Results 51 to 60 of about 1,259 (182)

Features of Chemical-Element Abundances in Open Star Clusters of the Galaxy

Open Astronomy, 2016
On the basis of the authors’ compiled catalog containing spectroscopic abundances of 14 chemical elements for 90 open star clusters of the Galaxy, we show that in the young clusters not only barium but also three other studied elements of slow neutron ...
Marsakov V. A., Koval’ V. V., Gozha M. L., Shpigel’ L. V.   +3 more
doaj   +1 more source

Elastic Properties of Titan Tholins Revealed by Brillouin Spectroscopy

Journal of Geophysical Research: Planets, Volume 131, Issue 10, October 2026.
Abstract Titan tholins, complex organic solids synthesized by simulating photochemical processes in Titan's atmosphere, are widely regarded as analogs to organic surface materials on the Saturnian moon. Their mechanical properties are critical for understanding the evolution of Titan's geomorphology and crustal layering.
Mark A. Johnson, Jose R. Montes‐Bojorquez, Adis Husić, Xinting Yu, Wenhao Su, Jia‐Sen Hu, Ryan Blase, Edward Patrick, Alan Whittington, Jin S. Zhang   +9 more
wiley   +1 more source

The Infrared Complex Refractive Index and Band Strengths of Coronene Thin Films

The Astrophysical Journal
Polycyclic aromatic hydrocarbon (PAH) molecules have long been theorized to be present in a multitude of interstellar environments. The radio-frequency detections of specific cyanosubstituted PAH molecules in the Taurus Molecular Cloud have provided new ...
J. E. Roser, L. Jovanović, A. Ricca
doaj   +1 more source

Photochemical effects of Mars‐like UV irradiation on carboxylic acids in carbonaceous chondrites and expectations for abiotic background organics on Mars

Meteoritics &Planetary Science, Volume 61, Issue 10, Page 2445-2465, October 2026.
Abstract In the search for life on Mars, understanding the origin of preserved organics is critical. Expected sources include exogenous delivery, endogenous synthesis, and potentially life. Environmental processing by ultraviolet (UV) irradiation can alter these organics, obscuring hallmarks of their origin. To deconvolve these effects, we conducted an
D. K. Buckner, J. C. Aponte, A. C. Schuerger, D. I. Foustoukos, F. Seguin, M. B. Wilhelm, G. Cooper, A. J. Williams   +7 more
wiley   +1 more source

A Solar Analog Model for Decrease in Far Ultraviolet Irradiance Under a Grand Minimum

Earth and Space Science, Volume 13, Issue 9, September 2026.
Abstract Solar analog field stars having a range of magnetic activity can provide an estimate of solar spectral irradiance (SSI) variability relevant to understanding the Sun's influence on terrestrial climate. This approach is particularly useful for far ultraviolet (FUV) irradiance that cannot be observed from the Earth surface.
D. Lubin, C. Melis, D. Tytler
wiley   +1 more source

Neutron Diffraction Evidence for Stress‐Induced Melting of Ice During Deformation of D2O‐Ice Ih—Fluorite Mixtures

Journal of Geophysical Research: Planets, Volume 131, Issue 9, September 2026.
Abstract Water ice is an important rock‐forming mineral, both on the Earth and on various extraterrestrial bodies. Naturally occurring ice is often “dirty”–an intimate mixture with harder mineral grains, which can have significant effects on the bulk properties of the aggregate. We have used neutron powder diffraction, with in situ triaxial deformation,
Ceri A. Middleton, A. Dominic Fortes, Peter M. Grindrod, Shu Yan Zhang, Stephen J. Covey‐Crump, Peter R. Sammonds, Ian G. Wood, David P. Dobson, Lidunka Vočadlo, Simon A. Hunt   +9 more
wiley   +1 more source

Strongly Depleted Methanol and Hypervolatiles in Comet C/2021 A1 (Leonard): Signatures of Interstellar Chemistry?

The Planetary Science Journal, 2023
We measured the chemical composition of comet C/2021 A1 (Leonard) using the long-slit echelle grating spectrograph iSHELL/IRTF on 2021 December 20 and on 2022 January 8 and 9.
Sara Faggi, Manuela Lippi, Michael J. Mumma, Geronimo L. Villanueva   +3 more
doaj   +1 more source

The abundance of interstellar chlorine in the galaxy [PDF]

Monthly Notices of the Royal Astronomical Society, 1984
Des largeurs equivalentes nouvellement deduites de spectres IUE ont ete combinees a des largeurs equivalentes de Copernicus pour evaluer les abondances interstellaires du chlore pour plus de 40 lignes de visee galactiques. L'abondance presente une decroissance marquee avec l'augmentation de n(H) suivant la relation approchee a(Cl)≃4,9-0,3 log [n(H) cm −
A. W. Harris, G. E. Bromage
openaire   +1 more source

When Communication Enables Catastrophe: Nuclear Risk and the Short Lifetimes of Technological Civilizations

Risk Analysis, Volume 46, Issue 9, September 2026.
ABSTRACT The Fermi paradox may partly reflect technological self‐destruction acting as a Great Filter during post‐industrial development. Because the empirical record consists of a single civilization observed over an eighty‐year nuclear age, the exercise reported here is best understood as a structured, historically anchored scenario analysis rather ...
Vincenzo Alfano
wiley   +1 more source

Detection of Deuterated Hydrocarbon Nanoparticles in the Whirlpool Galaxy, M51

The Astrophysical Journal Letters
Deuteration of hydrocarbon material, including polycyclic aromatic hydrocarbons (PAHs), has been proposed to account for the low gas-phase abundances of D in the interstellar medium (ISM). JWST spectra of four star-forming regions in M51 show an emission
B. T. Draine, Karin Sandstrom, Daniel A. Dale, J.-D. T. Smith, Ryan Chown, Grant P. Donnelly, Sara E. Duval, Cory M. Whitcomb, Angela Adamo, L. Armus, Danielle A. Berg, Torsten Böker, Alberto D. Bolatto, Martha L. Boyer, Daniela Calzetti, B. G. Elmegreen, Brandt A. L. Gaches, Karl D. Gordon, L. K. Hunt, R. C. Kennicutt, Ralf S. Klessen, Thomas S.-Y. Lai, Adam K. Leroy, Sean T. Linden, Alex Pedrini, Noah S. J. Rogers, Julia C. Roman-Duval, Eva Schinnerer, Evan B. Skillman, Fabian Walter, Tony D. Weinbeck, Benjamin F. Williams   +31 more
doaj   +1 more source