distance Dependence of the Interstellar N/O Abundance Ratio: A Gould Belt Influence? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1320528