Results 181 to 190 of about 156,409 (216)
Some of the next articles are maybe not open access.
Abundances in the Interstellar Medium
Annual Review of Astronomy and Astrophysics, 1994Recent developments in the theory of element production and the chemical evolution of the galaxy are presented. Following this, observational data and their interpretation are given. A case by case analysis of results for D, He, Li and CNO isotope data in the disk and center of our galaxy is presented; previous results for element gradients are also ...
R T Rood
exaly +3 more sources
From interstellar abundances to grain composition: the major dust constituents Mg, Si, and Fe
Astronomy and Astrophysics, 2010 We analyse observational correlations for three elements entering into the composition of interstellar silicate and oxide grains. Using current solar abundances, we converted the gas phase abundances into dust phase abundances for 196 sightlines.
Nikolai Voshchinnikov, Thomas Henning
exaly +2 more sources
Abundance And Chemistry Of Interstellar Hoco+
Astronomy and astrophysics, 1991Column densities of 10 to the 15th/sq cm toward the Galactic center and not more than 10 to the 12th/sq cm for cold dark clouds are derived from observations using an LVG model, and the chemical implications are discussed. The HOCO(+) 4(04)-3(03) line toward Sgr A is mapped. The fractional abundance of HOCO(+) in the Galactic center region was found to
MINH, YC +4 more
openaire +2 more sources
The Abundance of Interstellar Krypton
The Astrophysical Journal, 1997We present high signal-to-noise ratio HST Goddard High Resolution Spectrograph (GHRS) observations of the weak interstellar Kr I λ1236 absorption toward the stars τ CMa, κ Ori, e Ori, λ Ori, δ Sco, ω1 Sco, e Per, and ζ Per. In combination with previous GHRS measurements of Kr I in two other sight lines (ζ Oph and 1 Sco), these new observations yield a ...
Jason A. Cardelli, David M. Meyer
openaire +1 more source
Interstellar carbon abundance [PDF]
Acta Astronomica, 2000 We present 10 new measurements of carbon gas phase column density in the interstellar medium. We have used spectra made with the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope containing the CII 1334.5 Å and CII* 1335.7 Å lines.
openaire +1 more source
The Abundance of Interstellar CO
1987The current understanding of the abundance of CO in interstellar clouds is reviewed from both observational and theoretical points of view. In special circumstances, the CO and H2 column densities can be measured directly by ultraviolet and infrared absorption line techniques.
Ewine F. Dishoeck, John H. Black
openaire +1 more source
Abundances in the interstellar medium
The Astronomy and Astrophysics Review, 1992Recent developments in the theory of element production and the chemical evolution of the galaxy are presented. Following this, observational data and their interpretation are given. A case by case analysis of results for D, He, Li and CNO isotope data in the disk and center of our galaxy is presented; previous results for element gradients are also ...
T. L. Wilson, F. Matteucci
openaire +1 more source
Interstellar silicon abundance [PDF]
Acta Astronomica, 2003 We present 34 measurements of silicon gas phase column densities in the interstellar medium. We have used spectra containing the Si II 1808 Å line which were obtained with the Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope (HST).
openaire +1 more source
Interstellar Abundance Standards Revisited
The Astrophysical Journal, 2001We evaluate the stellar abundances often used to represent the total (gas plus dust) composition of the interstellar medium. Published abundances for B stars, young later type (F and G) stars, and the Sun are compared to the modeled dust-phase and measured gas-phase compositions of the interstellar medium.
Ulysses J. Sofia, David M. Meyer
openaire +1 more source
Interstellar abundances towards SN1987A
AIP Conference Proceedings, 1989We have derived abundances in three intermediate‐velocity clouds towards SN1987A, using high‐resolution data from the IUE. For the 70 km s−1 cloud, abundances are close to their solar values and a galactic halo origin is proposed for the cloud. The two other features, at 129 and 171 km s−1, have mean abundances of −0.59±0.15 dex and −0.46±0.15 dex ...
J. C. Blades, N. Panagia
openaire +1 more source