Results 41 to 50 of about 14,221 (195)
The Integral Field View of the Orion Nebula
Advances in Astronomy, 2014 This paper reviews the major advances achieved in the Orion Nebula through the use of integral field spectroscopy (IFS). Since the early work of Vasconcelos and collaborators in 2005, this technique has facilitated the investigation of global properties ...
Adal Mesa-Delgado
doaj +1 more source
The Astrophysical Journal, 2023 We continue to investigate long-term protoplanetary disk evolution and focus on the situation of strong disk self-gravity (DSG). We call such a disk a type III disk. A large amount of mass is stored in the disk due to large angular momentum.
Xin-Ming Wang
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Origin of Low-26Al/27Al Corundum/Hibonite Inclusions in Meteorites
The Astrophysical Journal, 2023 Most meteoritic calcium-rich, aluminum-rich inclusions formed from a reservoir with ^26 Al/ ^27 Al ≈ 5 × 10 ^−5 , but some record lower ${({}^{26}\mathrm{Al}/{}^{27}\mathrm{Al})}_{0}$ , demanding they sampled a reservoir without live ^26 Al.
Steven J. Desch +7 more
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Depletion of Moderately Volatile Elements by Open-System loss in the Early Solar Nebula [PDF]
, 2022 Rocky bodies of the inner solar system display a systematic depletion of the "Moderately Volatile Elements" (MVEs) that correlates with the expected condensation temperature of their likely host materials under protoplanetary nebula conditions. In this paper, we present and test a new hypothesis in which open system loss processes irreversibly remove ...
arxiv +1 more source
Herschel/HIFI observations of molecular emission in protoplanetary nebulae and young planetary nebulae [PDF]
Astronomy & Astrophysics, 2011 We performed Herschel/HIFI observations of intermediate-excitation molecular lines in the far-infrared/submillimeter range in a sample of ten protoplanetary nebulae and young planetary nebulae. The high spectral resolution provided by HIFI yields accurate measurements of the line profiles.
Gary J. Melnick +23 more
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Fullerenes, PAHs, Amino Acids and High Energy Astrophysics
Acta Polytechnica CTU Proceedings, 2014 We present theoretical, observational and laboratory work on the spectral properties of fullerenes and hydrogenated fullerenes. Fullerenes in its various forms (individual, endohedral, hydrogenated, etc.) can contribute to the UV bump in the extinction ...
Susana Iglesias-Groth
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The shaping effect of collimated fast outflows in the Egg nebula [PDF]
Astrophys.J.698:439-444,2009, 2008 We present high angular resolution observations of the HC$_3$N J=5--4 line from the Egg nebula, which is the archetype of protoplanetary nebulae. We find that the HC$_{\rm 3}$N emission in the approaching and receding portion of the envelope traces a clumpy hollow shell, similar to that seen in normal carbon rich envelopes.
arxiv +1 more source
Variability in Protoplanetary Nebulae. IX. Evidence for Evolution in a Decade
The Astrophysical Journal, 2022 Abstract We have carried out a new photometric V,R C study of 12 protoplanetary nebulae, objects in the short-lived transition between the asymptotic giant branch and planetary nebula phases of stellar evolution.
Bruce J. Hrivnak +3 more
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Atmospheres of protoplanetary cores: critical mass for nucleated instability [PDF]
Astrophys.J.648:666-682,2006, 2004 We study quasi-static atmospheres of accreting protoplanetary cores for different opacity behaviors and realistic planetesimal accretion rates in various parts of protoplanetary nebula. Atmospheres segregate into those having outer convective zone which smoothly merges with the nebular gas, and those having almost isothermal outer radiative region ...
arxiv +1 more source
Mid-infrared spectroscopy of protoplanetary and planetary nebulae [PDF]
Monthly Notices of the Royal Astronomical Society, 2002 We present medium-resolution (R ∼600), mid-infrared (7.5-14 μm) spectra of 15 young planetary nebulae. Linestrengths for observed forbidden transitions are presented, and numerous broad emission features from silicates, polyaromatic hydrocarbons (PAHs) and silicon carbide (SiC) are observed.
John C. Wilson +3 more
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