Results 21 to 30 of about 4,742 (219)
The Astrophysical Journal Supplement Series, 2023 Deuterium (D) was exclusively generated in the Big Bang, and the standard Big Bang nucleosynthesis (BBN) model predicts a primordial abundance of D/H ≈ 26 parts per million (ppm). As the Galaxy evolves, D/H gradually decreases because of astration.
X. J. Yang, Aigen Li
doaj +1 more source
Laboratory Measurement of Millimeter-wave Transitions of 13CH2DOH for Astronomical Use
The Astrophysical Journal, 2022 Methanol (CH _3 OH) is an abundant interstellar species and is known to be an important precursor of various interstellar complex organic molecules. Among the methanol isotopologues, CH _2 DOH is one of the most abundant isotopologues and it is often ...
Yuki Ohno +7 more
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Turbulence in the interstellar medium [PDF]
, 2014 Turbulence is ubiquitous in the insterstellar medium and plays a major role in several processes such as the formation of dense structures and stars, the stability of molecular clouds, the amplification of magnetic fields, and the re-acceleration and ...
Chian, A. C. -L. +9 more
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Measurement of Interstellar Extinction in Emission Line Stars [PDF]
Symposium - International Astronomical Union, 1970 Usually selective interstellar extinction is derived by comparing the spectrum of a reddened star with an unreddened nearby star, preferably of the same spectral type. But in many cases this comparison is not possible, so that new methods have to be used.A direct measure of this quantity is possible when a spectrum shows a number of emission lines as ...
openaire +1 more source
Technology requirements of exploration beyond Neptune by solar sail propulsion [PDF]
, 2010 This paper provides a set of requirements for the technology development of a solar sail propelled Interstellar Heliopause Probe mission. The mission is placed in the context of other outer solar systems missions, ranging from a Kuiper Belt mission ...
Macdonald, Malcolm +8 more
core +1 more source
Diagnosing the interstellar medium of galaxies with far-infrared emission lines [PDF]
, 2023 Context. Gas cooling processes in the interstellar medium (ISM) are key to understanding how star formation occurs in galaxies. Far-infrared (FIR) fine-structure emission lines can be used to infer gas conditions and trace different phases of the ISM ...
S. C. Trager +8 more
core +1 more source
Backscattering and Line Broadening in Orion
The Astronomical Journal, 2022 Examination of emission lines in high-velocity-resolution optical spectra of the Orion Nebula confirms that the velocity component on the red wing of the main ionization front emission line is due to backscattering in the Photon Dominated Region.
C. R. O’Dell +2 more
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Studies of the Large Magellanic Cloud Using Optical Interstellar Emission Lines [PDF]
Symposium - International Astronomical Union, 1991 Optical observations have been made of the halo of 30 Doradus, in the vicinity of SN 1987A and of giant shells in the LMC.
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Optimizing End-to-End System Performance for Millimeter and Submillimeter Spectroscopy of Protostars: Wideband Heterodyne Receivers and Sideband-Deconvolution Techniques for Rapid Molecular-Line Surveys [PDF]
, 2011 This thesis describes the construction, integration, and use of a new 230-GHz ultra-wideband heterodyne receiver, as well as the development and testing of a new sideband-deconvolution algorithm, both designed to enable rapid, sensitive molecular-line ...
Sumner, Matthew Casey
core +1 more source
The GBT Diffuse Ionized Gas Survey (GDIGS): Discrete Sources
The Astrophysical Journal, 2023 The Green Bank Telescope Diffuse Ionized Gas Survey (GDIGS) traces ionized gas in the Galactic midplane by observing radio recombination line (RRL) emission from 4 to 8 GHz. The nominal survey zone is 32.°3 > ℓ > −5°, ∣ b ∣ < 0.°5. Here, we analyze GDIGS
Dylan J. Linville +8 more
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