Aspherical supernova explosions: Hydrodynamics, radiation transport & observational consequences

2001 ◽  
Author(s):  
P. Höflich
Keyword(s):  
Radiation Transport ◽  
Supernova Explosions

scholarly journals Analytic solutions for neutrino-light curves of core-collapse supernovae

2020 ◽  
Author(s):  
Yudai Suwa ◽  
Akira Harada ◽  
Ken’ichiro Nakazato ◽  
Kohsuke Sumiyoshi
Keyword(s):  
Radiation Transport ◽  
Numerical Models ◽  
Average Energy ◽  
Analytic Solutions ◽  
Core Collapse ◽  
Central Engine ◽  
Supernova Explosions ◽  
Protoneutron Stars ◽  
Neutrino Luminosity ◽  
Physical Quantities

Abstract Neutrino is a guaranteed signal from supernova explosions in the Milky Way and is the most valuable messenger that can provide us with information about the deepest part of supernovae. In particular, neutrinos will provide us with physical quantities, such as the radius and mass of protoneutron stars (PNS), which are the central engine of supernovae. It requires a theoretical model that connects observables such as neutrino luminosity and average energy with physical quantities. Here we show analytic solutions for the neutrino-light curve derived from the neutrino radiation transport equation by employing the diffusion approximation and the analytic density solution of the hydrostatic equation for the PNS. The neutrino luminosity and the average energy as functions of time are explicitly presented, with dependence on PNS mass, radius, the total energy of neutrinos, surface density, and opacity. The analytic solutions provide good representations of the numerical models from a few seconds after the explosion and let our rough estimate of these physical quantities to be made from observational data.

scholarly journals The Optical Radiation of Supernovae

1986 ◽  
Vol 89 ◽  
pp. 167-181
Author(s):  
Robert Harkness
Keyword(s):  
Optical Radiation ◽  
Radiation Transport ◽  
Characteristic Temperature ◽  
Theoretical Models ◽  
Stellar Atmosphere ◽  
Optical Spectra ◽  
Type I ◽  
Type Ii ◽  
Recent Developments ◽  
Supernova Explosions

Most of our knowledge of supernovae comes from studies of their optical radiation. Very high quality optical spectra have been available for several years now. The new data have aided the development of theoretical models of supernova explosions, particularly Type I events, which until recently, were very poorly understood. Type II explosions, which are believed to arise from core collapse in massive stars (Woosley, this volume;, produce optical spectra which can be simply interpreted in terms of a nearly blackbody continuum with prominent lines of hydrogen superimposed. The Type II atmosphere is of near solar composition, expanding at a characteristic velocity of 5000 km/s and at least bears some resemblance to a more familiar stellar atmosphere. Type I supernovae produce a much more violent expansion and the optical spectrum cannot be so easily accounted for. The progress made in the last few years stems mostly from the work of David Branch (Branch 1980,1981; Branch et. al. 1982,1983,1985). His synthetic spectra for Type I’s showed that the spectrum can be explained in terms of the resonance lines of mostly singly ionised metals. The lines are formed in matter moving with a bulk velocity of about 11,000 km/s and at a characteristic temperature of approximately 10,000 K. Furthermore, Branch concluded that the density profile in this region should be relatively steep and that the matter was very deficient in hydrogen and helium. As we shall see, this description fits very well with the hypothesis that Type I supernovae originate in the incineration of white dwarfs. Following the focus of recent developments this discussion will be mainly limited to the early evolution of Type I models of this kind, although many of the important features of the radiation transport are directly relevant to Type II explosions.

scholarly journals Aspherical supernova explosions

2003 ◽  
Vol 212 ◽  
pp. 387-394 ◽  
Author(s):  
Peter A. Höflich ◽  
Dietrich Baade ◽  
Alexei M. Khokhlov ◽  
Lifan Wang ◽  
J. Craig Wheeler
Keyword(s):  
Axial Symmetry ◽  
Radiation Transport ◽  
Core Collapse ◽  
Intermediate Mass ◽  
Low Velocity ◽  
Transport Models ◽  
Sn 1987A ◽  
Direct Observations ◽  
Supernova Explosions ◽  
New Evidence

Core collapse supernovae (SN) are the final stages of stellar evolution in massive stars during which the central region collapses, forms a neutron star (NS), and the outer layers are ejected. Recent explosion scenarios assumed that the ejection is due to energy deposition by neutrinos into the envelope, but detailed models do not produce powerful explosions. There is new and mounting evidence for an asphericity and, in particular, for axial symmetry in several supernovae which may be hard to reconcile within the spherical picture. This evidence includes the observed high polarization and its variation with time, pulsar kicks, high velocity iron-group and intermediate-mass elements material observed in remnants, direct observations of the debris of SN 1987A, etc. Some of the new evidence is discussed in more detail. To be in agreement with the observations, any successful mechanism must invoke some sort of axial symmetry for the explosion. We consider jet-induced/dominated explosions of core collapse supernovae. Our study is based on detailed 3-d hydrodynamical and radiation transport models. We find that the observations can be explained by low velocity, massive jets which stall well within the SN envelope. Such outflows may be produced by MHD-mechanisms, convective dominated accretion disks on the central object or asymmetric neutrino emissions. Asymmetric density/chemical distributions and, for SN 2002ap, off-center energy depositions have been identified as crucial for the interpretation of the polarization.

Comparison of Radiation Transport Codes for Solar Particle Events Space Environment: II

2009 ◽  
Author(s):  
Ram Tripathi ◽  
Lawrence Townsend ◽  
Tony Gabriel ◽  
Lawrence PIinsky ◽  
Tony Slaba
Keyword(s):  
Radiation Transport ◽  
Space Environment ◽  
Solar Particle Events ◽  
Solar Particle

The Planet in a Pebble

2010 ◽  
Author(s):  
Jan Zalasiewicz
Keyword(s):  
Solar System ◽  
Volcanic Eruptions ◽  
Big Bang ◽  
Forensic Analysis ◽  
Mineral Matter ◽  
Supernova Explosions ◽  
Deep Underground ◽  
The Big Bang ◽  
The Universe

This is the story of a single pebble. It is just a normal pebble, as you might pick up on holiday - on a beach in Wales, say. Its history, though, carries us into abyssal depths of time, and across the farthest reaches of space. This is a narrative of the Earth's long and dramatic history, as gleaned from a single pebble. It begins as the pebble-particles form amid unimaginable violence in distal realms of the Universe, in the Big Bang and in supernova explosions and continues amid the construction of the Solar System. Jan Zalasiewicz shows the almost incredible complexity present in such a small and apparently mundane object. Many events in the Earth's ancient past can be deciphered from a pebble: volcanic eruptions; the lives and deaths of extinct animals and plants; the alien nature of long-vanished oceans; and transformations deep underground, including the creations of fool's gold and of oil. Zalasiewicz demonstrates how geologists reach deep into the Earth's past by forensic analysis of even the tiniest amounts of mineral matter. Many stories are crammed into each and every pebble around us. It may be small, and ordinary, this pebble - but it is also an eloquent part of our Earth's extraordinary, never-ending story.

A Monte Carlo study of radiation transport through multileaf collimators

2001 ◽  
Vol 28 (12) ◽  
pp. 2497-2506 ◽  
Author(s):  
Jong Oh Kim ◽  
Jeffrey V. Siebers ◽  
Paul J. Keall ◽  
Mark R. Arnfield ◽  
Radhe Mohan
Keyword(s):  
Monte Carlo ◽  
Radiation Transport ◽  
Monte Carlo Study ◽  
Multileaf Collimators
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