Results 31 to 40 of about 501,439 (210)
Interstellar processes: Ortho/para conversion, radiative association, and dissociative recombination
EPJ Web of Conferences, 2015 The study of the ortho-to-para ratio of assorted gas-phase interstellar molecules such as H2, H2O, NH3, and H2O+ has gained interest in recent years, based partially on new spectral observations of light hydrides by the Herschel Space Observatory ...
Herbst Eric
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Far-ultraviolet Dust Extinction and Molecular Hydrogen in the Diffuse Milky Way Interstellar Medium
The Astrophysical Journal, 2023 We aim to compare variations in the full-UV dust extinction curve (912–3000 Å), with the H i /H _2 /total H content along diffuse Milky Way sightlines, to investigate possible connections between ISM conditions and dust properties. We combine an existing
Dries Van De Putte +4 more
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EXCITATION OF C2IN DIFFUSE INTERSTELLAR CLOUDS
The Astrophysical Journal, 2012 We investigate the effects and the implications of incorporating new collision and radiative rates in modeling the excitation of diatomic carbon molecule. The present results suggest that diffuse and translucent interstellar clouds may present a structure in which regions with different densities and kinetic temperatures overlap along the line of sight,
S. Casu, Cesare Cecchi-Pestellini
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Magnetic Fields in Diffuse H I and Molecular Clouds [PDF]
, 2005 This book chapter reviews the current state of observations of magnetic fields in diffuse H I and in dense molecular clouds. It covers techniques for measuring magnetic fields, the analysis of the observations, and the role of magnetic fields in the ...
Heiles, Carl +3 more
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The formation of molecules in diffuse interstellar clouds
The Astrophysical Journal, 1977 A chemical system involving carbon and hydrogen is used to obtain steady-state abundances of a number of molecules over a wide range of densities. The calculated CH abundance agrees well with the astronomical observations. For reasonable values of the rate coefficients, the present system of reactions cannot explain, simultaneously, the measured ...
G. F. Mitchell +2 more
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Shaken or Stirred: The Diffuse Interstellar Medium with Exceptionally High SiO Abundance
The Astrophysical Journal, 2023 Interstellar shocks, a key element of stellar feedback processes, shape the structure of the interstellar medium (ISM) and are essential for the chemistry, thermodynamics, and kinematics of interstellar gas.
Daniel R. Rybarczyk +2 more
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On the detection of rubidium in diffuse interstellar clouds
The Astrophysical Journal, 1985 A search for absorption from neutral rubidium at 7800 A was conducted. No evidence for absorption to a 3 sigma limit of less than 1.5 mA was seen in the diffuse interstellar gas toward the stars omicron Persei, zeta Persei, and zeta Ophiuchi. Present results do not confirm the detection by Jura and Smith (1981) toward zeta Oph.
S. R. Federman +3 more
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A search for interstellar H2O(+) in diffuse clouds
The Astrophysical Journal, 1984 Searches for H2O(+) toward HD 187982, Zeta Oph, O micron Per, and Zeta Per have yielded significant upper limits for H2O(+) when compared with existing models for similar lines of sight. Using available oscillator strength data, the column density for HD 187982, for example, cannot exceed 3 x 10 to the 12th per sq cm H2O(+) molecules.
Wm. H. Smith +2 more
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The CS molecule in diffuse interstellar clouds
The Astrophysical Journal, 1989 The CS J = 2-1 emission line at 98 GHz has been searched for in 10 diffuse molecular clouds. CS column densities are derived by performing statistical equilibrium calculations for the rotational population distribution which includes collisional excitation by electrons as well as by neutral species.
Drdla, K. +2 more
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NaH and LiH in diffuse interstellar clouds
The Astrophysical Journal, 1978 It has been suggested that NaH may be detectable in diffuse interstellar clouds. We discuss the photodissociation process of NaH and calculate the rate of destruction by the interstellar radiation field. In the unshielded field, the mean lifetime is about 10 years. There appears to be no efficient gas-phase mechanism for the production of NaH. If it is
K. Kirby, A. Dalgarno
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