Results 81 to 90 of about 174,483 (232)

On the distances of planetary nebulae [PDF]

open access: yes, 2014
Reconsidering calibration of statistical distance scales for planetary nebulae leads naturally to examining precision and especially the systematic errors of other methods.
H. Smith
semanticscholar   +1 more source

Occurrence and characterization of nanosulfide‐rich regions on asteroid Ryugu: Insights from mackinawite and pyrrhotite

open access: yesMeteoritics &Planetary Science, Volume 61, Issue 1, Page 168-181, January 2026.
Abstract Samples returned from asteroid Ryugu by the Hayabusa2 mission are dominated by fine‐grained matrix material made of phyllosilicates and nanosulfides. Here, we report the mineralogical, textural, and chemical characteristics of nanosulfide‐rich regions identified in Ryugu particles.
Roberto Conconi   +9 more
wiley   +1 more source

Neutron-Capture Element Abundances in Planetary Nebulae

open access: yesGalaxies, 2020
Nebular spectroscopy is a valuable tool for assessing the production of heavy elements by slow neutron(n)-capture nucleosynthesis (the s-process). Several transitions of n-capture elements have been identified in planetary nebulae (PNe) in the last few ...
N. C. Sterling
doaj   +1 more source

Imaging the transition between pre-planetary and planetary nebulae: integral field spectroscopy of hot post-AGB stars with NIFS [PDF]

open access: yes, 2014
We present 2 to 2.4 micron integral field spectroscopy of a sample of hot post-AGB stars with early-B spectral types, using the NIFS instrument on Gemini North. These stars are just beginning to ionize their immediate environments and turn into planetary
T. Gledhill, K. Forde
semanticscholar   +1 more source

Lawnmower Poetry and the Poetry of Lawnmowers

open access: yes
Critical Quarterly, EarlyView.
Francesca Gardner
wiley   +1 more source

Physiology of nitrogen: A life or death matter

open access: yesExperimental Physiology, Volume 111, Issue 1, Page 270-282, 1 January 2026.
Abstract With each breath, four out of every five molecules we inspire are nitrogen (N2), since this gas constitutes ∼80% of the atmospheric air that surrounds us. Despite its abundance and unlike molecular oxygen, N2 has traditionally held less appeal among physiologists given its lack of reactivity and corresponding inability to support combustion or
Damian M. Bailey   +2 more
wiley   +1 more source

Irradiation Investigation: Exploring the Molecular Gas in NGC 7293

open access: yesGalaxies, 2020
Background: Many planetary nebulae retain significant quantities of molecular gas and dust despite their signature hostile radiation environments and energetic shocks.
Jesse Bublitz   +7 more
doaj   +1 more source

Weak magnetic fields in central stars of planetary nebulae [PDF]

open access: yes, 2014
It is not yet clear whether magnetic fields play an essential role in shaping planetary nebulae (PNe), or whether stellar rotation alone and/or a close binary companion can account for the variety of the observed nebular morphologies.
M. Steffen   +11 more
semanticscholar   +1 more source

Stable Nitrogen Isotope Analysis of Amino Acids by Orbitrap Mass Spectrometry: Application for Extraterrestrial Samples

open access: yesRapid Communications in Mass Spectrometry, Volume 39, Issue 23, 15 December 2025.
ABSTRACT Background Obtaining isotopic data on soluble organic compounds, such as amino acids, in extraterrestrial samples is crucial for understanding their origins, prebiotic chemistry, and potential contamination. Conventional GC‐IRMS requires grams of material to measure isotopic compositions, limiting the analysis of low‐concentration organics in ...
O. M. McIntosh   +9 more
wiley   +1 more source

Spectroscopy of Planetary Nebulae with Herschel: A Beginners Guide

open access: yesGalaxies, 2018
A brief overview of the Herschel Space Telescope PACS and SPIRE spectrographs is given, pointing out aspects of working with the data products that should be considered by anyone using them.
Katrina Exter
doaj   +1 more source

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