Results 41 to 50 of about 2,623 (182)

A Possible Chemical Clock in High-mass Star-forming Regions: N(HC3N)/N(N2H+)?

The Astrophysical Journal Supplement Series, 2023
We conducted observations of multiple HC _3 N ( J = 10−9, 12−11, and 16−15) lines and the N _2 H ^+ ( J = 1−0) line toward a large sample of 61 ultracompact (UC) H ii regions, through the Institut de Radioastronomie Millmétrique 30 m and the Arizona ...
Y. X. Wang, J. S. Zhang, H. Z. Yu, Y. Wang, Y. T. Yan, J. L. Chen, J. Y. Zhao, Y. P. Zou   +7 more
doaj   +1 more source

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

Interstellar Molecules - The Optical Region [PDF]

Highlights of Astronomy, 1971
Considerable attention has recently been given to the observation of interstellar molecules by radio methods. Interstellar molecules have also been given a boost because of excitation by the 3K black body radiation field (to use a convenient description).
openaire   +1 more source

The futuristic manifolds of REM sleep

Journal of Sleep Research, Volume 34, Issue 2, April 2025.
Summary Since one of its first descriptions 70 years ago, rapid eye movement sleep has continually inspired and excited new generations of sleep researchers. Despite significant advancements in understanding its neurocircuitry, underlying mechanisms and microstates, many questions regarding its function, especially beyond the early neurodevelopment ...
Liborio Parrino, Ivana Rosenzweig
wiley   +1 more source

H2 Ortho–Para Spin Conversion on Inhomogeneous Grain Surfaces. II. Impact of the Rotational Energy Difference between Adsorbed Ortho-H2 and Para-H2 and Implication for Deuterium Fractionation Chemistry

The Astrophysical Journal
We investigate how the H _2 ortho-to-para ratio (OPR) and deuterium fractionation in star-forming regions are affected by nuclear spin conversion (NSC) on dust grains. Particular focus is placed on the rotational energy difference between ortho-H _2 (o-H
Kenji Furuya, Toshiki Sugimoto, Kazunari Iwasaki, Masashi Tsuge, Naoki Watanabe   +4 more
doaj   +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

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

Over the possible role of metal atom clusters in cosmochemistry and in the origin of life

Revista de Química, 1992
We present here the hypothesis of a possible relationship between metal atom clusters and the formation of organic molecules in the interstellar medium and on small bodies as a possible pathway to the origin of such molecules.
Silvio Dioses Castro, Richard Korswagen
doaj  

Raman analysis of organic refractory materials after energetic processing: Evidence for amorphous carbon on TNOs and comets

Meteoritics &Planetary Science, EarlyView.
Abstract Amorphous carbon (αC) is found in various extraterrestrial particles, including those thought to originate from the outer Solar System. αC can form through two main processes involving C‐rich materials: exposure to energetic charged particles and thermal processing.
M. Germanà, A. Vyjidak, G. A. Baratta, B. M. Giuliano, R. G. Urso, C. Scirè, D. Fulvio, T. Grassi, P. Jusko, P. Caselli, M. E. Palumbo   +10 more
wiley   +1 more source