Results 61 to 70 of about 3,169 (205)

Insights Into the Gas‐Phase Structure and Internal Dynamics of Diphenylsilane: A Broadband Rotational Spectroscopy Study

open access: yesChemPhysChem, Volume 26, Issue 2, January 14, 2025.
The structure of diphenylsilane could be determined from the rotational spectra of all its singly substituted heavy atom isotopologues. A comparison with its oxygen analogue diphenylether revealed some interesting differences in the internal dynamics as well as in the gas‐phase structure.
Gayatri Batra, Melanie Schnell
wiley   +1 more source

Pre-main-sequence Brackett Emitters in the APOGEE DR17 Catalog: Line Strengths and Physical Properties of Accretion Columns

open access: yesThe Astrophysical Journal, 2022
Very young ( t ≲ 10 Myr) stars possess strong magnetic fields that channel ionized gas from the interiors of their circumstellar disks to the surface of the star.
Hunter Campbell   +23 more
doaj   +1 more source

Toward an efficient second‐order method for computing the surface gravitational potential on spherical‐polar meshes

open access: yesAstronomische Nachrichten, Volume 345, Issue 8, October 2024.
Abstract Astrophysical accretion discs that carry a significant mass compared with their central object are subject to the effect of self‐gravity. In the context of circumstellar discs, this can, for instance, cause fragmentation of the disc gas, and—under suitable conditions—lead to the direct formation of gas‐giant planets.
Oliver Gressel, Udo Ziegler
wiley   +1 more source

First direct detection of large polycyclic aromatic hydrocarbons on asteroid (162173) Ryugu samples: An interstellar heritage

open access: yesNatural Sciences, Volume 4, Issue 4, October 2024.
Large free aromatic species, with up to 61 carbon atoms, were detected in grains of the Ryugu carbonaceous asteroid using ultra‐sensitive two‐step laser mass spectrometry. This discovery confirms the presence of large polycyclic aromatic hydrocarbons in the interstellar medium and provides new information on the formation and evolution of organic ...
Hassan Sabbah   +3 more
wiley   +1 more source

Circumstellar Gas in the Wide Binary HD 188037

open access: yesThe Astrophysical Journal, 1997
We report radio, optical, and ultraviolet studies of the wide binary HD 188037 (=IRC +20439). We detect the CO (2-1) and (1-0) rotational lines from the circumstellar envelope in this system, which consists of a luminous (~7000 L☉) mass-losing M-type star and, at a separation of 075, a main-sequence A-type star. The strong (2-1) line has a very unusual
M. Jura, C. Kahane, D. Fischer, C. Grady
openaire   +1 more source

Chemical Modeling of Orion Nebula Cluster Disks: Evidence for Massive, Compact Gas Disks with Interstellar Gas-to-dust Ratios

open access: yesThe Astrophysical Journal, 2023
The stellar cluster environment is expected to play a central role in the evolution of circumstellar disks. We use thermochemical modeling to constrain the dust and gas masses, disk sizes, UV and X-ray radiation fields, viewing geometries, and central ...
Ryan D. Boyden, Josh A. Eisner
doaj   +1 more source

Electron microscopy observations of the diversity of Ryugu organic matter and its relationship to minerals at the micro‐ to nano‐scale

open access: yesMeteoritics &Planetary Science, Volume 59, Issue 8, Page 2023-2043, August 2024.
Abstract Transmission electron microscopy analyses of Hayabusa2 samples show that Ryugu organic matter exhibits a range of morphologies, elemental compositions, and carbon functional chemistries consistent with those of carbonaceous chondrites that have experienced low‐temperature aqueous alteration.
Rhonda M. Stroud   +112 more
wiley   +1 more source

A Multiwavelength ALMA View of Gas and Dust in Binary Protoplanetary System AS 205: Evidence of Dust Asymmetric Distribution

open access: yesThe Astrophysical Journal
We present Atacama Large Millimeter/submillimeter Array observations of multiwavelength dust emissions at 3.1 and 1.3 mm, along with molecular line emissions of CO(2–1), CO(3–2), ^13 CO(3–2), and C ^18 O(3–2) at spatial resolutions of 7–45 au toward the ...
Nguyen Thi Phuong, Nguyen Tat Thang
doaj   +1 more source

Revisiting the Chemical Composition of WD 1145+017: Impact of Circumstellar Disk Contamination on Photospheric Abundances

open access: yesThe Astrophysical Journal
We performed a chemical analysis of the asteroid-bearing white dwarf WD 1145+017 using optical and ultraviolet spectroscopic data from 25 epochs between 2015 and 2023.
Érika Le Bourdais   +2 more
doaj   +1 more source

Commentary on the role of polyoxometalates in nature cybernetic loop

open access: yesNatural Sciences, Volume 4, Issue 2-3, June-July 2024.
Polyoxometalates (POMs) are both synthetic and naturally occurring coordination compounds. In the biosphere, POMs can participate in many different life‐determining geochemical and biological processes. Future interdisciplinary research on POMs may reveal their potential for prebiotic and abiotic chemistry, as well as for the development of artificial ...
Kirill Yu. Monakhov
wiley   +1 more source

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