Results 111 to 120 of about 30,505 (211)

A mechanism for heating dense interstellar clouds

The Astrophysical Journal, 1977
The rate of rotation of an interstellar cloud tends to increase as it contracts. As differential rotation occurs within a cloud, magnetic field lines are bent and twisted. The deformation of the magnetic field lines produces hydromagnetic waves and leads to a damping of the rotation.
openaire   +1 more source

Molecular Evolution in Interstellar Clouds. I: Ion Chemistry in Dense Clouds [PDF]

Progress of Theoretical Physics, 1979
Molecular abundances are calculated time-dependently using a chemical scheme which is constructed to represent the evolutional feature of all molecules containing up to 2 heavy atoms (C, N, 0, S and Si) and consisted of the surface recombination of hydrogen on grains and2884gasphase reactions of 234 species. For the model adopted (nH=10'cm-•, T=30K, CH=
openaire   +1 more source

Binding Energies of N-bearing Species on Interstellar Water Ice Mantles by Quantum Chemical Calculations

The Astrophysical Journal
Of the about 300 gas-phase molecular species so far detected in the interstellar medium (ISM), mostly via observations of their rotational lines, around 40% contain nitrogen (N) atoms.
Berta Martínez-Bachs, Stefano Ferrero, Cecilia Ceccarelli, Piero Ugliengo, Albert Rimola   +4 more
doaj   +1 more source

Proposed Importance of HOCO Chemistry: Inefficient Formation of CO2 from CO and OH Reactions on Ice Dust

The Astrophysical Journal
With the advent of JWST ice observations, dedicated studies on the formation reactions of detected molecules are becoming increasingly important. One of the most interesting molecules in interstellar ice is CO _2 .
Atsuki Ishibashi, Germán Molpeceres, Hiroshi Hidaka, Yasuhiro Oba, Thanja Lamberts, Naoki Watanabe   +5 more
doaj   +1 more source

CCH N = 4-3 emission from dense interstellar clouds [PDF]

, 1988
The authors have searched for N = 4 - 3 rotational line emission from the ethynyl radical CCH, at 349 GHz toward a number of galactic molecular clouds. They have detected emission from ten giant molecular clouds and have derived CCH column densities on ...
Millar, T. J., van Ardenne, A., Watt, G. D., White, G. J.   +3 more
core  

Photocleavage of Aliphatic C–C Bonds in the Interstellar Medium

The Astrophysical Journal
Ultraviolet (UV) processing in the interstellar medium (ISM) induces the dehydrogenation of hydrocarbons. Aliphatics, including alkanes, are present in different interstellar environments, being prevalently formed in evolved stars; thus, the ...
Guillermo Tajuelo-Castilla, Jesús I. Mendieta-Moreno, Mario Accolla, Jesús M. Sobrado, Sofia Canola, Pavel Jelínek, Gary J. Ellis, José Ángel Martín-Gago, Gonzalo Santoro   +8 more
doaj   +1 more source

Galactic Cosmic Ray Interaction with the Perseus Giant Molecular Cloud Using Geant4 Monte Carlo Simulation

Universe
Galactic cosmic rays (GCRs), composed of protons and atomic nuclei, are accelerated in sources such as supernova remnants and pulsar wind nebulae, reaching energies up to the PeV range.
Luan Torres, Luiz Augusto Stuani Pereira
doaj   +1 more source

Playing with FIRE: A Galactic Feedback-halting Experiment Challenges Star Formation Rate Theories

The Astrophysical Journal
Stellar feedback influences the star formation rate (SFR) and the interstellar medium of galaxies in ways that are difficult to quantify numerically, because feedback is an essential ingredient of realistic simulations.
Shivan Khullar, Christopher D. Matzner, Norman Murray, Michael Y. Grudić, Dávid Guszejnov, Andrew Wetzel, Philip F. Hopkins   +6 more
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Grain mantles: The impact on grain evolution and selective extinction [PDF]

Depletion studies are used to infer the presence of mantles and to constrain grain evolutionary models in the diffuse interstellar medium. The presence of these mantles appears to be important in the evolution of the grains inside diffuse as well as ...
Joseph, Charles L.
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Dust Absorption toward Supernova Remnant W44

The Astronomical Journal
Supernova remnants (SNRs) can strongly affect the chemical composition of the interstellar dust. In this paper, we investigate to what degree the dust and ices are modified by observing four stars expected to be absorbed by a giant molecular cloud ...
Tian-Yu Tu, Adwin Boogert, Yang Chen, Wenlang He   +3 more
doaj   +1 more source