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Paper: Deconvolving the γ2 Vel Sight Line Using IX Vel as a Foreground Probe
Volume: 348, Astrophysics in the Far Ultraviolet: Five Years of Discovery with FUSE
Page: 73
Authors: Blair, W.P.; Oliveira, C.; Hebrard, G.; Sembach, K.R.; Friedman, S.D.; Moos, H.W.
Abstract: γ2 Velorum lies at a distance of ∼260 pc. IMAPS measurements of this star show a peculiar (high) D/H value of 21.8 parts per million. We have used FUSE to measure the interstellar gas toward IX Velorum, a cataclysmic variable that is only ∼95 pc distant and only 2.1° in angular distance from γ2 Velorum. We find the sight line toward IX Vel to be consistent with normal local interstellar gas, with a ‘normal to low’ D/H value of 12.3 parts per million. This implies an essentially primordial D/H value along the differential sight line between the two stars, which is intriguing since at least some of this intervening material is due to the Gum nebula, an old supernova remnant. In principle, the same foreground correction technique can be applied to other sight lines that probe beyond the wall of the Local Bubble, meaning that the observed dispersion in D/H reported in previous papers is even larger than measured by sight line averages.
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