Related papers: The Abundance of Boron in Diffuse Interstellar Clo…
The evolution and fate of massive stars are thought to be affected by rotationally induced internal mixing. The surface boron abundance is a sensitive tracer of this in early B-type main sequence stars. We test current stellar evolution…
We report on the abundance of interstellar neutral nitrogen (NI) for 30 sightlines, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope (HST). NI column densities are derived by measuring the…
We have observed the B I line at 2089.6 AA in the metal poor star HD 140283 with HST/STIS. The observation was an attempt to confirm the B abundances derived from the 2497 AA B I line in earlier works in general, and for for this star in…
We present interstellar C II (1334.5323 \AA) and C II* (1335.7077 \AA) column density measurements along 14 Galactic sight-lines. These sight-lines sample a variety of Galactic disk environments and include paths that range nearly two…
We report the first ensemble results from the FUSE survey of molecular hydrogen in lines of sight with A_V $\gtrsim$ 1 mag. We have developed techniques for fitting computed profiles to the low-J lines of H2, and thus determining column…
The non-local thermodynamic equilibrium (NLTE) line formation of neutral boron in the atmospheres of cool stars are investigated. Our results confirm that NLTE effects for the B I resonance lines, which are due to a combination of…
Molecular oxygen has been the subject of many observational searches as chemical models predicted it to be a reservoir of oxygen. Although it has been detected in two regions of the interstellar medium, its rarity is a challenge for…
In this paper, we report on the gas-phase abundance of singly-ionized iron (Fe II) for 51 lines of sight, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE). Fe II column densities are derived by measuring the equivalent…
Observations of interstellar dust are often used as a proxy for total gas column density $N_\mathrm{H}$. By comparing $\textit{Planck}$ thermal dust data (Release 1.2) and new dust reddening maps from Pan-STARRS 1 and 2MASS (Green et al.…
We use the absorption features from neutral argon at 1048 and 1066 A to determine interstellar abundances or their lower limits toward nine early-type stars. These features were observed with the Interstellar Medium Absorption Profile…
Current measurements indicate that the deuterium abundance in diffuse interstellar gas varies spatially by a factor of ~4 among sightlines extending beyond the Local Bubble. One plausible explanation for the scatter is the variable…
We report on new FUSE far-UV spectroscopy of the most metal-poor blue compact dwarf galaxy I Zw 18. The new data represent an improvement over previous FUSE spectra by a factor of 1.7 in the signal-to-noise. Together with a larger spectral…
Oxygen is the third most abundant element in the universe, but its chemistry in the interstellar medium is still not well understood. In order to critically examine the entire oxygen budget, we attempt here initially to estimate the…
Using observations of the 2496.7 A B I line with the HST GHRS at a nominal resolution of 90,000, we have found the abundance of boron of HD 140283 to be log epsilon_B (= 12 + log (N_B/N_H)) = 0.34 \pm 0.20. This result is found when a…
We present ultraviolet interstellar absorption line measurements for the sightline towards the O9.5 V star mu Columbae obtained with the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope. These archival data…
We investigate the correlation between OH and H2 column densities in diffuse Galactic clouds, in order to identify potential molecular tracers of interstellar H2. For this, we analyse near-UV spectra extracted from the ESO/VLT archives…
(Abridged) We have used the Far Ultraviolet Spectroscopic Explorer (FUSE) to search for H_2 absorption in five starburst galaxies: NGC 1705, NGC 3310, NGC 4214, M83 (NGC 5236), and NGC 5253. We tentatively detect weak absorption by H_2 in…
We have observed the B I 2497 A line to derive the boron abundances of two very metal-poor stars selected to help in tracing the origin and evolution of this element in the early Galaxy: BD +23 3130 and HD 84937. The observations were…
While it is well recognized that both the Galactic interstellar extinction curves and the gas-phase abundances of dust-forming elements exhibit considerable variations from one sight line to another, as yet most of the dust extinction…
We report results from a FUSE survey of interstellar molecular hydrogen (H2) in the Galactic disk toward 139 O-type and early B-type stars at Galactic latitudes $|b| < 10^{\circ}$, with updated photometric and parallax distances. The H2…