Results 71 to 80 of about 889,569 (256)

Aditional Ultra-High-Resolution Observations of Ca+ Ions in the Local Insterstellar Medium [PDF]

open access: yes, 1998
We present ultra-high-resolution (0.35 km s−1 FWHM) observations of the interstellar Ca K line towards seven nearby stars. The spectral resolution was sufficient to resolve the line profiles fully, thereby enabling us to detect hitherto unresolved ...
Crawford, IA, Lallement, R, Welsh, BY
core  

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

Modeling the Optical Colors of Galactic Cirrus Clouds in the Stripe 82 Region

open access: yesThe Astronomical Journal
Observations have shown that the optical colors of Galactic cirrus clouds differ significantly from those of extragalactic sources; thus, they can be used to distinguish Galactic cirrus from extragalactic low surface brightness (LSB) features.
Kwang-Il Seon   +4 more
doaj   +1 more source

The mass spectrum of interstellar clouds [PDF]

open access: yesInternational Astronomical Union Colloquium, 1989
AbstractThe abundance of 21-cm absorption lines seen in surveys at high latitudes can be translated into a line of sight abundance of clouds vs. column density using an empirical relationship between temperature and optical depth. As VLA surveys of 21-cm absorption at low latitudes are now becoming available, it is possible to study the variation of ...
John M. Dickey, Robert W. Garwood
openaire   +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

Mapping Galactic Dust Emission and Extinction with H I, H II, and H2

open access: yesThe Astrophysical Journal
Neutral hydrogen (H i ) emission closely traces the dust column density at high Galactic latitudes and is thus a powerful tool for predicting dust extinction. However, the relation between H i column density N _HI and high-latitude dust emission observed
Yun-Ting Cheng   +3 more
doaj   +1 more source

Putting the Diffuse Interstellar Bands on the map - literally!

open access: yes, 2013
In a quest to further our understanding of the diffuse interstellar medium (ISM) as well as the unidentified carriers of the diffuse interstellar bands (DIBs), we are mapping DIBs across the sky using hundreds of hot stars as background torches ...
van Loon, Jacco Th.
core   +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

Complex K: Supernova Origin of Anomalous-velocity H i Structure

open access: yesThe Astrophysical Journal
We address one of the lingering mysteries of high-velocity clouds: If the anomalous negative velocities are the result of the approaching gas from old supernovae, then where are the receding counterparts of the expanding shells?
G. L. Verschuur   +3 more
doaj   +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

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