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Session 42 - Orfeus & STIS.
Display session, Wednesday, June 11
South Main Hall,

[42.03] IMAPS Observations of Deuterium Toward Zeta Puppis and Gamma-2 Velorum

G. Sonneborn (NASA/GSFC), R. Ferlet, A. Vidal-Madjar, G. Hebrard (CNRS/IAP), C. Gry, O. Dupin (CNRS/LAS), M. Lemoine (U.Chicago), E. Jenkins (Princeton U.), U. J. Sofia (Villanova U.)

High resolution far ultraviolet spectra of Zeta Puppis (O4 Iaf) and Gamma-2 Velorum (WC8+O7.5e) were obtained with the Interstellar Medium Absorption Profile Spectrograph (IMAPS) during the 16-day ORFEUS-SPAS II mission in 1996 November as part of its Guest Investigator program. The IMAPS spectra cover the wavelength range \sim940--1150Å\ at a spectral resolution of c\Delta\lambda/\lambda \sim 3.5 km/sec. The LiF coatings on the optics performed very well so that good quality spectra for these stars were obtained at Lyman delta (949Åwhere the interstellar deuterium feature is resolved, unsaturated, and cleanly separated from interstellar H I. These data should provide a more accurate measurement of the deuterium-to-hydrogen ratio on these sightlines than was possible with Copernicus spectra 20 years ago. Analysis of the Lyman lines, in conjunction with several far-UV N I and O I transitions, will be presented.

Program listing for Wednesday