Results 41 to 50 of about 1,811,090 (221)

Chemical Kinetics of 2‐, 4‐, and 2,4‐Seleno‐Uracils at Low Temperatures: Tautomerizations and Rotamerizations on Inert Matrices

International Journal of Chemical Kinetics, EarlyView.
ABSTRACT In the interstellar medium, chemical reactions proceed under conditions vastly different to those on Earth; these include extremely low temperatures and densities and take place in the gas phase and on water–ice grains. Understanding the energetics and more importantly the kinetics of such reactions is of relevance to the consequences on how ...
Judith Wurmel, John M. Simmie
wiley   +1 more source

On the Question of Interstellar Silicate Absorption

The Astrophysical Journal, 1970
The observations of the absorption feature in the infrared spectrum by Knacke, Gaustad, Gillett, and Stein are discussed; and doubts concerning their identifying silicate minerals in interstellar grains are raised.
B. Donn, K. S. Krishna Swamy, C. Hunter
openaire   +1 more source

Interstellar absorption and color excess in SCO OB1 [PDF]

The Astronomical Journal, 1971
New spectral types and photometry are reported for numerous stars in Sco OB-1 and in the foreground of the association. The new data permit reddening in the local spiral arm to be subtracted out in a discussion of reddening in the gas and dust of an adjacent spiral arm.
Schild, R., Neugebauer, G., Westphal, J. A.   +2 more
openaire   +2 more sources

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

International Journal of Chemical Kinetics, EarlyView.
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

Isolation of a Highly Reactive CBNC Heterocumulene via Azidoborylene Photolysis: Facile Access to a Crystalline Dioxaborirane

Angewandte Chemie, Volume 138, Issue 29, 13 July 2026.
Azidoborylene photolysis results in the isolation of a reactive C═B═N═C heterocumulene bearing an ambiphilic boron centre. Addition of 3O2 to this species results in the clean conversion to a unique example of a dioxaborirane. ABSTRACT Oxidation of the formal boron(0) complex MeCAAC2B in the presence of tetrabutylammonium azide leads to the formation ...
Hayley King, Vignesh Pattathil, William Kennedy, Robert K. Szilagyi, Conor Pranckevicius   +4 more
wiley   +2 more sources

From Flybys to Sample Return: A Review of Space Probes and Robotic Sampling Technologies for Small Bodies

Journal of Field Robotics, EarlyView.
ABSTRACT As a crucial puzzle piece of deep space exploration, exploring small bodies can provide significant scientific insights and valuable mineral resources. Unlike missions to the Moon and Mars, small‐body missions pose distinct technical challenges, including communication delays, weak gravity, and uncertain environments. This paper reviews a full
Xin Zhang, Hao Zhou, Dalin Zhou, Zhaojie Ju   +3 more
wiley   +1 more source

The Great Cosmic Silence: What Does the Fermi Paradox Tell About the Future of Humanity?

Global Policy, EarlyView.
ABSTRACT This article examines how institutional time horizons shape the long‐term survival prospects of human technological civilisation. While research on global catastrophic and existential risks has expanded, the temporal structures of political‐economic institutions remain underexamined.
Heikki Patomäki
wiley   +1 more source

Evaluating maturity of organic matter in hydrated C1 and CM‐like clasts and a dehydrated clast within a polymict eucrite and a howardite

Meteoritics &Planetary Science, EarlyView.
Abstract Volatile‐rich xenolithic clasts in different types of brecciated meteorites represent unique pristine solar system material. This study investigates the maturity and thermal history of organic matter using Raman spectroscopy and aqueous alteration effects using infrared spectroscopy in the matrix of 15 volatile‐rich clasts (C1 and CM‐like ...
Swarna Prava Das, Alessandro Maturilli, Aurélie Van den Neucker, Markus Patzek, Dipak Kumar Panda, Gopal K. Pradhan, Guneshwar Thangjam, Surya Snata Rout   +7 more
wiley   +1 more source

Al2O Photochemistry

The Astrophysical Journal
The chemistry within the interstellar medium (ISM) is notably influenced by the interplay between kinetics and photochemical processes, which play significant roles in both the formation and destruction of molecular species.
Tarek Trabelsi, Joseph S. Francisco
doaj   +1 more source

Kinematics of a high-redshift galaxy: A case study [PDF]

Serbian Astronomical Journal, 2000
A kinematics of a z = 2.81 galaxy toward bright QSO 0528-250, as inferred from the absorption spectroscopy is discussed. There are sufficient arguments for a far-reaching conclusion that we are observing an older, uninvolved version of the local Galactic
Ćirković M.M.
doaj   +1 more source