Results 31 to 40 of about 1,259 (182)

Photochemical Generation and Spectroscopic Characterization of Parent 3‐Iminooxetane and 3‐Oxazoline From 3‐Azidooxetane

open access: yesChemistry – A European Journal, EarlyView.
Two previously uncharacterized heterocyclic imines, 3‐iminooxetane and 3‐oxazoline, are generated simultaneously by irradiation of 3‐azidooxetane under matrix isolation conditions. The infrared spectra provide reference data for future gas‐phase studies and may facilitate their search in the interstellar medium.
Mika Maehara   +4 more
wiley   +1 more source

Ne and Fe Abundances in the Interstellar Medium: Archival Study of Fe-L and Ne-K Edges in Chandra and XMM-Newton

open access: yesThe Astrophysical Journal
The abundance of elements in the interstellar medium is a key facet for many fields of astrophysical study. In the soft X-ray spectra, absorption by interstellar gas can result in deep absorption features that affect continuum measurements. In this paper,
D. L. Moutard   +4 more
doaj   +1 more source

VUV and mid‐UV photoabsorption cross sections of thin films of glycine and alanine: Application to their photochemistry in the solar system

open access: yesPhotochemistry and Photobiology, EarlyView.
Thin solid films of pure glycine or alanine (thicknesses ranging from 10 to 700 nm) were prepared on MgF2 windows using a vacuum sublimation/recondensation method. VUV‐UV spectroscopy of these films enabled us to characterize new absorption cross sections for glycine and alanine for VUV‐UV radiations between 120 and 300 nm.
Juliette Pastore   +6 more
wiley   +1 more source

Generalized Te([O iii])–Te(He i) Discrepancies in Ionized Nebulae: Possible Evidence of Case B Deviations and Temperature Inhomogeneities

open access: yesThe Astrophysical Journal
The physics of recombination lines in the He i singlet system is expected to be relatively simple, supported by accurate atomic models. We examine the intensities of He i singlets λ 3614,  λ 3965,  λ 5016,  λ 6678, and  λ 7281 and the triplet He i λ 5876
J. E. Méndez-Delgado   +13 more
doaj   +1 more source

The Astrodust+PAH Model: A Unified Description of the Extinction, Emission, and Polarization from Dust in the Diffuse Interstellar Medium

open access: yesThe Astrophysical Journal, 2023
We present a new model of interstellar dust in which large grains are a single composite material, “astrodust,” and nanoparticle-sized grains come in distinct varieties including polycyclic aromatic hydrocarbons (PAHs). We argue that a single-composition
Brandon S. Hensley, B. T. Draine
doaj   +1 more source

Abundances and Depletions of Interstellar Oxygen [PDF]

open access: yesThe Astrophysical Journal, 2005
62 total pages (37 text), 15 figures, 9 ...
Jensen, Adam G.   +2 more
openaire   +2 more sources

On Our Cosmic (In)significance

open access: yesRatio, EarlyView.
ABSTRACT This article discusses three interpretations of cosmic significance, all of which reveal something important about the notion of significance. Along the way, it proposes a unified view of significance by combining elements of each of the views.
Oskari Sivula
wiley   +1 more source

A Definitive Determination of the Interstellar Carbon Abundance toward ρ Ophiuchi A and B

open access: yesThe Astrophysical Journal Letters
We present the results of an effort to derive interstellar gas-phase C ii abundances along the lines of sight toward ρ  Oph A and B. Our analysis is based on high-resolution near-ultraviolet and far-ultraviolet archival spectra acquired with the Space ...
Adam M. Ritchey   +3 more
doaj   +1 more source

Cis–Trans Rotational Isomerism of Formic Acid, Sulfur, and Selenium Analogues and Their Dimers: Chemical Kinetics Under Interstellar Conditions

open access: yesInternational Journal of Chemical Kinetics, Volume 58, Issue 12, Page 1136-1145, December 2026.
ABSTRACT We present chemical kinetic rate constants for the cis to trans isomerisation or rotamerization of monomeric seleno‐, thio‐, and formic acids and that of three of their dimeric species, based on variational transition state theory and multidimensional tunneling calculations in the gas‐phase, from 10 K to 300 K. These provide, firstly, reliable
Judith Wurmel, John M. Simmie
wiley   +1 more source

Determining the Methanol Deuteration in the Disk Around V883 Orionis with Laboratory Measured Spectroscopy

open access: yesThe Astronomical Journal
Deuterium fractionation, as studied through mono-deuterated methanol, is frequently used as a diagnostic tool to trace the physical conditions and chemical evolution of interstellar sources. This study investigates methanol deuteration in the disk around
Shaoshan Zeng   +5 more
doaj   +1 more source

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