Results 21 to 30 of about 1,259 (182)
Interstellar magnesium abundances
The Astrophysical Journal, 1984 An improved evaluation of the Mg II 1240 A doublet oscillator strength is used in conjunction with recently published Copernicus observations to derive accurate Mg II column densities toward 74 stars. These imply an average of 40 percent of interstellar magnesium is in the gaseous phase.
M. J. Murray +3 more
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The Determination of Electron Abundances in Interstellar Clouds [PDF]
Symposium - International Astronomical Union, 1979 A new method for estimating electron fractions in shielded molecular clouds is proposed on the basis of gas phase ion-molecule reactions which involves measuring the quantity . Applied to existing data, it yields upper limits to Xe in the range from 10−8 to 10−7 for a variety of clouds, warm as well as cool.
A. Wootten, R. Snell, A. E. Glassgold
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THE ABUNDANCE OF BORON IN DIFFUSE INTERSTELLAR CLOUDS [PDF]
The Astrophysical Journal, 2011 We present a comprehensive survey of boron abundances in diffuse interstellar clouds from observations made with the Space Telescope Imaging Spectrograph (STIS) of the Hubble Space Telescope. Our sample of 56 Galactic sight lines is the result of a complete search of archival STIS data for the B II 1362 resonance line, with each detection confirmed by ...
Ritchey, A. M. +3 more
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The Astrophysical Journal, 2023 We examine the factors responsible for the variation in the ionization parameter ( U ) of high-redshift star-forming galaxies based on medium-resolution JWST/NIRSpec observations obtained by the Cosmic Evolution Early Release Science survey.
Naveen A. Reddy +4 more
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Interstellar Extinction and Elemental Abundances [PDF]
The Astrophysical Journal Supplement Series, 2021 Abstract Elements in the interstellar medium (ISM) exist in the form of gas or dust. The interstellar extinction and elemental abundances provide crucial constraints on the composition, size, and quantity of interstellar dust. Most of the extinction modeling efforts have assumed the total (gas and dust) abundances of the dust-forming ...
Zuo, W. B., Li, Aigen, Zhao, Gang
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Cyanopolyyne Chemistry in the L1544 Prestellar Core: New Insights from GBT Observations
The Astrophysical Journal, 2023 We report a comprehensive study of the cyanopolyyne chemistry in the prototypical prestellar core L1544. Using the 100 m Robert C. Byrd Green Bank Telescope, we observe three emission lines of HC _3 N, nine lines of HC _5 N, five lines of HC _7 N, and ...
Eleonora Bianchi +11 more
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The Effect of an Inert Solid Reservoir on Molecular Abundances in Dense Interstellar Clouds
Open Astronomy, 2012 The question, what is the role of freeze-out of chemical species in determining the molecular abundances in the interstellar gas is a matter of debate.
Kalvāns Juris, Shmeld Ivar
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The Abundance of Interstellar Boron
The Astrophysical Journal, 2000 Accepted for publication in The Astrophysical Journal. 13 pages, including 2 tables and 4 figures. Also available at http://fuse.pha.jhu.edu/~howk/Papers/
Howk, J. Christopher +2 more
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The Interaction Between Accretion from the Interstellar Medium and Accretion from the Evolved Binary Component in Barium Stars [PDF]
Journal of Astronomy and Space Sciences, 2018 The reanalysis of the previously published abundance pattern of mild barium star HD202109 (ζ Cyg) and the chemical compositions of 129 thin disk barium stars facilitated the search for possible correlations of different stellar parameters with second ...
Yeuncheol Jeong +2 more
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The abundance of interstellar lithium
The Astrophysical Journal, 1984 The interstellar Li I 6707-A absorption line is detected toward Rho Oph A at an equivalent width of 3.1 + or - 1.9 (3 sigma)mA. Upper limits near 1 mA also are found toward seven other stars, including 55 Cyg, toward which relatively strong Li I absorption was previously reported.
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