Results 61 to 70 of about 1,478 (224)

Correlated Molybdenum, Ruthenium, and Barium Isotope Anomalies in Presolar Silicon Carbide Grains

open access: yesThe Astrophysical Journal
We have analyzed molybdenum, ruthenium, and barium isotopes simultaneously in 55 individual presolar silicon carbide (SiC) grains from the Murchison CM2 meteorite using the Chicago Instrument for Laser Ionization (or CHILI).
Thomas Stephan   +5 more
doaj   +1 more source

The circumstellar matter distribution of massive young stellar objects [PDF]

open access: yes, 2016
A multiwavelength study of the circumstellar matter distribution of massive young stellar objects (MYSOs) was conducted. First, the potential of the new Herschel 70 micron data to resolve MYSOs in the Hi-GAL survey was analysed.
Olguin Choupay, Fernando Andres
core  

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

Detached and Continuous Circumstellar Matter in Type Ibc Supernovae from Mass Eruption

open access: yes, 2023
Some hydrogen-poor supernovae (SNe) are found to undergo interaction with dense circumstellar matter (CSM) that may originate from mass eruption(s) just prior to core-collapse. We model the interaction between the remaining star and the bound part of the
Takei, Yuki, Tsuna, Daichi
core   +1 more source

The Near-infrared Echo from SN 2023xgo: Evidence for a Massive Presupernova Eruption in a Type Ibn/Icn Supernova

open access: yesThe Astrophysical Journal Letters
We present near-infrared (NIR) and optical observations and analysis of the Type Ibn/Icn supernova (SN) 2023xgo, spanning the period from 2 to 100 days past explosion.
Masayuki Yamanaka, Takahiro Nagayama
doaj   +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

The circumstellar environment of IRAS 16293–2422 [PDF]

open access: yes, 2004
We present far-infrared (FIR) continuum observations of the deeply embedded source IRAS 16293–2422 performed with the Long Wavelength Spectrometer (LWS) on-board the Infrared Space Observatory (ISO).
P. Saraceno   +5 more
core   +1 more source

Gas-phase Molecules in Protoplanetary Nebulae with the 21 μm Emission Feature

open access: yesThe Astronomical Journal
It has been more than 30 years since the enigmatic 21 μ m emission feature was first discovered in protoplanetary nebulae (PPNs). Although dozens of different dust carrier candidates have been proposed, there is as yet no widely accepted one.
Jian-Jie Qiu   +8 more
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

JWST imaging of the closest globular clusters—I. Possible infrared excess among white dwarfs in NGC 6397

open access: yesAstronomische Nachrichten, Volume 345, Issue 6-7, July-August 2024.
Abstract We present James Webb Space Telescope observations of the globular cluster NGC 6397 and use them to extend to infrared wavelengths the characterization of the cluster's entire white dwarf (WD) cooling sequence (CS). The data allows us to probe fundamental astrophysical WD properties and to search for evidence in their colors for (or against ...
L. R. Bedin   +11 more
wiley   +1 more source

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