Results 31 to 40 of about 14,221 (195)
Study of protoplanetary nebulae [PDF]
Proceedings of the International Astronomical Union, 2016 AbstractWe have performed 3D hydrodynamic simulations of a symmetrical jet ejection following previous works (Raga et al. 2009, Riera et al. 2014, Velázquez et al. 2014). The jet is emitted from a binary system in elliptical orbit, and its direction changes describing a precession cone.
D. Estrella +4 more
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Fast outflows in protoplanetary nebulae and young planetary nebulae observed by Herschel/HIFI [PDF]
Astronomy & Astrophysics, 2021 Context. Fast outflows and their interaction with slow shells (generally known as the fossil circumstellar envelope of asymptotic giant branch stars) play an important role in the structure and kinematics of protoplanetary and planetary nebulae (pPNe, PNe).
Lorenzo, M. +6 more
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Lifetime of the Outer Solar System Nebula From Carbonaceous Chondrites [PDF]
JGR: Planets (2022), 2022 The evolution and lifetime of protoplanetary disks (PPDs) play a central role in the formation and architecture of planetary systems. Astronomical observations suggest that PPDs evolve in two timescales, accreting onto the star for up to several million years (Myr) followed by gas dissipation within <1 Myr.
arxiv +1 more source
Evolution of protoplanetary nebulae
The Astrophysical Journal, 1989 Model spectra of protoplanetary nebulae have been calculated assuming that mass loss on the asymptotic giant branch terminates when the hydrogen envelope is almost totally depleted. The models predict spectral characteristics of protoplanetary nebulae which can be used to search for new candidates of protoplanetary nebulae in the IRAS Low Resolution ...
Kevin Volk, Sun Kwok
openaire +2 more sources
Progress in Earth and Planetary Science, 2022 Enstatite chondrites are a small clan of meteorites, only ~ 1% out of all meteorite collection. However, they are the most reduced meteorites and have almost identical isotopic compositions to those of the Earth, suggestive of significant contributions ...
Yangting Lin
doaj +1 more source
Fast accretion of small planetesimals by protoplanetary cores [PDF]
Astron.J. 128 (2003) 1348, 2003 We explore the dynamics of small planetesimals coexisting with massive protoplanetary cores in a gaseous nebula. Gas drag strongly affects the motion of small bodies leading to the decay of their eccentricities and inclinations, which are excited by the gravity of protoplanetary cores. Drag acting on larger ($\gtrsim 1$ km), high velocity planetesimals
arxiv +1 more source
A search for CO+ in planetary nebulae [PDF]
Mon.Not.Roy.Astron.Soc.382:1139-1144,2007, 2007 We have carried out a systematic search for the molecular ion CO+ in a sample of 8 protoplanetary and planetary nebulae in order to determine the origin of the unexpectedly strong HCO+ emission previously detected in these sources. An understanding of the HCO+ chemistry may provide direct clues to the physical and chemical evolution of planetary ...
arxiv +1 more source
Breathing Life Into Dead-Zones
EPJ Web of Conferences, 2013 The terrestrial planet formation regions of protoplanetary disks are generally sufficiently cold to be con- sidered non-magnetized and, consequently, dynamically inactive.
Gressel Oliver +2 more
doaj +1 more source
Isolating Dust and Free–Free Emission in ONC Proplyds with ALMA Band 3 Observations
The Astrophysical Journal, 2023 The Orion Nebula Cluster (ONC) hosts protoplanetary disks experiencing external photoevaporation by the cluster’s intense UV field. These “proplyds” are comprised of a disk surrounded by an ionization front.
Nicholas P. Ballering +8 more
doaj +1 more source
Mechanical Modification of Chondrule Fine-grained Rims by Dusty Nebular Shocks
The Planetary Science Journal, 2023 The mechanical processes that convert an initially fluffy chondrule fine-grained rim (FGR) into a more compact structure remain poorly characterized.
Augusto Carballido +3 more
doaj +1 more source