Results 31 to 40 of about 55,496 (241)
Neutral carbon in the protoplanetary nebulae CRL 618 and CRL 2688 [PDF]
The Astrophysical Journal, 1997 The 609u 3P1 -> 3P0 line of neutral atomic carbon has been detected in the protoplanetary nebulae CRL 618 and CRL 2688. CI appears to be about 7% as abundant as CO in CRL 2688, and 70% as abundant as CO in CRL 618. CI emission arises primarily from the slow component of the wind from these objects.
arxiv +6 more sources
A Simplified Model for an Evolving Protoplanetary Nebula [PDF]
The Astrophysical Journal, 2003 The dynamical evolution of the protoplanetary nebula is investigated using analytical solutions of the surface density transport equations. Constant and beta viscosity turbulence models are compared with a functional analytical model and the well-known alpha viscosity formulation.
Sanford S. Davis
openalex +2 more sources
CHEMICAL EVOLUTION OF TURBULENT PROTOPLANETARY DISKS AND THE SOLAR NEBULA [PDF]
The Astrophysical Journal Supplement Series, 2011 This is the second paper in a series where we study the influence of transport processes on the chemical evolution of protoplanetary disks. Our analysis is based on a flared alpha-model of the DM Tau system, coupled to a large gas-grain chemical network.
D. Semenov, D. S. Wiebe
openalex +4 more sources
Individual and Average Behavior of Particles in a Protoplanetary Nebula [PDF]
The Astrophysical Journal, 2004 15 pages, 9 figures, submitted to ...
Pascale Garaud +2 more
openalex +5 more sources
Destruction of protoplanetary discs in the Orion Nebula Cluster [PDF]
Monthly Notices of the Royal Astronomical Society, 2001 We use numerical N-body simulations of the Orion Nebula Cluster (ONC) to investigate the destruction of protoplanetary disks by close stellar encounters and UV radiation from massive stars. The simulations model a cluster of 4000 stars, and we consider separately cases in which the disks have fixed radii of 100 AU and 10 AU.
Aylwyn Scally, Charlotte Clarke
openalex +4 more sources
THE SINTERING REGION OF ICY DUST AGGREGATES IN A PROTOPLANETARY NEBULA [PDF]
, 2011 S. Sirono
semanticscholar +2 more sources
On the Persistence of Small Regions of Vorticity in the Protoplanetary Nebula [PDF]
The Astrophysical Journal, 2000 The fate of small regions of vorticity in a barotropic model of the protoplanetary nebula is investigated over thousands of years using a finite difference model. It is found that the coherence time for a small island of vorticity depends on its size, strength, orientation, and radial location in the nebula. Anticyclonic vorticity retains its coherence
S. S. Davis +2 more
openalex +3 more sources
Polarimetry of the protoplanetary nebula AFGL 2688 [PDF]
Astronomy Reports, 2004 Our spectroscopic (with resolution R=75 000) and spectropolarimetric (R=15 000) observations with the 6-m telescope of the Special Astrophysical Observatory have enabled us to distinguish photospheric and circumstellar features in the optical spectrum of the bipolar protoplanetary nebula AFGL 2688 for the first time.
В. Г. Клочкова +3 more
openalex +3 more sources
Dynamics and Growth of Dust Grains in the Protoplanetary Nebula [PDF]
Publications of the Astronomical Society of the Pacific, 2002 In the standard scenario of planet formation, the planetesimals grow from primordial dust grains of interstellar origin embedded in a gas disk, the so-called protoplanetary nebula. Large-scale gaseous structures, such as spiral waves and vortices, are likely to survive for a large number of rotation periods and can strongly influence the dynamics and ...
C. de la Fuente Marcos
openalex +3 more sources
Condensation Front Migration in a Protoplanetary Nebula [PDF]
The Astrophysical Journal, 2005 Condensation front dynamics are investigated in the mid-solar nebula region. A quasi-steady model of the evolving nebula is combined with equilibrium vapor pressure curves to determine evolutionary condensation fronts for selected species. These fronts are found to migrate inwards from the far-nebula to final positions during a period of 10(exp 7 ...
Sanford S. Davis
openalex +4 more sources