Results 61 to 70 of about 2,128 (220)

Organic Chemistry in the H2-bearing, CO-rich Interstellar Ice Layer at Temperatures Relevant to Dense Cloud Interiors

open access: yesThe Astrophysical Journal
Ice chemistry in the dense, cold interstellar medium (ISM) is probably responsible for the formation of interstellar complex organic molecules (COMs). Recent laboratory experiments performed at T ∼ 4 K have shown that irradiation of CO:N _2 ice samples ...
Rafael Martín-Doménech   +3 more
doaj   +1 more source

Energetic secondary electrons in dense interstellar clouds

open access: yesThe Astrophysical Journal, 1977
We have calculated the steady-state distribution of secondary electrons in dense interstellar clouds that are produced in collisions between primary cosmic rays and thermal gas atoms. We find that if the magnetic field in such clouds is approx.100 microgauss, then the synchrotron volume emissivity in the clouds is sufficiently large that discrete ...
R. L. Brown, A. P. Marscher
openaire   +1 more source

Deciphering the “Missing Xenon Paradox” in Celestial Bodies: A Multifaceted Perspective Toward Demystifying This Enigma

open access: yesJournal of Geophysical Research: Planets, Volume 131, Issue 4, April 2026.
Abstract Xenon (Xe) is a heavy noble gas with intriguing chemical properties, such as having several stable isotopes and the ability to form compounds under extreme conditions. Despite the predictions based on cosmochemical models that suggest xenon should be relatively abundant in planetary reservoirs, empirical data indicate a significant depletion ...
Avinash Kumar Both   +2 more
wiley   +1 more source

First Principles Rovibronic Absorption Spectra of HF Molecule

open access: yesJournal of Computational Chemistry, Volume 47, Issue 6, March 5, 2026.
Hydrogen fluoride (HF) is astrophysically important, as it has been detected in sunspots, Venus, red giants, and the interstellar medium, serving as a probe of exoplanet atmospheres. This article presents an ab initio investigation of HF rovibronic spectroscopy, combining high‐level electronic‐structure data with nuclear‐motion solutions and refinement
Nariman Abu El Kher   +5 more
wiley   +1 more source

Discovery and Initial Investigation of a New Low Surface Brightness Planetary Nebula Candidate at High Galactic Latitude

open access: yesAstronomische Nachrichten, Volume 347, Issue 3, March 2026.
ABSTRACT Planetary nebulae represent a late evolutionary phase of low‐ to intermediate‐mass stars. In this article, we present the serendipitous discovery of a previously unknown, faint potential Galactic planetary nebula (PN) in the constellation Camelopardalis, identified during a survey‐inspection, aiming at the detection of dwarf companions of the ...
W. E. Celnik   +12 more
wiley   +1 more source

Electronic spectroscopy of cold ions in a radio-frequency trap [PDF]

open access: yes, 2010
The low density of ions in mass spectrometers generally precludes direct absorption measurements. The spectrum of ions can nonetheless be obtained by using resonance two-color photofragmentation or multiphoton photofragmentation techniques.
Rudnev, Vitaly S.
core   +1 more source

Encounters between stars and dense interstellar clouds

open access: yesThe Astrophysical Journal Supplement Series, 1977
From analysis of statistics of the properties of dense interstellar clouds, we show that a disk star the age of the Sun has probably passed through about 135 clouds of n (H) > or approx. =10/sup 2/ cm/sup -3/ and about 16 clouds with n (H) > or approx. =10/sup 3/ cm/sup -3/.
R. J., Jr. Talbot, M. J. Newman
openaire   +1 more source

Confined Chemistry in Space: Zeolite‐Supported Fe13 Nanoclusters Modulate CS Reactivity

open access: yesSmall Structures, Volume 7, Issue 3, March 2026.
The study explores how an Fe13 cluster confined in chabazite reshapes the reaction of CS and H2 under astrochemical conditions. Confinement promotes C–S bond cleavage over hydrogenation, directing chemistry toward CH4 and H2S formation. Additional CS enables CS2 and C2 species. Microkinetic analysis identifies protoplanetary environments where zeolites
Gerard Pareras, Albert Rimola
wiley   +1 more source

Coevolution of Giant Molecular Clouds, Filaments, and Clumps as a Function of the Dense Gas Mass Fraction

open access: yesThe Astrophysical Journal Supplement Series
We investigate the evolutionary dynamics with archival continuum and line data of 27 giant molecular clouds (GMCs) in the Milky Way, focusing on their influence on star formation. Examining the dense gas mass fraction (DGMF) among the GMCs, we categorize
Wenjun Zhang   +14 more
doaj   +1 more source

Atmospheric and Deposition Responses of 10Be to Volcanic Eruptions Inferred From the Aerosol‐Climate Model ECHAM6.3‐HAM2.3‐SALSA2.0: 10Be

open access: yesGeophysical Research Letters, Volume 53, Issue 4, 28 February 2026.
Abstract 10Be deposition in ice cores is widely used for solar reconstructions, but its interpretation is complicated by volcanic influences. Using the state‐of‐the‐art aerosol‐climate model ECHAM6.3‐HAM2.3‐SALSA2.0: 10Be, we assess the impacts of three major volcanic eruptions: Agung (1963), El Chichón (1982) and Pinatubo (1991). All eruptions enhance
Minjie Zheng   +8 more
wiley   +1 more source

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