The interstellar carbon abundance. II. Rho Ophiuchi and beta Scorpii.

Abstract

The authors describe a procedure designed to obtain increased sensitivity from high-dispersion IUE spectra by using a flat-field spectrum to remove nonrandom noise due to the response pattern of the SEC vidicon detector. Application of this procedure to spectra of ρ Oph and β¹Sco near the spin-forbidden interstellar λ2325 line of C II yields 2 σ upper limits on absorption of W_λ ⪉ 4 mÅ. The resulting depletion of carbon from the interstellar gas toward ρ Oph exceeds a factor of 1.4.